CN103593558A - Shield tunnel segment structure safety evaluation model and method - Google Patents

Abstract

The invention discloses a shield tunnel segment structure safety evaluation model and method. According to the model, subsystems are formed with bending moment zero point sections and first joint sections of a structure as boundaries, main sections and second joint sections between the bending moment zero point sections and the first joint sections are regarded as the subsystems connected in series respectively, and the failure of any subsystem represents the failure of the whole structure system; each segment main section subsystem comprises a plurality of segment main sections which are connected with one another in parallel. According to the method, all the sections in each subsystem are subject to safety checkup, and it is judged that the corresponding segment main section subsystem is damaged when the number of the main sections meeting damage conditions in the segment main section subsystem reaches 2/3 the total number of the main sections; when the joint sections meet the damage conditions, the joint section subsystem is damaged, and it is represented that the shield tunnel segment structure is damaged when any subsystem is damaged. By means of the shield tunnel segment structure safety evaluation model and method, judgment on ultimate states is more scientific and reasonable, and safety evaluation expression is simpler and clearer.

Description

A kind of duct pieces of shield tunnel evaluation of structural safety model and method

Technical field:

The invention discloses a kind of duct pieces of shield tunnel evaluation of structural safety model and method.

Background technology:

At present, safety assessment about similar indeterminate circular ring structures such as duct pieces of shield tunnel, mostly adopt the damaged terrace work in single cross section, as the < < Design of Railway Tunnel standard > > (TB10003-2005) of China, < < vcehicular tunnel design specifications > > (JTGD70-2004) etc., once think that wherein some cross sections can not meet corresponding permission safety coefficient requirement, judge this structural failure.This method is the very large irrationality of obvious existence for hyperstatic structure, in Practical Project practice process, also shows, the destruction in single cross section can't cause the destruction of total system.Meanwhile, still neither one, effectively for the method for expressing of the general safety coefficient of tunnel lining structure itself, makes when the safety assessment of this class formation so far, a fuzzy reference value often, and concept meaning is fuzzy.Therefore, in the urgent need to a kind of more scientific and reasonable, method of simple, intuitive or the safe condition that index characterizes this class formation.

Summary of the invention:

The object of the invention is to overcome the deficiencies in the prior art, a kind of duct pieces of shield tunnel structure safety evaluation model and computing method from total system angle.

In order to solve the existing problem of background technology, the present invention by the following technical solutions:

A kind of duct pieces of shield tunnel evaluation of structural safety model, it is characterized in that, take moment of flexure cross section at zero point and the joint cross section of structure is separatrix, partition sub-system, respectively moment of flexure cross section at zero point is considered as respectively to the subsystem of connecting with principal section and joint cross section between joint cross section, the inefficacy of any one subsystem represents that unit construction system lost efficacy; It is relation in parallel that each principal section, section of jurisdiction subsystem comprises between several ，Ge principal sections, principal section, section of jurisdiction.

Further, principal section, described section of jurisdiction subsystem, when inefficacy principal section number surpass total principal section number in this subsystem 2/3 time, this principal section subsystem failure; When lost efficacy in joint cross section, this joint cross section thrashing; Each cross section failure criteria adopts conventional reinforced concrete structure cross section failure criteria;

Further, by the load-bearing capacity of shield tunnel chip architecture, the unified vertical load that adopts represents.

The appraisal procedure that adopts this Security Evaluation Model, step comprises:

(1) set up according to a conventional method duct pieces of shield tunnel structural internal force calculation model, ask for internal force value and the distributional pattern thereof in each unit, section of jurisdiction and joint cross section;

(2) determine moment of flexure zero point, and to take moment of flexure zero point and joint cross section be separatrix, partition sub-system;

(3) according to the aforementioned internal force value that calculates, take subsystem as object, calculate respectively the safety coefficient in each all cross sections of subsystem;

(4) add up the safety coefficient in each all cross sections of subsystem, when in the subsystem of principal section, any section of jurisdiction, breaking section number surpasses 2/3 or joint cross section system destruction of total principal section number, assert that this subsystem destroys, otherwise, increase one-level load, be back to step (1), again calculate, until there is any one subsystem failure, stop calculating, assert that total system lost efficacy, current load is the ultimate bearing capacity of structure, and this load and the ratio of design or the actual load of bearing are the safety coefficient of structural system.

Compared with prior art, the invention has the beneficial effects as follows: the invention provides from duct pieces of shield tunnel structure safety evaluation model and the computing method of total system angle, make the judgement of its ultimate limit state more scientific and reasonable, safety assessment is expressed more simple and clear.

Accompanying drawing explanation:

Fig. 1 is existing shield tunnel construction internal force rated figure.

Fig. 2 is typical shield tunnel construction Bending moment distribution aspect graph.

Fig. 3 is that duct pieces of shield tunnel structural system subsystem of the present invention is divided schematic diagram.

Fig. 4 is duct pieces of shield tunnel structure system connection in series-parallel graph of a relation of the present invention.

Fig. 5 is duct pieces of shield tunnel evaluation of structural safety calculation flow chart of the present invention.

