A test method and system for studying the synergistic effect of surrounding rock and concrete support

Abstract

The present application relates to the technical field of tunnel construction, and provides an experimental method and system for studying the synergistic effect of surrounding rock and concrete support. The method includes: making a physical test model of tunnel surrounding rock and shotcrete support to obtain measured data; according to the physical test model of tunnel surrounding rock and shotcrete support, establishing a corresponding finite element simulation model to obtain finite element simulation data; arranging cohesive units between the surrounding rock units and the concrete support units in the finite element simulation model, and constructing its cohesive constitutive model considering Coulomb friction, and the cohesive constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support; based on the measured data and the finite element simulation data, using the gradient optimization algorithm to iteratively determine the optimal parameters of the cohesive model; importing the optimal parameters of the cohesive constitutive model into the finite element simulation model, and conducting tunnel surrounding rock and shotcrete support synergistic bearing mechanism analysis based on the finite element simulation model.

Description

Technical Field

[0001] The present application relates to the technical field of tunnel construction, and in particular to an experimental method, system, computer-readable storage medium and electronic device for studying the synergistic effect of surrounding rock and concrete support. Background Art

[0002] With the continuous advancement of high-speed railway and highway construction in my country, a large number of tunnels need to pass through soft rock formations. Large deformation of soft rock is very harmful and poses a serious threat to tunnel construction safety and operation. Strengthening the support of key parts of surrounding rock is an important means to control large deformation of soft rock. Among them, spraying concrete on the surface of surrounding rock to form initial support, so that the tunnel surrounding rock and concrete layer form a whole to jointly bear the surrounding rock pressure, which can ensure the stability of tunnel surrounding rock. Therefore, it is of great significance to study the mechanism of coordinated bearing action of tunnel surrounding rock-concrete support.

[0003] At present, the method of multiple tests is usually used to study the cooperative bearing mechanism of tunnel surrounding rock and concrete support, including: physical tests and numerical simulation tests. Among them, when using physical tests, obtaining different test data usually requires multiple physical test models to be made, which undoubtedly requires a lot of manpower, material and financial resources, and it is not easy to obtain the monitoring data inside the model based on the physical test model, and the integrity and validity of the data are difficult to guarantee. The numerical simulation test can obtain simulation results by repeatedly performing simulation tests on the simulation model, and then study the mechanism of support cooperative bearing. However, the numerical simulation test requires the input of the mechanical parameters of the rock mass and the support. The existing technology for the mechanical parameters of the soft rock large deformation support structure, especially the contact characteristics between the rock mass and the concrete support, is not accurate and comprehensive enough, resulting in the reliability of the numerical test results cannot be guaranteed, and then the numerical simulation test has a certain deviation from the actual working conditions, affecting the normal development of the tunnel surrounding rock-shotcrete support synergy mechanism for soft rock formations.

[0004] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0005] The purpose of this application is to provide an experimental method, system, computer-readable storage medium and electronic device for studying the synergistic effect of surrounding rock and concrete support, so as to solve or alleviate the problems existing in the above-mentioned prior art.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] The present application provides a test method for studying the synergistic effect of surrounding rock and concrete support, including:

[0008] Make a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data;

[0009] According to the physical test model of the tunnel surrounding rock-shotcrete support, a corresponding finite element simulation model is established to obtain finite element simulation data;

[0010] A cohesive force unit is arranged between the surrounding rock unit and the concrete support unit in the finite element simulation model, and a cohesive force constitutive model considering Coulomb friction is constructed, wherein the cohesive force constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support;

[0011] For the cohesive force constitutive model, based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model;

[0012] The optimal parameters of the cohesive force constitutive model are imported into the finite element simulation model, and the tunnel surrounding rock-shotcrete support collaborative bearing mechanism analysis is carried out based on the finite element simulation model.

[0013] Preferably, the physical test model is manufactured using a horizontal loading device according to similar basic principles of similar simulation experiments.

[0014] Preferably, the physical test model of tunnel surrounding rock-shotcrete support is made to obtain measured data, specifically:

[0015] According to the set load conditions, the load is applied to the physical test model in steps until the support structure is destroyed, and the physical test is ended; in this process, the deformation of the rock mass and concrete support in the physical test model is measured throughout the process mainly by digital image correlation technology and supplemented by single-point strain monitoring to obtain measured data.

[0016] Preferably, the digital image correlation technology includes at least one binocular camera, which is fixedly arranged inside the physical test model and facing the part to be tested;

[0017] Through an industrial computer, multiple slave computers are uniformly controlled to achieve synchronous measurement of digital image monitoring and single-point strain monitoring.

[0018] Preferably, the method further comprises: after the physical test is completed, screening the measured data to obtain representative measured data.

