A method for simulating seepage failure of porous media considering microscopic forces

Abstract

The present invention relates to a porous medium seepage destruction simulation method considering microscopic forces, and belongs to the field of flow-deformation coupling technology. Based on the seepage evolution law of soil under the action of deadweight, the present invention adopts mechanical tests to obtain the strength parameter characteristics of slope rock and soil materials, and constructs a standard strain softening model that characterizes the strength parameters of materials; based on the seepage evolution law of porous medium rock and soil, combined with buoyancy and surface tension, the stress-strain change law inside the soil under the action of seepage is determined, and the destruction mechanism and instability initiation mechanism of the soil under the action of water seepage are revealed. The slope instability destruction process is truly reflected, and the accuracy and reliability of numerical calculation results are improved.

Description

Technical Field

[0001] The invention relates to a porous medium seepage destruction simulation method considering microscopic forces, and belongs to the technical field of flow-deformation coupling. Background Art

[0002] As a loose and porous structure, how to correctly describe the coupled flow analysis of slope soil under water has been a hot topic and difficulty in recent years. Compared with the complexity of experimental research and the limitations of theoretical research, as long as reasonable constitutive relations and calculation parameters are given, numerical simulation can give accurate solutions and predictions. Therefore, the flow-deformation coupled numerical simulation method is increasingly favored by scholars at home and abroad.

[0003] Early studies on flow-deformation coupling in porous media were mainly based on the concept of a single porosity, assuming that the porosity is fully saturated and consists of a solid matrix and a single fluid phase. Any change in stress in the fluid, as a result of dynamic loading, is then accompanied by a corresponding change in the effective stress in the solid matrix, resulting in deformation of the porous medium. The Finite Element Method (FEM) is a robust numerical tool for solving such single saturated pore systems and has a wide range of applications in the dynamic response of saturated porous media, ground settlement above oil and gas reservoirs, multiphase fluid flow in deformable fractured reservoirs, deformation and localized behavior of unsaturated soils, etc. Although FEM gives satisfactory results, the method still has certain limitations, such as the need to mesh the problem domain and the problem of mesh distortion leading to non-convergence when calculating large deformations. Summary of the invention

[0004] In view of the problems that meshing is performed on the problem domain in existing studies on flow-deformation coupling in porous media, mesh distortion is prone to occur when calculating large deformations, resulting in non-convergence of calculations. This paper proposes a porous media seepage destruction simulation method considering microscopic forces, and uses the smoothed particle hydrodynamics (SPH) method combined with porosity changes to study the entire seepage movement process under different water level conditions in porous media slopes. The Drucker-Prager model and the non-associated flow law are used to expand the strain softening model, and the effects of buoyancy and surface tension on soil seepage are introduced and considered for the first time. An indoor scaled test is set up, and the corresponding slope SPH numerical model (such as Figure 2 ); The improved SPH algorithm effectively simulates the seepage change process and internal force change of soil; its research results can provide a new method and idea for studying slope seepage movement and stability analysis and revealing the mechanism of slope disaster.

[0005] Based on the SPH framework, the present invention obtains the strength parameter characteristics of slope rock and soil materials and their attenuation law (see strain softening formula), and constructs a strain softening model to characterize the attenuation of material strength parameters based on the ideal elastic-plastic constitutive model. Based on the non-single porosity factor, the pore water pressure and seepage resistance under porosity changes are considered, and then combined with the soil small deformation theory, the fluid surface tension and buoyancy are introduced. In the numerical calculation, the seepage destabilization and failure movement of porous medium rock and soil is simulated, the stability state of the slope under the seepage action is truly reflected, and the accuracy and reliability of the numerical calculation results are improved.

[0006] A method for simulating seepage failure of porous media considering microscopic forces, the specific steps are as follows:

[0007] S1. According to the slope height, slope foot and water level, establish the slope numerical calculation model; through the NS equation, build the fluid momentum conservation equation and mass conservation equation; construct the rock and soil momentum conservation equation and mass conservation equation, and the mass conservation equation takes into account the porosity change;

[0008] S2. Linked list search method searches for pairs of particles of the same phase and particles of different phases respectively;

[0009] S3. Fluid: The same phase particles use the pressure Poisson equation to update the pressure and introduce surface tension; the different phase particles generate pore water pressure, seepage resistance and buoyancy;

[0010] S4. Solid: The same-phase particles use the strain softening model to update the soil stress-strain; the heterogeneous particles are subject to pore water pressure, seepage resistance and buoyancy;

[0011] S5. Consider the change of rock and soil cohesion under the influence of seepage, and introduce the rock and soil cohesion change equation;

[0012] S6. Update the porosity s of the solid particles and ensure that the porosity s changes with the fluid particles and 0<s<1;

[0013] S7. Repeat steps S1.-S6 until the soil becomes unstable and fails.

