CN111709075B

CN111709075B - Tunnel local deformation identification method and device

Info

Publication number: CN111709075B
Application number: CN202010505577.3A
Authority: CN
Inventors: 王石磊; 宋国华; 齐法琳; 冯乾宽; 田甜; 王兆宁; 雷洋; 江波; 贾飞宇; 郑金涛
Original assignee: China Academy of Railway Sciences Corp Ltd CARS; Infrastructure Inspection Institute of CARS; Beijing IMAP Technology Co Ltd
Current assignee: China Academy of Railway Sciences Corp Ltd CARS; Infrastructure Inspection Institute of CARS; Beijing IMAP Technology Co Ltd
Priority date: 2020-06-05
Filing date: 2020-06-05
Publication date: 2023-01-24
Anticipated expiration: 2040-06-05
Also published as: CN111709075A

Abstract

The application discloses a tunnel local deformation identification method and a tunnel local deformation identification device, wherein the method comprises the following steps: determining the current axis of the segment according to the current geodetic coordinates of the space points in the current point group; adjusting the current axis to be parallel to the historical reference axis and the middle point to be coincident, determining the conversion coordinates of the space points in the current point group, further determining the coordinates of the projection points of the space points in the current point group on a plane perpendicular to the historical reference axis, and obtaining a current projection fitting function by utilizing NURBS fitting; determining projection point coordinates of each space point in the historical point group on a plane perpendicular to a historical reference axis according to historical geodetic coordinates of the space points in the historical point group, and obtaining a historical projection fitting function by utilizing NURBS fitting; determining local deformation parameters of the tunnel at a designated point on the fitting circle; and if the tunnel local deformation parameter is not equal to 0, determining the absolute value of the tunnel local deformation parameter as the tunnel deformation. The local deformation identification precision of the tunnel section can be improved.

Description

Tunnel local deformation identification method and device

Technical Field

The application relates to the technical field of tunnel detection, in particular to a tunnel local deformation identification method and device.

Background

This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

The tunnel structure mainly comprises a tunnel body and a tunnel door. In order to prevent the surrounding rock from deforming or collapsing, a permanent supporting structure constructed by reinforced concrete and other materials along the periphery of the tunnel body is called lining, the lining is generally arranged in sections along the length direction of a line, and joints are arranged among the sections. The round or oval shape is the main sectional form of the hole body. In order to improve the service life and the safety of the tunnel structure, the state evaluation of the tunnel structure needs to be carried out regularly, wherein the lining deformation of the tunnel body is an important index for representing the stress of the structure and the stability of the tunnel.

Acquiring geometric information of a tunnel body lining outline is basic work for carrying out deformation analysis of a tunnel structure. The three-dimensional laser scanning technology is widely applied to tunnel geometric information acquisition in a construction period or an operation period due to the advantages of high measurement precision, non-contact and the like, and is mainly divided into two types of station-by-station joint measurement and mobile type according to different measurement modes, wherein the station-by-station joint measurement is mainly applied to the tunnel construction period, the mobile type scanning has the advantages of high measurement efficiency, small traffic interference and the like, and is mainly applied to the operation period, and the working principle of the mobile type scanning is shown in figure 1.

Technicians at home and abroad carry out a great deal of research around tunnel three-dimensional scanning data, and mainly focus on adopting circles and ellipses to fit a tunnel section to obtain a contour circle center and a radius, and the method is suitable for analyzing the whole deformation of a tunnel structure, such as section convergence change caused by surrounding rock deformation and the whole deformation of the tunnel (a plurality of continuous sections) in an area range caused by geological activity; in fact, in addition to the above overall deformation of the tunnel structure, when local surrounding rock conditions of a single segment change (such as bias pressure, vault rock mass falling and the like), the tunnel body lining can also deform locally, and compared with the overall deformation of the tunnel, the local deformation of the tunnel body lining is easier to force the structure to be stressed or the tunnel to be stable and tend to be in an unsafe state. The traditional fitting method of the circular and elliptical sections is insensitive to the local deformation of the segments.

Disclosure of Invention

The embodiment of the application provides a tunnel local deformation identification method, which is used for improving the local deformation identification precision of a tunnel section and comprises the following steps:

dividing each segment of the tunnel into a plurality of units, and acquiring the current geodetic coordinates of each space point in the current point group on each unit under a geodetic coordinate system, the historical reference axis of each segment and the historical geodetic coordinates of each space point in the historical point group on each unit; determining the current axis of each segment according to the current geodetic coordinates of each space point in the current point group on each unit; adjusting the current axis to be parallel to the historical reference axis and the middle point of the current axis to coincide with the middle point of the historical reference axis, and converting the geodetic coordinates of each space point in the current point group on each unit into conversion coordinates when the current axis is parallel to the historical reference axis and the middle point of the current axis coincides with the middle point of the historical reference axis; determining the coordinates of the current projection points of all the space points in the current point group on a plane perpendicular to the historical reference axis according to the transformed coordinates of all the space points in the current point group on each unit, and obtaining a current projection fitting function by NURBS fitting; according to historical geodetic coordinates of each space point in the historical point group on each unit, determining historical projection point coordinates of each space point in the historical point group on a plane perpendicular to a historical reference axis, and obtaining a historical projection fitting function by utilizing NURBS fitting; determining the coordinates of the center of a circle of a fitting circle, the local coordinates of the specified points on the fitting circle, the coordinates of the current optimal projection points of the specified points on the fitting circle on the current projection fitting function, and the coordinates of the historical optimal projection points on the historical projection fitting function, wherein the fitting circle is obtained by fitting the projection points of all space points in the current point group on each unit on a plane vertical to the historical reference axis; determining a tunnel local deformation parameter at a specified point on a fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the specified point on the fitting circle and the circle center coordinate of the fitting circle; and if the tunnel local deformation parameter is not equal to 0, determining that the tunnel local deformation occurs, and determining the absolute value of the tunnel local deformation parameter as the tunnel deformation.

In one implementation, converting geodetic coordinates of respective spatial points in a current point group on each cell to converted coordinates when a current axis is parallel to a historical reference axis and a midpoint of the current axis coincides with a midpoint of the historical reference axis includes: according to (X) ⁽⁰⁾ ，Y ⁽⁰⁾ ，Z ⁽⁰⁾ ) ^T ＝R ₁ (X ⁽¹⁾ ，Y ⁽¹⁾ ，Z ⁽¹⁾ ) ^T +T ₁ Determining geodetic coordinates (X) of individual spatial points ⁽¹⁾ ，Y ⁽¹⁾ ，Z ⁽¹⁾ ) Corresponding transformed coordinate (X) ⁽⁰⁾ ，Y ⁽⁰⁾ ，Z ⁽⁰ ) ); wherein R is ₁ Representing a spatial rotation matrix, R ₁ ＝R(γ)·R(τ)·R(β)，

T ₁ Representing translation vectors, T ₁ ＝(x _c0 ，y _c0 ，z _c0 ) ^T -R ₁ (x _c1 ，y _c1 ，z _c1 ) ^T ；(x _c0 ，y _c0 ，z _c0 ) A midpoint coordinate representing a historical reference axis; (x) ₀ ，y ₀ ，z ₀ ) A unit direction vector representing a historical reference axis; (x) _c1， y _c1， z _c1 ) A midpoint coordinate representing a current axis; (x) ₁ ，y ₁ ，z ₁ ) A unit direction vector representing the current axis.

In one implementation, determining, according to the transformed coordinates of each spatial point in the current point group on each cell, coordinates of a current projection point of each spatial point in the current point group on a plane perpendicular to the historical reference axis, and obtaining a current projection fitting function by means of NURBS fitting, includes: establishing a vertical plane perpendicular to the historical reference axis in the center of each unit, and projecting each space point in the current point group on each unit onto the vertical plane to obtain a current projection point corresponding to each space point in the current point group; establishing a local coordinate system by taking the intersection point of the historical reference axis and the vertical plane as an original point, and determining the local coordinate of the current projection point under the local coordinate system according to the conversion coordinate of the space point in the current point group; utilizing the current projection point to fit a circle, determining the circle center and the circle center coordinate of the fit circle according to the local coordinate of the current projection point, and dividing the fit circle into a plurality of sectors by taking the circle center of the fit circle as the center and a preset angle as a central angle; and determining the characteristic points of the projection points in each fan-shaped range according to the local coordinates of the projection points in each fan-shaped range, and performing NURBS fitting on the characteristic points in all the fan-shaped ranges to obtain a current projection fitting function.

