Two-dimensional numerical method and device for simulating seepage softening of discontinuous surface of rock mass

Abstract

The invention provides a two-dimensional numerical method and device for simulating seepage softening of a discontinuous surface of a rock mass, and the method comprises the steps: determining a hydraulic joint unit in a two-dimensional model region at a current time step according to the type identifier of each joint unit in the two-dimensional model region corresponding to a target rock type; performing softening process calculation on the hydraulic joint unit to determine contact force acting on two walls of the hydraulic joint unit; performing seepage calculation on the hydraulic joint unit to determine first fluid pressure acting on each node of the hydraulic joint unit; determining a total equivalent node force acting on each node according to the contact force and the first fluid pressure; wherein the total equivalent nodal force is used for updating the type identification of the joint unit associated with the hydraulic joint unit. According to the method, seepage calculation and softening process calculation are conducted on the hydraulic joint unit, the prediction precision of rock mass disasters is improved, an effective prevention and control strategy can be adopted, and the method is suitable for discontinuous surface fluid-solid coupling calculation of various rocks.

Description

Technical Field

[0001] The present application relates to the technical fields of geotechnical engineering and energy environment technology, and particularly relates to a two-dimensional numerical method and device for simulating seepage softening of rock mass discontinuity surfaces. Background Art

[0002] A large number of discontinuity surfaces, such as joints and fissures, exist in natural rock masses. The seepage softening effect of rock mass discontinuity surfaces has a great impact on engineering stability problems such as the self-sustaining vulnerability of rock masses and energy extraction problems such as reservoir stimulation. The seepage softening process of rock mass discontinuity surfaces is essentially a fluid-solid coupling process.

[0003] In related technologies, discrete element and discontinuous deformation analysis methods are mainly used to solve the fluid-solid coupling problem of rock mass discontinuity surfaces. However, this method has a relatively high applicability to jointed rock masses without water-sensitive mechanical damage characteristics and a relatively poor applicability to highly water-sensitive rock masses, thus affecting the prediction accuracy of engineering soft rock mass disasters and the selection of prevention and control strategies. Summary of the Invention

[0004] A first aspect embodiment of the present application proposes a two-dimensional numerical method for simulating seepage softening of rock mass discontinuity surfaces, including: At the current time step, determine the hydraulic joint units in the two-dimensional model area according to the type identifiers of each joint unit in the two-dimensional model area corresponding to the target rock type; Perform a softening process calculation on the hydraulic joint units to determine the contact forces acting on the two walls of the hydraulic joint units; Perform a seepage calculation on the hydraulic joint units to determine the first fluid pressures acting on each node of the hydraulic joint units; Determine the total equivalent nodal forces acting on each node according to the contact forces and the first fluid pressures; wherein, the total equivalent nodal forces are used to update the type identifiers of the joint units associated with the hydraulic joint units.

[0005] A second aspect embodiment of the present application proposes a two-dimensional numerical device for simulating seepage softening of rock mass discontinuity surfaces, including: A first determination module, configured to determine the hydraulic joint units in the two-dimensional model area according to the type identifiers of each joint unit in the two-dimensional model area corresponding to the target rock type at the current time step; A softening process calculation module, configured to perform a softening process calculation on the hydraulic joint units to determine the contact forces acting on the two walls of the hydraulic joint units; A seepage calculation module, configured to perform a seepage calculation on the hydraulic joint units to determine the first fluid pressures acting on each node of the hydraulic joint units; A second determination module, configured to determine a total equivalent nodal force acting on each of the nodes according to the contact force and the first fluid pressure; wherein the total equivalent nodal force is used to update a type identifier of a joint unit associated with the hydraulic joint unit.

[0006] To achieve the above object, an embodiment of the third aspect of the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method as described in the embodiment of the first aspect.

[0007] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium, including: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method as described in the embodiment of the first aspect.

[0008] An embodiment of the fifth aspect of the present application provides a computer program product, including a computer program, which implements the method as described in the embodiment of the first aspect when executed by a processor.

[0009] The two-dimensional numerical method, device, electronic device, and storage medium for simulating seepage softening of rock mass discontinuities provided by the present application determine the hydraulic joint units in the two-dimensional model area at the current time step according to the type identifiers of the joint units in the two-dimensional model area corresponding to the target rock type, calculate the softening process of the hydraulic joint units, determine the contact forces acting on the two walls of the hydraulic joint units, calculate the seepage of the hydraulic joint units, determine the first fluid pressure acting on each node of the hydraulic joint units, and determine the total equivalent nodal force acting on the nodes based on the contact force and the first fluid pressure, so as to update the type identifier of the joint unit associated with the hydraulic joint unit. Thus, for the hydraulic joint units in the two-dimensional model area, not only seepage calculation is performed but also softening process calculation is performed, thereby improving the accuracy of the total equivalent nodal force acting on the nodes of the hydraulic joint units, improving the prediction accuracy of rock mass disasters, and then effective prevention and control strategies can be adopted, which is applicable to the fluid-solid coupling calculation of discontinuities of various rocks and improves the robustness and applicability.

