Pipe gallery deformation joint maximum setting distance prediction method and system

Abstract

The present application relates to a kind of pipe gallery deformation joint maximum setting pitch prediction method and system, comprising: determining pipe gallery deformation joint maximum setting pitch influencing factor;Design multi-factor orthogonal test scheme;Based on thermal coupling numerical calculation model and dichotomy, with the standard value of concrete axial tensile strength as threshold, carry out pipe gallery deformation joint maximum setting pitch orthogonal test;Based on least square method, establish the regression equation of each factor and maximum setting pitch;Using multiple linear regression analysis method, determine the maximum setting pitch prediction model of pipe gallery deformation joint, calculate pipe gallery deformation joint maximum setting pitch.The present application can more accurately predict pipe gallery deformation joint maximum setting pitch, and it is of great significance to optimize field construction procedure, reduce water seepage risk and reduce cost.

Description

Technical Field

[0001] This invention belongs to the field of integrated utility tunnel technology, specifically relating to the prediction technology for the maximum spacing of expansion joints in utility tunnels. Background Technology

[0002] Expansion joints are a general term encompassing both expansion joints and settlement joints. Primarily designed to address common issues in utility tunnel structures such as expansion and settlement to prevent structural damage, they are also prone to water leakage, becoming weak points in the waterproofing of utility tunnel structures. Surveys have revealed that water leakage is particularly prominent in integrated utility tunnel structures, with approximately 30% of leaks occurring at expansion joints. Once water seeps into expansion joints, it reduces the durability of the concrete, deteriorates the tunnel environment, affects the use of structural facilities, and creates difficulties for later management.

[0003] Currently, the longitudinal spacing of expansion joints in cast-in-place pipe gallery structures is generally 30m. However, in actual projects, a large number of expansion joints not only increases the waterproofing problem along the entire pipe gallery but also increases the construction difficulty and cost. Therefore, it is necessary to predict and optimize the spacing of expansion joints in pipe galleries.

[0004] Currently, the prediction of the maximum spacing of expansion joints in utility tunnels mainly employs theoretical calculation methods and numerical analysis methods. Theoretical calculation methods derive formulas based on the constraint characteristics between the concrete structure and the foundation, without considering the influence of soil and rock properties and overburden thickness. Numerical analysis methods are often based on modeling and calculations for individual projects and lack general applicability.

[0005] Therefore, existing methods cannot meet the requirements for accuracy and universality of prediction, and there is an urgent need for a prediction method for the maximum spacing of expansion joints in pipe corridors. Summary of the Invention

[0006] To address the accuracy issues of existing methods for predicting the maximum spacing of expansion joints in cast-in-place pipe gallery structures, the present invention aims to provide a method for predicting the maximum spacing of expansion joints in pipe gallery structures, which can more accurately predict the maximum spacing of expansion joints. Furthermore, the present invention provides a system capable of implementing this method for predicting the maximum spacing of expansion joints in pipe gallery structures.

[0007] To achieve the above objectives, the present invention provides a method for predicting the maximum spacing of expansion joints in pipe galleries, comprising the following steps:

[0008] (1) Factors affecting the maximum spacing of expansion joints in pipe gallery

[0009] Determine the external environmental influencing factors based on external conditions; determine the influencing factors on the structural design of the utility tunnel based on internal conditions.

[0010] (2) Constructing a multi-factor orthogonal experimental scheme

[0011] Determine the number and value of each influencing factor, select an orthogonal experimental table, and construct a multi-factor orthogonal experimental scheme.

[0012] (3) Orthogonal test of the maximum spacing of expansion joints in the pipe gallery

[0013] Based on the orthogonal test scheme determined in step (2), a thermo-coupling numerical calculation model was established to calculate the maximum longitudinal tensile stress of the pipe gallery under different expansion joint spacings S, and to determine the maximum expansion joint spacing S of the pipe gallery. max ;

[0014] (4) Establish regression equations between each factor and the maximum setting interval.

[0015] Based on the orthogonal test results of the maximum setting spacing of the pipe gallery expansion joint in step (3), the mean value k of the maximum setting spacing of each factor at different levels is calculated, and regression equations between each factor and the maximum setting spacing of the pipe gallery expansion joint are established respectively.

[0016] (5) Establish a prediction model for the maximum spacing of expansion joints in pipe corridors.

[0017] Based on the regression equations of each factor and the maximum setting spacing established in step (4), determine the expressions of all influencing factors and the maximum setting spacing of the pipe gallery expansion joint, and establish a prediction model for the maximum setting spacing of the pipe gallery expansion joint accordingly.

[0018] (6) Calculate the maximum spacing of expansion joints in the pipe gallery.

