Anchor rod prestress application simulation method, system and equipment and storage medium

Abstract

The invention relates to the field of rock mechanics and mine engineering, and discloses an anchor rod prestress applying simulation method, system and equipment and a storage medium. The method comprises the steps that surrounding rock excavation simulation is conducted on a surrounding rock numerical model, and after the surrounding rock numerical model reaches a balanced state, an anchor rod is activated and anchor rod parameters are input; prestress is applied to the surrounding rock numerical model, the state of the anchor rod is modified through a mixed finite element-discrete element method, and the anchor rod is divided into a shallow section and a deep section which are disconnected; oppositely stretching the shallow section and the deep section according to the pre-tightening force data until the numerical model of the surrounding rock reaches the balance state again; parameters of the anchor rod are modified, the shallow section and the deep section are bonded to obtain a complete anchor rod, and a prestress simulation result is generated through an anchor rod constitutive equation and a surrounding rock constitutive equation. According to the invention, the real process of forming the near-pressure and far-tension prestress in the surrounding rock by oppositely stretching the anchor rod can be reflected, and the interaction process between the pre-stressed anchor rod and the surrounding rock can be accurately captured.

Description

Technical Field

[0001] The present invention relates to the intersecting fields of rock mechanics and mining engineering, mine safety and surrounding rock control, computational geomechanics and numerical simulation, and in particular to a method, system, equipment and storage medium for simulating the application of anchor prestress. Background Art

[0002] Anchor support primarily utilizes the interaction between anchors and surrounding rock to form a holistic and stable rock reinforcement zone around the excavated rock mass, thereby controlling deformation, instability, and failure. To date, anchor support has been widely used in geotechnical engineering projects such as tunnels and slopes.

[0003] Prestressing in anchor support is gaining increasing attention in the geotechnical industry. The prevailing view is that prestressing significantly impacts support effectiveness. Consequently, prestressed anchor simulation has become a growing research hotspot. The key to prestressed anchor simulation is to rationally simulate the application of prestressing force on the anchor, building upon the simulation of the physical anchor.

[0004] The application of anchor prestress in real projects usually refers to the prestress formed in the reinforced surrounding rock by changing the stress distribution inside the surrounding rock after applying pre-tightening force to the anchor. With regard to anchors, in order to form prestress, the anchors need to be stretched in opposite directions, that is, the anchors in the shallow surrounding rock close to the excavation surface are pulled toward the deep surrounding rock, and the anchors in the deep surrounding rock far away from the excavation surface are pulled toward the shallow surrounding rock. With regard to the surrounding rock, prestressing is manifested as near compression and far tension, that is, the shallow surrounding rock close to the excavation surface exhibits compressive stress, and the deep surrounding rock far away from the excavation surface exhibits tensile stress. For this reason, the key to simulating the application of anchor prestressing is to reasonably "stretch" the anchors in opposite directions and thus form a "near compression and far tension" prestress in the surrounding rock.

[0005] The complexity of anchor prestressing mechanisms combined with the limitations of mainstream numerical simulation methods make the aforementioned anchor prestressing process extremely difficult to implement. Consequently, simulating anchor prestressing has long been a challenging area to overcome in excavation support simulation. Existing simulation methods for anchor prestressing suffer from four common problems: ① The anchor prestressing method is irrational and fails to reflect the actual process of "near compression and far tension" prestressing in the surrounding rock by "stretching" the anchor in opposite directions; ② Simplified structural elements such as rods and beams are typically used for anchors, rather than solid elements, making it difficult to truly capture the interaction between the anchor and the surrounding rock; ③ The simulation methods used are typically the finite element method (FEM), which excels at continuous problems, or the discrete element method (DEM), which excels at discontinuous problems. These methods fail to capture the gradual transformation of geomaterials from continuous (intact rock) to discontinuous (fractured into multiple blocks), a process that directly participates in the interaction between the prestressed anchor and the surrounding rock; and ④ Because the anchor is assumed to be elastic (without tensile or shear fracture properties), the tensile and shear fracture phenomena of the anchor in actual engineering cannot be captured. Regarding the core issue of anchor prestressing method, many prestressing methods described in the literature are seriously inconsistent with actual engineering conditions. For example, some literatures apply anchor prestress by continuously applying single-direction pressure or tension at the tail of the anchor, while some literatures reflect the magnitude of anchor prestress by changing the surrounding rock properties.

