Analysis method for time-history stress relaxation of anchoring force of pre-stressed anchor cable under high-pressure stress

Abstract

The invention provides a method for analyzing time-history stress relaxation of anchoring force of a pre-stressed anchor cable under high-pressure stress, and relates to the technical field of geotechnical engineering. According to the method, engineering geological investigation, ground stress testing and indoor triaxial rheological testing are systematically combined, a potential high-stress area is accurately recognized, key rheological parameters of a rock-soil body are obtained, and then the stress self-adaptive creep coupling constitutive model with the long-term strength of the rock body as the criterion is constructed; and finally, accurately predicting the time-history creep strain of the rock-soil body and the anchoring force loss of the anchor cable under the high stress condition through numerical calculation. According to the method, the defect that a traditional creep theory describes a nonlinear creep behavior in a high-pressure stress state and a prestress loss coupling mechanism is effectively overcome, and the prediction precision and reliability of mechanical response of an anchoring system are remarkably improved; a basis is provided for long-term stability evaluation and safety control of prestressed anchoring engineering under complex geological conditions, and geotechnical engineering anchoring design and safety early warning are developed towards the refined and intelligent direction.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a method for time-history stress relaxation analysis of prestressed anchor cable anchorage force under high pressure stress. Background Technology

[0002] As my country's infrastructure construction continues to extend into areas with complex geological conditions, the importance of prestressed anchoring technology in projects such as slope protection and deep foundation pits is becoming increasingly prominent. However, the significant rheological properties of soil and rock under high ground stress environments, as well as the complexity of the interaction between the anchoring system and the surrounding rock, pose serious challenges to traditional design theories. Existing creep theory models are significantly insufficient in describing the nonlinear creep behavior of soil and rock under high pressure stress and its coupling mechanism with the prestress loss of anchor cables. They are unable to accurately predict the mechanical response of the anchoring system during long-term service, directly affecting the safety and durability of the project.

[0003] The creep behavior of soil and rock masses exhibits a clear stress dependence. Under low stress conditions, soil and rock masses primarily exhibit decaying creep, with deformation eventually stabilizing. However, when the stress level exceeds the long-term strength of the rock mass, entering a high-pressure stress state, sustained isochronous creep or even accelerated creep stages occur, ultimately leading to rock mass failure. This shift in stress state significantly affects the relaxation law of anchor cable anchoring force, rendering traditional linear creep theory inapplicable. Therefore, establishing a computational model that can reflect the creep characteristics of soil and rock masses under different stress states, especially the nonlinear creep behavior under high-pressure stress, has become an urgent research need. Summary of the Invention

[0004] This invention provides a time-history stress relaxation analysis method for prestressed anchor cable anchorage force under high pressure stress, which solves the problem of inaccurate prediction in traditional linear creep theory models and improves the accuracy of anchor cable prestress analysis under high pressure stress.

[0005] In a first aspect, the present invention provides a method for time-history stress relaxation analysis of prestressed anchor cable anchorage force under high pressure stress. The method includes: for the engineering area to be tested, obtaining the maximum principal stress distribution through engineering geological survey and geostress testing, and preliminarily identifying potential high-stress zones in the engineering area to be tested; for each potential high-stress zone, accurately determining the key rheological parameters of the soil and rock samples through indoor triaxial rheological tests, the key rheological parameters including: instantaneous elastic modulus, hysteretic elastic modulus, viscosity coefficient, and long-term rock mass strength; based on the key rheological parameters and the anchor cable key parameters, constructing a stress-adaptive creep-coupled constitutive model with the long-term rock mass strength as the criterion; the anchor cable key parameters include the equivalent elastic modulus, cross-sectional area, and initial prestress value; based on the stress-adaptive creep-coupled constitutive model, performing numerical calculations to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions.

[0006] In one possible implementation, the construction of a stress-adaptive creep coupled constitutive model based on the key rheological parameters and anchor cable key parameters, with the long-term strength of the rock mass as the criterion, includes: constructing a first creep model to describe the stable creep behavior when the stress of the rock mass element under test is less than the long-term strength of the rock mass; constructing a second creep model to describe the unstable creep behavior when the stress of the rock mass element under test is greater than or equal to the long-term strength of the rock mass, wherein the second creep model includes an accelerated creep term and the prestressed anchor cable is equivalent to the Maxwell model; establishing a coupled system constitutive equation for the coordinated operation of the rock mass and anchor cable in the unstable creep stage based on the second creep model and the Maxwell model; and integrating the first creep model and the coupled system constitutive equation with the long-term strength of the rock mass as the criterion to form the stress-adaptive creep coupled constitutive model; wherein, when s < s s When the first creep model is used, when s ≥ s s When the constitutive equation of the coupled system is used, s The stress of the rock mass element to be measured is... s s This refers to the long-term strength of the rock mass.

