Structural surface shear failure constitutive model under true three-dimensional stress-seepage-aging coupling

Abstract

The invention discloses a true three-dimensional stress-osmotic pressure-aging coupled structural plane shear failure constitutive model, which comprises the following steps: carrying out a true three-dimensional stress-osmotic pressure-aging coupled multistage shear test on a rock mass structural plane to obtain the strength and deformation characteristics of the structural plane; based on a test result, determining a true three-dimensional stress loading shear damage Ds calculation method of the rock mass structural surface; determining an evolution function of a specific auscultation coefficient mu and a permeability coefficient k of the rock mass structural surface; establishing a true three-dimensional stress-osmotic pressure-aging coupled structural plane shear fracture constitutive model and a numerical method; and carrying out true three-dimensional stress-osmotic pressure-aging coupling multistage shear test numerical simulation verification and water-rich area structural plane tunnel permeability catastrophe analysis. The true three-dimensional stress-osmotic pressure-aging coupled structural plane shear fracture constitutive model provided by the invention has important significance for stability analysis and engineering disaster prediction of underground water-rich area rock mass structural plane engineering.

Description

Technical Field

[0001] The invention relates to the research fields of rock mechanics and rock engineering, and in particular to a method for constructing a shear failure constitutive model of a structural surface under true three-dimensional stress-seepage pressure-time coupling. Background Art

[0002] Deep underground projects are usually located in extremely complex environments, and many safety issues will be encountered during construction, especially the long-term stability of rock mass structural surfaces in a true three-dimensional stress and osmotic pressure multi-field coupling environment. Domestic and foreign scholars have proposed many rock mass constitutive models that consider factors such as osmotic pressure and aging for stability analysis and disaster prediction of underground projects, but most models are based on compression models under stress-osmotic pressure coupling. These models do not consider the changes in the Biot coefficient and permeability coefficient during rock mass rupture. There are relatively few models suitable for structural surface shear rupture analysis, and there is a lack of true three-dimensional stress-osmotic pressure-time-effect coupling structural surface failure criteria and damage degradation characterization. In addition, the existing structural surface aging models are usually based on traditional elastic elements, plastic elements, and viscous elements, and their characterization functions are relatively simple; there is a lack of fractional-order models that consider nonlinear shear aging damage, true three-dimensional stress-osmotic pressure-time-effect coupling effects, and accelerated deformation stages.

[0003] In view of the above shortcomings, the present invention proposes a constitutive model for shear failure of structural surfaces under true three-dimensional stress-seepage-time coupling. Considering the influence of the coupling effect of true three-dimensional stress loading, Biot coefficient change and time-dependent degradation on the evolution of shear fracture, a constitutive model and numerical method for shear failure of structural surfaces under true three-dimensional stress-seepage-time coupling are constructed, which is of great significance for the stability analysis of rock structural surface engineering in underground water-rich areas and the prediction of engineering disasters. Summary of the invention

[0004] The purpose of the present invention is to provide a method for constructing a shear failure constitutive model of structural surface under true three-dimensional stress-osmotic pressure-time coupling, analyze the shear fracture characteristics of rock mass under true three-dimensional stress, osmotic pressure and time, and provide a more scientific theoretical basis for rock engineering excavation design and disaster prevention.

[0005] In order to achieve the above technical objectives, the present invention provides a method for constructing a shear failure constitutive model of a structural surface under true three-dimensional stress-seepage-time coupling, the steps of which include:

[0006] Step 1: Conduct true three-dimensional shear aging tests at different stress levels and seepage pressures to obtain the strength, deformation and failure characteristics of the rock mass structural surface;

[0007] Step 2: Establish a true three-dimensional stress-seepage-time coupled structural surface shear failure constitutive model;

[0008] Step 3: Construct a numerical method for the shear failure constitutive model of the structural surface under true three-dimensional stress-seepage-time coupling;

[0009] Step 4: Conduct numerical verification of the shear failure constitutive model of the structural surface under true three-dimensional stress-seepage pressure-time coupling and analyze the seepage disaster of the structural surface tunnel in the water-rich area.