In one implementation, determining the feature point of the projection point in each sector range according to the local coordinate of the projection point in each sector range includes: and calculating the average value of the local coordinates of all the projection points in each fan-shaped range, and taking the point corresponding to the calculated average value as the characteristic point of the projection point in each fan-shaped range.

In one implementation, the designated point is an intersection point of a fan-shaped angular bisector divided on the fitting circle and the fitting circle; determining local coordinates of a specified point on the fitted circle, comprising: according to

Determining local coordinates of intersection points of angular bisectors of sectors divided on a fitting circle and the fitting circle

Wherein (x) _o ，y _o ) Representing the coordinates of the center of the fitting circle; r is _{Round (T-shaped)} Represents the radius of the fitted circle; i represents the ith sector of the partition;

represents the central angle of the fan;

the smaller of the two radii representing the sector lies in the clockwise direction at the x-axis of the local coordinate system.

In one implementation, determining a local deformation parameter of a tunnel at a specified point on a fitting circle according to a current optimal projection point coordinate, a historical optimal projection point coordinate, a local coordinate of the specified point on the fitting circle, and a circle center coordinate of the fitting circle, includes: according to

Determining the designated point P on the fitted circle _i Local deformation parameters delta rho of the tunnel; wherein the content of the first and second substances,

is represented by P _i Current optimal projected point coordinates of the points;

is represented by P _i Historical best projection point coordinates of the points;

representing the fitted circle P _i Local coordinates of the points;

representing the coordinates of the center of the fitting circle; denotes dot multiplication.

In one implementation, determining the current axis of each segment from geodetic coordinates of each spatial point in the current point group on each cell in the geodetic coordinate system comprises: aiming at each segment, selecting a target point at each of two ends of the vault of the segment, and determining an initial unit direction vector according to geodetic coordinates of the two target points; dividing each segment into a plurality of units with equal length along the direction of the initial unit direction vector, and constructing a plane perpendicular to the initial unit direction vector at the center of each unit to be used as a projection plane; constructing a local coordinate system by taking the intersection point of the projection plane and the initial unit direction vector as an origin; projecting each point on each unit to a projection plane, and determining the projection point projected to a specified range as an effective point; converting the geodetic coordinates of the effective points into local coordinates under a local coordinate system; fitting a circle on the projection plane by using the effective points of each unit, and determining the local coordinates of the circle center of the fitted circle; converting the local coordinates of the circle center into the geodetic coordinates of the circle center; performing space straight line fitting on the circular center geodetic coordinates of all units of each section to obtain a first axis; determining a first unit direction vector according to the first axis; determining a second axis and a second unit direction vector for each segment from the first unit direction vector using a method of determining the first axis and the first unit direction vector from the initial unit direction vector; determining a deviation of the first unit direction vector from the second unit direction vector; and if the deviation is less than or equal to the deviation threshold value, determining the second axis as the current axis of the section of the tunnel.

In one implementation, the two target points are P _s (x _s ，y _s ，z _s )、P _e (x _e ，y _e ，z _e ) Determining an initial unit direction vector according to the geodetic coordinates of the two target points, comprising: according to V _t ＝(x _t ，y _t ，z _t )＝(x _e -x _s ，y _e -y _s ，z _e -z _s ) (S) calculating an initial unit direction vector V _t (ii) a Wherein S is P _s To P _e The modulus of the vector is such that,

in one implementation, constructing a local coordinate system using an intersection of the projection plane and the initial unit direction vector as an origin includes: and constructing the local coordinate system by taking the intersection point of the projection plane and the initial unit direction vector as the origin of the local coordinate system, taking the X-axis direction in the geodetic coordinate system as the y-axis direction of the local coordinate system, taking the opposite direction of the projection of the Z-axis which points to the vertical elevation on the projection plane in the geodetic coordinate system as the X-axis direction of the local coordinate system, and taking the direction of the initial unit direction vector as the Z-axis direction of the local coordinate system.

In one implementation, before determining the projection point projected into the specified range as the valid point, the method further comprises: selecting two points with the largest distance in the y-axis direction from all the projection points as longitudinal axis outer edge points, selecting one point of the tunnel vault in the x-axis direction as a transverse axis outer edge point, and determining an outer boundary circle by using the two longitudinal axis outer edge points and the transverse axis outer edge point to obtain the circle center and the radius of the outer boundary circle; according to Δ d = α (Δ L | z) _t | +2 δ) determining a preset offset Δ d; wherein α represents an empirical coefficient; Δ L represents the length of the cell; | z _t | represents the absolute value of the subentry of the vector in the initial unit direction; delta represents the distance measurement precision of the tunnel geodetic coordinate measurement system; determining a circle which is concentric with the outer boundary circle and has a radius smaller than the radius of the outer boundary circle by a preset offset as an inner boundary circle; a circular ring formed by the inner boundary circle and the outer boundary circle is determined as a specified range.

In one implementation, before converting the geodetic coordinates of the effective point to local coordinates in a local coordinate system, the method further comprises: according to (x) _se-j ，y _se-j ，z _se-j )＝(j-0.5)SV _t /M+(x _s ，y _s ，z _s ) Determining the intersection point P of the projection plane and the initial unit direction vector _se-j Coordinate (x) of _se-j ，y _se-j ，z _se-j ) (ii) a Where j represents the jth cell of the division, j =1, 2.., M represents the total number of cells of the segment division; the converting the geodetic coordinates of the effective points into local coordinates in a local coordinate system includes: according to

Determining geodetic coordinates of active points

Using (x, y, z) ^T ＝R{(X，Y，Z) ^T + Q, converting the earth coordinates of the effective points into local coordinates; wherein, P _i Representing geodetic coordinates of the spatial points on the unit corresponding to the ith valid point; v _t Represents an initial unit direction vector; t represents a matrix transposition operation; z is a radical of _se-j Indicates the point of intersection P _se-j Z-axis coordinates of (a); x, y and z respectively represent coordinate values of an x axis, a y axis and a z axis in the local coordinate system; x, Y and Z respectively represent coordinate values of an X axis, a Y axis and a Z axis in a geodetic coordinate system; r represents a rotation matrix transformed from a geodetic coordinate system to a local coordinate system; q represents a translation vector transformed from the geodetic coordinate system to the local coordinate system; wherein the content of the first and second substances,

Q＝[-x _se-j -y _se-j -z _se-j ] ^T ，

u _z ＝(u _yi ，u _yj ，u _yk )＝V _t ＝(x _t ，y _t ，z _t )，u _y ＝(u _zi ，u _zj ，u _zk )＝u _z ×u _x ，u _x 、u _y、 u _z the unit coordinate vectors of the x axis, the y axis and the z axis of the local coordinate system in the geodetic coordinate system are respectively.

In one implementation, the coordinates of the centers of circles of all units of each segment are subjected to space straight line fitting to obtain a first axis; determining a first unit direction vector from the first axis, comprising: constructing a parametric equation for the first axis

Wherein a is ₁ 、a ₂ 、b ₁ 、b ₂ Is a parameter to be solved of a parameter equation; according to [ a ] ₁ a ₂ ] ^T ＝(Z ₁ Z ₁ ^T ) ^-1 Z ₁ X ₁ ，[b ₁ b ₂ ] ^T ＝(Z ₁ Z ₁ ^T ) ^-1 Z ₁ Y ₁ Determining a parameter a to be solved of a parameter equation ₁ 、a ₂ 、b ₁ 、b ₂ (ii) a Wherein X ₁ ＝[x ₁ x ₂ … x _M ] ^T ，Y ₁ ＝[y ₁ y ₂ … y _M ] ^T ，

(x ₁ ，y ₁ ，z ₁ )、...、(x _M ，y _M ，z _M ) Circle center geodetic coordinates of the first unit to the Mth unit which are divided into the segments respectively; according to

Determining a first unit direction vector V ^(t0) Geodetic coordinate (x) _t0 ，y _t0 ，z _t0 )。

In one implementation, the determining a deviation of the first unit direction vector from the second unit direction vector includes: according to C =1-V ^(t0) ·V ^(t1) ＝1-x _t0 x _t1 -y _t0 y _t1 -z _t0 z _t1 Determining a first unit direction vector V ^(t0) And a second unit direction vector V ^(t1) A deviation C of (a), wherein (x) _t1 ，y _t1 ，z _t1 ) Is a second unit direction vector V ^(t1) The geodetic coordinates of (a).

