Search

CN-121980893-A - Microcrack connection force deducing method based on graph neural network

CN121980893ACN 121980893 ACN121980893 ACN 121980893ACN-121980893-A

Abstract

The invention discloses a microcrack connection force deducing method based on a graph neural network, which is based on a parallel bonding model and a joint model, and provides a crack contact model considering connection substances in cracks by dividing crack contact into two parts which are not connected and connected for calculation. The invention relates to the technical field of engineering rock monitoring and analysis, in particular to a novel contact model, which obtains a high pressure-pull ratio by limiting the destruction of cementing to a mode controlled by contact force and moment of a connecting part only on the basis of providing a certain tensile strength and a shear strength for a unit. The microcrack connection force deducing method based on the graph neural network constructs and verifies the contact model through a contact surface force-displacement test and a crack-containing model loading and unloading test. The contact model was finally tested by simulated rock mechanics. The result shows that the contact model can effectively simulate the axial and radial strain rules of the rock at the same time.

Inventors

  • XIAO FUKUN
  • XIE JIE
  • SHAN LEI
  • HOU ZHIYUAN
  • ZHANG XI

Assignees

  • 黑龙江科技大学

Dates

Publication Date
20260505
Application Date
20251023

Claims (8)

  1. 1. The microcrack connection force pushing method based on the graph neural network is characterized by comprising the following steps of: s1, by two lengths The conceptual surface of (a) simulates two-side crack surfaces, the sizes and positions of connecting substances in the cracks are randomly distributed, and the acting force of a single connecting substance on the crack surfaces is as follows Wherein subscripts n and s represent the normal and tangential directions of the crack surface, respectively, the crack surface receives a resultant force of: Wherein N is the number of connecting substances, the angle mark L represents the connecting substance, and the distance from the connecting substance to the center of the crack is L i , so that the resultant moment applied by all the connecting substances to the crack surface is: Wherein, the So there are: S2, setting the effective modulus of the connecting substance as E i , wherein the rigidity of the connecting substance is as follows: Wherein A i is the effective area of the binding substance, L i is the effective length of the binding substance, In order to act on the normal force of the joining substance, For normal deformation of the joint material due to force, but for simplicity of calculation, a special stiffness concept is defined without considering the cell area with reference to the parallel bonding model: Then there are: Wherein, the For tangential stiffness, k * is the stiffness ratio, and the force of the ith connecting substance on the crack surface is calculated as follows: In the formula, In order to act on the tangential force of the connecting substance, Is the relative displacement of the crack surface at the connecting material; s3, setting the rigidity of the cementing surface as The cementing surface force is: In the formula, Is the relative displacement of the cementing surface at the center; therefore, there are: The solution can be obtained: And (3) the same principle: S4, when the included angle of the crack surface is theta b , the relation between the relative displacement of each connecting substance and the relative displacement of the crack center is as follows: Wherein, the A distance from the connecting material to the center of the crack surface; similarly, since the included angle θ b is smaller, the tangential displacement of the crack surface due to θ b is approximately 0, and thus the relative tangential displacement of any point on the crack surface can be replaced by the relative tangential displacement of the center of the crack surface: S5, assuming that the mechanical properties of the connecting substances in the same crack are similar, the rigidity of any connecting substance i can take the same value k, so that the method is simplified into: At the same time, normal force of connecting substance to crack surface The stress sigma l which is linearly distributed on the cementing surface can be equivalently replaced by: Wherein, the For connecting the equivalent acting area of the substance on the cementing surface, and Related to the ratio of the ith binding substance to the total amount of binding substance; Similarly, the tangential force of the connecting substance to the crack surface is equivalent to the tangential stress of the center of the cementing surface: s6, when the connecting substances in the same crack are regarded as the substance formulas with similar mechanical properties, the tensile strength and the bonding strength of any connecting substance i can also take the same value And c l , therefore, the tensile strength σ c and the bond strength c of the joining substance are also calculated equivalently in the cementing face, as in σ l and τ l : correspondingly, the judgment basis of the damage of the cementing surface is as follows: Wherein, the S7, equivalently replacing a part of the crack surface without connecting substances by using two conceptual surfaces, wherein when the crack surface is closed, the method comprises the following steps: Wherein, the For equivalent stiffness of the non-tie portion crack, g 0 is the crack initiation gap, Δu s is the tangential displacement within Δt time after crack closure. And when When the crack surface slides, finally Meanwhile, when an included angle theta b exists between crack surfaces, three closing conditions of complete non-contact, partial contact and complete contact exist on the crack surfaces of the part without the connector, so that the normal contact force and moment of the part need to be calculated in three conditions.
  2. 2. The method of claim 1, wherein the effective length L i of the bonding material in step S2 is different from the gap between the crack surfaces by considering the associated portion of the bonding material in the matrix on both sides of the crack.
  3. 3. The method for pushing and breaking micro-crack connection force based on the graphic neural network of claim 1, wherein in the step S3, N bonding substances are equivalently calculated from a single cementing surface assuming that each type of bonding substance is distributed relatively uniformly in the crack surface.
  4. 4. The method for pushing and breaking micro-crack connection force based on the graphic neural network according to claim 1, wherein in the step S4, the crack surfaces are centrosymmetric under the condition that various connecting substances are distributed relatively uniformly in the crack surfaces.
  5. 5. The method for pushing and breaking the microcrack connecting force based on the graphic neural network according to claim 1, wherein the crack is arranged at the contact position among particles, and the resultant force and the resultant moment of the two parts at the contact position are as follows: F=F l +F c ,M＝M l +M c 。
  6. 6. The method for breaking micro-crack connection force based on graphic neural network as set forth in claim 5, wherein the conceptual surface and the cementing surface are calculated in parallel, the displacement and rotation of the conceptual surface and the cementing surface are converted and recorded in the inter-particle contact plane, and when a new contact model is installed at the contact position, the position of the conceptual surface of the unconnected portion is initialized according to the crack spacing g 0 , namely
  7. 7. The method of breaking micro-crack connection force based on graphic neural network as set forth in claim 6, wherein after the cementation of the cementation portion is broken, the contact mode of the cementation portion is changed, and the broken connecting material is simulated by setting a conceptual plane parallel to the conceptual plane of the unconnected portion, wherein the distance between the conceptual plane of the connecting material portion and the conceptual plane of the unconnected portion is g 0 /2.
  8. 8. The method for pushing off micro-crack connection force based on graphic neural network as set forth in claim 7, wherein the magnitude of the residual shear stress is determined by the tangential stiffness and the total tangential displacement of the conceptual surface of the connecting portion, and the maximum value of the shear stress is determined by the normal stress and the friction coefficient, namely And M l is calculated from the degree of overlap of the converted conceptual facets.