[0006] In summary, the existing simulation method for anchor rod prestressing cannot reflect the actual process of forming "near compression and far tension" prestress in the surrounding rock by "stretching" the anchor rod in opposite directions, and cannot capture the interaction process between the prestressed anchor rod and the surrounding rock (prestressed anchor rod forms prestress in the surrounding rock → surrounding rock deformation-rupture-instability → anchor rod deformation-breakage-failure, and the gradual transformation process from continuous to discontinuous between the anchor rod and the surrounding rock).

[0007] The hybrid finite element-discrete element method (FDEM) excels at capturing the gradual transition from continuous to discontinuous in brittle materials and has the potential to address the four common issues mentioned above. However, existing FDEM-based anchor support simulations lack a robust method for simulating anchor prestressing. This method fails to capture the true process of "near compression and far tension" prestressing in the surrounding rock through the "opposite stretching" of the anchor, and cannot accurately capture the interaction between the prestressed anchor and the surrounding rock. Therefore, it is necessary to develop an FDEM-based method for simulating anchor prestressing. Summary of the Invention

[0008] In order to solve the problem that the existing technology cannot accurately simulate the deformation process of anchor support under prestressing, the present invention provides an anchor prestressing simulation method, system, device and storage medium.

[0009] In a first aspect, the present invention provides a method for simulating anchor prestressing, comprising: Constructing a surrounding rock numerical model, performing surrounding rock excavation simulation on the surrounding rock numerical model, and activating anchor rods and inputting anchor rod parameters in the surrounding rock numerical model after the surrounding rock numerical model reaches an equilibrium state; Applying prestress in the surrounding rock numerical model, modifying the anchor state of the anchor by using a hybrid finite element-discrete element method, and dividing the anchor into a disconnected shallow section and a deep section; obtaining preload data, and performing opposite stretching on the shallow section and the deep section according to the preload data until the surrounding rock numerical model reaches the equilibrium state again; The parameters of the anchor rod are modified to bond the shallow section and the deep section to obtain a complete anchor rod, the breaking parameters of the complete anchor rod are calculated using the anchor rod constitutive equation and the surrounding rock constitutive equation, and a prestress simulation result is generated based on the breaking parameters.

[0010] In an optional embodiment, activating the anchor rod in the surrounding rock numerical model and inputting anchor rod parameters include: After the anchor rod is activated, an intersection position between the anchor rod and the surrounding rock in the surrounding rock numerical model is obtained, a physical anchor rod is marked according to the intersection position, and an anchor rod interface corresponding to the physical anchor rod and a surrounding rock interface corresponding to the surrounding rock are determined; An interface relationship between the anchor rod interface and the surrounding rock interface is determined, and anchor rod parameters are assigned to the physical anchor rod, wherein the anchor rod parameters include mechanical parameters of the anchoring agent.

[0011] In an optional embodiment, marking the physical anchor rod according to the intersection position includes: Dividing the anchor rod into a plurality of anchor rod units and dividing the surrounding rock into a plurality of surrounding rock units; Obtaining a first vector corresponding to each of the anchor rod units, and obtaining a second vector corresponding to each of the surrounding rock units; Determining whether each of the first vectors and each of the second vectors intersects according to a vector intersection calculation formula; If they intersect, the physical anchor rod is marked according to the intersection position of the first vector and the second vector.

[0012] In an optional embodiment, calculating the fracture parameters of the complete anchor includes: Determining the fracture type of the complete anchor bolt, wherein the fracture type includes tension type, shear type and tension-shear type; According to the fracture type, the fracture parameters of the complete anchor are determined.

[0013] In an optional embodiment, determining the fracture parameters of the intact anchor bolt according to the fracture type includes: If the fracture type is the tensile type, determining the fracture parameter type as crack opening; Determine the interface unit between every two adjacent anchor units, and calculate the peak crack opening of the interface unit; The fracture parameter is determined according to the peak crack opening.

[0014] In an optional embodiment, determining the fracture parameters of the intact anchor bolt according to the fracture type includes: If the fracture type is the shear type, determining the fracture parameter type as tangential crack slip; If the interface unit is not separated, the tangential bond stress of the interface unit is determined according to the crack slip peak value of the tangential crack slip, the shear yield strength of the anchor bolt is calculated according to the tangential bond stress, and the shear yield strength is used as the fracture parameter: , in, τ y is the shear yield strength of the anchor rod, c is the internal bonding force of the anchor bolt, σ n is the normal stress applied to the interface element, is the internal friction angle, when the crack slip reaches the crack slip peak, the tangential bond stress is equal to the shear yield strength of the anchor bolt; If the interface unit is separated, the crack friction angle of the interface unit is obtained when the crack slip exceeds the crack slip peak and the tangential crack slip of the interface unit reaches the critical crack slip. The residual friction force is calculated based on the crack friction angle, and the residual friction force is used as the fracture parameter: , in, τ r is the residual friction force, is the crack friction angle.