[0007] In one possible implementation, the step of performing numerical calculations based on the stress-adaptive creep coupled constitutive model to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions includes: embedding the stress-adaptive creep coupled constitutive model into numerical analysis software through a preset material subroutine; establishing an engineering geological numerical model containing each potential high-stress zone in the numerical analysis software, and simulating the engineering excavation, anchor cable installation, and prestressing tensioning process; during the numerical calculation process, at each calculation step, determining the current stress state of each rock mass unit to be tested in each potential high-stress zone; when the stress of the rock mass unit to be tested is less than the long-term strength of the rock mass, calling the first creep model for calculation; when the stress of the rock mass unit to be tested reaches or exceeds the long-term strength of the rock mass, calling the model relationship based on the constitutive equation of the coupled system for calculation; dynamically calculating and outputting the calculation results of each potential high-stress zone to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions.

[0008] Secondly, embodiments of the present invention provide a time-history stress relaxation analysis device for prestressed anchor cable anchorage force under high pressure stress. This analysis device includes a communication module and a processing module. The communication module obtains the maximum principal stress distribution for the engineering area to be tested through engineering geological surveys and geostress testing. The processing module is used to initially identify potential high-stress zones within the engineering area to be tested. For each potential high-stress zone, key rheological parameters of the soil and rock samples are accurately determined through indoor triaxial rheological tests. These key rheological parameters include: instantaneous elastic modulus, hysteretic elastic modulus, viscosity coefficient, and long-term rock mass strength. Based on the key rheological parameters and the anchor cable's key parameters, a stress-adaptive creep-coupled constitutive model is constructed, using the long-term rock mass strength as the criterion. The anchor cable's key parameters include the equivalent elastic modulus, cross-sectional area, and initial prestress value. Based on the stress-adaptive creep-coupled constitutive model, numerical calculations are performed to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions.

[0009] In one possible implementation, the construction of a stress-adaptive creep coupled constitutive model based on the key rheological parameters and anchor cable key parameters, with the long-term strength of the rock mass as the criterion, includes: constructing a first creep model to describe the stable creep behavior when the stress of the rock mass element under test is less than the long-term strength of the rock mass; constructing a second creep model to describe the unstable creep behavior when the stress of the rock mass element under test is greater than or equal to the long-term strength of the rock mass, wherein the second creep model includes an accelerated creep term and the prestressed anchor cable is equivalent to the Maxwell model; establishing a coupled system constitutive equation for the coordinated operation of the rock mass and anchor cable in the unstable creep stage based on the second creep model and the Maxwell model; and integrating the first creep model and the coupled system constitutive equation with the long-term strength of the rock mass as the criterion to form the stress-adaptive creep coupled constitutive model; wherein, when s < s s When the first creep model is used, when s ≥ s s When the constitutive equation of the coupled system is used, s The stress of the rock mass element to be measured is... s s This refers to the long-term strength of the rock mass.

[0010] In one possible implementation, the step of performing numerical calculations based on the stress-adaptive creep coupled constitutive model to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions includes: embedding the stress-adaptive creep coupled constitutive model into numerical analysis software through a preset material subroutine; establishing an engineering geological numerical model containing each potential high-stress zone in the numerical analysis software, and simulating the engineering excavation, anchor cable installation, and prestressing tensioning process; during the numerical calculation process, at each calculation step, determining the current stress state of each rock mass unit to be tested in each potential high-stress zone; when the stress of the rock mass unit to be tested is less than the long-term strength of the rock mass, calling the first creep model for calculation; when the stress of the rock mass unit to be tested reaches or exceeds the long-term strength of the rock mass, calling the model relationship based on the constitutive equation of the coupled system for calculation; dynamically calculating and outputting the calculation results of each potential high-stress zone to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions.

[0011] Thirdly, embodiments of the present invention provide an electronic device including a memory and a processor. The memory stores a computer program, and the processor is configured to call and run the computer program stored in the memory to perform the steps of the method as described in the first aspect and any possible implementation thereof.

[0012] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the steps of the method as described in the first aspect and any possible implementation thereof.