Embodiment:

Below in conjunction with the drawings and specific embodiments, the invention will be further described:

The present invention is according to typical shield tunnel Bending moment distribution form (Fig. 2), adopted a kind of more rational new duct pieces of shield tunnel structural system failure mode, whole shield tunnel chip architecture is divided into principal section, some sections of jurisdiction and joint cross section subsystem (Fig. 3) by moment of flexure cross section at zero point and duct piece connector cross section, each subsystem adopts series relationship to connect, and each principal section, section of jurisdiction subsystem comprises several principal sections, each principal section adopts relation in parallel be connected (Fig. 4), can obtain the expression formula of the structural system failure event under shield tunnel joint cross section and principal section, section of jurisdiction associating failure mode:

$\stackrel{\&OverBar;}{G}=\left(\underset{k=A}{\overset{F}{\&cup;}}{\stackrel{\&OverBar;}{G}}_k\right)\&cup;\left[\underset{i=I}{\overset{X}{\&cup;}}\left(\underset{k=1}{\overset{k_i}{\&cap;}}{\stackrel{\&OverBar;}{G}}_k\right)\right]---\left(1\right)$

In formula, for the failure event of subsystem, first represents the failure event in A～F5 joint cross section, and in A～F5 joint cross section, lost efficacy in any one joint cross section, causes whole system to lose efficacy; And second portion is the failure event of 10 section of jurisdiction ring systems of I～X, and this any one principal section inefficacy wherein might not cause this subsystem failure, thinks when m is counted in the inefficacy cross section of each subsystem (section of jurisdiction loop section) _i>=(0.65～0.7) * k _i, to think and have an appointment 2/3 cross section in each subsystem while losing efficacy, subsystem lost efficacy thereupon, and then total system lost efficacy.

For making the meaning of duct pieces of shield tunnel evaluation of structural safety more short and sweet, the present invention is also unified to vertical load by horizontal loading, adopt vertical load to represent the load-bearing capacity of shield tunnel chip architecture, so, can obtain easily the safety coefficient of shield tunnel chip architecture, physical concept, mechanical meaning are clear and definite.

As shown in Figure 5, computing method of the present invention comprise following step:

(1) according to a conventional method (Fig. 1) sets up duct pieces of shield tunnel structural internal force calculation model, asks for internal force value and the distributional pattern (Fig. 2) thereof in each unit, section of jurisdiction and joint cross section;

(2) determine moment of flexure zero point, and to take moment of flexure zero point and joint cross section be separatrix, partition sub-system (Fig. 3 and Fig. 4);

(3) according to the aforementioned internal force value that calculates, take subsystem as object, calculate respectively the safety coefficient in each all cross sections of subsystem;

(4) add up the safety coefficient in each all cross sections of subsystem, when in the subsystem of principal section, any section of jurisdiction, breaking section number surpasses 2/3 or joint cross section system destruction of total principal section number, assert that this subsystem destroys, otherwise, increase one-level load, be back to step (1), again calculate, until there is any one subsystem failure, stop calculating, assert that total system lost efficacy, current load is the ultimate bearing capacity of structure, and this load and the ratio of design or the actual load of bearing are the safety coefficient of structural system.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims (4)

1. a duct pieces of shield tunnel evaluation of structural safety model, it is characterized in that, take moment of flexure cross section at zero point and the joint cross section of structure is separatrix, partition sub-system, respectively moment of flexure cross section at zero point is considered as respectively to the subsystem of connecting with principal section and joint cross section between joint cross section, the inefficacy of any one subsystem represents that unit construction system lost efficacy; It is relation in parallel that each principal section, section of jurisdiction subsystem comprises between several ，Ge principal sections, principal section, section of jurisdiction.

2. a kind of duct pieces of shield tunnel evaluation of structural safety model according to claim 1, is characterized in that, principal section, described section of jurisdiction subsystem, when inefficacy principal section number surpass total principal section number in this subsystem 2/3 time, this principal section subsystem failure; When lost efficacy in joint cross section, this joint cross section thrashing; Each cross section failure criteria adopts conventional reinforced concrete structure cross section failure criteria.

3. a kind of duct pieces of shield tunnel evaluation of structural safety model according to claim 1, is characterized in that, by the load-bearing capacity of shield tunnel chip architecture, the unified vertical load that adopts represents.

4. the appraisal procedure of Security Evaluation Model according to claim 1, is characterized in that comprising the steps:

(1) set up according to a conventional method duct pieces of shield tunnel structural internal force calculation model, ask for internal force value and the distributional pattern thereof in each unit, section of jurisdiction and joint cross section;

(2) determine moment of flexure zero point, and to take moment of flexure zero point and joint cross section be separatrix, partition sub-system;

(3) according to the aforementioned internal force value that calculates, take subsystem as object, calculate respectively the safety coefficient in each all cross sections of subsystem;

(4) add up the safety coefficient in each all cross sections of subsystem, when in the subsystem of principal section, any section of jurisdiction, breaking section number surpasses 2/3 or joint cross section system destruction of total principal section number, assert that this subsystem destroys, otherwise, increase one-level load, be back to step (1), again calculate, until there is any one subsystem failure, stop calculating, assert that total system lost efficacy, current load is the ultimate bearing capacity of structure, and this load and the ratio of design or the actual load of bearing are the safety coefficient of structural system.

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