[0015] In an optional embodiment, the determining the fracture parameters of the complete anchor bolt according to the fracture type includes: If the fracture type is the tensile shear type, determining the peak crack opening in the axial direction and the peak crack slip in the transverse direction of the intact anchor rod; respectively constructing a first constraint function corresponding to the peak crack opening and a second constraint function corresponding to the peak crack slip; The first constraint function and the second constraint function are solved using the anchor constitutive equation and the surrounding rock constitutive equation to calculate the anchor shear stress of the interface unit, and the anchor shear stress is used as the fracture parameter.

[0016] In a second aspect, the present invention provides an anchor prestressing simulation system, comprising: A construction module is used to build a surrounding rock numerical model, perform surrounding rock excavation simulation on the surrounding rock numerical model, and activate anchor rods and input anchor rod parameters in the surrounding rock numerical model after the surrounding rock numerical model reaches an equilibrium state; an applying module, configured to apply prestress in the surrounding rock numerical model, modify the anchor state of the anchor by a hybrid finite element-discrete element method, and divide the anchor into a disconnected shallow section and a deep section; an acquisition module, configured to acquire preload data, and perform opposite stretching on the shallow section and the deep section according to the preload data until the surrounding rock numerical model reaches the equilibrium state again; A calculation module is used to modify the parameters of the anchor rod and bond the shallow section and the deep section to obtain a complete anchor rod, calculate the breaking parameters of the complete anchor rod through the anchor rod constitutive equation and the surrounding rock constitutive equation, and generate prestress simulation results based on the breaking parameters.

[0017] In a third aspect, the present invention provides a computer device comprising a processor and a memory, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the anchor rod prestressing simulation method described in the aforementioned embodiment.

[0018] In a fourth aspect, the present invention provides a computer storage medium storing a computer program, which, when executed on a processor, implements the anchor rod prestressing simulation method described in the aforementioned embodiment.

[0019] The embodiments of the present invention have the following beneficial effects: The anchor rod prestressing simulation method provided by the present invention activates the anchor rod in a numerical model, assigns corresponding mechanical parameters to the anchor rod, then assigns prestress to the anchor rod, and studies the process of the anchor rod from integrity to breaking under the action of prestress. The present invention can accurately capture the interaction process between the prestressed anchor rod and the surrounding rock by stretching the anchor rod in opposite directions to form near-compression and far-tension prestress in the surrounding rock. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solutions of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. It is possible for a person skilled in the art to derive other relevant drawings based on these drawings without inventive effort.

[0021] Figure 1 A schematic flow chart of a method for simulating anchor prestressing provided by an embodiment of the present invention is shown; Figure 2 A schematic diagram showing a flow chart of a method for assigning anchor parameters provided by an embodiment of the present invention is shown; Figure 3 A schematic diagram showing the principle of an anchor unit search method provided by an embodiment of the present invention is shown; Figure 4 A schematic diagram of the force on an anchor rod before prestressing is applied is shown in an embodiment of the present invention; Figure 5 A schematic diagram of the force on an anchor rod after prestressing is applied according to an embodiment of the present invention is shown; Figure 6 A schematic diagram of an anchor rod interface relationship provided by an embodiment of the present invention is shown; Figure 7 Another schematic diagram of the relationship between anchor rod interfaces provided by an embodiment of the present invention is shown; Figure 8 A schematic diagram of a tensile breaking principle provided by an embodiment of the present invention is shown; Figure 9 A schematic diagram of a shear-type breaking principle provided by an embodiment of the present invention is shown; Figure 10 A schematic diagram of a tensile shear fracture principle provided by an embodiment of the present invention is shown; Figure 11 A schematic diagram of the framework structure of an anchor rod prestressing simulation system provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the figures is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort are intended to be within the scope of protection of the present invention.

[0024] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present invention, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0025] Furthermore, the terms “first,” “second,” “third,” etc., are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0026] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present invention pertain. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present invention.