[0019] Based on the prediction model of the maximum setting spacing of the pipe gallery expansion joint established in step (5), the maximum setting spacing of the pipe gallery expansion joint is calculated.

[0020] Further preferably, in step (1), the selected external environmental influencing factors include: the elastic modulus Es of the soil and rock mass, the cohesion c of the soil and rock mass, and the internal friction angle of the soil and rock mass. The soil cover thickness H, the internal and external temperature difference T; and / or the selected structural design factors of the utility tunnel include: structural length L, structural length-to-height ratio r, structural thickness t, and structural elastic modulus Ec.

[0021] In a further preferred embodiment, in step (2), based on the existing geological survey report, regional meteorological data, and design data of the cast-in-place pipe gallery project, the upper and lower limits of the selected influencing factors are determined, and several levels are taken for each factor, with each level taking values ​​evenly within the upper and lower limits; based on the number of selected factors and the number of levels, an orthogonal experimental table is selected, and a multi-factor orthogonal experimental scheme is prepared.

[0022] In a further preferred embodiment, step (3) involves establishing thermo-mechanical coupling numerical calculation models based on the orthogonal experimental schemes determined in step (2), specifically including:

[0023] (a) Based on the elastic modulus Es, cohesion c, and internal friction angle of the soil and rock mass determined by each test in the orthogonal test scheme. A numerical calculation model was established based on parameters such as soil cover thickness H, internal and external temperature difference T, structural length L, structural length-to-height ratio r, structural thickness t, and structural elastic modulus Ec. The model length was taken as 7 times the length of the pipe gallery, the height as 4 times the height of the pipe gallery plus the soil cover thickness, and the width as the spacing S of the pipe gallery expansion joints.

[0024] (b) The model adopts displacement boundary conditions, with the bottom edge of the model being a fixed boundary, horizontal movement restricted around the model, and the surface of the stratum being a free boundary.

[0025] (c) The soil and rock mass is modeled using the Mohr-Coulomb constitutive model and assigned values. The model's gravitational acceleration and lateral pressure coefficient are set, and the initial stress field of the model is calculated.

[0026] (d) Clear the displacement and velocity fields of the model nodes, use the null command to excavate the soil inside the pipe gallery, the pipe gallery adopts an elastic constitutive model and is assigned values, the liner structural element is used to simulate the deformation joint, the deformation joint is set in the middle of the pipe gallery, and the interface element is used to simulate the sliding between the pipe gallery and the soil.

[0027] (e) Open the thermodynamic analysis module, adopt the isotropic heat conduction model and assign values, fix the temperature inside and outside the pipe gallery, and set the model to be surrounded by thermal insulation boundaries to perform thermodynamic coupling calculations.

[0028] In a further preferred embodiment, in step (3), the maximum longitudinal tensile stress of the pipe gallery under different expansion joint spacings S is calculated based on the bisection method, and the maximum expansion joint spacing S of the pipe gallery is determined using the standard value of the axial tensile strength of concrete as the threshold. max .

[0029] In a further preferred embodiment, in step (3), the maximum spacing S of the expansion joints in the pipe gallery is determined. max Specifically, it includes:

[0030] (a) In accordance with the Code for Design of Concrete Structures GB50010-2010, the standard value of the axial tensile strength of concrete is selected as the threshold value;

[0031] (b) Based on the bisection method, take the lower limit S of the expansion joint spacing S. l =1m and upper limit S u =200m;

[0032] (c) Take S = (S l +S u The maximum longitudinal tensile stress of the pipe gallery is obtained based on the thermo-coupling calculation results and compared with a threshold. If the maximum longitudinal tensile stress is less than the threshold, then S is taken. l =S; if the maximum longitudinal tensile stress is greater than the threshold, then take S.u =S;

[0033] (d) Repeat step (c) until S u -S l <1, at this time S l This refers to the maximum spacing S of the expansion joints in the pipe gallery under this test. max .

[0034] In a further preferred embodiment, the mean k is calculated in step (4) using the following formula:

[0035]

[0036] In the formula, k ij Y represents the mean of the experimental results for factor j at level i. ijk p1 represents the result of the kth trial of factor j at level i, and p1 represents the number of trials of factor j at level i.

[0037] To achieve the above objectives, the present invention provides a prediction system for the maximum spacing of expansion joints in pipe galleries, comprising:

[0038] The module for determining the influencing factors of the maximum spacing of expansion joints in utility tunnels is configured to determine the external environmental influencing factors based on the existing geological survey report and regional meteorological data of cast-in-place utility tunnel projects; and to determine the structural design influencing factors of utility tunnels based on the engineering design data of the utility tunnels.

[0039] The multi-factor orthogonal experimental design module is configured to determine the number and value of each influencing factor, select the orthogonal experimental table, and construct a multi-factor orthogonal experimental design.