[0010] In the step 1, a true three-dimensional shear aging test with different normal and lateral stresses and seepage pressures is carried out to obtain the strength, deformation and failure characteristics of the rock mass structural surface;

[0011] In step 2, based on elastic-plastic mechanics, damage mechanics theory, effective stress principle and three-dimensional strength criterion, a constitutive model of shear failure of structural surface under true three-dimensional stress-seepage-time coupling is constructed. The specific steps are as follows:

[0012] True three-dimensional stress loading shear damage of rock mass structural surface s It is expressed as:

[0013]

[0014] Where: G0 is the initial shear stiffness of the rock mass structural surface, G s is the damage shear stiffness of the rock mass structural surface;

[0015]

[0016] Where dτ and dγ are the shear stress increment and shear strain increment of the rock mass structure surface during multi-stage loading, respectively;

[0017] Calculate the effective stress by the effective stress principle:

[0018]

[0019] Where: τ' is the effective shear stress, σ' n is the effective normal stress, σ' p is the effective lateral stress, μ and pw are the Biot coefficient and osmotic pressure, respectively;

[0020] The Biot coefficient μ of the rock mass structural surface is related to the shear damage D s Related functions:

[0021] μ=f(D s )+c s (4)

[0022] Where c s is the curve constant;

[0023] The true three-dimensional stress loading shear damage D of the rock mass structural surface is used. s To describe the evolution of the permeability coefficient k of the rock mass structural surface during shear failure:

[0024] k=g(D s ) (5)

[0025] The true three-dimensional stress-permeability-time-effect element model consists of four parts: the first part is the elastic element, the second part is a viscoelastic body composed of elastic elements and viscous elements in parallel, the third part is a fractional-order element, and the fourth part is a fractional-order viscoplastic body composed of fractional-order elements and plastic elements in parallel. The four-part model is used in series to describe the viscoelastic-plastic shear mechanical behavior of the rock mass structural surface.

[0026] The constitutive relation of the elastic model in the first part is:

[0027]

[0028] The constitutive relation of the elastic-viscous model in the second part is:

[0029]

[0030]

[0031] The constitutive relation of the fractional-order model in the third part is:

[0032]

[0033]

[0034] The constitutive relation of the fractional-order viscoplastic model in the fourth part is:

[0035]

[0036] Since the four-part model is connected in series, the constitutive relationship of the true three-dimensional stress-permeability-aging model is:

[0037]

[0038]

[0039] Establish the true three-dimensional stress-permeability-time-dependent coupled shear yield function F of rock mass in three-dimensional space s :

[0040]

[0041] Where: c jp is the cohesion of the structural surface, is the internal friction angle of the structural surface, P, σ ρ is the effective force, K is the effective lateral stress coefficient;

[0042] When the effective shear stress τ' is less than the effective crack initiation stress τ' ci When τ' is greater than or equal to τ', the rock mass structural surface only undergoes elastic deformation; ci When , the rock mass structural surface undergoes time-dependent deformation;

[0043]

[0044] When the effective shear stress τ' is greater than the effective damage stress τ' cd At this time, the rock mass structural surface enters the acceleration stage, the deformation rate of the rock mass structural surface gradually increases, and its internal cracks continue to expand and eventually lead to destruction;

[0045]

[0046] In step 3, the numerical method of the structural surface shear failure constitutive model under true three-dimensional stress-seepage pressure-time coupling is:

[0047] According to the elastic stress increment formula:

[0048]

[0049] Among them, G s and k n are the shear stiffness and normal stiffness, Δγ and Δε n are the shear and normal strain increments;

[0050] The model consists of elastic bodies, viscoelastic bodies, fractional-order elements and fractional-order viscoplastic bodies. The total strain ε is expressed as:

[0051] ε=ε e +ε ve +ε v +ε vp (18)

[0052] Where: ε e , ε ve , ε v , ε vp are the strain matrices of elastic body, viscoelastic body, fractional element and fractional viscoplastic body respectively;

[0053] Stress-strain relationship of elastic body:

[0054]

[0055]

[0056] Among them, the superscripts N and O represent the stress after and before the update;

[0057] Stress-strain relationship of viscoelastic body:

[0058]

[0059]

[0060] Stress-strain relationship of fractional-order elements:

[0061]

[0062]

[0063] The stress-strain relationship of fractional viscoplastic body:

[0064]

[0065]

[0066] True three-dimensional stress-seepage-pressure-time coupled shear yield function F of rock mass s and the tensile yield function F t :

[0067]

[0068] F t =σ′ t -σ' n (28)