[0013] This invention provides a time-history stress relaxation analysis method for prestressed anchor cable anchorage force under high pressure stress. By systematically combining engineering geological surveys, in-situ stress testing, and indoor triaxial rheological experiments, this invention accurately identifies potential high-stress zones and obtains key rheological parameters of the soil and rock mass. It then constructs a stress-adaptive creep-coupled constitutive model based on the long-term strength of the rock mass. Finally, through numerical calculations, it achieves accurate prediction of time-history creep strain and anchorage force loss of the soil and rock mass under high stress conditions. This invention effectively overcomes the shortcomings of traditional creep theory in describing nonlinear creep behavior and its coupling mechanism with prestress loss under high pressure stress, significantly improving the prediction accuracy and reliability of the mechanical response of the anchorage system during long-term service. It provides a scientific basis and technical support for the long-term stability assessment and safety control of prestressed anchorage projects under complex geological conditions, and powerfully promotes the development of geotechnical engineering anchorage design and safety early warning towards refinement and intelligence. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a Western source model provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating a time-history stress relaxation analysis method for prestressed anchor cable anchorage force under high pressure provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a time-history stress relaxation analysis device for prestressed anchor cable anchorage force under high pressure provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0016] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0017] In the description of this invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" and "more than one" refer to two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0018] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0019] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the steps or modules listed, but may optionally include other steps or modules not listed, or may optionally include other steps or modules inherent to such process, method, product, or device.

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0021] As described in the background section, this invention addresses the key technical challenge of calculating nonlinear creep behavior under high-pressure stress. It proposes a method for calculating time-history creep strain under high-pressure stress. By introducing the long-term strength of the rock mass as a threshold for stress state discrimination, a theoretical description of the entire process of stable and unstable creep is achieved, enabling accurate prediction of anchorage force loss and the creep development trajectory of soil and rock masses. The research results will directly promote the development of prestressed anchor cable reinforcement and safety monitoring and early warning technologies in geotechnical engineering towards greater precision and intelligence.

[0022] like Figure 1 As shown, this embodiment of the invention provides a Nishihara model. Under high pressure stress, the Nishihara model is used as a series combination of elastic elements, Kelvin-Voigt viscoelastic elements, and Bingham viscoplastic elements to study the time-history stress relaxation of prestressed anchor cable anchoring force.

[0023] First, solve... Figure 1 Constitutive equations of the Sino-Western origin model Figure 1 The constitutive equation of the generalized Kelvin model is: (1).

[0024] in, s K For stress in the generalized Kelvin model, This represents the first derivative of stress with respect to time t in the generalized Kelvin model. e K For strain in the generalized Kelvin model, This represents the first derivative of strain with respect to time t in the generalized Kelvin model. E H For the instantaneous elastic modulus of the rock mass, E K For the hysteresis elastic modulus, or K The equivalent viscosity coefficient of the rock mass is 1.

[0025] Figure 1The constitutive equation of the Bingham viscoplastic model is: (2) in, For the first derivative of strain with respect to time t in the Bingham viscoplastic model, s B For the stress in the Bingham viscoplastic model, or B Let be the equivalent viscosity coefficient of the rock mass. In the Xiyuan model, the total stress and total strain are expressed as: (3); (4); in, s For the total stress, e For the overall response, s K For stress in the generalized Kelvin model, e K For strain in the generalized Kelvin model, s B For the stress in the Bingham viscoplastic model, e B Strain in the Bingham viscoplastic model.

[0026] According to equation (3), we know (5); According to equation (4), we know (6); in, Let be the first derivative of the total stress with respect to time t. Let be the first derivative of the total strain with respect to time t.

[0027] The form of transformation (1) is as follows (7); Combining equations (7) and (2) and substituting them into equation (6), we can obtain... (8); According to equation (4), we know (9); Substituting equation (9) into equation (8) yields (10) The constitutive equation can then be expressed as: (11); Rearranging equation (11), we obtain the constitutive equation as follows: (12); Differentiating equation (12), we obtain the constitutive equation as follows: (13); in, s b and e b Represented as stress and strain in the Western model.

[0028] Rearranging equation (13), we can obtain the constitutive equation as follows: (14); among them, This represents the second derivative of stress with respect to time t in the Western model. This is the first derivative of stress with respect to time t in the Western source model. This is the second derivative of strain with respect to time t in the Western model. This is the first derivative of strain with respect to time t in the Western source model.

[0029] The constitutive equation of the Maxwell model is (15); in, This represents the first derivative of strain with respect to time t in the Maxwell model. This is the first derivative of stress with respect to time t in the Maxwell model.