[0014] In the step S1.

[0015] The fluid mass conservation equation is

[0016]

[0017] The fluid momentum conservation equation is

[0018]

[0019] The mass conservation equation of rock and soil is:

[0020]

[0021] The momentum conservation equation of rock and soil is

[0022]

[0023] In the formula: rho represents density; s represents pores; M, m a Represent the mass of soil and fluid respectively; v represents the particle velocity; p represents the pressure; g represents the gravitational acceleration; σ represents the soil stress; dWdx represents the derivative of the kernel function; x represents the particle distance; is a dimensionless constant; w represents the kernel function.

[0024] In step S3.

[0025] The Poisson equation for fluid pressure is:

[0026]

[0027] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w represents the kernel function.

[0028] The surface tension of the fluid is

[0029]

[0030] Where ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smoothing length; Pi represents the dimensionless constant Π.

[0031] Considering the surface tension, the momentum equation of the fluid particle is updated as follows:

[0032]

[0033] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w indicates that the kernel function ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smooth length; Pi represents the dimensionless constant Π; g represents the gravitational acceleration.

[0034] The strain softening model in step S4. is

[0035]

[0036] In the formula, represents the residual cohesion; represents the peak cohesion; similarly, Represent the residual internal friction angle and the peak internal friction angle respectively; e p represents the plastic deviatoric strain tensor; η represents the softening coefficient.

[0037] In step S4.

[0038] Seepage resistance:

[0039]

[0040] Where ζ is a dimensionless constant; Ψ is the permeability coefficient; v is the particle velocity; γ w is the fluid weight; rho is the fluid density; M represents the solid mass; x is the particle distance; is a dimensionless constant; w represents the kernel function; N represents the number of neighboring particles. Pore water pressure:

[0041]

[0042] Where p represents the fluid pressure; rho is the fluid density; M represents the solid mass; w represents the kernel function; and N represents the number of neighborhood particles.

[0043] buoyancy:

[0044] f c =-m a rhogZ / M

[0045] Where Z represents the solid volume; m a represents the mass of the fluid; M represents the mass of the solid; rho is the density of the fluid; g represents the acceleration due to gravity.

[0046] The soil momentum equation is updated as follows:

[0047]

[0048] Where rho is the fluid density; ζ is a dimensionless constant; γ w is the fluid density; Ψ is the permeability coefficient; M is the solid mass; s is the soil porosity; Z is the solid volume; x is the particle distance; [x ia ] represents the particle spacing mode length; is a dimensionless constant; p represents pressure; W represents the kernel function; σ represents the stress tensor; g represents the gravitational acceleration; and N represents the number of neighborhood particles.

[0049] The fluid momentum equation is updated as follows:

[0050]

[0051] In the formula, m a is the fluid mass; sw represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w represents the kernel function; x is the particle distance; ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smoothing length; ζ is a dimensionless constant; W represents the kernel function; Pi represents the dimensionless constant Π; Ψ represents the permeability coefficient; N represents the number of neighborhood particles.

[0052] In step S5, the equation for the change of rock and soil cohesion

[0053]

[0054] Where, T S Indicates soil saturation; They represent the initial cohesion and the cohesion of soil under saturated state respectively.

[0055] The porosity s of the solid phase particles in step S6. is

[0056]

[0057] Where M represents the solid mass; s represents the soil porosity; rho represents the fluid density; v represents the particle velocity; and W represents the kernel function.