[0069] According to the shear yield function F s , tensile yield function F t and plastic flow law to determine the shear plastic potential function g s and the tensile plastic potential function g t :

[0070]

[0071] g t =σ′ t (30)

[0072] Combining equations (17)-(26), the updated stress expression is:

[0073]

[0074]

[0075]

[0076] B=G1G2((t+Δt) α -t α ) (34)

[0077]

[0078] Effective lateral stress vector σ' p Perpendicular to the effective shear stress vector τ' and the effective normal stress vector σ' n , effective lateral stress vector σ' p It is expressed as:

[0079] σ' p =τ'×σ' n (36)

[0080] The effective lateral stress σ' of the unit on the structural surface p The magnitude is the principal stress vector σ on the element i '(i=1,2,3) in vector σ' p The sum of the projection sizes in the direction of :

[0081]

[0082] In step 4, the numerical verification of the structural surface shear failure constitutive model under true three-dimensional stress-seepage pressure-time coupling and the analysis of seepage disaster of structural surface tunnel in water-rich area are as follows:

[0083] By numerically simulating the true three-dimensional stress-permeability-aging coupled multi-stage shear test, the strength, deformation and failure results were obtained and compared with the test results.

[0084] A seepage disaster analysis was conducted on tunnel projects in water-rich areas, a three-dimensional tunnel numerical model of joint structural surfaces was established, and the shear failure constitutive model of the structural surface under true three-dimensional stress-seepage pressure-time coupling was used to simulate the tunnel excavation. The mechanical response of the structural surface surrounding rock under true three-dimensional stress-seepage pressure-time coupling was analyzed.

[0085] The beneficial effects of the present invention are:

[0086] 1. The present invention establishes a constitutive model and a numerical method for shear failure of structural surfaces under true three-dimensional stress-osmotic pressure-time coupling, which can be used to simulate and analyze the changes in mechanical properties of deeply buried rock masses under true three-dimensional stress, osmotic pressure and time coupling.

[0087] 2. After secondary development and programming, the model established by the present invention can be applied to the excavation design and disaster prevention of underground rock engineering in water-rich areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 It is a flow chart for constructing a constitutive model of shear failure of a structural surface under true three-dimensional stress-osmotic pressure-time coupling of the present invention;

[0089] Figure 2 It is the stress path of true three-dimensional stress-osmotic pressure-time-dependent coupled multi-stage shear test;

[0090] Figure 3 It is the shear strain-time curve of the true three-dimensional stress-osmotic pressure-aging coupled multi-stage shear test;

[0091] Figure 4 is the evolution of the rock mass Biot coefficient μ under true three-dimensional stress-permeability-time coupling;

[0092] Figure 5 is the evolution of rock mass permeability coefficient k under true three-dimensional stress-osmotic pressure-time coupling;

[0093] Figure 6 It is a true three-dimensional stress-osmotic pressure-time-dependent element model;

[0094] Figure 7 Shear strain-time curve and simulation results of true three-dimensional stress-osmotic pressure-aging coupled multi-stage shear test;

[0095] Figure 8 It is the surrounding rock plastic zone after the structural surface tunnel is excavated under the true three-dimensional stress-seepage-time coupling;

[0096] Fig. 9 This is a cloud diagram of the surrounding rock pore pressure after excavation of the structural surface tunnel under true three-dimensional stress-seepage pressure-time coupling. DETAILED DESCRIPTION

[0097] The specific implementation of the present invention is described below in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the specific implementation. It should be noted that all creations based on or dependent on the present invention are within the protection scope of the present invention.

[0098] This embodiment provides a true three-dimensional stress-seepage-time coupled structural surface shear failure constitutive model, using limestone as a rock mass sample and conducting engineering applications to verify the rationality and reliability of the model.