[0019] Preferably, the cohesive force constitutive model is as follows:

[0020]

[0021]

[0022] In the formula, σ n and σ τare the normal cohesion and the tangential cohesion, and are the normal cohesive strength and the tangential cohesive strength, δ represents the opening displacement, δ 0 is the final cracking failure displacement, k, δ 1 , δ 2 are the adjustment parameters of the cohesion model, τ f is the Coulomb friction force, τ f =μ|σ n |,σ n <0, μ is the friction coefficient.

[0023] Preferably, the finite element simulation data is obtained for the cohesive force constitutive model, and based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model, specifically:

[0024] Establishing an optimization objective function by using the mean square error of the measured data and the finite element simulation data;

[0025] After the initial parameters of the cohesive force constitutive model are given, the parameters of the cohesive force constitutive model of the current iteration step are iteratively calculated using a gradient optimization algorithm;

[0026] Based on the optimization objective function, it is determined whether the parameters of the cohesive force constitutive model at the current iteration step meet the convergence condition. If so, the parameters are used as the optimal parameters of the cohesive force constitutive model.

[0027] The present application embodiment provides a test system for studying the synergistic effect of surrounding rock and concrete support, including:

[0028] A measurement module configured to make a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data;

[0029] A finite element simulation module is configured to establish a corresponding finite element simulation model according to the physical test model of the tunnel surrounding rock-shotcrete support to obtain finite element simulation data;

[0030] A cohesive force model construction module is configured to arrange a cohesive force unit between a surrounding rock unit and a concrete support unit in a finite element simulation model, and construct a cohesive force constitutive model thereof considering Coulomb friction, wherein the cohesive force constitutive model is used to characterize contact characteristics between the surrounding rock and the concrete support;

[0031] A parameter optimization module is configured to iteratively determine the optimal parameters of the cohesive force model using a gradient optimization algorithm based on the measured data and the finite element simulation data for the cohesive force constitutive model;

[0032] The analysis module is configured to import the optimal parameters of the cohesive force constitutive model into the finite element simulation model, and carry out tunnel surrounding rock-shotcrete support collaborative bearing mechanism analysis based on the finite element simulation model.

[0033] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method described in any of the above embodiments is implemented.

[0034] An embodiment of the present application further provides an electronic device, comprising: a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor implements the method described in any of the above embodiments when executing the program.

[0035] The technical solution of this application has the following beneficial effects:

[0036] The present application provides an experimental method for studying the synergistic effect of surrounding rock and concrete support. The method comprises the following steps: making a physical test model of tunnel surrounding rock and shotcrete support to obtain measured data; establishing a corresponding finite element simulation model to obtain finite element simulation data; arranging a cohesive force unit between the surrounding rock unit and the concrete support unit in the finite element simulation model to construct a cohesive force constitutive model (hereinafter referred to as the cohesive force model) that takes into account Coulomb friction. The cohesive force constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support; for the cohesive force constitutive model, based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model; importing the optimal parameters of the cohesive force constitutive model into the finite element simulation model, and conducting an analysis of the synergistic bearing mechanism of tunnel surrounding rock and shotcrete support based on the finite element simulation model. The above technical solution ensures the accuracy and comprehensiveness of the contact characteristics research between rock mass and concrete support by constructing a cohesive force constitutive model that takes Coulomb friction into consideration. It iteratively optimizes the parameters of the cohesive force constitutive model through effective and complete measured data and finite element simulation data, reducing the numerical calculation error caused by inaccurate parameter settings. In addition, the proposed cohesive force constitutive model can change the cohesive force and opening displacement curve by adjusting the parameters, making it easier to find parameters close to the actual working conditions during optimization, improving the accuracy and precision of the numerical simulation test, and thus ensuring the normal development of the research on the synergistic mechanism of tunnel surrounding rock and shotcrete support for soft rock formations. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. Among them:

[0038] Figure 1A schematic diagram of the cohesive force constitutive model parameter optimization process provided according to some embodiments of the present application.

[0039] Figure 2 A schematic structural diagram of a physical test model provided according to some embodiments of the present application.

[0040] Figure 3 A block diagram of the composition of a data acquisition control system provided according to some embodiments of the present application.

[0041] Figure 4 A schematic diagram of a normal cohesion model provided according to some embodiments of the present application;

[0042] Figure 5 A schematic diagram of a tangential cohesion model provided according to some embodiments of the present application.

[0043] Figure 6 A schematic flow chart of an experimental method for studying the synergistic effect of surrounding rock and concrete support provided according to some embodiments of the present application.

[0044] Figure 7 A schematic diagram of the structure of an experimental system for studying the synergistic effect of surrounding rock and concrete support provided according to some embodiments of the present application.