[0027] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0028] Reference Figure 1 , Figure 1 The present invention provides a flow chart of a method for simulating anchor prestressing, which includes: S101 , constructing a surrounding rock numerical model, performing surrounding rock excavation simulation on the surrounding rock numerical model, and after the surrounding rock numerical model reaches an equilibrium state, activating anchor rods in the surrounding rock numerical model and inputting anchor rod parameters.

[0029] The surrounding rock numerical model can be generated using a mesh generator. Before prestressing is applied, the anchor rods are activated in the surrounding rock numerical model after the surrounding rock excavation reaches a balanced state. Various anchor rod parameters are input, such as the number of anchor rods and the coordinates of the endpoints of each anchor rod, so as to complete the search mark of the anchor rods and determine the interface relationship of the anchor rods. The anchor rod interface relationship can be the contact interface between anchor rods or the contact interface between anchor rods and surrounding rock. Then, the anchor rod mechanical parameters and anchor agent mechanical parameters are assigned to the anchor rod unit and the release interface.

[0030] S102: applying prestress in the surrounding rock numerical model, modifying the anchor state of the anchor by using a hybrid finite element-discrete element method, and dividing the anchor into a disconnected shallow section and a deep section.

[0031] In the surrounding rock numerical model, triangular elements can be used to represent the surrounding rock, and quadrilateral elements can be used to represent the middle position of the anchor rod. When prestress is applied in the surrounding rock numerical model, the state of the quadrilateral elements can be modified by the hybrid finite element-discrete element method (FDEM), thereby dividing the anchor rod from the middle position into two parts, namely the shallow section and the deep section.

[0032] S103 , obtaining preload data, and performing opposite stretching on the shallow section and the deep section according to the preload data until the surrounding rock numerical model reaches the equilibrium state again.

[0033] The preload force can be set in advance or obtained through simulation of the surrounding rock numerical model. According to the size of the preload force, the shallow and deep sections of the anchor rod are stretched in opposite directions, and then the surrounding rock numerical model reaches a new equilibrium state during the opposite stretching process.

[0034] S104, modifying the parameters of the anchor rod, bonding the shallow section and the deep section to obtain a complete anchor rod, calculating the breaking parameters of the complete anchor rod using the anchor rod constitutive equation and the surrounding rock constitutive equation, and generating prestress simulation results based on the breaking parameters.

[0035] The FDEM method is then used to modify the state of the quadrilateral unit in the middle of the anchor rod, and the shallow section and the deep section are re-bonded to re-form a complete prestressed anchor rod to play its role. Then, the elastic deformation and plastic fracture of the anchor rod and surrounding rock are directly calculated through the anchor rod constitutive equation and the rock constitutive equation, capturing the gradual transformation process from continuous to discontinuous during the destruction process of the prestressed anchor rod and the surrounding rock until the end of the simulation, thereby obtaining the entire process of the anchor rod transformation under the action of prestress.

[0036] This embodiment activates the anchor rod in the numerical model, assigns corresponding mechanical parameters to the anchor rod, then assigns prestress to the anchor rod, and studies the process of the anchor rod from integrity to breaking under the action of prestress. The present invention can accurately capture the interaction process between the prestressed anchor rod and the surrounding rock by stretching the anchor rod in opposite directions to form near-compression and far-tension prestress in the surrounding rock.

[0037] Reference Figure 2 , step S101 includes: steps S1011-S1012.

[0038] S1011. After the anchor rod is activated, obtain the intersection position between the anchor rod and the surrounding rock in the surrounding rock numerical model, mark the physical anchor rod according to the intersection position, and determine the anchor rod interface corresponding to the physical anchor rod and the surrounding rock interface corresponding to the surrounding rock.

[0039] Specifically, the anchor rod is first divided into multiple anchor rod units, and the surrounding rock is divided into multiple surrounding rock units. The first vector corresponding to each anchor rod unit is obtained, and the second vector corresponding to each surrounding rock unit is obtained. According to the vector intersection calculation formula, it is determined whether each first vector and each second vector intersect. If they intersect, the physical anchor rod is marked according to the intersection position of the first vector and the second vector.

[0040] Reference Figure 3 , Figure 3 A schematic diagram of the principle of an anchor unit search method provided in this embodiment.