[0058] The beneficial effects of the present invention are:

[0059] (1) Based on the seepage evolution law of soil under the action of deadweight, the present invention adopts mechanical tests to obtain the strength parameter characteristics of slope rock and soil materials, and constructs a standard strain softening model to characterize the attenuation of material strength parameters; based on the seepage evolution law of porous medium rock and soil, combined with buoyancy and surface tension, the internal stress-strain change law of soil under seepage is determined, and the destruction mechanism and instability initiation mechanism of soil under the action of water seepage are revealed; the instability and destruction process of slopes is truly reflected, and the accuracy and reliability of numerical calculation results are improved;

[0060] (2) In the numerical calculation process, the present invention takes into account the change process of soil porosity and introduces a strain softening model to characterize the attenuation characteristics of the strength parameters of geotechnical materials under the action of seepage, thus overcoming the defect that the strength parameters remain unchanged during the calculation process of the traditional elastic-plastic model, resulting in a large safety factor for seepage damage calculation, which in turn aggravates the potential danger of the project.

[0061] (3) The present invention takes into account the influence of microscopic forces on the seepage damage of porous media, has clear physical meaning and high reliability. Compared with the traditional seepage calculation process, it further considers the influence of buoyancy and surface tension on the internal particles of the soil, and can obtain a more realistic slope stability coefficient. It can provide a theoretical basis for studying the formation mechanism of slope seepage damage and instability, and for the design of coastal slope support systems, and has good prospects for practical engineering application. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a flow chart of the present invention;

[0063] Figure 2 is the example numerical model in Example 2;

[0064] Figure 3 It is the indoor scale model of the example in Example 2;

[0065] Figure 4 is a diagram of the slope seepage evolution process in Example 2;

[0066] Figure 5 This is a numerical simulation diagram of the slope seepage destabilization failure in Example 2. DETAILED DESCRIPTION

[0067] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0068] Example 1: A method for simulating seepage failure of porous media considering microscopic forces (see Figure 1 ), the specific steps are as follows:

[0069] S1. According to the geometric parameters of the reservoir bank slope height, slope foot and water level, a slope numerical calculation model is established by independently writing a program in Fortran language; through the NS equation, the fluid momentum conservation equation and mass conservation equation are constructed; the rock and soil momentum conservation equation and mass conservation equation are constructed, and the mass conservation equation takes into account the change of porosity;

[0070] The fluid mass conservation equation is

[0071]

[0072] The fluid momentum conservation equation is

[0073]

[0074] The mass conservation equation of rock and soil is:

[0075]

[0076] The momentum conservation equation of rock and soil is

[0077]

[0078] In the formula: rho represents density; s represents pores; M, m aRepresent the mass of soil and fluid respectively; v represents the particle velocity; p represents the pressure; g represents the gravitational acceleration; σ represents the soil stress tensor; dWdx represents the derivative of the kernel function; x represents the particle distance; is a dimensionless constant; w represents the kernel function;

[0079] S2. Linked list search method searches for pairs of particles of the same phase and particles of different phases respectively;

[0080] S3. Fluid: When calculating the internal particles of the fluid, the pressure Poisson equation is used to update the fluid pressure, and the microscopic force of surface tension is introduced to refine the external force of the fluid; while the particles in contact with the soil particles provide pore water pressure and seepage resistance and consider the influence of buoyancy on soil particles;

[0081] The Poisson equation for fluid pressure is:

[0082]

[0083] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w represents the kernel function;

[0084] The surface tension of the fluid is

[0085]

[0086] Where ξ is a dimensionless constant; [x ij ] represents the particle spacing mode length; h is the smooth length; Pi represents the dimensionless constant Π; considering the surface tension fluid particle momentum equation is updated as follows

[0087]

[0088] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w represents the kernel function; ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smooth length; Pi represents the dimensionless constant Π; g represents the gravitational acceleration;

[0089] S4. Solid: When calculating soil particles, the forces on internal particles and external particles must also be considered: for internal homogeneous particles, the strain softening model is used to update the soil stress-strain; external heterogeneous particles are additionally subject to pore water pressure, seepage resistance and buoyancy on the basis of the forces on internal particles;

[0090] The strain softening model is

[0091]

[0092] In the formula, represents the residual cohesion; represents the peak cohesion; similarly, Represent the residual internal friction angle and the peak internal friction angle respectively; e p represents the plastic deviatoric strain tensor; η represents the softening coefficient;

[0093] Seepage resistance:

[0094]

[0095] Where ζ is a dimensionless constant; Ψ is the permeability coefficient; v is the particle velocity; γ w is the fluid weight; rho is the fluid density; M represents the solid mass; x is the particle distance; is a dimensionless constant; w represents the kernel function; N represents the number of neighborhood particles.

[0096] Pore ​​water pressure:

[0097]

[0098] Where p represents fluid pressure; rho is fluid density; M represents solid mass; p represents pressure; w represents kernel function; and N represents the number of neighborhood particles.