In one implementation, after determining a deviation of the first unit direction vector from the second unit direction vector, the method further comprises: and if the deviation is greater than the deviation threshold value, taking the second unit direction vector as a new first unit direction vector, calculating a new second unit direction vector and a second axis according to the new first unit direction vector until the deviation of the calculated first unit direction vector and the second unit direction vector is less than or equal to the deviation threshold value, and determining the second axis obtained by the last calculation as the tunnel axis of the section of tunnel.

The embodiment of the present application further provides a tunnel local deformation identification device for improve tunnel segment's local deformation identification precision, the device includes:

the acquisition module is used for dividing each section of the tunnel into a plurality of units, acquiring the current geodetic coordinates of each space point in the current point group on each unit under a geodetic coordinate system, and the historical reference axis of each section and the historical geodetic coordinates of each space point in the historical point group on each unit; the determining module is used for determining the current axis of each segment according to the current geodetic coordinates of each space point in the current point group on each unit, which are acquired by the acquiring module; the coordinate conversion module is used for adjusting the current axis determined by the determination module to be parallel to the historical reference axis acquired by the acquisition module, enabling the midpoint of the current axis to coincide with the midpoint of the historical reference axis, and converting the geodetic coordinates of each space point in the current point group on each unit into conversion coordinates when the current axis is parallel to the historical reference axis and the midpoint of the current axis coincides with the midpoint of the historical reference axis; the determining module is also used for determining the coordinates of the current projection points of all the space points in the current point group on a plane perpendicular to the historical reference axis according to the conversion coordinates of all the space points in the current point group on each unit converted by the coordinate conversion module, and obtaining a current projection fitting function by NURBS fitting; according to historical geodetic coordinates of each space point in the historical point group on each unit, determining historical projection point coordinates of each space point in the historical point group on a plane perpendicular to a historical reference axis, and obtaining a historical projection fitting function by utilizing NURBS fitting; the determining module is further used for determining the circle center coordinates of the fitting circle, the local coordinates of the designated points on the fitting circle, the current optimal projection point coordinates of the designated points on the fitting circle on the current projection fitting function, and the historical optimal projection point coordinates on the historical projection fitting function, wherein the fitting circle is obtained by fitting the projection points of all space points in the current point group on each unit on a plane perpendicular to the historical reference axis; the determining module is further used for determining a tunnel local deformation parameter at the appointed point on the fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the appointed point on the fitting circle and the circle center coordinate of the fitting circle; and the determining module is further used for determining that the tunnel is locally deformed when the tunnel local deformation parameter is not equal to 0, and determining the absolute value of the tunnel local deformation parameter as the tunnel deformation.

In the embodiment of the application, the current axis is adjusted to be in a state parallel to the historical reference axis and the center of the current axis coincides with the historical reference axis, then, firstly, the projection point of the space point in the current point group on each unit of the tunnel segment in the current state on a plane perpendicular to the current axis is determined, and the current projection fitting function and the current optimal projection point coordinate of the projection point on the plane are determined by means of NURBS fitting, and furthermore, the historical projection fitting function and the historical optimal projection point coordinate of the space point in the historical point group on each unit of the tunnel segment in the historical state on the historical reference axis are determined. As the curve fitted by NURBS is more in accordance with the integral form of the projection point, compared with the prior art in which the fitting is directly carried out by using a circle or an ellipse, the local deformation identification precision of the tunnel segment is improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts. In the drawings:

FIG. 1 is a schematic diagram of a mobile scanning operation in an embodiment of the present application;

fig. 2 is a flowchart of a tunnel local deformation identification method in an embodiment of the present application;

FIG. 3 is a schematic view of a plane cut at a seam in an embodiment of the present application;

FIG. 4 is a flow chart of a method for determining a current axis according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a tunnel axis determination method according to an embodiment of the present application;

FIG. 6 is a schematic diagram illustrating a principle of determining a valid point in an embodiment of the present application;

FIG. 7 shows a V in the embodiment of the present application ^(t0) And V _t Schematic diagram of deviation of direction;

FIG. 8 is a schematic view of an updated segment axis in an embodiment of the present application;

FIG. 9 is an axis diagram illustrating the deviation of the segment axis calculated twice before and after in the embodiment of the present application within the deviation threshold range;

FIG. 10 is another flow chart of a tunnel axis determination method in an embodiment of the present application;

FIG. 11 is a diagram illustrating feature points of the embodiment of the present application;

FIG. 12 shows an arbitrary point in the embodiment of the present application

In the historical projection curve obtained by NURBS fitting

And the current projection curve

Best projected point of (2)

A schematic diagram of (a);

FIG. 13 is a graph comparing prior art tunnel fitting using a circle fitting method with spline fitting using NURBS in the present example;

fig. 14 is a schematic structural diagram of a tunnel local deformation identification device in an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present application are provided to explain the present application and should not be interpreted as limiting the present application.

The embodiment of the application provides a tunnel local deformation identification method, as shown in fig. 2, the method includes steps 201 to 207:

step 201, dividing each section of the tunnel into a plurality of units, and acquiring the current geodetic coordinates of each space point in the current point group on each unit in a geodetic coordinate system, the historical reference axis of each section and the historical geodetic coordinates of each space point in the historical point group on each unit.

The historical reference axis and the historical geodetic coordinates are acquired in a historical period, for example, acquired by measurement when the tunnel is built, or acquired at any period before the local deformation identification of the tunnel, for example, acquired at a current 5 years or 10 years before or at an equal period. Accordingly, in the embodiment of the present application, the state of the current tunnel and the state of the tunnel at the historical period of acquiring the historical reference axis are compared to determine whether the current tunnel is deformed relative to the tunnel at the historical period of acquiring the historical reference axis. For example, if the historical reference axis is acquired at the time of tunnel construction, it may be determined whether the current tunnel is deformed relative to the tunnel at the time of construction; if the historical reference axis was acquired 5 years ago, it can be determined whether the current tunnel is deformed relative to the tunnel 5 years ago.

The geodetic coordinates of each spatial point in the current point group of each unit and each spatial point in the historical point group on each section of the tunnel to be tested can be acquired by utilizing a three-dimensional laser scanning technology. When three-dimensional laser scanning is carried out, a tunnel vault point at the scanning starting point is generally determined as an origin, and a geodetic coordinate system is established according to a right-hand rule. In the established geodetic coordinate system, XOY is a horizontal plane, a Z axis indicates a vertical elevation, and a Y axis is consistent with the trend of the tunnel line. The three-dimensional laser scanner converts the acquired position information of each point on the tunnel to be measured into the geodetic coordinate under the geodetic coordinate system, and the geodetic coordinates of each space point acquired by the three-dimensional laser scanner can be directly acquired in the embodiment of the application.

It should be noted that, because there are countless points in the space, it is difficult for the three-dimensional laser scanner to obtain the geodetic coordinates of each point, but obtain the geodetic coordinates of some of the points, so that the spatial points scanned by the three-dimensional laser scanner are not exactly the same during different time scans or during multiple scans. Therefore, in the embodiment of the present application, a set of points scanned by the current three-dimensional laser scanner is referred to as a current point group, a set of points scanned in a certain historical period is referred to as a historical point group, and spatial points included in the current point group and the historical point group are not completely the same, may be partially the same, and may be different.

The tunnel is made up of a plurality of segments, where there are seams where different segments are joined, in the present embodiment, the tunnel axis of a segment is determined in units of one segment. Correspondingly, the geodetic coordinates of the tunnel points acquired by the three-dimensional laser scanner are segmented according to the segment to which the tunnel points belong, and the geodetic coordinates of all the points of the segment to be analyzed are obtained. Illustratively, fig. 1 and 3 each show a schematic representation of the joining seam between different segments, and the cutting plane at the seam.

In the embodiment of the present application, taking the mobile scanning data as an example, the length of each unit covers 2 to 5 spiral scanning lines, and when the unit is divided according to the length, the segment can be divided into an integer number of units. The length of each unit can be determined by a user according to actual conditions, and the lengths of different segment units can also be different, and the length of each unit is not limited herein. Illustratively, one cell j in one segment is labeled with Δ L in FIG. 5.

Step 202, determining the current axis of each segment according to the current geodetic coordinates of each space point in the current point group on each unit.

Referring to fig. 4, step 202 may be specifically executed as the following steps 2021 to 2028:

step 2021, for each segment, selecting a target point at each end of the vault of the segment, and determining an initial unit direction vector according to the geodetic coordinates of the two target points.