[0045] Description of reference numerals:

[0046] 1-loading device, 2-front pressure plate, 3-rear pressure plate, 4-left pressure plate, 5-right pressure plate, 6-bearing box bottom plate, 7-rock model, 8-shotcrete support model, 9-speckle, 10-binocular camera, 11-auxiliary light source, 12-camera bracket. DETAILED DESCRIPTION

[0047] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as a part of an embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desired that the present application includes such modifications and variations within the scope of the appended claims and their equivalents.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0049] Embodiment 1:

[0050] The synergistic bearing effect of tunnel surrounding rock and concrete support refers to the interaction and mutual influence between the surrounding rock and the shotcrete support structure during the construction or operation of the tunnel. As an initial support structure for a tunnel, one of its main functions is to provide the support and stability required during the construction and operation of the tunnel. When the shotcrete construction is completed, it can bear part of the external load and reduce the deformation and displacement of the surrounding rock. During the construction process, the deformation of the surrounding rock may affect the shotcrete support structure. Through the setting and design of the support structure, the deformation of the surrounding rock can be controlled and reduced, thereby protecting the integrity of the support structure. At the same time, shotcrete can also reinforce the surrounding rock, especially during the construction process to reinforce the surrounding rock to reduce the risk of collapse. The deformation between the surrounding rock and the shotcrete support will affect each other. The deformation of the surrounding rock may cause changes in the stress distribution of the support structure, and the deformation of the support structure may also affect the stability of the surrounding rock.

[0051] The key to studying the mechanism of tunnel surrounding rock-concrete support synergistic bearing is to clarify the contact between the surrounding rock and the support. In order to solve the problem that the existing numerical test method cannot accurately characterize the contact characteristics of the surrounding rock-concrete support, the embodiment of the present application provides a test method for studying the synergistic effect of the surrounding rock-concrete support, such as Figure 1 to Figure 6 As shown, the method includes:

[0052] Step S101: making a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data.

[0053] The test method provided in this embodiment mainly consists of a similar model physical test and a finite element numerical simulation test. Among them, the physical test model can be determined according to the original rock parameters and geometric information of the rock layer where the tunnel is located. The material and geometry of the physical test model are determined, and a horizontal loading device with simple loading and easy production of large-scale models is used to produce a tunnel surrounding rock-sprayed concrete support physical model based on the similar basic principle of similar model experiments. The horizontal loading device is a device for applying horizontal loads or stresses to a sample or structure, which can be applied to samples or structures of different sizes, shapes and materials, and can simulate a real engineering environment. Based on the similar basic principle of similar model experiments, the prototype system (such as a tunnel) is scaled, scaled or geometrically similar in the experimental test model to simulate the behavior and performance of the prototype system in a real environment, so as to ensure that the produced model fits the geometry and size of the actual tunnel and can fully represent the surrounding rock conditions of the tunnel project.

[0054] Figure 2 This is a schematic diagram of the structure of a physical test model provided according to some embodiments of the present application. Figure 2As shown, the horizontal loading device includes a bearing box and a loading device 1. The loading device 1 is used to apply a load to the rock model 7 through the bearing box. The bearing box is surrounded by a front pressure plate 2, a rear pressure plate 3, a left pressure plate 4, a right pressure plate 5 and a bearing box bottom plate 6. The bearing box has a space for placing the rock model 7. The upper side of the bearing box has an upper opening, which can be circular or elliptical, or other shapes. The loading device 1 is arranged outside the pressure plates 2, 3, 4, and 5. During the test, the loading device 1 applies a load to the rock model 7 through the pressure plate, and the stress condition of the rock model 7 can be observed in real time through the upper opening.

[0055] The rock model 7 can also be called a surrounding rock tunnel model. A shotcrete support system is constructed in the tunnel of the rock model 7, which is also called a shotcrete support model 8. After the rock model 7 is manufactured, the part to be tested on the inner wall of the tunnel is smoothed with fine sandpaper, sprayed with a layer of white matte primer, and then sprayed with black paint after drying to form uniform speckle 9. The speckle 9 is used for optical imaging simulation, so that the image of the rock model 7 collected during the test can more realistically show the light spots or spots that may appear in the actual imaging, thereby improving the authenticity of image acquisition and analysis.

[0056] In some embodiments, a physical test model of tunnel surrounding rock-shotcrete support is made to obtain measured data, which can be specifically achieved through the following steps: according to the set load conditions, the load is applied to the physical test model in steps until the support structure is destroyed, and the physical test is ended; in this process, the deformation of the rock mass and concrete support in the physical test model is measured throughout the process using digital image correlation technology (DIC) as the main method and single-point strain monitoring as the auxiliary method to obtain measured data.

[0057] Among them, the load condition can be set through a pre-established test plan. During the test, the load can be gradually applied according to the test plan until the support structure is destroyed. Each step of increasing the load can be maintained for a period of time to observe the response of the rock model 7. The load history of the rock model 7 in actual use can be simulated by gradually increasing the load to be closer to the actual working condition.