[0041] Anchor search and positioning is specifically achieved through the following formula:

[0042] The principle is as follows: when line segment AB representing the anchor intersects with triangular unit 012 representing the surrounding rock, triangular unit 012 is marked as an anchor unit; the intersection problem of line segment AB and triangular unit 012 can be decomposed into the intersection problem of line segment AB with line segment 01, line segment 12, and line segment 20. Taking the positional relationship between line segment AB and line segment 01 as an example, when the two satisfy the condition "line segment AB is distributed on both sides of line segment 01, and line segment 01 is distributed on both sides of line segment AB", they must intersect; this relationship is represented by the vector relationship in the above formula; similarly, it can be determined whether line segment AB intersects with line segment 12 or line segment 20; thus, the above vector relationship can be used to automatically search for and mark anchor units.

[0043] S1012: Determine the interface relationship between the anchor rod interface and the surrounding rock interface, and assign anchor rod parameters to the physical anchor rod, wherein the anchor rod parameters include mechanical parameters of the anchoring agent.

[0044] Reference Figure 4 , Figure 4 This is a schematic diagram of the anchor rod force before prestressing is applied provided in this embodiment.

[0045] Reference Figure 5 , Figure 5 A schematic diagram of the anchor rod force after prestressing is applied provided in this embodiment.

[0046] according to Figure 4 and Figure 5 It can be seen that after the surrounding rock is excavated, the prestressing force is compressed near and tensile far away, that is, the shallow surrounding rock close to the excavation surface shows compressive stress, while the deep surrounding rock far away from the excavation surface shows tensile stress.

[0047] Therefore, after the anchor search and marking are completed, it is necessary to apply prestress to the surrounding rock numerical model to study the process of the anchor from deformation to fracture under the action of prestress.

[0048] Refer to Table 1, which shows the surrounding rock mechanical parameters and boundary condition data.

[0049] Table 1:

[0050] Refer to Table 2, which shows the mechanical parameters of the anchor rod and the mechanical parameters of the anchor agent.

[0051] Table 2:

[0052] Reference Figure 6 , Figure 6 A schematic diagram of the anchor rod interface relationship provided in this embodiment.

[0053] Reference Figure 7 , Figure 7 Another schematic diagram of the anchor rod interface relationship provided in this embodiment.

[0054] exist Figure 6 and Figure 7 In the FDEM model, the anchoring agent bonds the anchor rod and the surrounding rock together to generate anchoring force. The effect of the anchoring agent is represented by the quadrilateral unit in FDEM. The anchor rod is represented by the quadrilateral unit, and the surrounding rock is represented by the triangular unit. The interface relationship between the triangular units, including the interface relationship between the surrounding rock and the surrounding rock, the anchor rod and the anchor rod, and the surrounding rock and the anchor rod, is represented by the quadrilateral unit in FDEM.

[0055] pass Figure 6 and Figure 7 The interface relationship in the simulation can accurately distinguish the anchor rod, surrounding rock and anchoring agent, which facilitates the analysis of the stress process in the subsequent simulation.

[0056] This embodiment uses vector calculation to quickly search and mark anchor rods from the surrounding rock numerical model, thereby facilitating subsequent research on changes in anchor rods under prestressing and improving research efficiency.

[0057] In one embodiment, calculating the fracture parameters of the intact anchor includes: The fracture type of the complete anchor bolt is determined, where the fracture types include tensile, shear, and tensile-shear.

[0058] According to the fracture type, the fracture parameters of the complete anchor are determined.

[0059] When an anchor bolt is damaged and breaks, it typically splits into two broken bolts. Therefore, to study the process of deformation and fracture under the action of prestress and other forces, the bolt can be first broken at the center to obtain a shallow and deep segment. Then, based on the magnitude of the prestress, the shallow and deep segments are stretched in opposite directions and simulated using a numerical model of the surrounding rock until a new equilibrium state is reached. FDEM is then used to modify the state of the quadrilateral element in the center of the bolt, and the bolt that was broken into the shallow and deep segments in the previous steps is reattached to function as a complete prestressed anchor bolt.

[0060] This embodiment uses simulation experiments to simulate the states of the anchor rod before, during and after breaking, and then simulates the surrounding rock numerical model to an equilibrium state in these three states, so as to facilitate subsequent study of the morphology and stress conditions of the anchor rod and surrounding rock in these three equilibrium states, thereby accurately determining the influence of prestress or other forces on the anchor rod and surrounding rock.

[0061] In one embodiment, determining the fracture parameters of the intact anchor bolt according to the fracture type includes: If the fracture type is the tensile type, the fracture parameter type is determined to be the crack opening.