[0099] refer to Figure 1 , Figure 1 The flowchart of constructing the shear failure constitutive model of the structural surface under true three-dimensional stress-osmotic pressure-time coupling is shown. The method includes steps 1 and 4;

[0100] In step 1, a true three-dimensional stress-osmotic pressure-time-dependent coupled multi-stage shear test is carried out on the limestone sample to obtain the time-dependent deformation results of the limestone. The stress path of the true three-dimensional stress-osmotic pressure-time-dependent coupled multi-stage shear test is as follows: Figure 2 As shown; Figure 3 The shear strain-time curve of the true three-dimensional stress-osmotic pressure-time-dependent coupled multi-stage shear test is shown;

[0101] In step 2, based on elastic-plastic mechanics, damage mechanics theory, effective stress principle and three-dimensional strength criterion, a true three-dimensional stress-seepage-time coupling structural surface shear failure constitutive model is constructed. The specific steps are as follows:

[0102] True three-dimensional stress loading shear damage of rock mass structural surface s It is expressed as:

[0103]

[0104] Where: G0 is 10.9GPa, G s is the damage shear stiffness of the rock mass structural surface;

[0105]

[0106] Where dτ and dγ are the shear stress increment and shear strain increment of the rock mass structure surface under multi-level loading;

[0107] Calculate the effective stress by the effective stress principle:

[0108]

[0109] Where: τ' is the effective shear stress, σ' n is the effective normal stress, σ' p is the effective lateral stress, μ and p w are Biot coefficient and osmotic pressure, respectively;

[0110] The Biot coefficient μ of the rock mass structural surface is related to the shear damage D s Related functions:

[0111]

[0112] Normal stress σ n =15MPa,σ p =10MPa and p w =1MPa under true three-dimensional stress-osmotic pressure-time coupling. Figure 4 As shown;

[0113] When the rock mass is disturbed by engineering such as excavation unloading, the generation and expansion of its cracks will lead to an increase in the permeability coefficient and gradually increase with the accumulation of damage until the dominant cracks are connected and gradually stabilize. Therefore, the permeability coefficient k of the rock mass structural surface can be calculated by D s To describe:

[0114]

[0115] Normal stress σ n =15MPa,σ p =10MPa and p w=1MPa under true three-dimensional stress-osmotic pressure-time coupling. Figure 5 As shown;

[0116] The true three-dimensional stress-permeability-time-effect element model consists of four parts: the first part is the elastic element, the second part is the viscoelastic body composed of the elastic element and the viscous element in parallel, the third part is the fractional-order element, and the fourth part is the fractional-order viscoplastic body composed of the fractional-order element and the plastic element in parallel. The four-part model is used in series to describe the viscoelastic-plastic shear mechanical behavior of the rock mass structural surface, such as Figure 6 As shown;

[0117] The constitutive relation of the elastic model in the first part is:

[0118]

[0119] The constitutive relation of the elastic-viscous model in the second part is:

[0120]

[0121]

[0122] The constitutive relation of the fractional-order model in the third part is:

[0123]

[0124]

[0125] The constitutive relation of the fractional-order viscoplastic model in the fourth part is:

[0126]

[0127] Establish the true three-dimensional stress-permeability-time-dependent coupled shear yield function F of rock mass in three-dimensional space:

[0128]

[0129] When the effective shear stress τ' is less than the effective crack initiation stress τ' ci =8MPa, the rock mass structural surface only undergoes elastic deformation; when the effective shear stress τ' is greater than or equal to τ' ci When , the rock mass structural surface undergoes time-dependent deformation;

[0130]

[0131] When the effective shear stress τ' is greater than or equal to the effective damage stress τ' cd =17MPa, the rock mass structural surface enters the acceleration stage;

[0132]

[0133] Since the four-part model is connected in series, the constitutive relation of the time-dependent model is:

[0134]

[0135]

[0136] In step 3, the numerical method of the structural surface shear failure constitutive model under true three-dimensional stress-seepage-time coupling is as follows:

[0137] According to the elastic stress increment formula:

[0138]

[0139] Among them, G s and k n are the shear stiffness and normal stiffness, Δγ and Δε n are the shear and normal strain increments;

[0140] The model consists of elastic bodies, viscoelastic bodies, fractional-order elements and fractional-order viscoplastic bodies. The total strain ε is expressed as:

[0141] ε=ε e +ε ve +ε v +ε vp

[0142] Where: ε e , ε ve , ε v , ε vp are the strain matrices of elastic body, viscoelastic body, fractional element and fractional viscoplastic body respectively;

[0143] Stress-strain relationship of elastic body:

[0144]

[0145]

[0146] Among them, the superscripts N and O represent the stress after and before the update;

[0147] Stress-strain relationship of viscoelastic body:

[0148]

[0149]

[0150] Stress-strain relationship of fractional-order elements:

[0151]

[0152]

[0153] The stress-strain relationship of fractional viscoplastic body:

[0154]

[0155]