[0058] During the test, the deformation of the rock mass and concrete support in the physical test model was measured using DIC technology as the main method and single-point strain monitoring as the auxiliary method to obtain measured data. The measured data may include: "load-time" data extracted from the loading device 1, "stress-time" data of the rock model 7 collected by the stress monitor, "strain-time" data of each monitoring point collected by the strain gauge, and images collected synchronously by DIC.

[0059] It should be noted that DIC technology is a non-contact optical measurement technology used to measure the deformation and movement of the surface of an object. It obtains high-precision digital images of the surface of the rock model 7 and imports them into the DIC analysis software for processing and analysis, thereby obtaining the full displacement field and strain field of the surface of the rock model 7. Since DIC technology can obtain more comprehensive deformation data in a larger area, supplemented by data collection methods for single-point stress / strain monitoring, it is easy to screen a sufficient number of representative measured data, thereby providing strong data support for finite element simulation numerical experiments.

[0060] In some embodiments, the digital image correlation technology includes at least one binocular camera 10, which is composed of two cameras, observing and capturing the same scene or object from different angles. In the experiment, the binocular camera 10 can be set to capture one picture every 1 second, and the picture name is marked with a time.

[0061] In addition, multiple binocular cameras 10 can be set according to working conditions and test conditions so as to observe the stress conditions of the rock model 7 from more angles.

[0062] In this embodiment, the binocular camera 10 is fixed inside the physical test model, for example, it can be fixed on the camera bracket 12 and facing the part to be tested. The camera bracket 12 can be flexibly set up according to the test site and the size of the test model to ensure that the bracket does not vibrate during the loading process.

[0063] In some optional schemes, the digital image correlation technology may further include an auxiliary light source 11, which is also mounted on the camera bracket 12, and is used to provide a uniform and stable light source to improve image quality, enhance recognition and tracking of surface features of objects, and improve experimental conditions.

[0064] In the experiment, it is only necessary to adjust the camera lens and the auxiliary light source 11 to obtain a clear speckle 9 image of the part to be tested.

[0065] In order to unify the time scale, the real-time load, the stress data collected by the stress monitor, the strain data collected by the resistance strain gauge and the deformation image taken by the binocular camera 10 should correspond one to one on the time scale. In this embodiment, the physical test also includes a data acquisition control system, which controls multiple slave computers uniformly through an industrial computer, and then the multiple slave computers control specific instruments to achieve synchronous measurement of digital image monitoring and single-point strain monitoring.

[0066] Specifically, Figure 3 FIG. 1 is a block diagram of a data acquisition control system according to some embodiments of the present application. Figure 3As shown, in order to ensure that the collected test data is effective and complete, and to ensure the consistency of load, stress and deformation data on a time scale, the data acquisition control system includes an industrial computer and multiple slave computers (e.g., slave computer 1, slave computer 2, slave computer 3, and slave computer 4). The industrial computer is also called a master industrial computer, or an upper computer. The upper computer uniformly controls multiple slave computers, and each slave computer specifically controls different components of the model. For example, the lower computer 1 can control the loading device 1 to apply different loads to the support structure to simulate different working conditions, the lower computer 2 can control the stress monitor to collect stress data, the lower computer 3 can control the resistance strain gauge to collect strain data, and the lower computer 4 can control the binocular camera 10 to collect digital images.

[0067] It is also necessary to understand that in order to obtain more comprehensive data, multiple stress monitors, resistance strain gauges or binocular cameras 10 can be provided. Multiple stress monitors, resistance strain gauges or binocular cameras 10 can be controlled by the same lower computer or by different lower computers, which is not limited in this application.

[0068] The resistance strain gauge is used to collect strain data at the monitoring point, wherein the monitoring point can be a key position of strain change or an area of ​​interest, and the number of the monitoring point is usually multiple. In practice, multiple monitoring points can be selected in the rock model 7 as needed, and strain gauges can be attached to connect with the resistance strain gauge.

[0069] In this embodiment, a main control industrial computer (host computer) is used to uniformly control multiple slave computers and then control the start and stop of the loading device, strain monitor and image acquisition device, so as to ensure that the collected real-time load, stress and deformation data correspond one to one on the time scale, which is conducive to the quantitative analysis of the subsequent test results.

[0070] In some embodiments, the method further includes: after the physical test is completed, the measured data is screened to obtain representative measured data. Specifically, after the physical test is completed, the real-time load of the loading device 1, the stress data collected by the stress monitor, the strain data collected by the resistance strain gauge, and the deformation picture taken by the binocular camera 10 can be extracted to screen representative measured data. The screening method can adopt data quality assessment method, statistical analysis method, expert analysis method, etc., and this application does not limit the screening method of measured data.