[0062] An interface unit between every two adjacent anchor units is determined, and a peak crack opening value of the interface unit is calculated.

[0063] The fracture parameter is determined according to the peak crack opening.

[0064] After the anchor rod is driven into the surrounding rock, it will be subjected to various forces. The different force directions and force types will also lead to different anchor rod breakage types. There are usually three types of anchor rod breakage types, namely tensile type, shear type and tensile shear type.

[0065] Reference Figure 8 , Figure 8 A schematic diagram of the tensile fracture principle is shown.

[0066] In the axial direction, when the crack opening of the interface element between two adjacent triangular elements is o Reach peak crack opening o p When - the normal bond stress of the corresponding interface element σ b Just reached the anchor yield strength σ y ;Exceed o p back, σ b along with o The increase from σ y Monotonically increasing to σ u ,correspond o Reach the maximum crack opening, that is, the critical crack opening o r .

[0067] Reference Figure 9 , Figure 9 A schematic diagram of the shear fracture principle is shown.

[0068] If the fracture type is the shear type, the fracture parameter type is determined to be tangential crack slip.

[0069] If the interface unit is not separated, the tangential bond stress of the interface unit is determined according to the crack slip peak value of the tangential crack slip, the shear yield strength of the anchor bolt is calculated according to the tangential bond stress, and the shear yield strength is used as the fracture parameter.

[0070] like Figure 9 As shown, when the tangential crack of the interface element slips s Reaching peak crack slip s p When - the tangential bond stress of the corresponding interface unit τ b Just reached the anchor shear yield strength τ y .

[0071] , in, τ y is the shear yield strength of the anchor rod, c is the internal bonding force of the anchor bolt, σ n is the normal stress applied to the interface element, is the internal friction angle. When the crack slip reaches the crack slip peak, the tangential bond stress is equal to the shear yield strength of the anchor.

[0072] When the tangential crack of the interface element slips s Exceed s p back, τ b along with s The increase in s Reaching the maximum tangential crack slip, that is, critical crack slip s r ——Corresponding residual friction τ r , that is, a pure friction force.

[0073] Therefore, if the interface unit is separated, the crack friction angle of the interface unit is obtained when the crack slip exceeds the crack slip peak and the tangential crack slip of the interface unit reaches the critical crack slip. The residual friction force is calculated based on the crack friction angle, and the residual friction force is used as the fracture parameter: , in, τ r is the residual friction force, is the crack friction angle.

[0074] Reference Figure 10 , Figure 10 This is a schematic diagram of the tensile shear fracture principle provided in this embodiment.

[0075] In the tensile shear type, although o and s Less than o r and s r , but rupture still occurs when both satisfy the following equation: , In the axial direction, the peak crack opening of the anchor o p By yield strength σ y With crack penalty parameter p f Sure: , In the transverse direction, the peak crack slip of the anchor s p Shear yield strength τ y With crack penalty parameter p f Sure: , In the axial direction, the axial yield strength of the anchor σ y , ultimate strength σ u , Type I fracture energy Gf I , peak crack opening o p , critical crack opening o r satisfy: , so o r Determined by the following formula , In the transverse direction, the shear yield strength of the anchor τ y , ultimate strength τ u , Type II fracture energy Gf II , peak crack slip s p , critical crack slip s r satisfy: , so s r Determined by the following formula:

[0076] Where, η According to the softening constitutive equation of the anchor bolt in the transverse direction f lateral ( D ) and determine, f lateral ( D ) ranges from 0 to 1; when Gf II ≈0, it can be considered that the anchor reaches τ y or τ u After that, it breaks immediately; when Gf II When the maximum value is taken, it can be considered that the anchor is in a rational elastic-plastic state in the transverse direction; In the axial direction, when in tension, the force applied to the interface element σ b for: , Where, f axial ( D) is the hardening function in the axial direction of the anchor, and its value range is 0 to 1. Different from the strain softening characteristics of rock materials, steel shows obvious strain hardening phenomenon after reaching the yield strength. Therefore, with the normalized crack opening or damage factor D The increase, f axial ( D ) is not monotonically decreasing, but monotonically increasing: , Where, D Determined by the following formula: , In the transverse direction, the shear stress of the anchor applied to the interface element is τ b for: , Where, τ y is the yield strength, f lateral ( D ) is the softening constitutive equation of the anchor bolt in the transverse direction.