[0040] The orthogonal test module for the maximum spacing of expansion joints in the utility tunnel is configured to design orthogonal test schemes based on the multi-factor orthogonal test scheme design module. It establishes thermo-mechanical coupling numerical calculation models and calculates the maximum longitudinal tensile stress in the utility tunnel under different expansion joint spacings S, thus determining the maximum spacing S of the expansion joints in the utility tunnel. max ;

[0041] The module for establishing regression equations between each factor and the maximum setting spacing is configured to calculate the mean value k of the maximum setting spacing of each factor at different levels based on the orthogonal test results of the maximum setting spacing of the pipe gallery expansion joint determined by the orthogonal test module for the maximum setting spacing of the pipe gallery expansion joint, and establish regression equations between each factor and the maximum setting spacing of the pipe gallery expansion joint respectively.

[0042] The module for establishing the prediction model of the maximum setting spacing of the pipe gallery expansion joint is configured to determine the expression of the maximum setting spacing of all influencing factors and the pipe gallery expansion joint based on the regression equation of each factor and the maximum setting spacing established by the module for establishing the regression equation of each factor and the maximum setting spacing, and establish the prediction model of the maximum setting spacing of the pipe gallery expansion joint accordingly.

[0043] The module for calculating the maximum spacing of expansion joints in utility tunnels is configured to calculate the maximum spacing of expansion joints in utility tunnels based on the prediction model for the maximum spacing of expansion joints in utility tunnels established by the module for establishing the prediction model for the maximum spacing of expansion joints in utility tunnels.

[0044] More preferably, the orthogonal test module for the maximum spacing of expansion joints in the utility tunnel calculates the maximum longitudinal tensile stress of the utility tunnel under different expansion joint spacings S using the bisection method, and determines the maximum spacing S of the expansion joints in the utility tunnel using the standard value of the axial tensile strength of concrete as the threshold. max .

[0045] In a further preferred embodiment, the module for establishing the prediction model of the maximum spacing of the expansion joints in the utility tunnel adopts a multiple linear regression analysis method, combined with the results of orthogonal experiments, to calculate the undetermined coefficients in the expression, thereby obtaining the prediction model of the maximum spacing of the expansion joints in the utility tunnel.

[0046] The maximum spacing prediction scheme for pipe gallery expansion joints provided by this invention has the following advantages over existing technologies:

[0047] 1. Based on existing geological survey reports, regional meteorological data, and pipe gallery engineering design data for cast-in-place pipe gallery projects, this invention determines the influencing factors of the maximum spacing of pipe gallery expansion joints. It can accurately reflect the influence of various factors in the prediction model, thereby improving the pertinence and universality of the prediction model.

[0048] 2. Based on the orthogonal experimental scheme, this invention establishes a thermo-coupling numerical calculation model and accurately determines the maximum spacing of the pipe gallery deformation joints under each test using the bisection method, thereby significantly improving the accuracy of the prediction model.

[0049] 3. Based on the regression equations of each factor and the maximum setting spacing, this invention establishes expressions for all influencing factors and the maximum setting spacing of the pipe gallery expansion joints, which effectively improves the reliability of the prediction model.

[0050] 4. This invention accurately predicts the maximum spacing of expansion joints in pipe corridors by establishing a prediction model, providing guidance for on-site construction and reducing the risk of water leakage in pipe corridors. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0052] Figure 1 The following is a flowchart illustrating the implementation of the method for predicting the maximum spacing of expansion joints in a pipe gallery, as an example of the present invention.

[0053] Figure 2 This is a schematic diagram of the thermo-coupling numerical calculation model formed in the example of the present invention;

[0054] Figure 3 The maximum longitudinal tensile stress cloud diagram of the pipe gallery was obtained by thermal coupling numerical calculation in the example of this invention;

[0055] Figure 4 This is a schematic diagram illustrating the deviation between the predicted and actual values ​​of the maximum spacing prediction model for pipe gallery expansion joints in an example of the present invention. Detailed Implementation

[0056] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0057] To address the challenges of predicting and optimizing the spacing of expansion joints in cast-in-place pipe gallery structures in practical engineering projects, this invention, based on the characteristics of expansion joints in cast-in-place pipe gallery structures in international engineering, provides a scheme for predicting the maximum spacing of expansion joints in pipe gallery structures. This scheme enables more accurate prediction of the maximum spacing of expansion joints and is of great significance for optimizing on-site construction procedures, reducing the risk of water seepage, and lowering costs.