[0071] Step S102: establishing a corresponding finite element simulation model based on the physical test model of tunnel surrounding rock-shotcrete support to obtain finite element simulation data.

[0072] It should be noted that finite element simulation is an engineering analysis method used to simulate and predict the behavior of complex tunnel engineering under different load conditions. The finite element simulation model is based on the finite element method, which decomposes the actual structure into a finite number of units and performs numerical calculations on these units to simulate the overall behavior. The actual tunnel engineering structure is discretized into a finite number of units, such as quadrilaterals, hexagons, triangles, and nodes between them. The combination of these units and nodes constitutes a discretized finite element mesh. By establishing mathematical equations on each unit to describe the relationship between parameters such as stress and deformation of each unit, and then determining the boundary conditions of the finite element simulation model to simulate the external effects and constraints under actual working conditions, finally mathematical methods are used to solve (usually using computer software for solution and analysis) large linear or nonlinear equations to obtain the structural response under different loads, that is, to obtain finite element simulation data.

[0073] Step S103: arrange a cohesive force unit between the surrounding rock unit and the concrete support unit in the finite element simulation model, and construct a cohesive force constitutive model that takes Coulomb friction into consideration. The cohesive force constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support.

[0074] In this embodiment, in order to study the contact characteristics between the surrounding rock unit and the concrete support unit, a cohesive force unit is arranged between the surrounding rock unit and the concrete support unit in the finite element simulation model. The stress-deformation curve (that is, the constitutive model) of the cohesive force unit is the cohesive force constitutive model, and the cohesive force constitutive model reflects the contact characteristics between the surrounding rock and the concrete support.

[0075] Furthermore, in order to reflect the contact characteristics between the surrounding rock and the concrete support in actual working conditions and accurately describe the bonding force and friction between the two, this embodiment provides an expression of the cohesive force constitutive model, which is as follows:

[0076]

[0077]

[0078] In the formula, σ n and σ τ are the normal cohesion and the tangential cohesion, and are the normal cohesive strength and the tangential cohesive strength, δ represents the opening displacement, δ 0 is the final cracking failure displacement, k, δ 1 , δ 2 are the adjustment parameters of the cohesion model, τ f is the Coulomb friction force, τ f =μ|σ n |,σn <0, μ is the friction coefficient.

[0079] The above formula (1) and formula (2) are the normal cohesion model and the tangential cohesion model respectively, and their corresponding curves are as follows: Figure 4 , Figure 5 shown.

[0080] The cohesive constitutive model provided in this application takes into account the influence of Coulomb friction, and the interlayer anti-slip ability is provided by friction and adhesion, which more accurately characterizes the contact characteristics of the rock-shotcrete interface during the damage and destruction process.

[0081] It should be pointed out that the prior art also provides some cohesion constitutive models, such as bilinear, trapezoidal, exponential, etc. These cohesion constitutive models have their own advantages and disadvantages. For example, some structures are more accurately described by bilinear cohesion models, and some structures are more suitable for expression by trapezoidal cohesion models. In addition, the existing models usually do not consider the influence of friction. The present embodiment not only considers the influence of Coulomb friction, but also sets the adjustment parameters k, δ in the cohesion constitutive model. 1 , δ 2 , through k, δ 1 , δ 2 To change the cohesion and opening displacement curves, it is easier to find parameters close to the actual working conditions during optimization.

[0082] Specifically, the value of k can be 0 or 1. For the normal cohesion model, when k = 0, the cohesion constitutive model can be transformed into a trapezoidal cohesion model; when k = 0, δ 1 =δ 2 When , the cohesive force constitutive model can also be transformed into a bilinear cohesive force model, such as Figure 4 As shown in (a) in .

[0083] For the tangential cohesion model, Figure 5 As shown, when the opening displacement δ reaches a certain shear separation degree δ 2 , the interface undergoes initial debonding. If the interface is squeezed, friction will be generated. The friction increases with the increase of shear slip until the interface is completely separated and destroyed. At this time, only Coulomb friction τ f =μ|σ n |,σ n <0, μ is the friction coefficient.

[0084] In summary, this example proposes a new cohesive constitutive model that takes Coulomb friction into account. The interlayer anti-slip capacity is provided by friction and adhesion, which more accurately characterizes the contact characteristics of the rock mass-shotcrete interface during the damage and failure process. This cohesive constitutive model can be modified by changing the parameter δ 1 , δ2 and k provide a variety of traction-separation relationships, such as bilinear, trapezoidal and trapezoidal curves, so as to obtain a cohesion model closer to the actual situation during parameter inversion.

[0085] Step S104: for the cohesive force constitutive model, based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model.

