CN115522579A

CN115522579A - Crossed three-dimensional channel pre-reinforcing and hole-opening construction method

Info

Publication number: CN115522579A
Application number: CN202211239106.8A
Authority: CN
Inventors: 韩健勇; 赵明城; 刘�东; 曹加伟; 王庆海; 于浩; 王军; 宁秉正; 张森; 崔中全; 芦凯
Original assignee: First Construction Co Ltd of China Construction Eighth Engineering Division Co Ltd
Current assignee: First Construction Co Ltd of China Construction Eighth Engineering Division Co Ltd
Priority date: 2022-10-11
Filing date: 2022-10-11
Publication date: 2022-12-27

Abstract

The invention discloses a cross three-dimensional channel pre-reinforcing and hole-opening construction method, which relates to the field of building construction, and adopts the technical scheme that the method comprises the following steps of S1, post-pile soil body reinforcement; s2, arranging channel steel cross supports above the pre-opening hole; s3, integrally reinforcing the pile body at the upper part of the opening; s4, breaking the hole; s5, transversely supporting and reinforcing the double-row steel beams of the cut pile body; s6, erecting a steel upright post; s7, breaking the pile body; s8, backfilling; s9, communicating the upper layer; s10, cutting off and reinforcing part of the pile body of the upper side communication connection port; s11, breaking the wall body. The invention has the beneficial effects that: firstly, constructing a lower-layer structure and then constructing an upper-layer structure by adopting 'lower-first and upper-second'; firstly supporting and then dismantling, namely firstly supporting before dismantling, and then dismantling the pile on the premise of ensuring safety; the reinforcement is synchronous, and the reinforcement is carried out simultaneously after the pile foundation is dismantled, so that the construction safety is ensured.

Description

Crossed three-dimensional channel pre-reinforcing and hole-opening construction method

Technical Field

The invention relates to the field of building construction, in particular to a crossed three-dimensional channel pre-reinforcing and holing construction method.

Background

In urban planning, the engineering of nearly subway is mostly commercial synthesis, and in order to drive commercial development, the peripheral building of subway often can plug into the intercommunication with the subway station to reach the subway traffic trade center that unites two into one. However, under the condition that the subway station is not close to but the rail transit penetrates through the land, in order to increase commercial potential, the engineering land needs to be connected and communicated to form a whole on the premise of ensuring the normal operation of the rail transit, and the condition is often the key point of the design and construction of the near subway project. When the channel needs to be reset after underground rail transit (or subway) construction is completed, the main design scheme is that the channel structure is reserved on the side wall of the existing structure for connection treatment, so that the basement is integrally communicated. However, because the underground structure is stressed complexly, huge risks often exist in the processing stage of the existing underground structure breaking and connection interface. Especially, the urban public safety is greatly threatened by improper treatment of a multi-line transfer subway station. In addition, the stress states of new and old structure foundations are greatly different, so that the interface cracking and even the structural damage caused by the uneven settlement of new and old buildings are very likely to occur, and how to effectively solve the problem that the stress and the waterproof treatment of the connection interface are the same key for the communication connection construction of the rail transit.

Through research and investigation aiming at the problem of communication connection of the existing subway station in recent years, the problem of communication connection is a complex technical problem appearing in recent years. The prior researches have proved the influence rule of the subway station structure opening on the structure stress, but the researches are mostly concentrated on one opening direction, and for the cross three-dimensional station channel communication connection, the opening types are more various, so that the development of the construction method for the close connection of the existing underground structure three-dimensional communication connection is necessary.

Disclosure of Invention

Aiming at the technical problem, the invention provides a crossed three-dimensional channel pre-reinforcing and punching construction method.

The technical scheme comprises the following steps:

s1, reinforcing a soil body behind a pile: before pile cutting, grouting and reinforcing soil behind the pile, wherein the grouting operation range is the outer edge of the pre-opening;

s2, setting channel steel cross bracing above the pre-opening hole: channel steel cross supports are arranged on the outer sides of the first row of support piles above the pre-opening hole, the pre-cut piles and adjacent non-cut pile bodies on two sides are connected into a whole, and embedded parts are installed on the pile bodies above the pre-opening hole;

s3, integrally reinforcing the pile body at the upper part of the opening: after the channel steel cross support is installed, integrally reinforcing the pile body at the upper part of the hole, drilling holes in each pile body above the hole, penetrating three rows of pile bodies by the depth of the drilled holes, inserting steel pipes with certain thickness after the holes are drilled, and grouting the inside and the outside of the steel pipes;