[0030] Equation (15) can be transformed into the following form: (16); Differentiating equations (14) and (15) can be expressed as follows: (17); in, Let be the third derivative of stress with respect to time t in the Western model. This is the third derivative of strain with respect to time t in the Western model.

[0031] (18); in, This represents the second derivative of strain with respect to time t in the Maxwell model. This is the second derivative of stress with respect to time t in the Maxwell model.

[0032] (19); in, This represents the third derivative of strain with respect to time t in the Maxwell model. This is the third derivative of stress with respect to time t in the Maxwell model.

[0033] In the improved coupling model, the total stress is expressed as: (20); (twenty one); (twenty two); (twenty three); in, For stress in the Maxwell model, Let be the second derivative of the total stress with respect to time t. Let be the third derivative of the total stress with respect to time t.

[0034] The total strain is expressed as follows: (twenty four); (25); (26); (27); in, Let O1 be the strain in the Maxwell model. Substituting the undetermined constants O1, V1, and K1 into equations (17) to (19), we can see that: (28); (29); (30); By combining equations (28), (29), and (30), we can obtain... (31); Substituting the undetermined constants A, B, and C into equations (23), (22), and (21) respectively, and combining them with equation (20), we can obtain: (32); (33); (34); (35); (36); Comparing equations (31) and (36), we can obtain: (37); (38); (39); In addition, equation (39) can be expressed as (40); Based on equations (37), (38), and (40), we can obtain: (41); (42); According to (36), we can obtain (43); (44); (45); Therefore, equation (31) can be expressed as (46); Introducing equations (40), (41), and (42) into equation (46), we obtain the constitutive equation as follows: (47); in, (48); (49); (50); The variation of stress over time can describe the stress relaxation behavior of a material. Under constant strain... e conditions, when e = e c , e c Since is a constant, equation (47) can be expressed as (51); Equation (51) is a cubic nonhomogeneous linear differential equation with constant coefficients. Its general solution is the general solution of the homogeneous differential equation plus the particular solution of the nonhomogeneous differential equation.

[0035] First, solve for a particular solution to equation (51). The general form of the right side of equation (51) is: (52); Where λ is a constant 0, p m ( t ) is an m-degree polynomial of t, which is a constant here.

[0036] Therefore, the particular solution of equation (51) can be expressed as follows: (53); in, Q m ( t ) is with p m ( t For polynomials of the same degree, where k is a constant, k takes the values ​​0, 1, or 2 depending on whether λ=0 is a root of the characteristic equation, λ is a simple root of the characteristic equation, or λ is a repeated root of the characteristic equation.

[0037] The characteristic equation of equation (51) can be expressed as: (54); In the formula r is the eigenvalue of the equation.

[0038] Substituting λ=0 into equation (54) yields (55); Therefore, λ=0 is not a root of the characteristic equation (54), i.e., k=0.

[0039] Assuming Qm(t) is a constant Q, substituting λ=0 and k=0 into equation (53) yields a particular solution to equation (51). for (56); According to equation (56), we know (57); (58); Substituting equations (57) and (58) into equation (51), we can obtain Q expressed as: (59); Dividing both sides of the characteristic equation (54) by A, we obtain the standard cubic equation form. (60); remember (61); (62); In the formula p To simplify the coefficients of the linear terms in a cubic equation, q To simplify the constant term in the cubic equation.

[0040] Calculate the discriminant Δ. (63); When Δ>0, there exists 1 real root + 2 conjugate complex roots.

[0041] When Δ=0, there are 3 real roots (at least 2 repeated roots).

[0042] When Δ < 0, there are 3 distinct real roots (trigonometric function solutions).

[0043] When there are 3 distinct real roots r 1. r 2. r 3. The general solution of the homogeneous differential equation can be expressed as: (64); When there exists a pair of complex roots α ± iβ and a real root, the general solution of the homogeneous differential equation can be expressed as: (65); Then the general solution of equation (51) is a cubic nonhomogeneous linear differential equation in one variable. (66); (67); in, k 1. k 2 and k 3 is a constant. It is determined based on the initial stage anchor tension monitoring values. k 1. k 2 and k 3.