[0077] According to the above method, the parameters of the anchor rod during the process from the intact state to the broken state can be obtained, so that the process can be simulated by software based on these parameters.

[0078] For example, the FDEM solver is first used to output a file in a corresponding format that it can recognize, and then the file is used to visualize the simulation results. The visualization of the simulation results includes velocity cloud maps, displacement cloud maps, stress cloud maps, strain cloud maps, yield mode maps, failure mode maps, and animations composed of the above maps of the prestressed anchor rods and surrounding rocks.

[0079] Reference Figure 11 , Figure 11 The framework structure of an anchor prestressing simulation system 110 provided in this embodiment includes: A construction module 111 is used to build a surrounding rock numerical model, perform surrounding rock excavation simulation on the surrounding rock numerical model, and activate anchor rods in the surrounding rock numerical model and input anchor rod parameters after the surrounding rock numerical model reaches an equilibrium state; an applying module 112 for applying prestress in the surrounding rock numerical model, modifying the anchor state of the anchor by a hybrid finite element-discrete element method, and dividing the anchor into a disconnected shallow section and a deep section; an acquisition module 113 for acquiring preload force data, and performing opposite stretching on the shallow section and the deep section according to the preload force data until the surrounding rock numerical model reaches the equilibrium state again; The calculation module 114 is used to modify the parameters of the anchor rod and bond the shallow section and the deep section to obtain a complete anchor rod, calculate the breaking parameters of the complete anchor rod through the anchor rod constitutive equation and the surrounding rock constitutive equation, and generate prestress simulation results based on the breaking parameters.

[0080] It can be understood that the anchor rod prestressing simulation system of this embodiment corresponds to the anchor rod prestressing simulation method of the above embodiment, and the options in the above embodiment are also applicable to this embodiment, so they will not be repeated here.

[0081] The present invention also provides a computer device. Exemplarily, the computer device includes a processor and a memory, wherein the memory stores a computer program, and the processor runs the computer program to enable the computer device to execute the functions of the above-mentioned anchor rod prestressing simulation method or the various modules in the above-mentioned anchor rod prestressing simulation system.

[0082] The processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including at least one of a central processing unit (CPU), a graphics processing unit (GPU), a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor, and can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present invention.

[0083] The memory may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM). The memory is used to store computer programs, and the processor can execute the computer programs accordingly after receiving an execution instruction.

[0084] The present invention also provides a computer storage medium for storing the computer program used in the aforementioned computer device. The computer storage medium may be a readable storage medium, a non-volatile storage medium, or a volatile storage medium. For example, the computer storage medium may include, but is not limited to, various media capable of storing program code, such as a USB flash drive, a removable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0085] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, program segment or part of the code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in alternative implementations, the functions marked in the boxes can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or flowchart, as well as the combination of boxes in the structure diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0086] In addition, the functional modules or units in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0087] If the functions are implemented as software modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for causing a computer device (such as a smartphone, personal computer, server, or network device) to execute all or part of the steps of the methods described in various embodiments of the present invention.

[0088] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A method for simulating anchor prestressing, characterized in that: include: Constructing a surrounding rock numerical model, performing surrounding rock excavation simulation on the surrounding rock numerical model, and activating anchor rods and inputting anchor rod parameters in the surrounding rock numerical model after the surrounding rock numerical model reaches an equilibrium state; Applying prestress in the surrounding rock numerical model, modifying the anchor state of the anchor by using a hybrid finite element-discrete element method, and dividing the anchor into a disconnected shallow section and a deep section; obtaining preload data, and performing opposite stretching on the shallow section and the deep section according to the preload data until the surrounding rock numerical model reaches the equilibrium state again; The parameters of the anchor rod are modified to bond the shallow section and the deep section to obtain a complete anchor rod, the breaking parameters of the complete anchor rod are calculated using the anchor rod constitutive equation and the surrounding rock constitutive equation, and a prestress simulation result is generated based on the breaking parameters.

2. The anchor rod prestressing simulation method according to claim 1, characterized in that: Activating the anchor rod in the surrounding rock numerical model and inputting anchor rod parameters include: After the anchor rod is activated, an intersection position between the anchor rod and the surrounding rock in the surrounding rock numerical model is obtained, a physical anchor rod is marked according to the intersection position, and an anchor rod interface corresponding to the physical anchor rod and a surrounding rock interface corresponding to the surrounding rock are determined; An interface relationship between the anchor rod interface and the surrounding rock interface is determined, and anchor rod parameters are assigned to the physical anchor rod, wherein the anchor rod parameters include mechanical parameters of the anchoring agent.