s4, breaking the hole: after grouting reaches the design strength, when the two channels need to be communicated for construction, the lower hole needs to be broken first, and then the upper hole needs to be broken;

s5, transversely supporting and reinforcing the cut double-row steel beams of the pile body: after the pile body part of the area near the installation of the double-row steel beams of the first row of support piles is cut off, transversely supporting and reinforcing the cut double-row steel beams of the pile body;

s6, erecting a steel upright column: after the connection of the double-row steel beams at the corners is finished, steel backing plates are directly additionally arranged at the bottoms of the crossed double-row steel beams at the corners to support steel upright columns;

s7, pile body breaking: the residual pile bodies at the lower part of the first row are broken to the designed size by adopting a static breaking method, the second row of piles and the third row of piles are broken, the wall body of the channel structure is broken, and a communication channel interface is poured;

s8, backfilling: after the lower-layer supporting structure is broken and reinforced, constructing a lower-layer main body structure, and backfilling plain concrete or plain soil; if the foundation pit is internally provided with the inner support, the inner support of the foundation pit can be removed after backfilling is finished so as to enlarge the construction space of the upper-layer structure;

s9, upper layer communication construction: after the lower-layer structure is completely constructed, carrying out upper-layer communication construction, wherein an upper-layer communication connection port is generally positioned on the side surface of a lower-layer hole and is arranged according to the function requirement of the actual underground structure;

s10, cutting off and reinforcing part of pile body of the upper side communication connection port: pre-cutting off a first row of partial pile bodies to provide space for subsequent installation of double-row steel beams, cutting off the pile body parts of the areas near the installation of the double-row steel beams of the first row of support piles, and reinforcing and breaking the second row of piles and the third row of piles;

s11, breaking the wall: and after the three rows of pile bodies are completely reinforced and broken, adopting a rope saw static cutting process to assist the light electric pick to cooperatively work to break the wall body.

Preferably, in the step S2, the embedded part includes a steel plate with a hole and a long screw, a groove is formed in the middle of the steel plate, two long screws are arranged in the groove, and the screws are welded with the steel plate.

Preferably, because pile construction error and stratum difference, the pile position often is inconsistent, still include three kinds of situations in step S2:

s201, projecting a pile body: before installing the embedded part, planing the cambered surface of the pile side, wherein the planed surface is 50mm larger than the plane of the connecting steel plate;

s202, sinking the pile body: drilling holes according to the installation positions of the long screws of the embedded parts, inserting the long screws on the steel plates into the drilled holes, then erecting a formwork around the steel plates and grouting, welding and connecting channel steel and newly added steel plates into a whole to form a cross truss, and installing a pair of parallel strain gauges at the cross supporting intersection;

s203, when the opening is large and is positioned at the corner of the foundation pit: the two sides of the opening are respectively provided with channel steel cross supports, the channel steel supports on the two sides are respectively connected with pile bodies which are not cut off on the two sides, and the other two groups of channel steel supports on one end are welded into a whole through steel plates.

Preferably, the specific steps in step S3 are: and a double-hole grouting stop plug is arranged at the end part of the drilling hole.

Preferably, the specific steps in step S4 are: and cutting off a part of the pile body which is cut off in advance, and additionally arranging a steel upright post at the corner of the section steel beam for supporting.

Preferably, the specific steps in step S5 are: the double-row steel beam connecting method comprises steel base plate connection, embedded part connection and double-row steel beam connection at corners of the double-row steel beams, wherein the two ends of the double-row steel beams are welded with the embedded parts and existing pile body steel bars, plugging and grouting are performed after welding is completed, and cement-based materials or bar planting glue can be selected as grouting materials.

Preferably, the specific steps in step S6 are: the upper part of the steel upright post is provided with a shaft dynamometer, and two end parts of the upright post are provided with brackets;

the bottom of the steel upright post is fixed in the bottom foundation through a column base anchor bolt and a steel base plate, and the top end of the upright post is connected with the steel base plate at the bottom of the axial force meter in a welding mode.

Preferably, step S7 further includes:

s701: the residual pile bodies at the lower part of the first row are broken to the designed size by adopting a static force breaking method, and the dismantling sequence is that the pile bodies are dismantled from the corners to the two sides;

s702: after the first row of piles are reinforced, the second row of waterproof curtain piles are broken;

s703: and (5) after the second row of pile bodies are broken, breaking the third row of pile bodies, wherein the method is the same as the step (S701).