[0010] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Description of the Drawings

[0011] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where: Figure 1 It is a schematic flow diagram of a two-dimensional numerical method for simulating seepage softening of rock mass discontinuities provided by an embodiment of the present application; Figure 2 It is a schematic diagram of the joint element type provided by an embodiment of the present application Figure 1 ; Figure 3 It is a schematic diagram of the joint element provided by an embodiment of the present application; Figure 4 It is a schematic diagram of the joint element type provided by an embodiment of the present application Figure 2 ; Figure 5 It is a schematic diagram of the equivalent nodal force for fluid pressure calculation provided by an embodiment of the present application; Figure 6 It is a schematic structural diagram of a two-dimensional numerical device for simulating seepage softening of rock mass discontinuities provided by an embodiment of the present application. Detailed Embodiments

[0012] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0013] The two-dimensional numerical method and device for simulating seepage softening of rock mass discontinuities according to embodiments of the present application are described below with reference to the accompanying drawings.

[0014] In some embodiments, the distinct element method and the discontinuous deformation analysis method mainly simplify the rock mass discontinuity into parallel plates, establish the relationship between the aperture of the rock mass discontinuity and the fluid flow rate using the cubic law, and realize the fluid-solid coupling calculation of the rock mass discontinuity by updating the fluid pressure acting on the two walls of the discontinuity and the aperture of the discontinuity. However, this method has poor applicability to highly water-sensitive rock masses, which will affect the prediction accuracy of engineering soft rock mass disasters and the selection of prevention and control strategies.

[0015] Based on this, an embodiment of the present application proposes a two-dimensional numerical method for simulating seepage softening of rock mass discontinuities. Figure 1 It is a schematic flow diagram of a two-dimensional numerical method for simulating seepage softening of rock mass discontinuities provided by an embodiment of the present application.

[0016] As Figure 1 shown, the two-dimensional numerical method for simulating seepage softening of rock mass discontinuities includes the following steps: Step 101, at the current time step, according to the type identification of each joint unit in the two-dimensional model area corresponding to the target rock type, determine the hydraulic joint unit in the two-dimensional model area.

[0017] The target rock type may be any rock type, for example, the target rock type may be any rock type among mudstone, shale, mud sandstone, granite, and marble.

[0018] In this application, discrete fracture network lines used to characterize discontinuities in the rock mass can be generated in the two-dimensional model area of the target rock type, and used as mesh boundaries to divide into triangular entity unit meshes, such as Figure 2 Afterwards, the node topology of the triangular solid element can be updated so that all triangular solid elements have independent node numbers, thereby embedding joint elements that can simulate the continuation-fracture process between adjacent triangular solid elements, and the joint elements have four nodes. Figure 2 The boundary area between the middle triangles can be considered as the joint unit.

[0019] In order to facilitate the understanding of joint units, the following Figure 3 Provide explanation. Figure 3 In the figure, before updating the node topology structure, the two triangular entity units have common nodes a and b. After updating the node topology structure, the two triangular entity units have independent node numbers. The node a in the upper triangular entity unit is numbered a1, and the node b is numbered b1. The node a in the lower triangular entity unit is numbered a2, and the node b is numbered b2. If a joint unit is embedded between the two triangular entity units, the four nodes of the joint unit are node a1, node a2, node b1, and node b2.

[0020] It should be noted that Figure 3 In the figure, the coordinates of the node a1 and the node a2 may be the same or different, and the coordinates of the node b1 and the node b2 may be the same or different, and there is no limitation on this.

[0021] In some embodiments, the joint units in the two-dimensional model region can be divided into fracture joint units representing discontinuous surfaces and bonding joint units representing continuous surfaces, such as Figure 2 As shown in Figure 2, the bonded joint unit will transform into a fractured joint unit when certain conditions are met.

[0022] In some embodiments, at the initial time step, the discontinuous surfaces in the two-dimensional model region can be marked as fractured joint elements, the continuous surfaces between the remaining triangular solid elements can be marked as bonded joint elements, and the bonded joint elements on the hydraulic boundary can be marked as hydraulic joint elements. At subsequent time steps, the fractured joint elements connected to the hydraulic boundary are also marked as hydraulic joint elements.

[0023] For example, Figure 2 the circular hole in Figure 2 represents a water hole, and the boundary of this water hole is the hydraulic boundary. The two-dimensional model region shown in Figure 2 has bonded joint elements, fractured joint elements, and hydraulic joint elements. As time goes by, Figure 4 some of the fractured joint elements in

[0024] become hydraulic joint elements, as shown in

[0025] In this application, at the current time step, each joint element in the two-dimensional model region can be traversed. According to the type identifier of each joint element, the type of each joint element in the two-dimensional template region can be determined, and thus the hydraulic joint elements in the two-dimensional model region can be determined.