[0058] The present invention provides a scheme for predicting the maximum spacing of expansion joints in utility tunnels. This scheme first determines the influencing factors of the maximum spacing of expansion joints in utility tunnels; then, it designs a multi-factor orthogonal experimental scheme; next, based on a thermo-coupled numerical calculation model and the bisection method, using the standard value of the axial tensile strength of concrete as the threshold, it conducts orthogonal experiments on the maximum spacing of expansion joints in utility tunnels; then, based on the least squares method, it establishes regression equations between each factor and the maximum spacing; next, it uses a multiple linear regression analysis method to determine the prediction model for the maximum spacing of expansion joints in utility tunnels; finally, it calculates the maximum spacing of expansion joints in utility tunnels.

[0059] In response to the above-mentioned scheme for predicting the maximum spacing of expansion joints in pipe corridors, this invention further constructs a system for predicting the maximum spacing of expansion joints in pipe corridors that can realize the scheme.

[0060] Specifically, the prediction system for the maximum spacing of expansion joints in this utility tunnel consists of several functional modules that work together to determine the influencing factors of the maximum spacing of expansion joints in the utility tunnel, design a multi-factor orthogonal test scheme, conduct orthogonal tests on the maximum spacing of expansion joints in the utility tunnel, establish regression equations for each factor and the maximum spacing, establish a prediction model for the maximum spacing of expansion joints in the utility tunnel, and calculate the maximum spacing of expansion joints in the utility tunnel.

[0061] Among them, the module for determining the influencing factors of the maximum spacing of expansion joints in pipe corridors is configured to determine the external environmental influencing factors based on the existing geological survey report of cast-in-place pipe corridor projects and regional meteorological data; and to determine the structural design influencing factors of pipe corridors based on the pipe corridor engineering design data.

[0062] The multi-factor orthogonal test scheme design module interacts with the module for determining the influencing factors of the maximum setting spacing of pipe gallery expansion joints, and is configured to determine the number and value of each influencing factor, select the orthogonal test table, and establish a multi-factor orthogonal test scheme.

[0063] The orthogonal test module for the maximum spacing of expansion joints in the utility tunnel interacts with the multi-factor orthogonal test scheme design module and is configured to establish a thermo-coupling numerical calculation model based on the orthogonal test scheme determined by the multi-factor orthogonal test scheme design module. The maximum longitudinal tensile stress of the utility tunnel under different expansion joint spacings S is calculated using the bisection method. The maximum spacing S of the expansion joints in the utility tunnel is determined using the standard value of the axial tensile strength of concrete as a threshold. max .

[0064] The module for establishing regression equations between each factor and the maximum setting spacing interacts with the orthogonal test module for the maximum setting spacing of pipe gallery expansion joints. It is configured to calculate the mean value k of the maximum setting spacing of each factor at different levels based on the orthogonal test results of the maximum setting spacing of pipe gallery expansion joints determined by the orthogonal test module for the maximum setting spacing of pipe gallery expansion joints. Based on the least squares method, regression equations between each factor and the maximum setting spacing of pipe gallery expansion joints are established respectively.

[0065] The module for establishing the prediction model of the maximum spacing of expansion joints in utility tunnels interacts with the module for establishing regression equations between various factors and the maximum spacing. It is configured to determine the expression of the maximum spacing of expansion joints in utility tunnels based on the regression equations between various factors and the maximum spacing established by the module for establishing regression equations between various factors and the maximum spacing. Using the multiple linear regression analysis method and combined with the results of orthogonal experiments, the undetermined coefficients in the expression are calculated to obtain the prediction model of the maximum spacing of expansion joints in utility tunnels.

[0066] The module for calculating the maximum spacing of expansion joints in the utility tunnel interacts with the module for establishing the prediction model of the maximum spacing of expansion joints in the utility tunnel, and is configured to calculate the maximum spacing of expansion joints in the utility tunnel based on the prediction model of the maximum spacing of expansion joints in the utility tunnel established by the module for establishing the prediction model of the maximum spacing of expansion joints in the utility tunnel.

[0067] The resulting prediction system for the maximum spacing of expansion joints in utility tunnels can accurately predict the maximum spacing of expansion joints in practical applications, while also being universally applicable.

[0068] The following specific application examples further illustrate the prediction scheme for the maximum setting spacing of pipe gallery expansion joints provided by the present invention.

[0069] See Figure 1 The diagram shown is a flowchart of the prediction scheme for the maximum setting spacing of pipe gallery expansion joints provided by the present invention in practical application.

[0070] Therefore, the implementation process of this prediction scheme for the maximum spacing of expansion joints in utility tunnels in utility tunnel engineering is as follows:

[0071] (1) Factors affecting the maximum spacing of expansion joints in pipe gallery

[0072] This step involves determining external environmental influencing factors based on existing geological survey reports and regional meteorological data for cast-in-place utility tunnel projects; and determining structural design influencing factors based on utility tunnel engineering design data.

[0073] The external environmental factors selected here include: the elastic modulus Es of the soil and rock mass, the cohesion c of the soil and rock mass, and the internal friction angle of the soil and rock mass. Cover thickness H, internal and external temperature difference T.