Preferably, the specific steps in step S8 are: and after the lower-layer supporting structure is broken and reinforced, constructing a lower-layer main structure, and backfilling plain concrete or plain soil.

Preferably, step S9 further includes:

s901: pre-cutting off a first row of partial pile bodies, wherein the pile cutting position is positioned above the pre-cut hole, the pile bodies are symmetrically cut from the middle to two sides during pile cutting, and the double-row steel beams of the cut pile bodies are transversely supported and reinforced;

s902: after the first row of piles are reinforced, reinforcing and breaking the second row of waterproof curtain piles;

s903: and after the second row of pile bodies are broken, breaking the third row of pile bodies, and transversely supporting and reinforcing the double rows of steel beams of the cut pile bodies.

The technical scheme provided by the embodiment of the invention has the following beneficial effects: 1. the invention discloses a novel method for comprehensive reinforcement and construction of a deep foundation pit close-connected existing underground structure through cross three-dimensional complex communication connection, which comprises the steps of firstly constructing a lower-layer structure and then constructing an upper-layer structure by adopting 'first descending and then ascending'; firstly supporting and then dismantling, wherein supporting is firstly carried out before dismantling, and then the piles are dismantled on the premise of ensuring safety; the reinforcement is synchronous, and the reinforcement is carried out simultaneously after the pile foundation is dismantled, so that the construction safety is ensured. The influence on the existing structure in the construction process under the crossed three-dimensional complex condition is reduced to the maximum extent, and the safety of the existing structure is ensured.

2. Before the pile body is cut off, the cross channel steel is used for pre-reinforcing the pile body on the upper portion of the opening, particularly for a three-dimensional opening, the cross channel steel of adjacent planes is welded and reinforced to form a cross truss, so that the integrity of a supporting structure is enhanced, and the structural deformation generated by internal force redistribution when the existing pile body is broken is guaranteed to be within a control range.

3. Through the mode of drilling on the pile body and pouring after inserting the steel pipe, connect first row of piles, second row of waterproof curtain, third row of piles as an organic whole, undertake soil pressure jointly, reduce horizontal or vertical displacement that broken pile construction arouses, improve three rows of pile body and strut the effect

4. Set up the support steel stand in three-dimensional entrance to a cave position, steel stand top adds establishes ring flange and bracket, can effectively transmit upper portion pile body load to the stand on, makes the intercommunication construction of plugging into safer to cause unnecessary casualties and economic loss.

5. The double-hole grouting stop plug is arranged at the end part of the drilled hole, but the double-hole grouting stop plug is different from the conventional single Kong Zhijiang plug, so that slurry inside a steel pipe and slurry between the outer wall of the steel pipe and a pile body can be effectively blocked, the grouting quality is fully ensured, and a premise is provided for the steel pipe to effectively transfer the load of the pile body.

6. The construction scheme fully considers the problem of the size of the opening caused by the section steel beam, adopts a stepped hole-opening reinforcing mode to adjust the size of the opening, meets the feasibility of subsequent construction, and ensures the construction operation space of opening and connecting.

7. Newly-increased built-in fitting simple to operate can solve the problem that the pile body position differs in a flexible way to the built-in fitting steel sheet can be dismantled and retrieve, reduces the material cost.

8. The rope saw static force cutting process is adopted for punching the shear wall, the light electric pick is assisted to operate in a matching mode, the reasonable breaking stress of the existing station shear wall is effectively guaranteed, the safe stress system is converted, and the influence on the stability of the existing structure is reduced.

9. For the safety of later-stage construction and displacement deformation control, the profile steel is adopted for reinforcing support, and the strain gauge is arranged on the profile steel (so that the stress deformation of the double-row steel beam can be monitored in real time), thereby ensuring the safety of the construction working face.

Drawings

Fig. 1 is a schematic view of an entire construction area according to an embodiment of the present invention.

Fig. 2 is a plan view of a steel pipe pre-reinforcement according to an embodiment of the present invention.

FIG. 3 is a schematic view of the lower opening breaking in accordance with the embodiment of the present invention.

Fig. 4 is a schematic view of transverse supporting and reinforcing of the double-row steel beam of the cut-off pile body according to the embodiment of the invention.

Fig. 5 is a schematic diagram of removing the remaining piles in the first row according to the embodiment of the present invention.

FIG. 6 is a schematic diagram of a second row of waterproof curtains breaking according to the embodiment of the present invention.