[0099] buoyancy:

[0100] f c =-m a rhogZ / M

[0101] In the formula, Z represents the solid volume; M represents the solid mass; rho is the fluid density; g represents the gravitational acceleration m a is the fluid mass;

[0102] The soil momentum equation is updated as follows:

[0103]

[0104] Where rho is the fluid density; ζ is a dimensionless constant; γ w is the fluid density; Ψ is the permeability coefficient; M is the solid mass; s is the soil porosity; Z is the solid volume; x is the particle distance; [x ia ] represents the particle spacing mode length; is a dimensionless constant; p represents pressure; W represents the kernel function;

[0105] The fluid momentum equation is updated as follows:

[0106]

[0107] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; ξ is a dimensionless constant; [x ij ] represents the particle spacing norm; h is the smoothing length; ζ is a dimensionless constant; W represents the kernel function; Pi represents the dimensionless constant Π; g represents the gravitational acceleration; N represents the number of neighborhood particles.

[0108] S5. In the soil seepage process, the fluid continuously seeps into the soil. At this time, the soil is affected by the fluid, and its cohesion is significantly reduced compared with the unsaturated state. Considering the change of soil cohesion under the influence of seepage, the equation of soil cohesion change is introduced;

[0109] Equation of cohesion change of rock and soil

[0110]

[0111] Where, T S Indicates soil saturation; They represent the initial cohesion and the soil cohesion in saturated state respectively;

[0112] S6. Particles update field variables such as density, pressure and stress. Considering the change degree of porosity after the fluid particles enter the soil, the change of porosity is additionally considered, and the porosity s of the solid phase particles is updated, and it is ensured that the porosity s changes with the fluid particles and 0<s<1;

[0113] The porosity s of the solid phase particles is

[0114]

[0115] Where M represents the solid mass; s represents the soil porosity; rho represents the fluid density; v represents the particle velocity; W represents the kernel function;

[0116] S7. Repeat steps S1.-S6 until the soil becomes unstable and fails.

[0117] Example 2: Determine the mechanical parameters of the slope rock material through mechanical tests (see Table 1), the fluid parameter is density rho = 1000 kg / m 3 , the interparticle distance is 0.2m;

[0118] Table 1 Mechanical parameters of rock and soil

[0119]

[0120]

[0121] A method for simulating seepage failure of porous media considering microscopic forces (see Figure 1 ), the specific steps are as follows:

[0122] S1. Set up an indoor slope seepage test with a slope height of 2m, a slope foot of 45°, a slope bottom width of 3.32m, a soil thickness of 1m, and continuous water addition until the water level reaches 1.2m (see Figure 3 ), and used Fortran language to independently write a program to establish the corresponding slope numerical calculation model (see Figure 2 ) Through the NS equation, the momentum conservation equation and mass conservation equation of the fluid are constructed; the momentum conservation equation and mass conservation equation of the rock and soil are constructed, and the mass conservation equation takes into account the change of porosity;

[0123] The fluid mass conservation equation is

[0124]

[0125] The fluid momentum conservation equation is

[0126]

[0127] The mass conservation equation of rock and soil is:

[0128]

[0129] The momentum conservation equation of rock and soil is

[0130]

[0131] In the formula: rho represents density; s represents pores; M, m a Represent the mass of soil and fluid respectively; v represents the particle velocity; p represents the pressure; g represents the gravitational acceleration; σ represents the soil stress; dWdx represents the derivative of the kernel function; x represents the particle distance; is a dimensionless constant; w represents the kernel function.

[0132] S2. Linked list search method searches for pairs of particles of the same phase and particles of different phases respectively;

[0133] S3. Fluid: When calculating the internal particles of the fluid, the pressure Poisson equation is used to update the fluid pressure, and the microscopic force of surface tension is introduced to refine the external force of the fluid; while the particles in contact with the soil particles provide pore water pressure and seepage resistance and consider the influence of buoyancy on soil particles;

[0134] The Poisson equation for fluid pressure is:

[0135]

[0136] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w represents the kernel function; Pi represents the dimensionless constant Π; g represents the gravitational acceleration;

[0137] The surface tension of the fluid is

[0138]

[0139] Where ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smoothing length; Pi represents the dimensionless constant Π.