[0026] It should be noted that the above type identifiers are only examples and can be determined according to actual needs. This application does not limit this.

[0027] In some embodiments, for the bonded joint elements in the two-dimensional model region, the bonded transition zone model can be used to calculate the stress state of the bonded joint elements. The stress state includes normal stress and shear stress, and the normal stress and shear stress are equivalent to nodal forces, that is, the stress state is converted into equivalent nodal forces, and the equivalent nodal forces are applied to the four nodes of the bonded joint elements.

[0028] For example, the stress state can be calculated using the following formulas (1) and (2): (1) (2) where the stress state includes the normal stress and the shear stress ; represents the shape function, , D represents the dimensionless damage parameter, a , b and c are the fitting parameters of the empirical curve; denotes the tensile strength; denotes the normal stress on the interaction edge, where the interaction edge is the two edges of the two triangular entities that make up the joint element; c and are the cohesion and internal friction angle of the rock, respectively.

[0029] In some embodiments, for the fractured joint elements in the two-dimensional model area, a discrete contact algorithm can be used to solve the contact force between the two walls of the fractured joint element and convert the contact force into an equivalent nodal force, that is, convert the contact force into an equivalent nodal force and apply the equivalent nodal force to the four nodes of the fractured joint element. Among them, the contact force between the two walls of the fractured joint element can include the normal repulsive stress and the tangential friction stress.

[0030] Exemplarily, the normal repulsive stress between the contact elements (i.e., contact pairs) can be calculated by using the distributed contact force penalty function method. Here, the contact pair can refer to the triangular solid elements on both sides of the joint element. For example, it can be assumed that the contact pairs can penetrate each other, and by calculating the size and shape of the overlapping area and introducing the normal contact stiffness, the normal repulsive stress can be calculated.

[0031] Exemplarily, a friction model considering the characteristics of the discontinuity surface can be used to calculate the tangential friction stress between the two walls of the fractured joint element. Among them, the calculation formula of the tangential friction stress can be as follows formula (3) shown: (3) Where, h is the side length of the triangular solid element; is the tangential contact stiffness; is the peak shear strength, , denotes the normal stress on the interaction edge, is the basic friction angle, JRC is the discontinuity surface roughness coefficient, JCS is the wall rock strength, Other optimized JRC-JCS formulas and three-dimensional shear strength theory formulas can also be used; is the residual shear strength, , is the residual friction angle; The sign of is the same as the sign of the slip distance variable , is the time step, is the relative velocity of the interaction edge; is the sliding distance corresponding to the peak shear strength, .

[0032] Step 102, perform a softening process calculation on the hydraulic joint element to determine the contact forces acting on the two walls of the hydraulic joint element.

[0033] Among them, the contact forces acting on the two walls of the hydraulic joint element may include normal repulsive stress, tangential friction stress, etc.

[0034] In some embodiments, a discrete contact algorithm can be used to solve the contact forces acting on the two walls of the hydraulic joint element. The contact forces also include normal repulsive stress and tangential friction stress. Among them, the calculation method of the normal repulsive stress can refer to the above calculation of the normal repulsive stress acting on the two walls of the hydraulic joint element, which will not be elaborated here.

[0035] Due to the softening effect of the hydraulic joint element, as the immersion time increases, the wall strength of the discontinuity surface may become smaller, and as the immersion time increases, the basic friction angle, residual friction angle, etc. will also be affected.

[0036] Based on this, in some embodiments, a friction model considering the characteristics of the discontinuity surface can be adopted, combined with the attenuation of the wall strength and the attenuation of the friction angle, to perform a softening process calculation on the hydraulic joint element to determine the tangential friction stress acting on the two walls of the hydraulic joint element. Since the attenuation of strength and the attenuation of the friction angle are considered, the accuracy of the tangential friction stress can be improved.

[0037] Exemplarily, the interface softening function and the friction angle attenuation function corresponding to the target rock type can be obtained, and according to the interface softening function, the basic friction angle can be corrected to obtain the corrected basic friction angle. According to the friction angle attenuation function, the wall strength parameter can be corrected to obtain the corrected wall strength parameter. According to the corrected basic friction angle and the corrected wall strength parameter, the corrected peak shear strength can be determined, and then according to the corrected peak shear strength, the tangential friction stress can be determined.

[0038] Among them, the interface softening function can be an attenuation function of the parameter measuring the wall strength of the discontinuity surface with the immersion time, and the friction angle attenuation function can be an attenuation function of the friction angle with the immersion time. The friction angle here can include the basic friction angle, residual friction angle, etc.