Fig. 7 is a schematic diagram of a third row of pile body breaking according to the embodiment of the invention.

FIG. 8 is a schematic view of a hole breaking apparatus according to an embodiment of the present invention.

Fig. 9 is a schematic illustration of a plain soil backfill according to an embodiment of the invention.

FIG. 10 is a schematic diagram of a cut-away of the pile body of the first row of the upper opening according to an embodiment of the present invention.

Fig. 11 is a schematic view of lateral support reinforcement of the first row of piles at the upper opening according to the embodiment of the invention.

FIG. 12 is a schematic diagram of a second row of waterproof curtains in the upper opening according to an embodiment of the present invention.

FIG. 13 is a schematic view of a third row of upper openings of an embodiment of the present invention.

Fig. 14 is a schematic view of a wall breaking according to an embodiment of the present invention.

FIG. 15 is a schematic structural diagram of a grout stop plug according to an embodiment of the present invention.

Fig. 16 is a sectional view in the direction 1-1 of fig. 15.

Wherein the reference numerals are: 1. a first row of piles; 2. channel steel; 3. embedding parts; 4. a steel pipe; 5. an upper opening; 6. a lower opening; 7. a pre-grouting area; 8. a foundation; 9. a crown beam; 10. a second row of piles; 11. a third row of piles; 12. a steel upright; 13. a section steel beam; 14. a strain gauge; 15. an axial force meter; 16. cutting off the cross section of the second row of piles; 17. a shear wall; 18. to break the hole; 19. backfilling; 20. a channel; 21. a grout stopping plug; 22. and (4) a grouting opening.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative of the invention and are not intended to be limiting.

It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings, which are merely for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected" and "connected" are to be construed broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

Example 1

Referring to fig. 1 to 14, the present invention provides a cross three-dimensional channel pre-reinforcing and holing construction method, including the following steps:

s1, reinforcing a soil body behind a pile: before pile cutting, grouting and reinforcing soil behind the pile, wherein the grouting operation range is the outer edge of the pre-opening hole, and the range of the pre-grouting area 7 is larger than that of the pre-opening hole;

s2, setting channel steel 2 cross supports above the pre-opening hole: channel steel 2 cross supports are arranged on the outer sides of the first row of support piles above the pre-opening hole, the pre-cut piles and adjacent non-cut pile bodies on two sides are connected into a whole, and embedded parts 3 are installed on the pile bodies above the pre-opening hole;

s3, integrally reinforcing the pile body at the upper part of the opening: after the channel steel 2 cross support is installed, integrally reinforcing the pile body at the upper part of the hole, drilling holes in each pile body above the hole, penetrating three rows of pile bodies by the drilling depth, inserting steel pipes 4 with certain thickness after drilling, and grouting the inner parts of the steel pipes 4 and the outer parts of the steel pipes 4;

s4, breaking the hole: after grouting reaches the designed strength, when the two channels 20 need to be communicated for construction, the lower hole 6 needs to be broken first, and then the upper hole 5 needs to be broken;

s5, transversely supporting and reinforcing the cut double-row steel beam 13 of the pile body: after the pile body part of the area near the installation of the double-row steel beams 13 of the first row of support piles is cut off, transversely supporting and reinforcing the cut double-row steel beams 13 of the pile body;

s6, erecting a steel upright 12: after the connection of the double-row steel beams 13 at the corners is finished, steel tie plates are directly additionally arranged at the bottoms of the crossed double-row steel beams 13 at the corners to support the steel upright posts 12;

s7, pile body breaking: the residual pile bodies at the lower part of the first row are broken to the designed size by adopting a static force breaking method, the second row of piles and the third row of piles are broken, the wall body of the channel structure is broken, and a communicating channel connector is poured;

s8, backfilling: after the lower-layer supporting structure is broken and reinforced, constructing a lower-layer main structure, and backfilling plain concrete or plain soil; if the foundation pit is internally provided with the inner support, the inner support of the foundation pit can be removed after backfilling is finished so as to enlarge the construction space of the upper-layer structure;

s9, upper layer communication construction: after the lower-layer structure is completely constructed, carrying out upper-layer communication construction, wherein the upper-layer communication connection port is generally positioned on the side surface of the lower-layer hole and is arranged according to the function requirement of the actual underground structure;

s10, cutting off and reinforcing part of pile body of the upper side communication connection port: pre-cutting off a first row of partial piles to provide space for subsequent installation of the double-row steel beams 13, cutting off part of the piles in the area near the installation of the double-row steel beams 13 of the first row of support piles, and reinforcing and breaking second and third rows of piles;

s11, breaking the wall body: and after the three rows of pile bodies are completely reinforced and broken, adopting a rope saw static cutting process to assist the light electric pick to cooperatively work to break the wall body.