The point at which the Z value is maximum at each port of the vault is selected as the target point. The two selected target points are respectively P _s (x _s ，y _s ，z _s )、P _e (x _e ，y _e ，z _e ) Calculating an initial unit direction vector V according to the following formula _t ：

V _t ＝(x _t ，y _t ，z _t )＝(x _e -x _s ，y _e -y _s ，z _e -z _s )/S

Wherein S is P _s To P _e The modulus of the vector is such that,

step 2022, a plane perpendicular to the initial unit direction vector is constructed at the center of each cell and is used as a projection plane, and a local coordinate system is constructed by taking an intersection point of the projection plane and the initial unit direction vector as an origin.

Let the total number of segmented units be M, and the number of each unit be j, j =1, 2. Referring to FIG. 5, a vector V corresponding to the first unit direction is constructed at the center of the cell j _t Perpendicular plane

V _t And a plane

Has a point of intersection of P _se-j Point of intersection P _se-j The coordinates are expressed as (x) in the geodetic coordinate system _se-j ，y _se-j ，z _se-j ) The calculation formula is as follows:

(x _se-j ，y _se-j ，z _se-j )＝(j-0.5)SV _t /M+(x _s ，y _s ，z _s )

projection plane

The equation is calculated as:

x _t (x-x _se-j )+y _t (y-y _se-j )+z _t (z-z _se-j )＝0

to facilitate the use of least squares on the projection plane

Constructing a fitting circle, constructing a local coordinate system on the projection plane, wherein the local coordinate system follows a right-hand spiral rule, and the origin is arranged at the intersection point P of the projection plane and the initial unit direction vector _se-j Taking the X-axis direction in the geodetic coordinate system as the y-axis direction of the local coordinate system, taking the opposite direction of the projection plane of the Z-axis in the geodetic coordinate system, which is directed to the vertical elevation, as the X-axis direction of the local coordinate system, taking the direction of the initial unit direction vector as the Z-axis direction of the local coordinate system, and laying out the local coordinate systemAs shown in fig. 5.

Step 2023, projecting each point on each unit to a projection plane, and determining the projection points projected to a specified range as effective points; and converting the geodetic coordinates of the effective points into local coordinates in a local coordinate system.

Referring to fig. 6, fig. 6 is a schematic diagram of a projection plane after each point on one cell is projected onto the projection plane. The x-axis direction and the y-axis direction of the local coordinate system are shown in fig. 6.

In the embodiment of the application, two points with the largest distance are selected as longitudinal axis outer edge points in all projection points along the y-axis direction, one point of the tunnel vault is selected as a transverse axis outer edge point along the x-axis direction, and an outer boundary circle is determined by utilizing the two longitudinal axis outer edge points and the transverse axis outer edge point to obtain the circle center and the radius of the outer boundary circle; determining a circle which is concentric with the outer boundary circle and has a radius smaller than the radius of the outer boundary circle by a preset offset as an inner boundary circle; and determining a circular ring consisting of the inner boundary circle and the outer boundary circle as a specified range. As shown in fig. 6, the projected points falling within the inner and outer boundary rings are regarded as valid points, and the remaining points are regarded as invalid points. The instability of the tunnel wall electrification hanging column, the ventilation pipeline, the traffic indication, the lighting, the communication, the decoration and other accessory facilities and the measurement system is a main factor causing the generation of invalid points.

The preset offset delta d is determined by the distance measurement precision of a measuring system for measuring geodetic coordinates such as a tunnel longitudinal slope and a three-dimensional laser scanner, and the specific calculation mode is as follows:

Δd＝α(ΔL|z _t |+2δ)

wherein alpha represents an empirical coefficient and is used for linearly and comprehensively adjusting the tunnel longitudinal slope and measuring the precision influence of the system; Δ L represents the length of the cell; | z _t | represents a subentry absolute value of the first unit direction vector; and delta represents the ranging precision of the tunnel geodetic coordinate measuring system, namely the ranging precision of measuring systems such as a three-dimensional laser scanner and the like. In addition, since a measurement system such as a three-dimensional laser scanner measures parameters such as a distance and an angle to obtain geodetic coordinates by conversion, and since distance measurement accuracy is generally given in the measurement system, δ used here can be directly obtained from δDirectly acquiring the data in geodetic coordinate measuring systems such as a three-dimensional laser scanner and the like.

Current geodetic coordinate of P on each cell _i After each space point of (2) is projected to the projection plane, the geodetic coordinates of the projection point in the geodetic coordinate system

The calculation was performed according to the following method:

wherein, T represents a matrix transposition operation; z is a radical of formula _se-j Indicates the point of intersection P _se-j Z-axis coordinate of (c).

Placing the unit j in a plane

The calculation method for converting the coordinates (X, Y, Z) of any point in the geodetic coordinate system into the coordinates (X, Y, Z) in the local coordinate system comprises the following steps:

(x，y，z) ^T ＝R{(X，Y，Z) ^T +Q}

wherein, x, y and z respectively represent coordinate values of an x axis, a y axis and a z axis in a local coordinate system; x, Y and Z respectively represent coordinate values of an X axis, a Y axis and a Z axis in a geodetic coordinate system; r represents a rotation matrix transformed from a geodetic coordinate system to a local coordinate system; q represents a translation vector transformed from the geodetic coordinate system to the local coordinate system;

specifically, R and Q are calculated according to the following methods, respectively:

Q＝[-x _se-j -y _se-j -z _se-j ] ^T

in the above formula, u _x ＝(u _xi ，u _xj ，u _xk )，u _z ＝(u _yi ，u _yj ，u _yk )，u _y ＝(u _zi ，u _zj ，u _zk )，u _x 、u _y 、u _z The unit coordinate vectors of the x axis, the y axis and the z axis of the local coordinate system in the geodetic coordinate system are respectively.

Due to u _x In projection plane with the Z axis of the geodetic coordinate system

The upward projection is consistent in the opposite direction and has a coordinate of P _i Projection plane from any point in space

Projected coordinates of

Calculation method of calculating projection plane

The unit coordinate vector of the x-axis of the inner local coordinate system in the geodetic coordinate system. In particular, u _x 、u _z 、u _y The calculation was performed according to the following method:

u _z ＝V _t ＝(x _t ，y _t ，z _t )

u _y ＝u _z ×u _x

u is obtained by calculation _x 、u _z 、u _y Then, R can be determined.

Step 2024, fitting a circle on the projection plane by using the effective points of each unit, determining a circle center local coordinate of the fitted circle, and converting the circle center local coordinate into a circle center geodetic coordinate.

It should be noted that fitting a circle by using coordinates of points and a least square method and determining coordinates of a center of the circle are common technical means in the art, and details of the specific process are not described herein.

The calculation method for converting the local coordinates of the circle center into the geodetic coordinates of the circle center under the geodetic coordinate system comprises the following steps:

(X，Y，Z) ^T ＝R ^-1 (x，y，z) ^T -Q

2025, performing spatial straight line fitting on the geodetic coordinates of the circle centers of all units of each section to obtain a first axis; a first unit direction vector is determined from the first axis.

The center-to-earth coordinates of each unit in the segment can be determined according to the methods in steps 2022 to 2024, and the first axis can be obtained by performing a spatial line fitting on the center-to-earth coordinates of all the units, for example, as shown in fig. 5, ax ^(t0) I.e. from the center of the circle

Fitting the resulting first axis.

Any M space coordinate points are fitted with a space straight line projective equation, namely a parameter equation of the first axis is as follows:

in the above equation, a matrix to be solved constructed by equation coefficients is constructed:

A＝[a ₁ a ₂ ] ^T ＝(Z ₁ Z ₁ ^T ) ^-1 Z ₁ X ₁

B＝[b ₁ b ₂ ] ^T ＝(Z ₁ Z ₁ ^T ) ^-1 Z ₁ Y ₁

wherein, X ₁ 、Y ₁ 、Z ₁ As M point coordinates (x) ₁ ，y ₁ ，z ₁ )、...、(x _M ，y _M ，z _M ) The constructed computing element is constructed by the following method:

X ₁ ＝[x ₁ x ₂ … x _M ] ^T ，Y ₁ ＝[y ₁ y ₂ … y _M ] ^T ，

a can be determined according to the above formula ₁ And b ₁ I.e. the direction vector (a) of the first axis can be determined ₁ ，b ₁ ，1)。

The first unit direction vector V ^(t0) Geodetic coordinate (x) _t0 ，y _t0 ，z _t0 ) Comprises the following steps:

step 2026 determines a second axis and a second unit direction vector for each segment from the first unit direction vector using a method of determining a first axis and a first unit direction vector from the initial unit direction vector.

Target point P picked up by vault at two ends of segment _s 、P _e For artificial selection, the direction of the section possibly deviates from the direction of the tunnel axis, and a second unit direction vector V of the section is obtained after fitting ^(t0) And V _t The directions are deviated as shown in fig. 7.