[0039] Among them, the parameters used to measure the wall strength of the discontinuity surface can include uniaxial compressive strength (UCS), wall rock strength, etc.

[0040] Exemplarily, the sliding distance variable on the interaction edge of the hydraulic joint element and the sliding distance corresponding to the peak shear strength can be determined. If the absolute value of the sliding distance variable is less than or equal to the sliding distance, the tangential frictional stress is determined according to the modified peak shear strength and the sliding distance variable. If the absolute value of the sliding distance variable is greater than the sliding distance, the residual friction angle is corrected according to the friction angle attenuation function, and the modified residual shear strength is determined according to the corrected residual friction angle. Then, the tangential frictional stress is determined according to the modified peak shear strength, the sliding distance variable, and the modified residual shear strength.

[0041] Exemplarily, the tangential frictional stress can be determined according to the ratio between the absolute value of the sliding distance variable and the absolute value of the sliding distance, the modified peak shear strength, and the modified residual shear strength.

[0042] As an example, the above formula (3) can be used to calculate the tangential frictional stress, and the following formulas (4) and (5) are used to obtain the modified peak shear strength and the modified residual shear strength: (4) (5) Wherein, is the friction angle attenuation function; is the interface softening function; represents the immersion time, that is, the existence duration of the hydraulic joint element. For example, if a fractured joint element is marked as a hydraulic joint element at time step , then the current time step minus is the immersion time .

[0043] For example, to calculate the tangential frictional stress of the hydraulic joint element at the current time step, the immersion time can be determined according to the current time step, and then the peak shear strength and the residual shear strength can be calculated according to formulas (4) and (5), and then substituted into formula (3) to calculate the tangential frictional stress of the hydraulic joint element.

[0044] Step 103, perform seepage calculation on the hydraulic joint element to determine the first fluid pressure acting on each node of the hydraulic joint element.

[0045] In this application, for each node in the hydraulic joint element, the first fluid pressure exerted by the water in the hydraulic joint element on each node at the current time step can be calculated.

[0046] In some embodiments, for any one of the nodes, the first fluid pressure of any one of the nodes at the current time step can be determined according to the second fluid pressure of any one of the nodes at the previous time step.

[0047] Exemplarily, if the second fluid pressure of any one of the nodes at the previous time step is greater than the first threshold, the first fluid pressure can be determined according to the second fluid pressure and the sum of the flows of all the hydraulic joint units to which any one of the nodes belongs. For example, the first threshold can be 0.

[0048] Exemplarily, if the second fluid pressure is less than the first threshold, the second fluid pressure can be assigned to the first threshold, and the second node saturation of any one of the nodes at the current time step can be determined according to the first node saturation of any one of the nodes at the previous time step.

[0049] Wherein, the second node saturation can be used to determine the flow of the hydraulic joint unit with any one of the nodes as the starting node of the seepage direction.

[0050] Exemplarily, if the first node saturation of any one of the nodes at the previous time step is less than the second threshold, the second node saturation of any one of the nodes at the current time step can be determined according to the first node saturation and the sum of the flows of all the hydraulic joint units to which any one of the nodes belongs. For example, the second threshold can be 1.

[0051] Exemplarily, if the first node saturation of any one of the nodes at the previous time step is greater than the second threshold, the first node saturation can be assigned to the second threshold, and the first fluid pressure can be determined according to the second fluid pressure and the sum of the flows of all the hydraulic joint units to which any one of the nodes belongs.

[0052] As an example, for any one of the nodes of the hydraulic joint unit, the sum of the flows of all the hydraulic joint units connected to the node can be calculated , where i is the hydraulic joint unit number, i = 0, 1, 2, 3, ……, n. Wherein, the flow of the hydraulic joint unit with the number i connected to the node, that is, the flow between two adjacent nodes in the seepage direction , can be calculated by the following formula (6): (6) Wherein, μ is the viscosity of the fluid; L is the length of the hydraulic joint unit; is the aperture of the hydraulic joint unit; is the saturation empirical function, which can be expressed as , where is the time step The saturation of the starting node flowing towards this node in the direction of seepage at that time; is the pressure difference between two adjacent nodes in the seepage direction, , where, is the density of the fluid, g is the acceleration due to gravity, and and are the elevations of two adjacent nodes respectively.

[0053] Furthermore, according to the flow rates of all the hydraulic joint elements connected to any node and , the fluid pressure of this node can be calculated using the following formula (7): (7) where, and are the fluid pressures of the node at time steps t and t - 1 respectively; K is the bulk modulus of the fluid; is the time step interval; , , where, and are the volumes of the above node at time steps and respectively. If , for time step , formula (7) is used for calculation. If , the fluid is not sufficient to fill the node cavity, then , and then the saturation of the node is updated using the following formula (8): (8) where, and are the saturations of this node at time steps and respectively. If , then , for time step , the saturation of the node is updated using formula (8), and formula (7) is not used to calculate the fluid pressure of the node; if , then , for time step , the fluid pressure of the node is calculated using formula (7).