In the step S2, the embedded part 3 comprises a steel plate with a hole and long screw rods, the middle of the steel plate is provided with a groove, two long screw rods are arranged in the groove, and the screw rods are welded with the steel plate.

Because pile body construction error and stratum difference, the pile body position often is inconsistent, still includes three kinds of situations in step S2:

s201, projecting a pile body: before installing the embedded part 3, planing the cambered surface of the pile side, wherein the planed surface is 50mm larger than the plane of the connecting steel plate; holes can be drilled in the pile body in advance according to the positions of the long screws of the embedded parts 3, and meanwhile, bar planting glue is smeared between the steel plates of the embedded parts 3 and the planing surface and in the drilled holes, so that the firm connection between the pile body and the embedded parts 3 is ensured;

s202, sinking the pile body: drilling holes according to the installation positions of the long screws of the embedded parts 3, inserting the long screws on the steel plates into the drilled holes, then erecting formwork around the steel plates for grouting, firmly connecting the embedded parts 3 with the existing pile body structure, and welding and connecting the channel steel 2 and the newly added steel plates into a whole to form a cross truss; a pair of parallel strain gauges 14 are arranged at the cross support intersection points, so that the stress deformation condition of the section steel can be monitored in real time conveniently, and the subsequent work can be started after the cross support of the channel steel 2 is finished;

s203, when the opening is large and is positioned at the corner of the foundation pit: the pre-opening hole is not in one plane but is a three-dimensional hole, the planes on two sides of the hole are respectively provided with channel steel 2 cross supports, the channel steel 2 supports on two sides are respectively connected with pile bodies which are not cut on two sides, and the other two groups of channel steel 2 supports on one end are welded into a whole through steel plates.

The specific steps in step S3 are: the end part of the drilling hole is provided with a double-hole grouting stop plug 21, the stop plug 21 comprises a circular plate-shaped end plate, one side of the end plate is fixedly provided with an inner layer plug and an outer layer plug which are annular sleeve-shaped, the middle part of the other side of the end plate is fixedly provided with a valve, the bodies of the inner layer plug and the outer layer plug are respectively provided with a tubular grouting opening 22 and an exhaust hole, one end of the grouting opening 22 and one end of the exhaust hole penetrate through the end plate, the grouting opening 22 is convenient for an operator to perform grouting inside and outside the steel pipe, and the exhaust hole can exhaust gas in the hole to the outer side of the stop plug 21;

the inner plug and the outer plug are inflatable rubber bags, the inner plug and the outer plug are inflated and deflated through a valve, holes are conveniently plugged through the grout stop plug 21, the inner plug is inserted into the steel pipe 4 to plug the inside of the steel pipe, and the outer plug plugs the outside of the steel pipe 4;

prevent through only thick liquid stopper 21 that the thick liquid from leaking outward, after the concrete initial set in the drilling, open the valve, to inner plug and outer stopper gassing, can extract only thick liquid stopper 21, connect three rows of piles as whole through steel pipe 4, safety when guaranteeing the entrance to a cave excavation, after the maintenance reaches design concrete intensity, alright carry out follow-up construction. The grout stopping plug 21 can effectively block the grout inside the steel pipe and the grout between the outer wall of the steel pipe and the pile body, fully ensures the grouting quality and provides a premise for effectively transferring the load of the pile body by the steel pipe.

The specific steps in step S4 are: cutting off a pre-cut part of the pile body to provide space for subsequent installation of the double-row steel beams 13 and the steel upright columns 12, wherein the position where the pile body starts to be cut off is determined according to the requirement of a designed hole opening, the height of the double-row steel beams 13 and the erection quantity, the size of the hole opening is enlarged, the height is enlarged by about 200-300mm, the width is enlarged by about two times of the pile diameter, and the pile cutting position is positioned above the pre-cut hole opening;

when the crossed three-dimensional opening construction is carried out, the opening is not a plane, the steel upright 12 needs to be additionally arranged at the corner of the steel beam 13 for supporting, so that the pile body at the corner needs to be broken off completely, the breaking range needs to meet the supporting requirement of the steel upright 12, the diameter of the pile is about one pile diameter, the cutting height needs to meet the installation requirement of the double-row steel beam 13, the pile is cut off symmetrically from the middle to two sides when being cut off, the cut bottom surface and the cut side surface of each pile body need to be flat and smooth, the stress is uniform when the double-row steel beam 13 is installed, for the pile body at the adjacent side of the pile body to be broken off, the 1/2 section close to the opening side is cut off, the concrete is broken off in principle, but the original reinforcing steel bar is kept in the original state, the surface of the reinforcing steel bar is cleaned by using a steel wire brush, and the stress needs to be poured together with the double-row steel beam 13 subsequently.