[0086] In some embodiments, finite element simulation data is obtained for the cohesive force constitutive model, and based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model. This can be specifically achieved through the following steps: using the mean square error of the measured data and the finite element simulation data to establish an optimization objective function; after the initial parameters of the cohesive force constitutive model are given, a gradient optimization algorithm is used to iteratively calculate the parameters of the cohesive force constitutive model of the current iteration step; based on the optimization objective function, it is determined whether the parameters of the cohesive force constitutive model of the current iteration step meet the convergence conditions, and if so, they are used as the optimal parameters of the cohesive force constitutive model.

[0087] Specifically, the parameters required to input the cohesive force constitutive model are δ 0 , k, δ 1 , δ 2 and μ, and determining these cohesive force model parameters is the key to ensuring the reliability of numerical test results.

[0088] Assume X is the parameter vector of the cohesive constitutive model The optimization objective function is established by using the mean square error of the finite element numerical simulation data and the measured data of the physical test:

[0089]

[0090] Where S(X) is the mean square error, N is the number of samples, is the deformation simulation value of the nth sampling point, is the measured deformation value of the nth sampling point.

[0091] The gradient optimization algorithm is used to iteratively calculate X. The principle is as follows:

[0092] X i+1 =X i -λ i ω i (4)

[0093] Where i is the iteration step, ω i is the descending direction, λ i is the search step size.

[0094] ω iIt can be determined according to the following formula:

[0095]

[0096] λ i It can be determined according to the following formula:

[0097]

[0098] According to the principle of the above gradient optimization algorithm, numerical experiments are carried out, and the initial parameters X of the cohesive force constitutive model are given. 0 , start the Abaqus software to calculate the simulation model and obtain Start iteration to update the cohesive force constitutive model parameters. The iteration process is as follows: Calculate the cohesive force constitutive model parameters as X i ω i and λ i , and then obtain X i+1 Update the cohesive force constitutive model parameters to X i+1 , start the Abaqus software to calculate the simulation model and obtain According to the convergence criterion S(X i+1 )<ε (ε is the preset error threshold) to determine whether it converges. If it converges, the calculation is stopped and the current parameters are used as the optimal parameters of the cohesive force constitutive model. Otherwise, the parameters of the cohesive force constitutive model are recalculated as X i ω i and λ i And enter the next iteration process.

[0099] The above-mentioned cohesive force constitutive model parameter optimization process is carried out based on the measured data provided by the physical test. The optimal parameters of the cohesive force constitutive model are determined by the gradient optimization algorithm + finite element analysis inversion, which reduces the error caused by inaccurate parameter setting of the cohesive force constitutive model and improves the calculation accuracy of the numerical experiment.

[0100] Step S105: import the optimal parameters of the cohesive force constitutive model into the finite element simulation model, and carry out tunnel surrounding rock-shotcrete support collaborative bearing mechanism analysis based on the finite element simulation model.

[0101] In summary, the test method for studying the synergistic effect of surrounding rock and concrete support provided in this application, the test system is mainly composed of similar model physical test and finite element numerical simulation test. The physical test adopts a data acquisition method based on digital image correlation technology (DIC) and supplemented by single-point stress / strain monitoring to obtain a larger area and more comprehensive deformation data. According to the physical test model, a corresponding finite element simulation model is established for numerical testing. A new cohesive force model considering Coulomb friction, that is, the cohesive force constitutive model, is proposed to more accurately characterize the contact characteristics between the surrounding rock and concrete support. Taking the minimization of the mean square error of the measured data and the simulation data as the optimization goal, the cohesive force model parameters are determined by the gradient optimization algorithm, which reduces the numerical calculation error caused by inaccurate parameter setting.

[0102] As an example, according to the test method provided in this application, the test process can be implemented according to the following steps:

[0103] (1) According to the original rock parameters of the rock stratum where the tunnel is located, a similar test model of tunnel surrounding rock-shotcrete support is made.

[0104] (2) After the model is made, the part to be tested is smoothed with fine-grit sandpaper, sprayed with a layer of white matte primer, and then sprayed with black paint after drying to form uniform speckles 9.

[0105] (3) The camera bracket 12 is flexibly set up according to the test site and the size of the test model to ensure that the bracket does not vibrate during the loading process. A binocular camera 10 and an auxiliary light source 11 are installed on the bracket, and the lens and light source are adjusted to obtain a clear speckle 9 image of the part to be tested.

[0106] (4) Select multiple monitoring points as needed, stick strain gauges, and connect them to the resistance strain gauge.

[0107] (5) Apply load to the load-bearing model box according to the set load condition. The industrial computer controls each lower computer to turn on the camera and the resistance strain gauge at the same time. The camera is set to capture one picture every 1 second, and the picture name is marked with the time.

[0108] (6) The load is applied step by step until the supporting structure is destroyed and the physical test is completed.

[0109] (7) Extract the data measured by loading device 1, resistance strain gauge and DIC, and screen representative measured data.