[0044] Based on the initial conditions, assume that the elastic deformation occurs at the instant the initial prestress is applied (t=0). e c If the stress is completed instantaneously and the loss of prestress is not considered, then the stress can be expressed as: (68); Furthermore, according to the elastic stage of anchor cable axial force t The anchor cable stress at time 2 can be used to calculate the first derivative of the stress. Let's assume the first and second derivatives of the stress are expressed as follows: (69); (70)

[0045] There exist 3 distinct real roots r 1. r 2. r Taking 3 as an example, to calculate the unknowns in the general solution, substituting equation (68) into equation (66) yields the following result. (71); Substituting equation (69) into equation (66) yields (72); Substituting equations (69), (70), and (66) into equation (51), we get (73); but k 1 represents (74); Substituting equation (74) into equation (72) yields (75); Substituting equation (74) into equation (73) yields (76) By combining equations (75) and (76), we can obtain k 2 is (77) Equation (66) or (67) is the relaxation equation of the coupling effect calculation model. When the initial strain is known, the above equation can be used to reasonably predict the long-term prestress of the anchor cable. Assuming that the axial force of the anchor cable is uniformly distributed in the surrounding rock, the long-term prestress level can be expressed as follows: (78)

[0046] in, The long-term prestress of the anchor cable at time t is... Let be the stress of the anchor cable at time t. This represents the effective cross-sectional area of ​​the anchor cable.

[0047] based on Figure 1 The Western Origin Model shown, such as Figure 2 As shown, this embodiment of the invention provides a method for time-history stress relaxation analysis of prestressed anchor cable anchorage force under high pressure stress. The method includes steps S101-S104.

[0048] S101. For the engineering area to be inspected, the maximum principal stress distribution is obtained through engineering geological survey and geostress testing, and potential high-stress areas in the engineering area to be inspected are preliminarily identified.

[0049] S102. For each potential high-stress zone, key rheological parameters of the soil and rock samples are accurately determined through indoor triaxial rheological tests.

[0050] In some embodiments, key rheological parameters include: instantaneous elastic modulus, hysteretic elastic modulus, viscosity coefficient, and long-term rock mass strength.

[0051] S103. Based on key rheological parameters and anchor cable key parameters, a stress-adaptive creep coupled constitutive model with long-term rock mass strength as the criterion is constructed.

[0052] In some embodiments, key parameters of the anchor cable include the equivalent elastic modulus, cross-sectional area, and initial prestress value.

[0053] As one possible implementation, step S103 can be specifically implemented as steps S1031-S1034.

[0054] S1031. Construct a first creep model to describe the stable creep behavior of the rock mass element under test when the stress is less than the long-term strength of the rock mass.

[0055] S1032. Construct a second creep model to describe the unsteady creep behavior when the stress of the rock mass element under test is greater than or equal to the long-term strength of the rock mass.

[0056] The second creep model includes an accelerated creep term and equates the prestressed anchor cable to the Maxwell model.

[0057] S1033. Based on the second creep model and the Maxwell model, establish the constitutive equations of the coupled system of soil and rock mass and anchor cable working together in the unsteady creep stage.

[0058] In some embodiments, the constitutive equation of the coupled system is: ; in, ; ; ; ; ; ; .

[0059] in, s The stress of the rock mass element to be measured is... The first derivative of stress with respect to time t, Let be the second derivative of stress with respect to time t. e The strain of the rock mass element to be measured is... The first derivative of strain with respect to time t, The second derivative of strain with respect to time t, dt Let A be the time differential symbol, B be the inertia term coefficient, C be the stress term integral coefficient, D be the time-varying stiffness term coefficient, E be the strain rate term coefficient one, F be the strain rate term coefficient two, and G be the strain rate term coefficient three. E M The equivalent elastic modulus of the anchor cable. or M Let be the equivalent viscosity coefficient of the anchor cable. E H The instantaneous elastic modulus of the rock mass element to be tested, E K The hysteresis elastic modulus of the rock mass element to be tested, or K and or B is the equivalent viscosity coefficient of the rock mass element to be tested.

[0060] S1034. Using the long-term strength of the rock mass as the criterion, the first creep model and the constitutive equation of the coupled system are integrated to form a stress-adaptive creep coupled constitutive model.

[0061] Among them, when s < s s When the first creep model is used, when s ≥ ss When using the constitutive equations of a coupled system, s The stress of the rock mass element to be measured is... s s This refers to the long-term strength of the rock mass.

[0062] Furthermore, this invention can also derive and solve the time-history creep strain equation of the system. Based on the constitutive equation, under constant initial load conditions, the system creep equation is obtained, and its analytical form is: ; Where C1 and C2 are constants. C1 and C2 are determined based on the initial anchor tension monitoring values. ; ; ; ; Where α is the first derivative of the anchor strain value in the elastic stage of the anchor force, i.e. .

[0063] in addition, s c1 The stress is constant. Based on the anchor cable strain value during the elastic stage of the anchor cable axial force, the first derivative of the strain can be obtained. Let the first derivative of the strain be expressed as... .