The specific steps in step S5 are: the double-row steel beam 13 connecting method comprises steel backing plate connection, embedded part 3 connection and double-row steel beam 13 connection at the corner of the double-row steel beam 13, wherein a steel backing plate is additionally arranged on the cross section of the bottom of a pile body to be cut off by using a steel bar planting adhesive, the embedded part 3 in the pile body is not cut off at two adjacent sides, axial force meters 15 are arranged at the bottoms of two ends of the double-row steel beam 13, two ends of the double-row steel beam 13 are welded with the embedded part 3 and the existing pile body steel bars, plugging and grouting are carried out after the welding is finished, and a grouting material can be a cement-based material or a steel bar planting adhesive;

the double-row steel beam 13 corner is located at the corner pile and is connected in a welding mode, specifically, the flange of the double-row steel beam 13 on one side can be cut off and then inserted into the web plate of the double-row steel beam 13 on the other side to be welded with the web plate.

The specific steps in step S6 are: the upper part of the steel upright post 12 is provided with an axial force meter 15, and two end parts of the upright post are provided with brackets;

when the steel upright post 12 is erected, the cross section of the broken pile is leveled, and high-strength polymer mortar is adopted for repairing and leveling if necessary, so that the verticality of the steel upright post 12 is ensured;

the bottom of the steel upright post 12 is fixed in the bottom foundation 8 through a pedestal anchor bolt and a steel backing plate, and the top end of the upright post is welded with the steel backing plate at the bottom of the axial force meter 15.

Step S7 further includes:

s701: the residual pile bodies at the lower part of the first row are broken to the designed size by a static breaking method, the dismantling sequence is that the pile bodies are dismantled from corners to two sides, and the concrete method is that a rope saw is used for cutting off the pile bodies, and each section is cut off by about 1 to 1.5m;

s702: after the first row of piles 1 are reinforced, breaking second row of waterproof curtain piles, when a foundation pit supporting structure is closely connected with an existing structure or the distance between the foundation pit supporting structure and the existing structure is small and soil mass between the foundation pit supporting structure and an original supporting structure of the existing structure is small, removing the soil mass behind the waterproof curtain while removing the waterproof curtain, wherein a specific method can adopt a manual pneumatic pick to match an oil drill until the soil mass leaks out of the shear wall 17;

if the strength of the soil body behind the cement soil is not high, grouting and reinforcing the soil body in the excavation area by using a small guide pipe, excavating, and meanwhile, spraying concrete by using a net, and if the strength is sufficient, directly spraying the concrete by using the net;

s703: after the second row of piles 10 are broken, breaking the third row of piles 11, wherein the method is the same as the step S701; the breaking range is determined according to the height and erection quantity of the double-row steel beams 13 on the basis of the second row of piles 10, and the additionally-arranged range of the double-row steel beams 13 and the pile body breaking range are determined.

The specific steps in step S8 are: after the lower-layer supporting structure is broken and reinforced, constructing a lower-layer main body structure, wherein the backfill 19 is generally plain concrete or plain soil;

if the foundation pit is internally provided with the inner support, the inner support of the foundation pit is removed after backfilling is finished so as to enlarge the construction space of the upper-layer structure.

Step S9 further includes:

s901: pre-cutting off a first row of partial pile bodies to provide space for subsequently installing the double-row steel beams 13; the position of the pile body for beginning to be broken is determined according to the requirement of designing the opening, the height of the double-row steel beams 13 and the erection quantity, the size of the opening is enlarged, the height is enlarged by about 200-300mm, and the width is enlarged by about one time or two times of the diameter of the pile;

the pile cutting position is positioned above the pre-cut hole, and the cutting height needs to meet the installation requirement of the double-row steel beam 13; when the pile is cut, the pile bodies are symmetrically cut from the middle to two sides, and the cut bottom surfaces and the cut side surfaces of the pile bodies need to be smooth;