[0110] (8) A finite element simulation model is established based on the actual test model of the surrounding rock tunnel comprehensive support.

[0111] (9) The cohesive constitutive model of the surrounding rock-concrete support interface is constructed, and the parameters of the cohesive constitutive model are iteratively calculated using the gradient optimization algorithm to obtain the optimal parameters of the cohesive model.

[0112] (10) The optimal parameters of the cohesive force model are imported into the finite element simulation model, and the finite element analysis of the tunnel surrounding rock-shotcrete support collaborative bearing process is carried out.

[0113] Embodiment 2:

[0114] The present application embodiment provides a test system for studying the synergistic effect of surrounding rock and concrete support. Figure 7 As shown, the system includes: a measurement module 701, a finite element simulation module 702, a cohesion model construction module 703, a parameter optimization module 704 and an analysis module 705. Among them:

[0115] The measurement module 701 is configured to make a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data.

[0116] The finite element simulation module 702 is configured to establish a corresponding finite element simulation model according to the physical test model of the tunnel surrounding rock-shotcrete support to obtain finite element simulation data.

[0117] The cohesive force model construction module 703 is configured to arrange the cohesive force unit between the surrounding rock unit and the concrete support unit in the finite element simulation model, and construct its cohesive force constitutive model considering Coulomb friction. The cohesive force constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support.

[0118] The parameter optimization module 704 is configured to iteratively determine the optimal parameters of the cohesive force model using a gradient optimization algorithm based on the measured data and the finite element simulation data.

[0119] The analysis module 705 is configured to import the optimal parameters of the cohesive force constitutive model into the finite element simulation model, and perform tunnel surrounding rock-shotcrete support collaborative bearing mechanism analysis based on the finite element simulation model.

[0120] An experimental system for studying the synergistic effect of surrounding rock and concrete support provided in an embodiment of the present application can implement the steps and processes of the experimental method for studying the synergistic effect of surrounding rock and concrete support provided in any of the above embodiments, and achieve the same technical effects, which will not be repeated here one by one.

[0121] Embodiment 3:

[0122] An embodiment of the present application provides an electronic device, the electronic device comprising:

[0123] one or more processors;

[0124] The computer-readable storage medium may be configured to store one or more programs, and when one or more processors execute the one or more programs, the following steps are implemented:

[0125] A physical test model of tunnel surrounding rock-shotcrete support is made to obtain measured data. According to the physical test model of tunnel surrounding rock-shotcrete support, a corresponding finite element simulation model is established to obtain finite element simulation data. Cohesive force units are arranged between the surrounding rock units and the concrete support units in the finite element simulation model to construct a cohesive force constitutive model considering Coulomb friction, which is used to characterize the contact characteristics between the surrounding rock and the concrete support. For the cohesive force constitutive model, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model based on the measured data and finite element simulation data. The optimal parameters of the cohesive force constitutive model are imported into the finite element simulation model, and the collaborative bearing mechanism analysis of tunnel surrounding rock-shotcrete support is carried out based on the finite element simulation model.

[0126] The hardware structure of the electronic device may include: a processor, a communication interface, a computer-readable storage medium (also referred to as a memory), and a communication bus.

[0127] The processor, the communication interface, and the computer-readable storage medium communicate with each other via a communication bus.

[0128] A computer-readable storage medium may be configured to store one or more programs.

[0129] Optionally, the communication interface may be an interface of a communication module, such as an interface of a GSM module.

[0130] Among them, the processor executes one or more programs, which implement the following steps: making a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data; establishing a corresponding finite element simulation model based on the physical test model of tunnel surrounding rock-shotcrete support to obtain finite element simulation data; arranging cohesive force units between the surrounding rock units and the concrete support units in the finite element simulation model, and constructing its cohesive force constitutive model considering Coulomb friction, and the cohesive force constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support; for the cohesive force constitutive model, based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force model; importing the optimal parameters of the cohesive force constitutive model into the finite element simulation model, and conducting a collaborative bearing mechanism analysis of the tunnel surrounding rock-shotcrete support based on the finite element simulation model.

[0131] The processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc. It may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0132] The electronic device of the embodiment of the present application exists in various forms, including but not limited to:

[0133] (1) Mobile communication devices: These devices are characterized by their mobile communication functions and their main purpose is to provide voice and data communications. These terminals include: smart phones (e.g., iPhone), multimedia phones, functional phones, and low-end phones.

[0134] (2) Ultra-mobile personal computer devices: These devices fall into the category of personal computers, have computing and processing capabilities, and generally also have mobile Internet access features. These terminals include: PDA, MID and UMPC devices, such as iPad.

[0135] (3) Portable entertainment devices: These devices can display and play multimedia content. They include audio and video players (such as iPods), handheld game consoles, e-books, smart toys, and portable car navigation devices.