[0064] S104. Based on the stress-adaptive creep coupled constitutive model, numerical calculations are performed to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high stress conditions.

[0065] As one possible implementation, step S104 can be specifically implemented as steps S1041-S1044.

[0066] S1041. The stress-adaptive creep coupled constitutive model is implanted into the numerical analysis software through a preset material subroutine.

[0067] S1042. In the numerical analysis software, an engineering geological numerical model containing each potential high-stress zone is established, and the engineering excavation, anchor cable installation and prestressing tensioning process are simulated.

[0068] S1043. During the numerical calculation process, at each calculation step, determine the current stress state of each rock mass unit to be measured in each potential high-stress zone.

[0069] For example, when the stress of the rock mass element to be tested is less than the long-term strength of the rock mass, the first creep model is invoked for calculation; when the stress of the rock mass element to be tested reaches or exceeds the long-term strength of the rock mass, the model relationship based on the constitutive equation of the coupled system is invoked for calculation.

[0070] S1044. Dynamically calculate and output the calculation results for each potential high-stress zone to obtain the time-history creep strain of the soil and rock mass and the anchorage force loss of the prestressed anchor cable under high-stress conditions.

[0071] This invention provides a time-history stress relaxation analysis method for prestressed anchor cable anchorage force under high pressure stress. By systematically combining engineering geological surveys, in-situ stress testing, and indoor triaxial rheological experiments, it accurately identifies potential high-stress zones and obtains key rheological parameters of the soil and rock mass. Then, it constructs a stress-adaptive creep-coupled constitutive model based on the long-term strength of the rock mass. Finally, through numerical calculation, it achieves accurate prediction of time-history creep strain and anchorage force loss of the soil and rock mass under high stress conditions. This invention effectively overcomes the shortcomings of traditional creep theory in describing nonlinear creep behavior and its coupling mechanism with prestress loss under high pressure stress, significantly improving the prediction accuracy and reliability of the mechanical response of the anchorage system during long-term service. It provides a scientific basis and technical support for the long-term stability assessment and safety control of prestressed anchorage projects under complex geological conditions, and powerfully promotes the development of geotechnical engineering anchorage design and safety early warning towards refinement and intelligence.

[0072] Thus, this invention enables coupled calculation and long-term prediction in numerical simulation, embedding the stress-adaptive constitutive model into the numerical analysis software via a user-defined material subroutine. An engineering geological numerical model is established to simulate excavation, anchor cable installation, and prestressing tensioning processes. In the calculations, based on the creep equation under high stress, time-history creep strain and anchor cable prestress loss are dynamically calculated.

[0073] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0074] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0075] Figure 3 A schematic diagram of a time-history stress relaxation analysis device for prestressed anchor cable anchorage force under high pressure, provided by an embodiment of the present invention, is shown. The analysis device 200 includes a communication module 201 and a processing module 202.

[0076] The communication module 201 obtains the maximum principal stress distribution for the engineering area to be tested through engineering geological survey and geostress testing.

[0077] Processing module 202 is used to initially identify potential high-stress zones in the engineering area to be tested. For each potential high-stress zone, key rheological parameters of the soil and rock samples are accurately determined through indoor triaxial rheological tests. The key rheological parameters include: instantaneous elastic modulus, hysteretic elastic modulus, viscosity coefficient, and long-term rock mass strength. Based on the key rheological parameters and anchor cable key parameters, a stress-adaptive creep coupled constitutive model is constructed with the long-term rock mass strength as the criterion. The anchor cable key parameters include equivalent elastic modulus, cross-sectional area, and initial prestress value. Based on the stress-adaptive creep coupled constitutive model, numerical calculations are performed to obtain the time-history creep strain of the soil and rock mass under high stress conditions and the anchorage force loss of the prestressed anchor cable.

[0078] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The electronic device 300 includes: a processor 301, a memory 302, and a computer program 303 stored in the memory 302 and executable on the processor 301. When the processor 301 executes the computer program 303, it implements the steps in the above-described method embodiments. Alternatively, when the processor 301 executes the computer program 303, it implements the functions of each module / unit in the above-described device embodiments.

[0079] For example, the computer program 303 may be divided into one or more modules / units, which are stored in the memory 302 and executed by the processor 301 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 303 in the electronic device 300.

[0080] The processor 301 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0081] The memory 302 can be an internal storage unit of the electronic device 300, such as a hard disk or memory of the electronic device 300. The memory 302 can also be an external storage device of the electronic device 300, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD) card, flash card, etc., equipped on the electronic device 300. Furthermore, the memory 302 can include both internal and external storage units of the electronic device 300. The memory 302 is used to store the computer program and other programs and data required by the terminal. The memory 302 can also be used to temporarily store data that has been output or will be output.