[0054] For example, the seepage direction of a certain hydraulic joint element is from node d to node e. When calculating the fluid pressure of node e currently, the saturation of node e is updated, and when calculating the flow rate between node d and node e, the saturation of node e is used.

[0055] Step 104: Determine the total equivalent nodal force acting on each node according to the contact force and the first fluid pressure.

[0056] Among them, the total equivalent nodal force acting on each node of the hydraulic joint element can be used to update the type identifier of the joint element associated with the hydraulic joint element.

[0057] Exemplarily, the joint element associated with the hydraulic joint element may refer to other types of hydraulic joint elements having common nodes with the hydraulic joint element. For example, the joint element associated with the hydraulic joint element may include a bonded joint element, a fractured joint element, etc. In this application, the contact force and the first fluid pressure of each node can be respectively converted into equivalent nodal forces. For any node of the hydraulic joint element, the total equivalent nodal force acting on the node can be determined according to these two equivalent nodal forces.

[0058] As an example, the fluid pressure of each node acts as the surface pressure on the two walls of the hydraulic joint element, and the fluid pressure is converted into an equivalent nodal force through Equation (9), as Figure 5 shown: (9) where is the fluid pressure on the two walls of the hydraulic joint element, , p 1 is the fluid pressure between node 0 and node 3, p 1 is the fluid pressure between node 1 and node 3; , , and are respectively Figure 5 the coordinates of the four nodes of the hydraulic joint element shown.

[0059] Since the hydraulic joint element has common nodes with other joint elements such as bonded joint elements and fractured joint elements, that is to say, the nodes of the hydraulic joint element may also belong to bonded joint elements, fractured joint elements, etc. Based on this, in some embodiments, for any node in the hydraulic joint element, all the joint elements to which the node belongs can be determined, and the sum of the equivalent nodal forces obtained by performing corresponding type of mechanical calculations on all the joint elements to which it belongs is the total equivalent nodal force. For example, if a certain node belongs to the hydraulic joint element A1, the bonded joint element A2, and the fractured joint element A3, the equivalent nodal force obtained according to the contact force on the two walls of the hydraulic joint element A1 and the fluid pressure of the node, the equivalent nodal force equivalently obtained from the stress state of the bonded joint element A2, and the equivalent nodal force equivalently obtained from the contact force on the two walls of the fractured joint element A3 can be added together to obtain the total equivalent nodal force acting on the node.

[0060] For any node in the hydraulic unit, the acceleration can be determined based on the total equivalent nodal force of the node and the mass of the node. Based on the acceleration and the time step interval, the velocity can be determined. Based on the velocity and the time step interval, the displacement can be determined. Based on the displacement, the coordinates of the node are updated to obtain the updated coordinates of the node. Based on the updated coordinates of the node, the type identifier of the joint unit associated with the hydraulic unit is updated. Among them, the mass of the node can be equal to one-third of the mass of a triangular solid element.

[0061] Exemplarily, in the same way, the updated coordinates of other nodes in the associated joint unit can be determined, and based on the updated coordinates of each node in the associated joint unit, the type identifier of the joint unit associated with the hydraulic unit is updated.

[0062] For example, the associated joint unit includes a bonded joint unit. Based on the updated coordinates of each node of the bonded joint unit, it is determined whether the bonded joint unit has been damaged. If it has been damaged, the type identifier of the bonded joint unit can be updated to the type identifier of the fractured joint unit. Then, for the fractured joint unit, it can be determined whether the fractured joint unit is a hydraulic joint unit. If so, the type identifier of the fractured joint unit is updated to the type identifier of the hydraulic joint unit. After that, the softening process calculation and seepage calculation can be performed on the hydraulic joint unit.

[0063] Exemplarily, if the normal distance between the midpoints of two sides of the bonded joint unit is greater than the normal distance threshold, it can be considered that the bonded joint unit is damaged, and thus the bonded joint unit is determined to be a fractured joint unit.

[0064] Exemplarily, if the lateral slip distance of the bonded joint unit is greater than the lateral slip distance, it can be considered that the bonded joint unit is damaged, and thus the bonded joint unit becomes a fractured joint unit.

[0065] Exemplarily, if the square root of the sum of the squares of the normal distance and the lateral slip distance of the bonded joint unit is outside the preset envelope area, it can be considered that the bonded joint unit is damaged, and thus the bonded joint unit becomes a fractured joint unit.