[0156] True three-dimensional stress-seepage-pressure-time coupled shear yield function F of rock mass s and the tensile yield function F t :

[0157]

[0158] F t =σ t '-σ' n

[0159] According to the shear yield function F s , tensile yield function F t and plastic flow law to determine the shear plastic potential function g s and the tensile plastic potential function g t :

[0160]

[0161] g t =σ t '

[0162] Combining the above formula, the updated stress is expressed as:

[0163]

[0164]

[0165]

[0166] B=G1G2((t+Δt) α -t α )

[0167]

[0168] Effective lateral stress vector σ' p Perpendicular to the effective shear stress vector τ' and the effective normal stress vector σ' n :

[0169] σ' p =τ'×σ' n

[0170] The effective lateral stress σ' of the unit on the structural surface p The magnitude is the principal stress vector σ on the element i '(i=1,2,3) in vector σ' p The sum of the projection sizes in the direction of :

[0171]

[0172] In step 4, the shear failure constitutive model of the structural surface under true three-dimensional stress-seepage-time coupling is verified by conducting true three-dimensional stress-seepage-time coupling multi-stage shear test numerical simulation and engineering application analysis:

[0173] Numerical simulation of true three-dimensional stress-osmotic pressure-time-dependent coupled multi-stage shear test. Figure 7 The shear strain-time curve and simulation results of the true three-dimensional stress-osmotic pressure-time-dependent coupled multi-stage shear test are presented;

[0174] A three-dimensional tunnel numerical model of joint structure surface was established. The size of the tunnel model was 60m×60m×30m, and the tunnel radius was 3.6m. Two joints with an inclination angle of 60° were set on the arch of the tunnel model, and the tunnel grid units were locally encrypted.

[0175] Tables 1, 2, and 3 list the initial geostress, mechanical parameters, and model parameters, respectively. The permeability coefficient is 1e-7 m / s, and the initial pore water pressure is 1.2 MPa;

[0176] Figure 8 and Fig. 9 This is the cloud diagram of the plastic zone and pore pressure of the surrounding rock after excavation of the structural surface tunnel under true three-dimensional stress-seepage pressure-time coupling.

[0177] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention. Table 1 Initial ground stress of surrounding rock Table 2 Mechanical parameters Table 3 Model parameters

Claims

1. Establish a true three-dimensional stress-seepage-time coupling structural surface shear failure constitutive model, including the following steps: S1. Carry out true three-dimensional stress-seepage pressure-time-dependent coupled multi-stage shear tests on the rock mass structure surface at different stress levels and seepage pressures to obtain strength and deformation characteristics; S2. Determine the shear damage D of the rock mass structure surface under true three-dimensional stress s ; S3. Calculate the effective shear stress τ' and effective normal stress σ' by the effective stress principle n , effective lateral stress σ' p ; S4. Determine the Biot coefficient μ and permeability coefficient K of the rock mass structural surface and the shear damage D s The relationship function of Biot coefficient μ of rock mass structural surface and shear damage D s The relationship function: Where: a s , b s and c s is the Biot coefficient curve constant; The true three-dimensional stress loading shear damage D of the rock mass structural surface is used. s To describe the evolution of the permeability coefficient k of the rock mass structural surface during shear failure: Where: a k , b k and c k is the permeability curve constant; S5. Establish a true three-dimensional stress-permeability-time-dependent element model, which consists of four parts: the first part is the elastic element, the second part is an elastic-viscous body composed of elastic elements and viscous elements in parallel, the third part is a fractional-order element, and the fourth part is a fractional-order viscoplastic body composed of fractional-order elements and plastic elements in parallel. The four-part model is used in series to describe the viscoelastic-plastic shear mechanical behavior of the rock mass structural surface; The constitutive relation of the elastic model in the first part is: The constitutive relation of the viscoelastic model in the second part is: The constitutive relation of the fractional-order model in the third part is: The constitutive relation of the fractional-order viscoplastic model in the fourth part is: Since the four-part model is connected in series, the constitutive relation of the time-dependent model is: τ'=τ1 ' =τ2 ' =τ3 ' =τ4 ' γ=γ1+γ2+γ3+γ4 Establish the true three-dimensional stress-permeability-time-dependent coupled shear yield function F of rock mass in three-dimensional space: Among them, c jp is the cohesion of the structural surface, is the internal friction angle of the structural surface, P, σ ρ is the effective force, K is the effective lateral stress coefficient; When the effective shear stress τ' is less than the effective crack initiation stress τ' ci When the effective shear stress τ' is greater than or equal to τ', the rock mass structural surface only undergoes elastic deformation; ci When , the rock mass structural surface undergoes time-dependent deformation; When the effective shear stress τ' is greater than or equal to the effective damage stress τ' cd At this time, the rock mass structural surface enters the acceleration stage, the deformation rate of the rock mass structural surface gradually increases, and its internal cracks continue to expand and eventually lead to destruction; S6. A numerical method for constructing a true three-dimensional stress-permeability-time-dependent coupled shear failure constitutive model of the structural surface; S7. Numerical verification of the shear failure constitutive model of structural surface under true three-dimensional stress-seepage pressure-time coupling and analysis of seepage disaster of structural surface tunnel in water-rich area.