[0140] Considering the surface tension, the momentum equation of the fluid particle is updated as follows:

[0141]

[0142] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; w represents the kernel function; ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smooth length; Pi represents the dimensionless constant Π; g represents the gravitational acceleration;

[0143] S4. Solid: When calculating soil particles, the forces on internal particles and external particles must also be considered: for internal homogeneous particles, the strain softening model is used to update the soil stress-strain; external heterogeneous particles are additionally subject to pore water pressure, seepage resistance and buoyancy on the basis of the forces on internal particles;

[0144] The strain softening model is

[0145]

[0146] In the formula, represents the residual cohesion; represents the peak cohesion; similarly, Represent the residual internal friction angle and the peak internal friction angle respectively; e p represents the plastic deviatoric strain tensor; η represents the softening coefficient;

[0147] Seepage resistance:

[0148]

[0149] Where ζ is a dimensionless constant; Ψ is the permeability coefficient; v is the particle velocity; γw is the fluid weight; rho is the fluid density; M represents the solid mass; x is the particle distance; is a dimensionless constant; w represents the kernel function; N represents the number of neighborhood particles.

[0150] Pore ​​water pressure:

[0151]

[0152] In the formula, p represents fluid pressure; rho is fluid density; M represents solid mass; p represents pressure; and w represents kernel function.

[0153] buoyancy:

[0154] f c =-m a rhogZ / M

[0155] In the formula, Z represents the solid volume; M represents the solid mass; rho is the fluid density; g represents the gravitational acceleration; m a is the fluid mass

[0156] The soil momentum equation is updated as follows:

[0157]

[0158] Where rho is the fluid density; ζ is a dimensionless constant; γ w is the fluid density; Ψ is the permeability coefficient; M is the solid mass; s is the soil porosity; Z is the solid volume; x is the particle distance; [x ia ] represents the particle spacing mode length; is a dimensionless constant; p represents pressure; W represents the kernel function; σ represents the stress tensor; g represents the gravitational acceleration; N represents the number of neighborhood particles.

[0159] The fluid momentum equation is updated as follows:

[0160]

[0161] In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; is a dimensionless constant; x is the particle distance; ξ is a dimensionless constant; [x ij ] represents the particle spacing norm; h is the smoothing length; ζ is a dimensionless constant; W represents the kernel function; Pi represents the dimensionless constant Π; g represents the gravitational acceleration; N represents the number of neighborhood particles.

[0162] S5. In the soil seepage process, the fluid continuously seeps into the soil. At this time, the soil is affected by the fluid, and its cohesion is significantly reduced compared with the unsaturated state. Considering the change of soil cohesion under the influence of seepage, the equation of soil cohesion change is introduced;

[0163] Equation of cohesion change of rock and soil

[0164]

[0165] Where, T S Indicates soil saturation; They represent the initial cohesion and the soil cohesion in saturated state respectively;

[0166] In order to reflect the seepage stability characteristics of the slope under the influence of microscopic forces and the influence of cohesion changes, the strain softening model is used to analyze the slope; the whole process of instability and destruction of the reservoir bank slope under the action of fluid seepage is as follows: Figure 4 As shown;

[0167] S6. Particles update field variables such as density, pressure and stress. Considering the change degree of porosity after the fluid particles enter the soil, the change of porosity is additionally considered, and the porosity s of the solid phase particles is updated, and it is ensured that the porosity s changes with the fluid particles and 0<s<1;

[0168] The porosity s of the solid phase particles is

[0169]

[0170] Where M represents the solid mass; s represents the soil porosity; rho represents the fluid density; v represents the particle velocity; W represents the kernel function;

[0171] S7. Repeat steps S1.-S6 until the soil is unstable and damaged;

[0172] Figure (4) shows that, based on the SPH framework, the entire development process from initial contact to stability in the slope seepage process can be simulated after introducing porosity changes;

[0173] As can be seen from Figure (5), when buoyancy and surface tension are introduced and strain softening is used as the constitutive model of the soil for soil seepage failure analysis, it is obvious that this improved SPH numerical simulation calculation method can better fit the real soil.