[0066] Exemplarily, the following method can be used to determine whether a fractured joint unit is a hydraulic joint unit: It can be determined whether the fractured joint unit is connected to the hydraulic boundary. If the fractured joint unit is connected to the hydraulic boundary, it can be determined that the fractured joint unit becomes a hydraulic joint unit.

[0067] As an example, it can be determined whether any node in the fractured joint unit belongs to any hydraulic joint unit. If any node in the fractured joint unit belongs to any hydraulic joint unit, it can be considered that the fractured joint unit is connected to the hydraulic boundary, and it can be determined that the fractured joint unit is a hydraulic joint unit.

[0068] It can be understood that for each node of the joint element in the two-dimensional model region, the acceleration can be determined according to the sum of all equivalent nodal forces acting on the node and the mass of the node. Based on the acceleration and the time step interval, the velocity can be determined. Based on the velocity and the time step interval, the displacement amount can be determined. According to the displacement amount, the coordinates of the node can be updated. Thus, for the bonded joint element in the two-dimensional model region, it can be determined whether the bonded joint element has failed according to the updated coordinates of the nodes of the bonded joint element. If a failure occurs, the type identifier of the bonded joint element can be updated to the type identifier of the fractured joint element. Then, for the fractured joint element, it can be determined whether the fractured joint element is a hydraulic joint element. If so, the type identifier of the fractured joint element can be updated to the type identifier of the hydraulic joint element, and the softening process calculation and seepage calculation are performed on the hydraulic joint element.

[0069] For example, the class identifier of the bonded joint element is 0, the type identifier of the fractured joint element is 1, and the type identifier of the hydraulic joint element is marked with 2. If a bonded joint element is damaged, that is, it becomes a fractured joint element, then the type identifier of the joint element is updated from 0 to 1. If the fractured joint element is a hydraulic joint element, then the type identifier of the joint element can be updated from 1 to 2.

[0070] In the embodiment of the present application, by determining the hydraulic joint elements in the two-dimensional model region according to the type identifiers of the joint elements in the two-dimensional model region corresponding to the target rock type, performing the softening process calculation on the hydraulic joint elements to determine the contact force acting on the two walls of the hydraulic joint elements, performing the seepage calculation on the hydraulic joint elements to determine the first fluid pressure acting on each node of the hydraulic joint elements, and based on the contact force and the first fluid pressure, determining the total equivalent nodal force acting on the nodes for updating the type identifiers of the joint elements associated with the hydraulic joint elements. Thus, for the hydraulic joint elements in the two-dimensional model region, not only the seepage calculation is performed but also the softening process calculation is performed, so that the accuracy of the total equivalent nodal force acting on the nodes of the hydraulic joint elements can be improved, the prediction accuracy of rock mass disasters can be improved, and then effective prevention and control strategies can be adopted, which is applicable to the fluid-solid coupling calculation of the discontinuity surface of various rocks and improves the robustness and applicability.

[0071] In addition, when performing the softening process calculation on the hydraulic joint elements, the attenuation of the discontinuity surface wall strength with the immersion time and the attenuation of the friction angle with the immersion time are considered. Based on the interface softening function and the friction angle attenuation function, the corrected peak shear strength and the corrected residual friction angle are obtained. Based on the corrected peak shear strength and the corrected residual friction angle, the tangential friction stress of the hydraulic joint elements is calculated, which improves the accuracy of the tangential friction stress, and further improves the accuracy of the equivalent nodal force converted from the tangential friction stress.

[0072] To implement the above embodiments, the present application further proposes a two-dimensional numerical device for simulating seepage softening of rock mass discontinuities.

[0073] Figure 6 The structural schematic diagram of a two-dimensional numerical device for simulating seepage softening of rock mass discontinuities provided by an embodiment of the present application.

[0074] As Figure 6 shown, the two-dimensional numerical device 600 for simulating seepage softening of rock mass discontinuities includes: A first determination module 610, configured to determine hydraulic joint units in the two-dimensional model region according to the type identifiers of each joint unit in the two-dimensional model region corresponding to the target rock type at the current time step; A softening process calculation module 620, configured to perform a softening process calculation on the hydraulic joint units to determine the contact forces acting on the two walls of the hydraulic joint units; A seepage calculation module 630, configured to perform a seepage calculation on the hydraulic joint units to determine the first fluid pressures acting on each node of the hydraulic joint units; A second determination module 640, configured to determine the total equivalent nodal forces acting on each node according to the contact forces and the first fluid pressures; wherein, the total equivalent nodal forces are used to update the type identifiers of the joint units associated with the hydraulic joint units.