[0074] The selected factors influencing the design of the utility tunnel structure include: structural length L, structural length-to-height ratio r, structural thickness t, and structural elastic modulus Ec.

[0075] (2) Design a multi-factor orthogonal experimental scheme

[0076] In this step, the number and value of each influencing factor are determined, an orthogonal experimental table is selected, and a multi-factor orthogonal experimental design is developed.

[0077] Specifically, based on the existing geological survey report, regional meteorological data, and design data of the cast-in-place pipe gallery project, the upper and lower limits of the selected influencing factors are determined, and several levels are selected for each factor, with each level taking values ​​evenly within the upper and lower limits. Based on the number of selected factors and levels, an orthogonal experimental table is selected to construct a multi-factor orthogonal experimental scheme.

[0078] As an example, considering the actual range of values ​​for each factor, the level number is set to 4, and the level values ​​for each factor are shown in Table 1.

[0079] Table 1. Levels of each influencing factor

[0080]

[0081] Based on the selected 9 factors and 4 levels, an orthogonal experimental table was chosen, and a multi-factor orthogonal experimental scheme was developed, as shown in Table 2.

[0082] Table 2. Multi-factor orthogonal experimental scheme

[0083]

[0084]

[0085]

[0086] (3) Orthogonal test of the maximum spacing of expansion joints in the pipe gallery

[0087] In this step, based on the orthogonal test scheme determined in step (2), a thermo-coupling numerical calculation model is established. The maximum longitudinal tensile stress of the pipe gallery under different expansion joint spacings S is calculated using the bisection method. The maximum spacing S of the expansion joints in the pipe gallery is determined by using the standard value of the axial tensile strength of concrete as the threshold. max .

[0088] Specifically, this step is implemented through the following steps:

[0089] (a) Select each experiment in the orthogonal experimental scheme in sequence. First, based on the bisection method, take the lower limit S of the expansion joint spacing S. l =1m and upper limit S u =200m;

[0090] (b) Take S = (S l +S u );

[0091] (c) Based on the elastic modulus Es, cohesion c, and internal friction angle of the soil and rock determined in each test A numerical calculation model is established using parameters such as soil cover thickness H, internal and external temperature difference T, structural length L, structural length-to-height ratio r, structural thickness t, and structural elastic modulus Ec. Figure 2 As shown, the model length is 7 times the pipe gallery length, the height is 4 times the pipe gallery height plus the soil cover thickness, and the width is the spacing S of the pipe gallery expansion joints.

[0092] (d) The model adopts displacement boundary conditions. The bottom edge of the model is a fixed boundary, the horizontal movement of the model is restricted around the perimeter, and the surface of the stratum is a free boundary.

[0093] (e) The soil and rock mass is modeled using the Mohr-Coulomb constitutive model and assigned values. The model's gravitational acceleration and lateral pressure coefficient are set, and the initial stress field of the model is calculated.

[0094] (f) Clear the displacement and velocity fields of the model nodes, use the null command to excavate the soil inside the pipe gallery, the pipe gallery adopts an elastic constitutive model and is assigned values, the liner structural element is used to simulate the deformation joint, the deformation joint is set in the middle of the pipe gallery, and the interface element is used to simulate the sliding between the pipe gallery and the soil.

[0095] (g) Open the thermodynamic analysis module, adopt the isotropic heat conduction model and assign values, fix the temperature inside and outside the pipe gallery, and make thermal insulation boundaries around the model to perform thermodynamic coupling calculations.

[0096] (h) In accordance with the Code for Design of Concrete Structures GB50010-2010, the standard value of the axial tensile strength of concrete is selected as the threshold value;

[0097] (i) The maximum longitudinal tensile stress of the pipe gallery is obtained based on the thermo-coupling calculation results (e.g., Figure 3 (As shown) and compare it with the threshold. If the maximum longitudinal tensile stress is less than the threshold, then take S. l =S; if the maximum longitudinal tensile stress is greater than the threshold, then take S. u =S;

[0098] (j) Repeat step (b) until S u -S l <1, at this time S l This refers to the maximum spacing S of the expansion joints in the pipe gallery under this test. max .

[0099] In the above steps, the bisection method is simple, efficient, and can obtain approximately accurate results. Within a predefined interval, it can quickly and accurately find the maximum spacing S of the expansion joints in the pipe gallery under this test. max The thermo-coupling numerical calculation model established through the above steps, with reasonable model dimensions, boundary conditions, and calculation steps, considers the effects of thermo-coupling and sliding between the pipe gallery and the soil. This numerical calculation model better reflects the actual situation of the pipe gallery and can therefore accurately calculate the maximum longitudinal tensile stress, providing a basis for determining the maximum spacing S of the pipe gallery's expansion joints. max Lay the foundation.