3. The anchor rod prestressing simulation method according to claim 2, characterized in that: The marking of the physical anchor rod according to the intersection position includes: Dividing the anchor rod into a plurality of anchor rod units and dividing the surrounding rock into a plurality of surrounding rock units; Obtaining a first vector corresponding to each of the anchor rod units, and obtaining a second vector corresponding to each of the surrounding rock units; Determining whether each of the first vectors and each of the second vectors intersects according to a vector intersection calculation formula; If they intersect, the physical anchor rod is marked according to the intersection position of the first vector and the second vector.

4. The anchor rod prestressing simulation method according to claim 3, characterized in that: Calculating the fracture parameters of the complete anchor bolt includes: Determining the fracture type of the complete anchor bolt, wherein the fracture type includes tension type, shear type and tension-shear type; According to the fracture type, the fracture parameters of the complete anchor are determined.

5. The anchor rod prestressing simulation method according to claim 4, characterized in that: The determining of the fracture parameters of the complete anchor bolt according to the fracture type includes: If the fracture type is the tensile type, determining the fracture parameter type as crack opening; Determine the interface unit between every two adjacent anchor units, and calculate the peak crack opening of the interface unit; The fracture parameter is determined according to the peak crack opening.

6. The anchor rod prestressing simulation method according to claim 5, characterized in that: The determining of the fracture parameters of the complete anchor bolt according to the fracture type includes: If the fracture type is the shear type, determining the fracture parameter type as tangential crack slip; If the interface unit is not separated, the tangential bond stress of the interface unit is determined according to the crack slip peak value of the tangential crack slip, the shear yield strength of the anchor bolt is calculated according to the tangential bond stress, and the shear yield strength is used as the fracture parameter: ， in, τ y is the shear yield strength of the anchor rod, c is the internal bonding force of the anchor bolt, σ n is the normal stress applied to the interface element, is the internal friction angle, when the crack slip reaches the crack slip peak, the tangential bond stress is equal to the shear yield strength of the anchor bolt; If the interface unit is separated, the crack friction angle of the interface unit is obtained when the crack slip exceeds the crack slip peak and the tangential crack slip of the interface unit reaches the critical crack slip. The residual friction force is calculated based on the crack friction angle, and the residual friction force is used as the fracture parameter: ， in, τ r is the residual friction force, is the crack friction angle.

7. The anchor rod prestressing simulation method according to claim 6, characterized in that: The determining of the fracture parameters of the complete anchor bolt according to the fracture type includes: If the fracture type is the tensile shear type, determining the peak crack opening in the axial direction and the peak crack slip in the transverse direction of the intact anchor rod; respectively constructing a first constraint function corresponding to the peak crack opening and a second constraint function corresponding to the peak crack slip; The first constraint function and the second constraint function are solved using the anchor constitutive equation and the surrounding rock constitutive equation to calculate the anchor shear stress of the interface unit, and the anchor shear stress is used as the fracture parameter.

8. An anchor prestressing simulation system, characterized in that: include: A construction module is used to build a surrounding rock numerical model, perform surrounding rock excavation simulation on the surrounding rock numerical model, and activate anchor rods and input anchor rod parameters in the surrounding rock numerical model after the surrounding rock numerical model reaches an equilibrium state; an applying module, configured to apply prestress in the surrounding rock numerical model, modify the anchor state of the anchor by a hybrid finite element-discrete element method, and divide the anchor into a disconnected shallow section and a deep section; an acquisition module, configured to acquire preload data, and to perform opposite stretching on the shallow section and the deep section according to the preload data until the surrounding rock numerical model reaches the equilibrium state again; A calculation module is used to modify the parameters of the anchor rod and bond the shallow section and the deep section to obtain a complete anchor rod, calculate the breaking parameters of the complete anchor rod through the anchor rod constitutive equation and the surrounding rock constitutive equation, and generate prestress simulation results based on the breaking parameters.

9. A computer device, characterized in that: The computer device includes a processor and a memory, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the anchor prestressing simulation method according to any one of claims 1 to 7.

10. A computer storage medium, characterized in that It stores a computer program, which, when executed on a processor, implements the anchor rod prestressing simulation method according to any one of claims 1 to 7.

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