2. The true three-dimensional stress-osmotic pressure-time-dependent coupled structural surface shear failure constitutive model according to claim 1 is characterized in that: In step S2, the true three-dimensional stress loading shear damage D of the rock mass structural surface is determined. s : Where: G0 is the initial shear stiffness of the rock mass structural surface, G s is the damage shear stiffness of the rock mass structural surface; Where: dτ and dγ are the shear stress increment and shear strain increment of the rock mass structural surface under multi-level loading.

3. The true three-dimensional stress-osmotic pressure-time-dependent coupled structural surface shear failure constitutive model according to claim 1 is characterized in that: In step S3, the effective stress is calculated according to the effective stress principle: Where τ' is the effective shear stress, σ' n is the effective normal stress, σ' p is the effective lateral stress, μ and p w are the Biot coefficient and osmotic pressure, respectively.

4. The true three-dimensional stress-osmotic pressure-time-dependent coupled structural surface shear failure constitutive model according to claim 1 is characterized in that: In the step S6, a numerical method for constructing a shear failure constitutive model of a structural surface under true three-dimensional stress-seepage-time coupling is implemented; According to the elastic stress increment formula: Δτ'=G s Dg Ds' n =k n No n Among them, G s and k n are the shear stiffness and normal stiffness, Δγ and Δε n are the shear and normal strain increments; The model consists of elastic bodies, viscoelastic bodies, fractional-order elements and fractional-order viscoplastic bodies. The total strain ε is expressed as: e=e e +e ve +e v +e vp Where: ε e , ε ve , ε v , ε vp are the strain matrices of elastic body, viscoelastic body, fractional element and fractional viscoplastic body respectively; Stress-strain relationship of elastic body: Among them, the superscripts N and O represent the stress after and before the update; Stress-strain relationship of viscoelastic body: Stress-strain relationship of fractional-order elements: The stress-strain relationship of fractional viscoplastic body: True three-dimensional stress-seepage-pressure-time coupled shear yield function F of rock mass s and the tensile yield function F t : F t =s t '-s' n According to the shear yield function F s , tensile yield function F t and plastic flow law to determine the shear plastic potential function g s and the tensile plastic potential function g t : g t =s t ' The updated stress is expressed as: B=G1G2((t+Δt) α -t α ) Effective lateral stress vector σ' p Perpendicular to the effective shear stress vector τ' and the effective normal stress vector σ' n ,but: s p ' =τ'×σ n ' The effective lateral stress σ' of the unit on the structural surface p The magnitude is the principal stress vector σ on the element i '(i=1,2,3) in vector σ' p The sum of the projection sizes in the direction of :

5. The true three-dimensional stress-osmotic pressure-time-dependent coupled structural surface shear failure constitutive model according to claim 1 is characterized in that: In the step S7, the numerical verification of the structural surface shear failure constitutive model under true three-dimensional stress-seepage pressure-time coupling and the seepage disaster analysis of the structural surface tunnel in the water-rich area are carried out; By numerically simulating true three-dimensional stress-seepage pressure-time-effect coupled multi-stage shear tests at different stress levels and seepage pressures, the deformation and failure results are obtained and compared with the test results. A three-dimensional tunnel numerical model of joint structural surfaces is established, and the tunnel excavation simulation is carried out using the shear failure constitutive model of the structural surface under true three-dimensional stress-seepage pressure-time-effect coupling, and the seepage disaster analysis of tunnel projects in water-rich areas is carried out.

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