[0136] (4) Server: A device that provides computing services. The server consists of a processor, hard disk, memory, system bus, etc. The server is similar to a general computer architecture, but because it needs to provide highly reliable services, it has higher requirements in terms of processing power, stability, reliability, security, scalability, and manageability.

[0137] (5) Other electronic devices with data interaction functions.

[0138] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0139] The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or implemented as computer code originally stored in a remote recording medium or a non-temporary machine storage medium downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor or programmable or dedicated hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the experimental method for studying the synergy of surrounding rock-concrete support described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0140] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and constraints involved in the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0141] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0142] The device and system embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components described as units may or may not be physical units, i.e., they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative work.

[0143] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A test method for studying the synergistic effect of surrounding rock and concrete support, characterized in that: include: Make a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data; According to the physical test model of the tunnel surrounding rock-shotcrete support, a corresponding finite element simulation model is established to obtain finite element simulation data; A cohesive force unit is arranged between the surrounding rock unit and the concrete support unit in the finite element simulation model, and a cohesive force constitutive model considering Coulomb friction is constructed, wherein the cohesive force constitutive model is used to characterize the contact characteristics between the surrounding rock and the concrete support; For the cohesive force constitutive model, based on the measured data and the finite element simulation data, a gradient optimization algorithm is used to iteratively determine the optimal parameters of the cohesive force constitutive model; The optimal parameters of the cohesive force constitutive model are imported into the finite element simulation model, and the tunnel surrounding rock-shotcrete support collaborative bearing mechanism analysis is carried out based on the finite element simulation model.

2. The method according to claim 1, characterized in that The physical test model is manufactured by using a horizontal loading device according to similar basic principles of similar simulation experiments.

3. The method according to claim 1, characterized in that The physical test model of tunnel surrounding rock-shotcrete support is made to obtain measured data, specifically: According to the set load conditions, the load is applied to the physical test model in steps until the support structure is destroyed, and the physical test is ended; in this process, the deformation of the rock mass and concrete support in the physical test model is measured throughout the process mainly by digital image correlation technology and supplemented by single-point strain monitoring to obtain measured data.

4. The method according to claim 3, characterized in that The digital image correlation technology includes at least one binocular camera, which is fixedly arranged inside the physical test model and facing the part to be tested; Through an industrial computer, multiple slave computers are uniformly controlled to achieve synchronous measurement of digital image monitoring and single-point strain monitoring.

5. The method according to claim 3, characterized in that: Also includes: After the physical test is completed, the measured data are screened to obtain representative measured data.

6. The method according to claim 1, characterized in that The cohesive force constitutive model is as follows: In the formula, σ n and σ τ are the normal cohesion and the tangential cohesion, and are the normal cohesive strength and the tangential cohesive strength, δ represents the opening displacement, δ0 is the final cracking failure displacement, k, δ1, δ2 are the adjustment parameters of the cohesive model, τ f is the Coulomb friction force, τ f =μ|σ n |,σ n <0, μ is the friction coefficient.

7. The method according to claim 1, characterized in that The finite element simulation data is obtained for the cohesive force constitutive model, and based on the measured data and the finite element simulation data, the optimal parameters of the cohesive force model are iteratively determined using a gradient optimization algorithm, specifically: Establishing an optimization objective function by using the mean square error of the measured data and the finite element simulation data; After the initial parameters of the cohesive force constitutive model are given, the parameters of the cohesive force constitutive model of the current iteration step are iteratively calculated using a gradient optimization algorithm; Based on the optimization objective function, it is determined whether the parameters of the cohesive force constitutive model at the current iteration step meet the convergence condition. If so, the parameters are used as the optimal parameters of the cohesive force constitutive model.

8. An experimental system for studying the synergistic effect of surrounding rock and concrete support, characterized in that: include: A measurement module configured to make a physical test model of tunnel surrounding rock-shotcrete support to obtain measured data; A finite element simulation module is configured to establish a corresponding finite element simulation model according to the physical test model of the tunnel surrounding rock-shotcrete support to obtain finite element simulation data; A cohesive force model construction module is configured to arrange a cohesive force unit between a surrounding rock unit and a concrete support unit in a finite element simulation model, and construct a cohesive force constitutive model thereof considering Coulomb friction, wherein the cohesive force constitutive model is used to characterize contact characteristics between the surrounding rock and the concrete support; a parameter optimization module configured to iteratively determine the optimal parameters of the cohesive force constitutive model using a gradient optimization algorithm based on the measured data and the finite element simulation data; The analysis module is configured to import the optimal parameters of the cohesive force constitutive model into the finite element simulation model, and carry out tunnel surrounding rock-shotcrete support collaborative bearing mechanism analysis based on the finite element simulation model.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program is the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: include: A memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 7 when executing the program.

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