[0075] Further, in a possible implementation manner of the embodiment of the present application, the contact force includes a tangential friction stress, and the softening process calculation module 620 is configured to: Obtain an interface softening function and a friction angle attenuation function corresponding to the target rock type; wherein, the interface softening function is a decay function of the parameter for measuring the strength of the discontinuity wall surface with the immersion time, and the friction angle attenuation function is a decay function of the friction angle with the immersion time; wherein, the friction angle includes a basic friction angle; According to the interface softening function, correct the basic friction angle to obtain a corrected basic friction angle; According to the friction angle attenuation function, correct the wall surface strength parameter to obtain a corrected wall surface strength parameter; According to the corrected basic friction angle and the corrected wall surface strength parameter, determine a corrected peak shear strength; According to the corrected peak shear strength, determine the tangential friction stress.

[0076] Further, in a possible implementation manner of the embodiment of the present application, the friction angle further includes a residual friction angle, and the softening process calculation module 620 is configured to: Determine the sliding distance variable on the interaction edge of the hydraulic joint unit and the sliding distance corresponding to the peak shear strength; In response to the absolute value of the sliding distance variable being less than or equal to the sliding distance, determine the tangential frictional stress according to the corrected peak shear strength and the sliding distance variable; In response to the absolute value of the sliding distance variable being greater than the sliding distance, correct the residual friction angle according to the friction angle attenuation function, and determine the corrected residual shear strength according to the corrected residual friction angle; Determine the tangential frictional stress according to the corrected peak shear strength, the sliding distance variable, and the corrected residual shear strength.

[0077] Further, in a possible implementation manner of the embodiment of the present application, the seepage calculation module 630 is configured to: For any one of the nodes, determine the first fluid pressure of the any one of the nodes at the current time step according to the second fluid pressure of the any one of the nodes at the previous time step.

[0078] Further, in a possible implementation manner of the embodiment of the present application, the seepage calculation module 630 is configured to: In response to the second fluid pressure being greater than the first threshold, determine the first fluid pressure according to the second fluid pressure and the sum of the flow rates of all the hydraulic joint units to which the any one of the nodes belongs.

[0079] Further, in a possible implementation manner of the embodiment of the present application, the device may further include: A third determination module, configured to, in response to the second fluid pressure being less than the first threshold, assign the second fluid pressure to the first threshold, and determine the second node saturation of the any one of the nodes at the current time step according to the first node saturation of the any one of the nodes at the previous time step; Wherein, the second node saturation is used to determine the flow rate of the hydraulic joint unit with the any one of the nodes as the starting node of the seepage direction.

[0080] Further, in a possible implementation manner of the embodiment of the present application, the third determination module is configured to: In response to the first node saturation being less than the second threshold, determine the second node saturation according to the first node saturation and the sum of the flow rates.

[0081] It should be noted that the foregoing explanation of the embodiment of the two-dimensional numerical method for simulating the seepage softening of rock mass discontinuities also applies to the two-dimensional numerical device for simulating the seepage softening of rock mass discontinuities in this embodiment, and details are not described herein again.

[0082] In the embodiments of the present application, for the hydraulic joint units in the two-dimensional model area, not only seepage calculation but also softening process calculation are performed, so as to improve the accuracy of the total equivalent nodal forces acting on the nodes of the hydraulic joint units, improve the prediction accuracy of rock mass disasters, and then effective prevention and control strategies can be adopted. It is applicable to the fluid-solid coupling calculation of discontinuity surfaces of various rocks, and improves the robustness and applicability.

[0083] To implement the above embodiments, the present application also provides an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided in the foregoing embodiments. To implement the above embodiments, the present application also provides a computer-readable storage medium storing computer-executable instructions, and the computer-executable instructions are used to implement the method provided in the foregoing embodiments when executed by a processor.

[0084] To implement the above embodiments, the present application also provides a computer program product including a computer program, and the computer program implements the method provided in the foregoing embodiments when executed by a processor.

[0085] In the present application, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information comply with the provisions of relevant laws and regulations and do not violate public order and good customs.

[0086] It should be noted that personal information from users should be collected for legal and reasonable purposes and not shared or sold outside of these legal uses. In addition, such collection / sharing should be carried out after obtaining the informed consent of the user, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization including authorizing relevant user information before the user uses the function. In addition, any necessary steps should be taken to safeguard and protect access to such personal information data and ensure that others with access to personal information data comply with their privacy policies and procedures.

[0087] The present application anticipates providing an implementation plan for users to selectively block the use or access of personal information data. That is, the present disclosure anticipates providing hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, the risk can be minimized by restricting data collection and deleting data. In addition, when applicable, personal identifiers are removed from such personal information to protect the privacy of users.