This step consists in updating the segment axis calculation. To obtain V ^(t0) Rear, along V ^(t0) The units are divided again, and each unit constructs a new projection plane

To the axis Ax ^(t0) Perpendicular to and passing through the axis Ax ^(t0) Division point P _Ax0-j Projecting the point group in the unit j to

The point-to-plane projection calculation method is shown in step 2023. At P _Ax0-j Constructing a local coordinate system (x-y-z) at the point, wherein the local coordinate system follows a right-hand spiral rule, and the origin is arranged at P _Ax0-j Here, the local coordinate system setting is consistent with the method of step 2022. Converting the coordinates of the point group from the geodetic coordinate system to the local coordinate system, and for each unitThe points in the element are grouped in

Fitting the circle with the projection point according to least square method to obtain the coordinate of the circle center in the local coordinate system, converting the coordinate in the local coordinate system to the geodetic coordinate system to obtain the coordinate of the circle center

The calculation method for converting the coordinates of the point group from the geodetic coordinate system to the local coordinate system is shown in step 2023, and the calculation method for converting the coordinates of the point group from the local coordinate system to the geodetic coordinate system is shown in step 2024. The center coordinates of the circle under the geodetic coordinate system calculated by M units

Fitting a space straight line to obtain an axis Ax ^(t1) And a unit vector V ^(t1) Is provided with V ^(t1) ＝(x _t1 ，y _t1 ，z _t1 ) The method for fitting the spatial straight line and calculating the unit vector thereof is shown in step 2025. The updated segment axis is shown in fig. 8.

Step 2027, determine the deviation of the first unit direction vector from the second unit direction vector.

In particular, according to C =1-V ^(t0) ·V ^(t1) ＝1-x _t0 x _t1 -y _t0 y _t1 -z _t0 z _t1 Determining a first unit direction vector V ^(t0) And a second unit direction vector V ^(t1) The deviation C of (a).

Step 2028, if the deviation is less than or equal to the deviation threshold, determining the second axis as the current axis of the segment of the tunnel.

Steps

2027 and 2028 are performed to determine the degree of coincidence (or referred to as parallelism) between the updated segment axis and the initially calculated segment axis, and if the deviation between the two is within the range of the deviation threshold, the two calculated segment axes are considered to be parallel to each other, and the second axis is determined as the tunnel axis of the segment tunnel. The axis deviation of the two segments before and after is within the limit value, and the state is shown in fig. 9.

If there is a deviation between the two, which exceeds the deviation threshold, referring to fig. 10, the second unit direction vector is used as a new first unit direction vector, a new second unit direction vector and a second axis are calculated according to the new first unit direction vector until the deviation between the first unit direction vector and the second unit direction vector obtained in the extreme is less than or equal to the deviation threshold, and the second axis obtained in the last calculation is determined as the tunnel axis of the segment of tunnel.

Each segment of the tunnel is calculated according to the method in steps 2022 to 2027, and the current axes of all segments of the tunnel can be obtained.

If the historical geodetic coordinates are acquired and the historical reference axis is not acquired, the historical reference axis may be determined by the method in the above steps 2021 to 2028, and the current geodetic coordinates of each spatial point used in the above steps 2021 to 2028 may be replaced by the corresponding historical geodetic coordinates.

In the above steps 2021 to 2028, each section of the tunnel is divided into units, the points on each unit are projected onto a projection plane, the projection points in the designated range are reserved as effective points, the effective points are subjected to circle fitting to determine the center of a unit circle, the centers of the plurality of divided units are fitted to determine an axis, and the axis of the section of the tunnel is determined by iterative updating, so that the accurate axis of the section of the tunnel can be obtained, the obtained axis has high accuracy, and the method is suitable for deformation analysis in the tunnel operation period and provides a basis for local deformation analysis of the tunnel.

And step 203, adjusting the current axis to be parallel to the historical reference axis and the middle point of the current axis to coincide with the middle point of the historical reference axis, and converting the geodetic coordinates of each space point in the current point group on each unit into converted coordinates when the current axis is parallel to the historical reference axis and the middle point of the current axis coincides with the middle point of the historical reference axis.

Considering that there may be differences in the coordinate systems of the acquired data in different states, in order to compare the deformed state with the reference state, the deformed axis and the reference axis need to be superposed, and the axis superposition criterion is as follows: (1) maintaining the historical reference axis unchanged, and adjusting the current axis to enable the adjusted current axis to be parallel to the historical reference axis; (2) and coinciding the middle point of the adjusted current axis with the middle point of the historical reference axis. For this purpose, the current geodetic coordinates of the current axis and the spatial points in the current point group need to be transformed spatially, and the transformation method of any point or vector is as follows:

(X ⁽⁰⁾ ，Y ⁽⁰⁾ ，Z ⁽⁰⁾ ) ^T ＝R ₁ (X ⁽¹⁾ ，Y ⁽¹⁾ ，Z ⁽¹⁾ ) ^T +T ₁

wherein (X) ⁽¹⁾ ，Y ⁽¹⁾ ，Z ⁽¹⁾ ) Geodetic coordinates representing the spatial points to be transformed; (X) ⁽⁰⁾ ，Y ⁽⁰⁾ ，Z ⁽⁰⁾ ) The transformed coordinates corresponding to the geodetic coordinates representing the respective spatial points; r ₁ Representing a spatial rotation matrix, R ₁ ＝R(γ)·R(τ)·R(β)。

T ₁ Representing translation vectors, T ₁ ＝(x _c0 ，y _c0 ，z _c0 ) ^T -R ₁ (x _c1 ，y _c1 ，z _c1 ) ^T ；(x _c0 ，y _c0 ，z _c0 ) A midpoint coordinate representing a historical reference axis; (x) ₀ ，y ₀ ，z ₀ ) A unit direction vector representing a historical reference axis; (x) _c1 ，y _c1 ，z _c1 ) A midpoint coordinate representing a current axis; (x) ₁ ，y ₁ ，z ₁ ) A unit direction vector representing the current axis.

204, determining the current projection point coordinates of each space point in the current point group on a plane perpendicular to the historical reference axis according to the conversion coordinates of each space point in the current point group on each unit, and obtaining a current projection fitting function by NURBS fitting; and determining the historical projection point coordinates of each space point in the historical point group on a plane perpendicular to the historical reference axis according to the historical geodetic coordinates of each space point in the historical point group on each unit, and obtaining a historical projection fitting function by NURBS fitting.

Specifically, a vertical plane perpendicular to the historical reference axis is established in the center of each unit, and each space point in the current point group on each unit is projected onto the vertical plane to obtain a current projection point corresponding to each space point in the current point group; taking the intersection point of the historical reference axis and the vertical plane as an origin, constructing a local coordinate system, and determining the local coordinate of the current projection point under the local coordinate system according to the conversion coordinate of the space point in the current point group; utilizing the current projection point to fit a circle, determining the circle center and the circle center coordinate of the fit circle according to the local coordinate of the current projection point, and dividing the fit circle into a plurality of sectors by taking the circle center of the fit circle as the center and a preset angle as a central angle; and determining the characteristic points of the projection points in each sector range according to the local coordinates of the projection points in each sector range, and performing Non-Uniform Rational B-Splines (NURBS) fitting on the characteristic points in all the sector ranges to obtain a current projection fitting function.

It should be noted that the method for determining the historical projection fitting function is the same as the method for determining the current projection fitting function, and details are not repeated here.

And (3) averaging the local coordinates of all projection points in each sector range, namely respectively averaging the x-axis, the y-axis and the z-axis, and taking the obtained average x-coordinate, average y-coordinate and average z-coordinate as the local coordinates of the feature points in the sector range.

The method for performing NURBS fitting based on feature points to obtain a fitting function C (u) is as follows:

in the above formula, p is the polynomial degree, omega _i Are weight vector elements. N is a radical of _i，p (u) is a basis function equation, solvingThe method comprises the following steps:

in the above formula, u _i For non-uniform monotonic node vector U elements, U is defined as follows:

the following constraints are satisfied between the number m +1 of the node vector elements, the polynomial degree p and the feature point number n + 1:

m＝n+p+1

step 205, determining the coordinates of the center of the circle of the fitting circle, the local coordinates of the designated point on the fitting circle, the current best projection point coordinates of the designated point on the fitting circle on the current projection fitting function, and the historical best projection point coordinates on the historical projection fitting function.

And fitting the fitting circle by the projection point of each space point in the current point group on each unit on a plane vertical to the current axis. In the fitting, a least squares method is used.