[0100] Continuing with the previous example, based on the numerical calculation results of thermo-coupling, the orthogonal test results of the maximum spacing of the expansion joints in the pipe gallery are shown in Table 3.

[0101] Table 3 Results of the multi-factor orthogonal experiment

[0102]

[0103]

[0104] (4) Establish regression equations between each factor and the maximum setting interval.

[0105] Based on the orthogonal test results of the maximum setting spacing of the pipe gallery expansion joint in step (3), the mean value k of the maximum setting spacing of each factor at different levels is calculated; based on the least squares method, regression equations between each factor and the maximum setting spacing of the pipe gallery expansion joint are established respectively.

[0106] The mean k in this step is calculated using the following formula:

[0107]

[0108] In the formula, k ij Y represents the mean of the experimental results for factor j at level i. ijkp1 represents the result of the kth trial of factor j at level i, and p1 represents the number of trials of factor j at level i.

[0109] Continuing with the previous example, the mean k of the maximum setting interval results for each factor at different levels in this step is shown in Table 4.

[0110] Table 4. Calculation of the mean k of each factor at different levels.

[0111]

[0112] Based on the calculation results in Table 4, the least squares method was used to fit the relationship between each influencing factor and the maximum spacing of the expansion joint of the pipe gallery using exponential, linear, logarithmic, quadratic polynomial, and power functions. The function with the best fit was selected as the regression equation for each factor and the maximum spacing of the expansion joint of the pipe gallery, as shown in Table 5 below.

[0113] Table 5 Regression equations of various factors and the maximum spacing of pipe gallery expansion joints

[0114]

[0115]

[0116] (5) Establish a prediction model for the maximum spacing of expansion joints in pipe corridors.

[0117] Based on the regression equations of each factor and the maximum setting spacing established in step (4), the expressions of all influencing factors and the maximum setting spacing of the pipe gallery expansion joints are determined; using the multiple linear regression analysis method and combined with the orthogonal test calculation results, the undetermined coefficients in the expressions are calculated to obtain the prediction model of the maximum setting spacing of the pipe gallery expansion joints.

[0118] By establishing regression equations between each factor and the maximum setting spacing, as well as the correlation coefficients between them, it can be determined that there are good regression relationships between each influencing factor and the maximum setting spacing of the expansion joint, with high accuracy.

[0119] Therefore, in this step, when establishing the expression for all influencing factors and the maximum spacing of the pipe gallery expansion joints, S is set. max With Es, c 2 c H, T 2 ,T,L,r 2 ,r,e 1.2608t There is a linear relationship between ln(Ec) and Ec:

[0120]

[0121] In the formula, a i (i = 1 - 13) are undetermined coefficients.

[0122] Further analysis was conducted using SPSS statistical software and multiple linear regression analysis to determine the values ​​of each undetermined coefficient, ultimately yielding a prediction model for the maximum spacing of expansion joints in the utility tunnel.

[0123]

[0124] In the formula: S max The maximum spacing of the expansion joints in the pipe gallery is given in meters; Es is the elastic modulus of the soil and rock mass in MPa; c is the cohesion of the soil and rock mass in kPa. denoted as φ, where φ is the internal friction angle of the soil / rock, °; H is the overburden thickness, m; T is the internal / external temperature difference, ℃; L is the structural length, m; r is the structural length-to-height ratio; t is the structural thickness, m; and Ec is the structural elastic modulus, GPa.

[0125] Finally, based on the prediction model of the maximum setting spacing of the pipe gallery expansion joints established in step (5), the maximum setting spacing of the pipe gallery expansion joints is calculated.

[0126] See Figure 4 The figure shows the deviation between the predicted and actual values ​​of the prediction model for the maximum spacing of expansion joints in the pipe gallery established in step (5). As can be seen from the figure, the goodness of fit of this model is 0.975, indicating that the model has high prediction accuracy and is reliable.

[0127] The method, specific system unit, or part thereof of the present invention described above is a pure software architecture. It can be deployed via program code on physical media, such as hard disks, optical discs, or any electronic device (such as smartphones or computer-readable storage media). When a machine loads and executes the program code (e.g., a smartphone loads and executes it), the machine becomes an apparatus for implementing the present invention. The method and apparatus of the present invention can also be transmitted in program code form via transmission media, such as cables, optical fibers, or any transmission method. When the program code is received, loaded, and executed by a machine (e.g., a smartphone), the machine becomes an apparatus for implementing the present invention.