after the pile body part of the area near the installation of the first row of support pile double-row steel beams 13 is cut off, transversely supporting and reinforcing the cut pile body double-row steel beams 13; the double-row steel beam 13 is connected by steel backing plates; a steel backing plate is additionally arranged on the bottom section of the pile body to be cut off by using bar planting glue, the steel backing plate is welded with the section steel beam 13, the bottoms of two ends of the double-row section steel beam 13 are provided with a shaft dynamometer 15, and the double-row section steel beam 13 is provided with a pair of parallel strain gauges 14;

the residual pile bodies at the lower part of the first row are broken to the designed size by adopting a static breaking method; the dismantling sequence is that the dismantling is carried out from the middle to the two sides; the concrete method is that a rope saw is used for cutting off the pile body, each section is cut off about 1 to 1.5m, and the hoisting and the transportation are convenient;

s902: after the first row of piles 1 are reinforced, reinforcing and breaking the second row of waterproof curtain piles, wherein the broken range of the first row of piles 1 is smaller than that of the second row of piles 1; when the foundation pit supporting structure is closely attached to the existing structure or the distance between the foundation pit supporting structure and the existing structure is smaller and the soil mass between the foundation pit supporting structure and the original supporting structure of the existing structure is smaller, the second row is broken, and the soil mass behind the waterproof curtain is removed while the waterproof curtain is removed;

s903: after the second row of piles 10 are completely broken, the third row of piles 11 are broken, and the broken range of the second row of piles 10 is smaller than that of the second row of piles 10 due to the reinforcement of the second row of piles; after the pile body part of the area near the installation of the double-row steel beams 13 of the third row of support piles is cut off, transversely supporting and reinforcing the cut double-row steel beams 13 of the pile body;

the connecting method of the double-row steel beams 13 comprises the steps of connecting the steel base plates and the embedded parts 3, and connecting the double-row steel beams 13 at the corners of the double-row steel beams 13;

steel backing plates are additionally arranged on the bottom cross section of the pile body to be cut off by using bar planting glue, embedded parts 3 in the pile body are not cut off adjacently at two sides, so that two ends of a double-row steel beam 13 can be conveniently fixed, shaft force meters 15 are arranged at the bottoms of the two ends of the double-row steel beam 13, and two ends of the double-row steel beam 13 are welded with the embedded parts 3 and existing pile body steel bars;

after welding, plugging and grouting are carried out, wherein the grouting material can be a cement-based material or a bar-planting adhesive; the double-row steel beam 13 is provided with a pair of parallel strain gauges 14 so as to facilitate the real-time monitoring of the stress deformation condition of the section steel.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A crossed three-dimensional channel pre-reinforcing and holing construction method is characterized by comprising the following steps of:

s2, arranging channel steel (2) cross supports above the pre-opening hole: channel steel (2) cross supports are arranged on the outer sides of the first row of support piles above the pre-opening hole, the pre-cut piles and adjacent non-cut pile bodies on two sides are connected into a whole, and an embedded part (3) is installed on the pile bodies above the pre-opening hole;

s3, integrally reinforcing the pile body at the upper part of the opening: after the channel steel (2) is supported in a crossing manner and installed, integrally reinforcing the pile body at the upper part of the hole, drilling each pile body above the hole, penetrating three rows of pile bodies by the drilling depth, inserting a steel pipe (4) with a certain thickness after drilling, and grouting the inside of the steel pipe (4) and the outside of the steel pipe (4);

s4, breaking the hole: after grouting reaches the design strength, when the two channels (20) need to be communicated for construction, the lower hole needs to be broken first, and then the upper hole needs to be broken;

s5, transversely supporting and reinforcing the cut double-row steel beams (13) of the pile body: after the pile body part of the area near the installation of the first row of support pile double-row steel beams (13) is cut off, transversely supporting and reinforcing the cut pile body double-row steel beams (13);

s6, erecting a steel upright post (12): after the connection of the double-row steel beams (13) at the corners is finished, steel backing plates are directly additionally arranged at the bottoms of the crossed double-row steel beams (13) at the corners to support steel upright posts (12);

s8, backfilling: after the lower-layer supporting structure is broken and reinforced, constructing a lower-layer main body structure, and backfilling plain concrete or plain soil; if the foundation pit is internally provided with the inner support, the inner support of the foundation pit can be removed after backfilling is finished so as to enlarge the construction space of the superstructure;

s10, cutting and reinforcing part of the pile body of the upper side communication connection port: pre-cutting off a first row of partial pile bodies to provide space for subsequent installation of double-row steel beams (13), cutting off the pile body part of an area near the installation of the double-row steel beams (13) of the first row of support piles, and reinforcing and breaking a second row of piles and a third row of piles;

s11, breaking the wall body: after the three rows of pile bodies are completely reinforced and broken, a rope saw static force cutting process is adopted to assist the light electric pick to work cooperatively to break the wall body.