It should be noted that the determination of the local coordinates of the projection points by using the transformed coordinates of the spatial points in the current point group, the fitting of the circle by using the projection points, and the determination of the center and the center coordinates of the fitted circle according to the local coordinates of the projection points may be implemented according to step 2023 and step 2024, and details of the specific process are not described herein.

Illustratively, FIG. 11 shows the center of the fitted circle as the center, and

and dividing the fitting circle into a plurality of fan-shaped schematic diagrams for the fan-shaped central angle. Referring to fig. 11, each sector includes a plurality of projection points, and the sectors are numbered to obtain a projection point sequence U ₀ ～U _N 。

Let the radius of the fitting circle be R _{Round (T-shaped)} Center of fitting circle

The local coordinate in the local coordinate system is (x) _o ，y _o ) The intersection of the fan-shaped angular bisector and the fitted circle profile line, i.e., the designated point (i.e., the divided point on the circle shown in FIG. 12)

The calculation method of local coordinates in the local coordinate system is as follows:

indicating an included angle formed by one edge of one divided fan and the x axis of the local coordinate system in the clockwise direction, wherein two edges of the fan can form an included angle with the x axis respectively, and a smaller included angle is taken as the included angle

Illustratively, in FIG. 12 is labeled

Calculating arbitrarily assigned points

In the historical projection curve obtained by NURBS fitting

And current projection curve

Best projected point of

As shown in fig. 12.

The method of the principle of calculation from any point of the plane to the optimal projection point of the curve C (u) is as follows:

(1) constructing a function f (u) in relation to curve C (u):

f(u)＝C′(u)·(C(u)-P)

(2) setting an initial value of u in the range of (0, 1), and carrying out iterative calculation, wherein the relation between the k +1 th value and the k-th value of u is as follows:

c' in the above formula (u) _k ) The marking curve C (u) is at u _k First derivative of (C') (u) _k ) The marking curve C (u) is at u _k The second derivative vector of (d).

(3) The iterative calculation convergence criterion is as follows:

based on the driving of the calculation formulas (1) and (2), under the constraint of (3), the node value u corresponding to the optimal projection point from any point of the plane to the curve C (u) can be obtained _opt Node value u _opt The optimal projection point coordinate P can be obtained by substituting the curve C (u) function ^(u) 。

From (1) to (3) above, P can be specified _i Current best projection point coordinates on current projection fitting function

And historical optimal projection point coordinates on the historical projection fitting function

And step 206, determining the local deformation parameters of the tunnel at the specified point on the fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the specified point on the fitting circle and the circle center coordinate of the fitting circle.

The designated point P on the fitting circle _i The local deformation parameter Δ ρ of the tunnel is calculated according to the following formula:

wherein the content of the first and second substances,

represents P _i Current optimal projection point coordinates of the points;

represents P _i Historical optimal projected point coordinates of the points;

representing the fitted circle P _i Local coordinates of the points;

representing the coordinates of the center of the fitting circle; represents dot multiplication.

And step 207, if the tunnel local deformation parameter is not equal to 0, determining that the tunnel local deformation occurs, and determining the absolute value of the tunnel local deformation parameter as the tunnel deformation.

If the local deformation parameter of the tunnel is greater than 0, determining that the tunnel is deformed relative to the historical state corresponding to the historical reference axis, wherein the deformation direction is radial centripetal; and if the local deformation parameter of the tunnel is less than 0, determining the historical state of the tunnel corresponding to the historical reference axis, deforming, and setting the deformation direction as radial centrifugation. The absolute value of Δ ρ is the amount of tunnel deformation, that is, the magnitude of tunnel deformation, and the larger the absolute value of Δ ρ is, the larger the tunnel deformation is.

Referring to FIG. 13, a comparison graph of a conventional fitting method using a circle to a tunnel and a NURBS spline fitting in the embodiment of the present application is shown, wherein the reference state circle fitting and the deformed circle fitting are conventional fitting using a circle or an ellipse respectivelyFitting curve obtained by fitting the tunnel in the historical state and the current state by a section fitting method, and reference state

Post deformation state

Fitting curves obtained by spline fitting of the tunnels in the historical state and the current state by using NURBS respectively, obviously, the deviation between the fitting curve of the reference state circle fitting and the fitting curve of the deformed circle fitting is small, and whether the tunnels are deformed or not can not be determined definitely; and a reference state

Fitted curve and post-deformation state of

The deviation between the fitting curves is large, and the deformation of the tunnel can be obviously seen.

In the embodiment of the application, the current axis is adjusted to be parallel to and coincident with the historical reference axis, then, the projection point of the space point in the current point group on each unit of the tunnel segment in the current state on the plane perpendicular to the current axis is determined, the current projection fitting function and the current optimal projection point coordinate of the space point on the plane are determined by using NURBS fitting, and the historical projection fitting function and the historical optimal projection point coordinate of the space point in the historical point group on each unit of the tunnel segment in the historical state on the plane perpendicular to the historical reference axis are also determined. As the curve fitted by NURBS is more in accordance with the integral form of the projection point, compared with the prior art in which the fitting is directly carried out by using a circle or an ellipse, the local deformation identification precision of the tunnel segment is improved.

The embodiment of the present application further provides a tunnel local deformation identification apparatus, as shown in fig. 14, the apparatus 1400 includes an obtaining module 1401, a determining module 1402 and a coordinate transformation module 1403.

An obtaining module 1401, configured to divide each segment of the tunnel into a plurality of units, obtain a current geodetic coordinate of each spatial point in a current point group on each unit in a geodetic coordinate system, and obtain a historical geodetic coordinate of each spatial point in a historical point group on each unit and a historical reference axis of each segment.

A determining module 1402, configured to determine a current axis of each segment according to the current geodetic coordinates of each spatial point in the current point group on each unit acquired by the acquiring module 1401.

And a coordinate conversion module 1403, configured to adjust the current axis determined by the determination module 1402 to be parallel to the historical reference axis acquired by the acquisition module 1401 and a midpoint of the current axis to coincide with the midpoint of the historical reference axis, and convert the geodetic coordinates of each spatial point in the current point group on each unit into conversion coordinates when the current axis is parallel to the historical reference axis and the midpoint of the current axis coincides with the midpoint of the historical reference axis.

A determining module 1402, further configured to determine, according to the transformed coordinates of each spatial point in the current point group on each unit transformed by the coordinate transforming module 1403, the current coordinates of the projection point of each spatial point in the current point group on the plane perpendicular to the historical reference axis, and obtain a current projection fitting function by means of NURBS fitting; and determining the historical projection point coordinates of each space point in the historical point group on a plane perpendicular to the historical reference axis according to the historical geodetic coordinates of each space point in each unit historical point group, and obtaining a historical projection fitting function by using NURBS fitting.

The determining module 1402 is further configured to determine coordinates of a center of a circle of the fitting circle, local coordinates of the designated point on the fitting circle, coordinates of a current best projection point of the designated point on the fitting circle on the current projection fitting function, and coordinates of a historical best projection point on the historical projection fitting function, where the fitting circle is obtained by fitting projection points of each space point in the current point group on each cell on a plane perpendicular to the historical reference axis.

The determining module 1402 is further configured to determine a local deformation parameter of the tunnel at the specified point on the fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the specified point on the fitting circle, and the circle center coordinate of the fitting circle.

The determining module 1402 is further configured to determine that the tunnel is locally deformed when the tunnel local deformation parameter is not equal to 0, and determine an absolute value of the tunnel local deformation parameter as a tunnel deformation amount.

In an implementation manner of the embodiment of the present application, the coordinate transformation module 1403 is configured to:

according to (X) ⁽⁰⁾ ，Y ⁽⁰⁾ ，Z ⁽⁰⁾ ) ^T ＝R ₁ (X ⁽¹⁾ ，Y ⁽¹⁾ ，Z ⁽¹⁾ ) ^T +T ₁ Determining geodetic coordinates (X) of each spatial point in a current point group ⁽¹⁾ ，Y ⁽¹⁾ ，Z ⁽¹⁾ ) Corresponding transformed coordinate (X) ⁽⁰⁾ ，Y ⁽⁰⁾ ，Z ⁽⁰⁾ )；

Wherein R is ₁ Representing a spatial rotation matrix, R ₁ ＝R(γ)·R(τ)·R(β)，

T ₁ Representing translation vectors, T ₁ ＝(x _c0 ，y _c0 ，z _c0 ) ^T -R ₁ (x _c1 ，yc ₁ ，z _c1 ) ^T ；(x _c0 ，y _c0 ，z _c0 ) A midpoint coordinate representing a historical reference axis; (x) ₀ ，y ₀ ，z ₀ ) A unit direction vector representing a historical reference axis; (x) _c1 ，y _c1 ，z _c1 ) A midpoint coordinate representing a current axis; (x) ₁ ，y ₁ ，z ₁ ) A unit direction vector representing the current axis.