[0128] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for predicting the maximum spacing of expansion joints in pipe galleries, characterized in that, The steps include the following: (1) Factors affecting the maximum spacing of expansion joints in pipe gallery Determine the external environmental influencing factors based on external conditions; determine the influencing factors on the structural design of the utility tunnel based on internal conditions. The selected external environmental influencing factors include: the elastic modulus Es of the soil and rock mass, the cohesion c of the soil and rock mass, the internal friction angle φ of the soil and rock mass, the overburden thickness H, and the internal and external temperature difference T; and / or the selected structural design influencing factors of the pipe gallery include: the structural length L, the length-to-height ratio r of the structure, the structural thickness t, and the structural elastic modulus Ec. (2) Construct a multi-factor orthogonal experimental design Determine the number and value of each influencing factor, select an orthogonal experimental table, and construct a multi-factor orthogonal experimental scheme. (3) Orthogonal test of maximum spacing of expansion joints in pipe gallery Based on the orthogonal test scheme determined in step (2), a thermo-coupling numerical calculation model was established. The maximum longitudinal tensile stress of the pipe gallery under different expansion joint spacings S was calculated using the bisection method. The maximum spacing S of the expansion joints in the pipe gallery was determined using the standard value of the axial tensile strength of concrete as the threshold. max ; The establishment of the thermo-coupling numerical calculation model specifically includes: (a) Based on the elastic modulus Es, cohesion c, internal friction angle φ, overburden thickness H, internal and external temperature difference T, structural length L, structural length-to-height ratio r, structural thickness t and structural elastic modulus Ec determined by each test in the orthogonal test scheme, a numerical calculation model is established. The model length is taken as 7 times the pipe gallery length, the height is taken as 4 times the pipe gallery height plus the overburden thickness, and the width is taken as the spacing S of the pipe gallery deformation joints. (b) The model adopts displacement boundary conditions, with the bottom edge of the model being a fixed boundary, horizontal movement restricted around the model, and the surface of the stratum being a free boundary; (c) The soil and rock mass adopts the Mohr-Coulomb constitutive model and is assigned values. The model's gravitational acceleration and lateral pressure coefficient are set, and the initial stress field of the model is calculated. (d) Clear the displacement and velocity fields of the model nodes, use the null command to excavate the soil inside the pipe gallery, the pipe gallery adopts an elastic constitutive model and is assigned values, the liner structural element is used to simulate the deformation joint, the deformation joint is set in the middle of the pipe gallery, and the interface element is used to simulate the sliding between the pipe gallery and the soil. (e) Open the thermodynamic analysis module, adopt the isotropic heat conduction model and assign values, fix the temperature inside and outside the pipe gallery, and make the model surrounded by thermal insulation boundaries to perform thermodynamic coupling calculations; (4) Establish regression equations between each factor and the maximum setting interval. Based on the orthogonal test results of the maximum setting spacing of the pipe gallery expansion joint in step (3), calculate the mean value k of the maximum setting spacing of each factor at different levels, and establish the regression equations of each factor with the maximum setting spacing of the pipe gallery expansion joint respectively. (5) Establish a prediction model for the maximum spacing of expansion joints in pipe corridors. Based on the regression equations of each factor and the maximum setting spacing established in step (4), determine the expressions of all influencing factors and the maximum setting spacing of the pipe gallery expansion joint, and establish a prediction model for the maximum setting spacing of the pipe gallery expansion joint accordingly. (6) Calculate the maximum spacing of expansion joints in the pipe gallery. Based on the prediction model of the maximum setting spacing of the pipe gallery expansion joint established in step (5), the maximum setting spacing of the pipe gallery expansion joint is calculated.

2. The method for predicting the maximum spacing of expansion joints in pipe galleries according to claim 1, characterized in that, In step (2), based on the existing geological survey report, regional meteorological data and design data of the cast-in-place pipe gallery project, the upper and lower limits of the selected influencing factors are determined, and several levels are taken for each factor, with each level taking values ​​evenly within the upper and lower limits; based on the number of selected factors and the number of levels, an orthogonal experimental table is selected, and a multi-factor orthogonal experimental scheme is established.

3. The method for predicting the maximum spacing of expansion joints in pipe galleries according to claim 1, characterized in that, In step (3), the maximum spacing S of the expansion joints in the pipe gallery is determined. max Specifically, it includes: (a) According to the Code for Design of Concrete Structures GB50010-2010, the standard value of the axial tensile strength of concrete is selected as the threshold value; (b) Based on the dichotomy method, take the lower limit S of the expansion joint spacing S. l =1m and upper limit S u =200m; (c) Take S = (S l +S u The maximum longitudinal tensile stress of the pipe gallery is obtained based on the thermo-coupling calculation results and compared with a threshold. If the maximum longitudinal tensile stress is less than the threshold, then S is taken. l =S; if the maximum longitudinal tensile stress is greater than the threshold, then take S. u =S; (d) Repeat step (c) until S u -S l <1, at this time S l This refers to the maximum spacing S of the expansion joints in the pipe gallery under this test. max .