2. The crossed three-dimensional channel pre-reinforcing and holing construction method according to claim 1, characterized in that in step S2, the embedded part (3) comprises a steel plate with holes and long screws, a groove is formed in the middle of the steel plate, two long screws are arranged in the groove, and the screws are welded with the steel plate.

3. The cross three-dimensional channel pre-reinforcing and holing construction method according to claim 2, wherein the pile position is often inconsistent due to pile construction error and stratum difference, and the step S2 further includes three conditions:

s201, projecting a pile body: before the embedded part (3) is installed, the cambered surface of the pile side is planed, and the planed surface is extended by 50mm from the plane of the connecting steel plate;

s202, sinking the pile body: drilling holes according to the installation positions of the long screws of the embedded parts (3), inserting the long screws on the steel plates into the drilled holes, then erecting forms around the steel plates for grouting, welding and connecting the channel steel (2) and the newly added steel plates into a whole to form a cross truss, and installing a pair of parallel strain gauges (14) at the cross supporting intersection;

s203, when the opening is large and is positioned at the corner of the foundation pit: the two side planes of the opening are respectively provided with channel steel (2) cross supports, the channel steel (2) supports on the two sides are respectively connected with pile bodies which are not cut off on the two sides, and the other two groups of channel steel (2) supports on one end are welded into a whole through steel plates.

4. The crossed three-dimensional channel pre-reinforcing and holing construction method according to claim 3, characterized in that the concrete steps in step S3 are: and a double-hole grouting stop plug (21) is arranged at the end part of the drilled hole.

5. The crossed three-dimensional channel pre-reinforcing and holing construction method according to claim 4, wherein the specific steps in the step S4 are as follows: and cutting off a part of the pile body which is cut off in advance, and additionally arranging a steel upright post (12) at the corner of the section steel beam (13) for supporting.

6. The crossed three-dimensional channel pre-reinforcing and holing construction method according to claim 5, wherein the concrete steps in the step S5 are as follows: the connecting method of the double-row steel beam (13) comprises steel backing plate connection, embedded part (3) connection and double-row steel beam (13) connection at the corner of the double-row steel beam (13), wherein two ends of the double-row steel beam (13) are welded with the embedded part (3) and the existing pile body steel bar, plugging and grouting are performed after welding is completed, and the grouting material can be cement-based material or bar planting glue.

7. The crossed three-dimensional channel pre-reinforcing and holing construction method according to claim 6, wherein the concrete steps in step S6 are as follows: the upper part of the steel upright post (12) is provided with an axial force meter (15), and two end parts of the upright post are provided with brackets;

the bottom of the steel upright post (12) is fixed in the bottom foundation (8) through a column base anchor bolt and a steel backing plate, and the top end of the upright post is welded with the steel backing plate at the bottom of the axial force meter (15).

8. The crossed three-dimensional type channel pre-reinforcing and holing construction method according to claim 7, wherein the step S7 further comprises:

s702: after the first row of piles (1) are reinforced, breaking the second row of waterproof curtain piles;

s703: and (5) after the second row of piles (10) are completely broken, breaking the third row of piles (11), wherein the method is the same as the step (701).

9. The crossed three-dimensional channel pre-reinforcing and holing construction method according to claim 8, wherein the concrete steps in step S8 are: and after the lower-layer supporting structure is broken and reinforced, constructing a lower-layer main body structure, and backfilling plain concrete or plain soil.

10. The method for pre-reinforcing and perforating a crossed three-dimensional channel as claimed in claim 9, wherein the step S9 further comprises:

s901: the method comprises the following steps of cutting off a first row of partial pile bodies in advance, wherein pile cutting positions are located above pre-cut holes, the pile bodies are symmetrically cut off from the middle to two sides during pile cutting, and double rows of steel beams (13) of the cut pile bodies are transversely supported and reinforced;

s902: after the first row of piles (1) are reinforced, reinforcing and breaking the second row of waterproof curtain piles;

s903: and after the second row of piles (10) are completely broken, the third row of piles (11) are broken, and the double-row steel beams (13) of the cut piles are transversely supported and reinforced.