[0174] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for simulating seepage failure of porous media considering microscopic forces, characterized in that: The specific steps are as follows: S1. According to the slope height, slope foot and water level, establish the slope numerical calculation model; through the NS equation, build the fluid momentum conservation equation and mass conservation equation; construct the rock mass momentum conservation equation and mass conservation equation, and the mass conservation equation takes into account the porosity change; S2. Linked list search method searches for pairs of particles of the same phase and particles of different phases respectively; S3. Fluid: Homogeneous particles use the pressure Poisson equation to update the pressure and introduce surface tension; heterogeneous particles generate pore water pressure, seepage resistance and buoyancy; S4. Solid: The same-phase particles use the strain softening model to update the soil stress-strain; the heterogeneous particles are subject to pore water pressure, seepage resistance and buoyancy; the strain softening model is In the formula, represents the residual cohesion; represents the peak cohesion; similarly, Represent the residual internal friction angle and the peak internal friction angle respectively; e p represents the plastic deviatoric strain tensor; η represents the softening coefficient; S5. Consider the change of rock and soil cohesion under the influence of seepage, and introduce the rock and soil cohesion change equation; S6. Update the porosity s of the solid particles and ensure that the porosity s changes with the fluid particles and 0<s<1; S7. Repeat steps S1.-S6 until the soil becomes unstable and fails.

2. The porous media seepage failure simulation method considering microscopic forces according to claim 1, characterized in that: In step S1. The fluid mass conservation equation is The fluid momentum conservation equation is The mass conservation equation of rock and soil is: The momentum conservation equation of rock and soil is In the formula: rho represents density; s represents pores; M, m a They represent the mass of soil and fluid respectively; v represents particle velocity; p represents pressure; g represents gravitational acceleration; σ represents soil stress; dWdx represents the derivative of kernel function; x represents particle distance; θ is a dimensionless constant; and w represents kernel function.

3. The porous media seepage failure simulation method considering microscopic forces according to claim 2, characterized in that: In step S3. The Poisson equation for fluid pressure is: In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; θ is a dimensionless constant; w represents the kernel function; The surface tension of the fluid is Where ξ is a dimensionless constant; [x ij ] represents the particle spacing mode length; h is the smoothing length; Considering the surface tension, the momentum equation of the fluid particle is updated as follows: In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; θ is a dimensionless constant; w represents the kernel function; ξ is a dimensionless constant; [x ij ] represents the particle spacing modulus; h is the smooth length; Pi represents the dimensionless constant Π; g represents the gravitational acceleration.

4. The porous media seepage failure simulation method considering microscopic forces according to claim 3, characterized in that: Seepage resistance: Where ζ is a dimensionless constant; Ψ is the permeability coefficient; v is the particle velocity; γ w is the fluid weight; rho is the fluid density; M is the solid mass; x is the particle distance; θ is a dimensionless constant; w is the kernel function; N is the number of neighborhood particles; Pore ​​water pressure: In the formula, p represents fluid pressure; rho represents fluid density; M represents solid mass; w represents kernel function; N represents the number of neighborhood particles; buoyancy: f c =-m a rhogZ / M Where Z represents the solid volume; m a represents the mass of the fluid; rho is the density of the fluid; g represents the acceleration of gravity; M represents the mass of the solid The soil momentum equation is updated as follows: Where rho is the fluid density; ζ is a dimensionless constant; γ w is the fluid density; Ψ is the permeability coefficient; M is the solid mass; s is the soil porosity; Z is the solid volume; x is the particle distance; [x ia ] represents the particle spacing norm; θ is a dimensionless constant; p represents pressure; W represents the kernel function; σ represents the stress tensor; g represents the gravitational acceleration; N represents the number of neighborhood particles; The fluid momentum equation is updated as follows: In the formula, m a is the fluid mass; s w represents the fluid porosity; rho is the fluid density; p represents the pressure; x is the particle distance; θ is a dimensionless constant; w represents the kernel function; ξ is a dimensionless constant; [x ij ] represents the particle spacing norm; h is the smoothing length; ζ is a dimensionless constant; W represents the kernel function; Pi represents the dimensionless constant Π; M represents the solid mass; and N represents the number of neighborhood particles.

5. The porous media seepage failure simulation method considering microscopic forces according to claim 4, characterized in that: Step S5. Equation of cohesion variation of rock and soil Where, T S Indicates soil saturation; They represent the initial cohesion and the cohesion of soil under saturated state respectively.

6. The porous media seepage failure simulation method considering microscopic forces according to claim 5, characterized in that: Step S6. The solid phase particle porosity s is Where M represents the solid mass; s represents the soil porosity; rho represents the fluid density; v represents the particle velocity; and W represents the kernel function.

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