In an implementation manner of the embodiment of the present application, the determining module 1402 is configured to:

establishing a vertical plane perpendicular to the historical reference axis in the center of each unit, and projecting each space point in the current point group on each unit onto the vertical plane to obtain a current projection point corresponding to each space point in the current point group;

taking the intersection point of the historical reference axis and the vertical plane as an origin, constructing a local coordinate system, and determining the local coordinate of the current projection point under the local coordinate system according to the conversion coordinate of the space point in the current point group;

utilizing the current projection point to fit a circle, determining the circle center and the circle center coordinate of the fit circle according to the local coordinate of the current projection point, and dividing the fit circle into a plurality of sectors by taking the circle center of the fit circle as the center and a preset angle as a central angle;

and determining the characteristic points of the projection points in each fan-shaped range according to the local coordinates of the projection points in each fan-shaped range, and performing NURBS fitting on the characteristic points in all the fan-shaped ranges to obtain a current projection fitting function.

and calculating the average value of the local coordinates of all the projection points in each fan-shaped range, and taking the point corresponding to the calculated average value as the characteristic point of the projection point in each fan-shaped range.

In an implementation manner of the embodiment of the application, the designated point is an intersection point of a sector angular bisector divided on the fitting circle and the fitting circle; a determining module 1402 for:

according to

Determining local coordinates of intersection points of angular bisectors of sectors divided on the fitting circle and the fitting circle

Wherein (x) _o ，y _o ) Representing the coordinates of the center of the fitting circle; r _{Round (T-shaped)} Represents the radius of the fitted circle; i represents the ith sector of the partition;

represents the central angle of the fan;

the smaller of the two radii representing the sector is the clockwise angle from the x-axis of the local coordinate system.

according to

Determining the designated point P on the fitted circle _i Local deformation parameters delta rho of the tunnel;

wherein, the first and the second end of the pipe are connected with each other,

represents P _i Current optimal projection point coordinates of the points;

represents P _i Historical optimal projected point coordinates of the points;

representing the fitted circle P _i Local coordinates of the points;

In an implementation manner of the embodiment of the present application, the determining module 1402 is configured to

Aiming at each segment, selecting a target point at each of two ends of a vault of the segment, and determining an initial unit direction vector according to geodetic coordinates of the two target points;

constructing a plane perpendicular to the initial unit direction vector at the center of each unit as a projection plane, and constructing a local coordinate system by using the intersection point of the projection plane and the initial unit direction vector as an origin;

projecting each point on each unit to a projection plane, and determining the projection point projected to a specified range as an effective point; converting the geodetic coordinates of the effective points into local coordinates under a local coordinate system;

fitting a circle on the projection plane by using the effective points of each unit, determining the circle center local coordinate of the fitted circle, and converting the circle center local coordinate into a circle center geodetic coordinate;

performing space straight line fitting on the circular center geodetic coordinates of all units of each segment to obtain a first axis; determining a first unit direction vector according to the first axis;

determining a second axis and a second unit direction vector for each segment from the first unit direction vector using a method of determining the first axis and the first unit direction vector from the initial unit direction vector;

determining a deviation of the first unit direction vector from the second unit direction vector;

if the deviation is less than or equal to a deviation threshold, determining the second axis as the current axis of the segment of the tunnel.

In an implementation manner of the embodiment of the present application, two target points are P respectively _s (x _s ，y _s ，z _s )、P _e (x _e ，y _e ，z _e ) A determining module 1402 configured to:

according to V _t ＝(x _t ，y _t ，z _t )＝(x _e -x _s ，y _e -y _s ，z _e -z _s ) Calculating a first unit direction vector V _t ；

Wherein S is P _s To P _e The modulus of the vector is a function of,

and taking the intersection point of the projection plane and the initial unit direction vector as the origin of a local coordinate system, taking the X-axis direction in the geodetic coordinate system as the y-axis direction of the local coordinate system, taking the opposite direction of the projection of the Z-axis which points to the vertical elevation on the projection plane in the geodetic coordinate system as the X-axis direction of the local coordinate system, and taking the direction of the initial unit direction vector as the Z-axis direction of the local coordinate system to construct the local coordinate system.

In an implementation manner of the embodiment of the present application, the determining module 1402 is further configured to

Selecting two points with the largest distance from all the projection points along the y-axis direction as outer edge points of a longitudinal axis, selecting one point of the vault of the tunnel along the x-axis direction as an outer edge point of a transverse axis, and determining an outer boundary circle by using the two outer edge points of the longitudinal axis and the outer edge point of the transverse axis to obtain the circle center and the radius of the outer boundary circle;

according to Δ d = α (Δ L | z) _t | +2 δ) determining a preset offset Δ d; wherein α represents an empirical coefficient; Δ L represents the length of the cell; | z _t I represents the absolute value of the subentry of the vector in the initial unit direction; δ represents the range accuracy of the tunnel geodetic surveying system.

Determining a circle which is concentric with the outer boundary circle and has a radius smaller than the radius of the outer boundary circle by a preset offset as an inner boundary circle;

and determining a circular ring consisting of the inner boundary circle and the outer boundary circle as a specified range.

In an implementation manner of the embodiment of the present application, the determining module 1402 is further configured to:

according to (x) _se-j ，y _se-j ，z _se-j )＝(j-0.5)SV _t /M+(x _s ，y _s ，z _s ) Determining the intersection point P _se-j Coordinate (x) of _se-j ，y _se-j ，z _se-j )；

Where j represents the jth cell of the division, j =1, 2.

A determining module 1402 for:

according to

Determining geodetic coordinates of an active point

Using (x, y, z) ^T ＝R{(X，Y，Z) ^T + Q, converting the earth coordinates of the effective points into local coordinates;

wherein, P _i Representing geodetic coordinates of the spatial points on the unit corresponding to the ith valid point; v _t Represents an initial unit direction vector; t represents a matrix transposition operation; z is a radical of _se-j Indicates the point of intersection P _se-j Z-axis coordinates of (a); x, y and z respectively represent coordinate values of an x axis, a y axis and a z axis in a local coordinate system; x, Y and Z respectively represent coordinate values of an X axis, a Y axis and a Z axis in a geodetic coordinate system; r represents a rotation matrix transformed from a geodetic coordinate system to a local coordinate system; q represents a translation vector transformed from the geodetic coordinate system to the local coordinate system;

wherein the content of the first and second substances,

Q＝[-x _se-j -y _se-j -z _se-j ] ^T ，

u _z ＝(u _yi ，u _yj ，u _yk )＝V _t ＝(x _t ，y _t ，z _t )，u _y ＝(u _zi ，u _zj ，u _zk )＝u _z ×u _x ，u _x 、u _y 、u _z the coordinate vectors are respectively unit coordinate vectors of an x axis, a y axis and a z axis of the local coordinate system in a geodetic coordinate system.

constructing a parametric equation for a first axis

Wherein a is ₁ 、a ₂ 、b ₁ 、b ₂ Is a parameter to be solved of the parameter equation;

according to [ a ] ₁ a ₂ ] ^T ＝(Z ₁ Z ₁ ^T ) ^-1 Z ₁ X ₁ ，[b ₁ b ₂ ] ^T ＝(Z ₁ Z ₁ ^T ) ^-1 Z ₁ Y ₁ Determining a parameter a to be solved of a parameter equation ₁ 、a ₂ 、b ₁ 、b ₂ (ii) a Wherein, X ₁ ＝[x ₁ x ₂ … x _M ] ^T ，Y ₁ ＝[y ₁ y ₂ … y _M ] ^T ，

(x ₁ ，y ₁ ，z ₁ )、...、(x _M ，y _M ，z _M ) Circle center geodetic coordinates of a first unit to an Mth unit which are divided for the segments respectively;

according to

according to C =1-V ^(t0) ·V ^(t1) ＝1-x _t0 x _t1 -y _t0 y _t1 -z _t0 z _t1 Determining a first unit direction vector V ^(t0) And a second unit direction vector V ^(t1) A deviation C of (a), wherein (x) _t1 ，y _t1 ，z _t1 ) Is a second unit direction vector V ^(t1) The geodetic coordinates of (a).

and if the deviation is greater than the deviation threshold value, taking the second unit direction vector as a new first unit direction vector, calculating a new second unit direction vector and a second axis according to the new first unit direction vector until the deviation of the calculated first unit direction vector and the second unit direction vector is less than or equal to the deviation threshold value, and determining the second axis obtained by the last calculation as the tunnel axis of the section of tunnel.