[0082] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for time-dependent stress relaxation analysis of anchoring force of a prestressed cable under high pressure stress, characterized by, The method comprises the following steps: For the engineering area to be detected, the maximum principal stress distribution is obtained through engineering geological investigation and ground stress test, and the potential high stress area in the engineering area to be detected is preliminarily identified; For each potential high stress area, the key rheological parameters of the rock-soil sample are accurately determined through indoor triaxial rheological test, the key rheological parameters including instantaneous elastic modulus, hysteresis elastic modulus, viscous coefficient and long-term strength of rock mass; Based on the key rheological parameters and the key parameters of the anchor cable, a stress self-adaptive creep coupling constitutive model taking the long-term strength of rock mass as the criterion is constructed, the key parameters of the anchor cable including equivalent elastic modulus, cross-sectional area and initial prestress value; Based on the stress self-adaptive creep coupling constitutive model, numerical calculation is carried out to obtain the time-history creep strain of rock-soil mass and the anchoring force loss of prestressed anchor cable under high stress condition.

2. The time history stress relaxation analysis method of the prestressed cable anchoring force under high pressure stress according to claim 1, characterized in that, The method of constructing the stress self-adaptive creep coupling constitutive model taking the long-term strength of rock mass as the criterion based on the key rheological parameters and the key parameters of the anchor cable comprises: A first creep model for describing the stable creep behavior when the stress of the rock mass unit to be detected is less than the long-term strength of rock mass is constructed; A second creep model for describing the unstable creep behavior when the stress of the rock mass unit to be detected is greater than or equal to the long-term strength of rock mass is constructed, wherein the second creep model contains an accelerated creep term and the prestressed anchor cable is equivalent to a Maxwell model; Based on the second creep model and the Maxwell model, a coupling system constitutive equation of the rock-soil mass and the anchor cable working together in the unstable creep stage is established; The stress self-adaptive creep coupling constitutive model is formed by integrating the first creep model and the coupling system constitutive equation with the long-term strength of the rock mass as a criterion; when the stress is less than or equal to the long-term strength of the rock mass, the first creep model is used; and when the stress is greater than the long-term strength of the rock mass, the coupling system constitutive equation is used. The coupling system constitutive equation is: The method of carrying out numerical calculation based on the stress self-adaptive creep coupling constitutive model to obtain the time-history creep strain of rock-soil mass and the anchoring force loss of prestressed anchor cable under high stress condition comprises: s The stress self-adaptive creep coupling constitutive model is implanted into the numerical analysis software through a preset material subroutine; ≥ In the numerical analysis software, an engineering geological numerical model containing each potential high stress area is established, and the processes of engineering excavation, anchor cable installation and prestressed tension are simulated; s , In the numerical calculation process, at each calculation time step, the current stress state of each rock mass unit to be detected in each potential high stress area is judged; when the stress of the rock mass unit to be detected is less than the long-term strength of rock mass, the first creep model is called for calculation; when the stress of the rock mass unit to be detected reaches or exceeds the long-term strength of rock mass, the model relationship based on the coupling system constitutive equation is called for calculation; is the stress of the rock mass unit to be measured, The calculation results of each potential high stress area are dynamically calculated and output to obtain the time-history creep strain of rock-soil mass and the anchoring force loss of prestressed anchor cable under high stress condition. s is the long-term strength of the rock mass.​​ 3. The time-history stress relaxation analysis method of the prestressed cable anchoring force under high pressure stress according to claim 2, characterized in that, The analysis device comprises: ； wherein ; ； ； ； ； ； ； wherein, A communication module, which is used to obtain the maximum principal stress distribution through engineering geological investigation and ground stress test for the engineering area to be detected; is the stress of the rock mass unit under test, is the first derivative of the stress with respect to time t, is the second derivative of the stress with respect to time t, ​ is the strain of the rock mass unit under test, is the first derivative of the strain with respect to time t, is the second derivative of the strain with respect to time t, ​ is the time differential symbol, A is the coefficient of the inertia term, B is the coefficient of the damping term, C is the coefficient of the stress term integral, D is the coefficient of the time-varying stiffness term, E is the coefficient of the strain rate term one, F is the coefficient of the strain rate term two, G is the coefficient of the strain rate term three, E M is the equivalent elastic modulus of the anchor cable, ​ M is the equivalent viscous coefficient of the anchor cable, E H is the instantaneous elastic modulus of the rock mass unit under test, E K is the hysteresis elastic modulus of the rock mass unit under test, ​ K and ​ B is the equivalent viscous coefficient of the rock mass unit under test.