[0088] In the description of the foregoing embodiments, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0089] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0090] Any process or method description in a flowchart or described in other ways herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logic function or process, and the scope of the preferred embodiments of the present application includes additional implementations, where the functions may be performed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0091] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definable sequence list of executable instructions for implementing logical functions, which can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: electrical connection parts with one or more wirings (electronic devices), portable computer disk cartridges (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber devices, and portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0092] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having suitable combinational logic gate circuits, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

[0093] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0094] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, may exist separately physically for each unit, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0095] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A two-dimensional numerical method for simulating seepage softening of rock mass discontinuities, characterized in that, Including the following steps: At the current time step, determine the hydraulic joint elements in the two-dimensional model area according to the type identifiers of the joint elements in the two-dimensional model area corresponding to the target rock type; Perform a softening process calculation on the hydraulic joint elements to determine the contact forces acting on the two walls of the hydraulic joint elements; Perform a seepage calculation on the hydraulic joint elements to determine the first fluid pressure acting on each node of the hydraulic joint elements; Determine the total equivalent nodal forces acting on each of the nodes according to the contact forces and the first fluid pressure; wherein, the total equivalent nodal forces are used to update the type identifiers of the joint elements associated with the hydraulic joint elements.

2. The method according to claim 1, wherein The contact force includes a tangential frictional stress, and the performing a softening process calculation on the hydraulic joint elements to determine the contact forces acting on the two walls of the hydraulic joint elements includes: Obtain an interface softening function and a friction angle attenuation function corresponding to the target rock type; wherein, the interface softening function is a decay function of a parameter for measuring the strength of the discontinuous surface wall with respect to the immersion time, and the friction angle attenuation function is a decay function of the friction angle with respect to the immersion time; wherein, the friction angle includes a basic friction angle; Correct the basic friction angle according to the interface softening function to obtain a corrected basic friction angle; Correct the wall strength parameter according to the friction angle attenuation function to obtain a corrected wall strength parameter; Determine a corrected peak shear strength according to the corrected basic friction angle and the corrected wall strength parameter; Determine the tangential frictional stress according to the corrected peak shear strength.

3. The method according to claim 2, characterized in that The friction angle further includes a residual friction angle, and the determining the tangential frictional stress according to the corrected peak shear strength includes: Determine the sliding distance variable on the interaction side of the hydraulic joint element and the sliding distance corresponding to the peak shear strength; In response to the absolute value of the sliding distance variable being less than or equal to the sliding distance, determine the tangential frictional stress according to the corrected peak shear strength and the sliding distance variable; In response to the absolute value of the sliding distance variable being greater than the sliding distance, correct the residual friction angle according to the friction angle attenuation function, and determine a corrected residual shear strength according to the corrected residual friction angle; Determine the tangential frictional stress according to the corrected peak shear strength, the sliding distance variable, and the corrected residual shear strength.

4. The method according to claim 1, wherein The performing a seepage calculation on the hydraulic joint elements to determine the first fluid pressure acting on each node of the hydraulic joint elements includes: For any one of the nodes, determine the first fluid pressure of the any one node at the current time step according to the second fluid pressure of the any one node at the previous time step.

5. The method according to claim 4, characterized in that, The determining the first fluid pressure of the any one node at the current time step according to the second fluid pressure of the any one node at the previous time step includes: In response to the second fluid pressure being greater than the first threshold, determine the first fluid pressure according to the second fluid pressure and the sum of the flows of all the hydraulic joint units to which any one of the nodes belongs.

6. The method according to claim 5, characterized in that The method further includes: In response to the second fluid pressure being less than the first threshold, assign the second fluid pressure to the first threshold, and determine the second node saturation of any one of the nodes at the current time step according to the first node saturation of any one of the nodes at the previous time step; Wherein, the second node saturation is used to determine the flow rate of the hydraulic joint unit with any one of the nodes as the starting node of the seepage direction.

7. The method according to claim 6, wherein The determining the second node saturation of any one of the nodes at the current time step according to the first node saturation of any one of the nodes at the previous time step includes: In response to the first node saturation being less than the second threshold, determine the second node saturation according to the first node saturation and the sum of the flows.

8. A two-dimensional numerical device for simulating seepage softening of rock mass discontinuities, characterized in that, including: A first determination module, configured to determine the hydraulic joint units in the two-dimensional model area according to the type identifiers of the joint units in the two-dimensional model area corresponding to the target rock type at the current time step; A softening process calculation module, configured to perform a softening process calculation on the hydraulic joint units to determine the contact force acting on the two walls of the hydraulic joint units; A seepage calculation module, configured to perform a seepage calculation on the hydraulic joint units to determine the first fluid pressure acting on each node of the hydraulic joint units; A second determination module, configured to determine the total equivalent nodal force acting on each of the nodes according to the contact force and the first fluid pressure; wherein, the total equivalent nodal force is used to update the type identifier of the joint unit associated with the hydraulic joint unit.

9. An electronic device, characterized in that, including: A processor, and a memory communicatively connected to the processor; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to implement the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer execution instructions, and when the computer execution instructions are executed by a processor, they are used to implement the method according to any one of claims 1-7.

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