4. The method for predicting the maximum spacing of expansion joints in pipe galleries according to claim 1, characterized in that, In step (4), the mean k is calculated using the following formula: ； In the formula, This represents the mean of the experimental results for factor j at level i. This represents the result of the k-th trial of factor j at level i. This represents the number of trials for factor j at level i.

5. A prediction system for the maximum spacing of expansion joints in pipe galleries, characterized in that, include: The module for determining the influencing factors of the maximum spacing of expansion joints in pipe galleries is configured to determine the external environmental influencing factors based on the existing geological survey report and regional meteorological data of cast-in-place pipe galleries projects. Based on the design data of the utility tunnel project, determine the factors influencing the structural design of the utility tunnel; The external environmental influencing factors include: the elastic modulus Es of the soil and rock mass, the cohesion c of the soil and rock mass, the internal friction angle φ of the soil and rock mass, the overburden thickness H, and the internal and external temperature difference T; and / or the selected pipe gallery structure design influencing factors include: the structural length L, the structural length-to-height ratio r, the structural thickness t, and the structural elastic modulus Ec. The multi-factor orthogonal experimental design module is configured to determine the number and value of each influencing factor, select the orthogonal experimental table, and construct a multi-factor orthogonal experimental design. The orthogonal test module for the maximum spacing of expansion joints in utility tunnels is configured to design orthogonal test schemes based on the multi-factor orthogonal test scheme design module. It establishes thermo-coupling numerical calculation models and calculates the maximum longitudinal tensile stress in the utility tunnel under different expansion joint spacings S using the bisection method. The maximum spacing S of the expansion joints in the utility tunnel is then determined using the standard value of the axial tensile strength of concrete as the threshold. max ; Establishing a thermo-coupling numerical calculation model specifically includes: (a) Based on the elastic modulus Es, cohesion c, internal friction angle φ, overburden thickness H, internal and external temperature difference T, structural length L, structural length-to-height ratio r, structural thickness t and structural elastic modulus Ec determined by each test in the orthogonal test scheme, a numerical calculation model is established. The model length is taken as 7 times the pipe gallery length, the height is taken as 4 times the pipe gallery height plus the overburden thickness, and the width is taken as the spacing S of the pipe gallery deformation joints. (b) The model adopts displacement boundary conditions, with the bottom edge of the model being a fixed boundary, horizontal movement restricted around the model, and the surface of the stratum being a free boundary; (c) The soil and rock mass adopts the Mohr-Coulomb constitutive model and is assigned values. The model's gravitational acceleration and lateral pressure coefficient are set, and the initial stress field of the model is calculated. (d) Clear the displacement and velocity fields of the model nodes, use the null command to excavate the soil inside the pipe gallery, the pipe gallery adopts an elastic constitutive model and is assigned values, the liner structural element is used to simulate the deformation joint, the deformation joint is set in the middle of the pipe gallery, and the interface element is used to simulate the sliding between the pipe gallery and the soil. (e) Open the thermodynamic analysis module, adopt the isotropic heat conduction model and assign values, fix the temperature inside and outside the pipe gallery, and make the model surrounded by thermal insulation boundaries to perform thermodynamic coupling calculations; The module for establishing regression equations between each factor and the maximum setting spacing is configured to calculate the mean value k of the maximum setting spacing of each factor at different levels based on the orthogonal test results of the maximum setting spacing of the pipe gallery expansion joint determined by the orthogonal test module for the maximum setting spacing of the pipe gallery expansion joint, and establish regression equations between each factor and the maximum setting spacing of the pipe gallery expansion joint respectively. The module for establishing the prediction model of the maximum setting spacing of the pipe gallery expansion joint is configured to determine the expression of the maximum setting spacing of all influencing factors and the pipe gallery expansion joint based on the regression equation of each factor and the maximum setting spacing established by the module for establishing the regression equation of each factor and the maximum setting spacing, and establish the prediction model of the maximum setting spacing of the pipe gallery expansion joint accordingly. The module for calculating the maximum spacing of expansion joints in utility tunnels is configured to calculate the maximum spacing of expansion joints in utility tunnels based on the prediction model for the maximum spacing of expansion joints in utility tunnels established by the module for establishing the prediction model for the maximum spacing of expansion joints in utility tunnels.

6. The prediction system for the maximum spacing of expansion joints in pipe galleries according to claim 5, characterized in that, The module for establishing the prediction model of the maximum spacing of expansion joints in the utility tunnel adopts the multiple linear regression analysis method, combined with the orthogonal experimental calculation results, to calculate the undetermined coefficients in the expression and obtain the prediction model of the maximum spacing of expansion joints in the utility tunnel.

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