In the embodiment of the application, the current axis is adjusted to be in a state parallel to the historical reference axis and the center of the current axis coincides with the historical reference axis, then, firstly, the projection point of the space point in the current point group on each unit of the tunnel segment in the current state on a plane perpendicular to the current axis is determined, and the current projection fitting function and the current optimal projection point coordinate of the projection point on the plane are determined by means of NURBS fitting, and furthermore, the historical projection fitting function and the historical optimal projection point coordinate of the space point in the historical point group on each unit of the tunnel segment in the historical state on the historical reference axis are determined. Because the curve fitted by NURBS is more in accordance with the integral form of the projection point, compared with the prior art in which the fitting is directly carried out by utilizing a circle or an ellipse, the local deformation identification precision of the tunnel segment is improved.

The embodiment of the present application further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, any one of the methods described in steps 201 to 207 and various implementations thereof is implemented.

The embodiment of the present application further provides a computer-readable storage medium, where a computer program for executing any one of the methods described in steps 201 to 207 and various implementation manners thereof is stored in the computer-readable storage medium.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, compact Disk Read Only Memory (CD-ROM), optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above-mentioned embodiments are further described in detail for the purpose of illustrating the invention, and it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A tunnel local deformation identification method is characterized by comprising the following steps:

dividing each segment of the tunnel into a plurality of units, and acquiring the current geodetic coordinates of each space point in the current point group on each unit under a geodetic coordinate system, the historical reference axis of each segment and the historical geodetic coordinates of each space point in the historical point group on each unit;

determining the current axis of each segment according to the current geodetic coordinates of each space point in the current point group on each unit;

adjusting the current axis to be parallel to the historical reference axis and the middle point of the current axis to coincide with the middle point of the historical reference axis, and converting the geodetic coordinates of each space point in the current point group on each unit into conversion coordinates when the current axis is parallel to the historical reference axis and the middle point of the current axis coincides with the middle point of the historical reference axis;

determining the coordinates of the current projection points of all the space points in the current point group on a plane perpendicular to the historical reference axis according to the transformed coordinates of all the space points in the current point group on each unit, and obtaining a current projection fitting function by NURBS fitting; according to historical geodetic coordinates of each space point in the historical point group on each unit, determining historical projection point coordinates of each space point in the historical point group on a plane perpendicular to a historical reference axis, and obtaining a historical projection fitting function by NURBS fitting;

determining the center coordinates of a fitting circle, the local coordinates of designated points on the fitting circle, the current optimal projection point coordinates of the designated points on the fitting circle on a current projection fitting function, and the historical optimal projection point coordinates on a historical projection fitting function, wherein the fitting circle is obtained by fitting the projection points of all space points in the current point group on each unit on a plane perpendicular to the historical reference axis;

determining a tunnel local deformation parameter at a specified point on a fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the specified point on the fitting circle and the circle center coordinate of the fitting circle;

and if the tunnel local deformation parameter is not equal to 0, determining that the tunnel local deformation occurs, and determining the absolute value of the tunnel local deformation parameter as the tunnel deformation.

2. The method of claim 1, wherein converting the geodetic coordinates of each spatial point in the current point group on each cell to converted coordinates when the current axis is parallel to the historical reference axis and the midpoint of the current axis coincides with the midpoint of the historical reference axis comprises:

3. The method of claim 1 or 2, wherein determining the coordinates of the current projection point of each spatial point in the current point group on a plane perpendicular to the historical reference axis from the transformed coordinates of each spatial point in the current point group on each cell, and using NURBS fitting to obtain the current projection fitting function, comprises:

establishing a local coordinate system by taking the intersection point of the historical reference axis and the vertical plane as an original point, and determining the local coordinate of the current projection point under the local coordinate system according to the conversion coordinate of the space point in the current point group;

and determining the characteristic points of the projection points in each sector range according to the local coordinates of the projection points in each sector range, and performing NURBS fitting on the characteristic points in all the sector ranges to obtain a current projection fitting function.

4. The method of claim 3, wherein determining the feature points of the projection points in each sector based on the local coordinates of the projection points in each sector comprises:

5. The method according to claim 3, wherein the specified point is an intersection point of an angular bisector of a sector divided on the fitting circle and the fitting circle;

determining local coordinates of a specified point on the fitted circle, comprising:

according to

represents the central angle of the fan;

6. The method of claim 1, wherein determining the local deformation parameter of the tunnel at the designated point on the fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the designated point on the fitting circle, and the center coordinate of the fitting circle comprises:

according to

Determining the designated point P on the fitting circle _i Local deformation parameters delta rho of the tunnel;

wherein the content of the first and second substances,

represents P _i Current optimal projected point coordinates of the points;

represents P _i Historical best projection point coordinates of the points;

representing the fitted circle P _i Local coordinates of the points;

7. The method of claim 1, wherein determining the current axis of each segment from the geodetic coordinates of the respective spatial point of the current point group on each unit in the geodetic coordinate system comprises:

aiming at each segment, selecting a target point at each of two ends of the vault of the segment, and determining an initial unit direction vector according to geodetic coordinates of the two target points;

dividing each segment into a plurality of units with equal length along the direction of the initial unit direction vector, and constructing a plane perpendicular to the initial unit direction vector at the center of each unit to be used as a projection plane; constructing a local coordinate system by taking the intersection point of the projection plane and the initial unit direction vector as an origin;

fitting a circle on the projection plane by using the effective points of each unit, and determining the local coordinates of the circle center of the fitted circle; converting the local coordinates of the circle center into the geodetic coordinates of the circle center;

performing space straight line fitting on the circular center geodetic coordinates of all units of each section to obtain a first axis; determining a first unit direction vector from the first axis;

determining a second axis and a second unit direction vector for each segment from the first unit direction vector using a method of determining a first axis and a first unit direction vector from an initial unit direction vector;

and if the deviation is less than or equal to the deviation threshold value, determining the second axis as the current axis of the section of the tunnel.

8. The method of claim 7, wherein after determining the deviation of the first unit direction vector from the second unit direction vector, the method further comprises:

9. An apparatus for identifying local deformation of a tunnel, the apparatus comprising:

the acquisition module is used for dividing each section of the tunnel into a plurality of units, acquiring the current geodetic coordinates of each space point in the current point group on each unit under a geodetic coordinate system, the historical reference axis of each section and the historical geodetic coordinates of each space point in the historical point group on each unit;

the determining module is used for determining the current axis of each segment according to the current geodetic coordinates of each space point in the current point group on each unit, which are acquired by the acquiring module;

the coordinate conversion module is used for adjusting the current axis determined by the determination module to be parallel to the historical reference axis acquired by the acquisition module, enabling the midpoint of the current axis to coincide with the midpoint of the historical reference axis, and converting the geodetic coordinates of each space point in the current point group on each unit into conversion coordinates when the current axis is parallel to the historical reference axis and the midpoint of the current axis coincides with the midpoint of the historical reference axis;

the determining module is also used for determining the coordinates of the current projection points of all the space points in the current point group on a plane perpendicular to the historical reference axis according to the conversion coordinates of all the space points in the current point group on each unit converted by the coordinate conversion module, and obtaining a current projection fitting function by NURBS fitting; according to historical geodetic coordinates of each space point in the historical point group on each unit, determining historical projection point coordinates of each space point in the historical point group on a plane perpendicular to a historical reference axis, and obtaining a historical projection fitting function by utilizing NURBS fitting;

the determining module is further used for determining the circle center coordinates of the fitting circle, the local coordinates of the designated points on the fitting circle, the current optimal projection point coordinates of the designated points on the fitting circle on the current projection fitting function, and the historical optimal projection point coordinates on the historical projection fitting function, wherein the fitting circle is obtained by fitting the projection points of all space points in the current point group on each unit on a plane perpendicular to the historical reference axis;

the determining module is further used for determining a tunnel local deformation parameter at the appointed point on the fitting circle according to the current optimal projection point coordinate, the historical optimal projection point coordinate, the local coordinate of the appointed point on the fitting circle and the circle center coordinate of the fitting circle;

and the determining module is further used for determining that the tunnel is locally deformed when the tunnel local deformation parameter is not equal to 0, and determining the absolute value of the tunnel local deformation parameter as the tunnel deformation.

10. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of any of claims 1 to 8 when executing the computer program.

11. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 1 to 8.