4. The time-history stress relaxation analysis method of the prestressed cable anchoring force under high pressure stress according to claim 1, characterized in that, ​ ​ ​ ​ ​ 5. A device for time-stress relaxation analysis of anchoring force of a prestressed cable under high pressure stress, characterized in that, ​ ​ The processing module is used for preliminarily identifying a potential high stress area in a to-be-detected engineering area; for each potential high stress area, key rheological parameters of a rock-soil sample are accurately measured through an indoor triaxial rheological test, the key rheological parameters including: instantaneous elastic modulus, hysteresis elastic modulus, viscous coefficient and rock mass long-term strength; a stress self-adaptive creep coupling constitutive model taking the rock mass long-term strength as a criterion is constructed based on the key rheological parameters and anchor key parameters, the anchor key parameters including equivalent elastic modulus, cross-sectional area and initial prestress value; based on the stress self-adaptive creep coupling constitutive model, numerical calculation is carried out to obtain time-history creep strain of the rock-soil mass and anchoring force loss of the prestressed anchor cable under high stress conditions.

6. The device for time-stress relaxation analysis of anchoring force of a prestressed cable under high pressure stress according to claim 5, characterized in that, The processing module is configured to construct a first creep model for describing stable creep behavior when stress of a rock mass unit to be measured is less than long-term strength of the rock mass; construct a second creep model for describing unstable creep behavior when the stress of the rock mass unit to be measured is greater than or equal to the long-term strength of the rock mass, wherein the second creep model contains an accelerated creep term, and prestressed anchor cable is equivalent to a Maxwell model; based on the second creep model and the Maxwell model, establish a coupled system constitutive equation of the rock-soil body and the anchor cable working together in the unstable creep stage; take the long-term strength of the rock mass as a criterion, integrate the first creep model and the coupled system constitutive equation to form the stress-adaptive creep coupled constitutive model; when σ < σ s the first creep model is used, and when σ ≥ σ s the coupled system constitutive equation is used, σ is the stress of the rock mass unit to be measured, σ s is the long-term strength of the rock mass.

7. The device for time-stress relaxation analysis of anchoring force of a prestressed cable under high pressure stress according to claim 6, characterized in that, The coupling system constitutive equation is: ； wherein ; ； ； ； ； ； ； wherein, σ is the stress of the rock mass unit under test, is the first derivative of the stress with respect to time t, is the second derivative of the stress with respect to time t, ε is the strain of the rock mass unit under test, is the first derivative of the strain with respect to time t, is the second derivative of the strain with respect to time t, dt is the time differential symbol, A is the coefficient of the inertia term, B is the coefficient of the damping term, C is the coefficient of the stress term integral, D is the coefficient of the time-varying stiffness term, E is the coefficient of the strain rate term one, F is the coefficient of the strain rate term two, G is the coefficient of the strain rate term three, E M is the equivalent elastic modulus of the anchor cable, η M is the equivalent viscous coefficient of the anchor cable, E H is the instantaneous elastic modulus of the rock mass unit under test, E K is the hysteretic elastic modulus of the rock mass unit under test, η K and η B is the equivalent viscous coefficient of the rock mass unit under test.

8. The device for time-stress relaxation analysis of anchoring force of a prestressed cable under high pressure stress according to claim 5, characterized by, The processing module is used for implanting the stress self-adaptive creep coupling constitutive model into numerical analysis software through a preset material subroutine; and in the numerical analysis software, an engineering geology numerical model containing each potential high stress area is established, and an engineering excavation, anchor installation and prestressed tension process are simulated; in the numerical calculation process, at each calculation time step, a current stress state of each to-be-detected rock mass unit in each potential high stress area is judged; When the stress of the to-be-detected rock mass unit is less than the rock mass long-term strength, the first creep model is called for calculation; when the stress of the to-be-detected rock mass unit reaches or exceeds the rock mass long-term strength, a model relationship based on the coupling system constitutive equation is called for calculation; calculation results of each potential high stress area are dynamically calculated and output to obtain time-history creep strain of the rock-soil mass and anchoring force loss of the prestressed anchor cable under high stress conditions. 9.An electronic device, comprising a memory and a processor, the memory storing a computer program, and the processor being configured to invoke and run the computer program stored in the memory to execute the method of any one of claims 1 to 4.

10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 9. The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 4.

Images