Description

Microcrack connection force deducing method based on graph neural network Technical Field The invention relates to the technical field of engineering rock monitoring and analysis, in particular to a microcrack connection force breaking method based on a graph neural network. Background Rock materials are main materials which are mainly composed and cannot be ignored in the exploitation process of energy sources such as coal mines, oil gas and the like and in the engineering construction process of tunnels, subways and the like. The mechanical properties of the rock material determine not only the construction scheme of the project, but also the safety in the construction process. But unlike other engineering materials, the rock presents complex mechanical characteristics during loading due to the relatively rich microcracks within most of the rock. In engineering analysis, calculation and simulation, the action mechanism of cracks in the rock is understood and reduced, and the safety development and use of engineering are further guaranteed. The particle flow simulation method can better simulate the heterogeneous material characteristics of the rock through the particle materials and the contact model. The method is helpful for researchers to understand the damage mechanism of the rock material from a fine view, and is well applied to engineering simulation. However, the existing contact model lacks consideration on rock cracks, and has limitation in simulating the action mechanism of microcracks on the rock. Therefore, in order to further understand and restore the influence of microcracks on the complete mechanical behavior of the rock through a particle flow simulation method, a particle contact model needs to be further constructed by combining the microcrack characteristics in the rock. The particle flow numerical simulation method can better simulate the heterogeneous material characteristics and the destructive behavior of the rock, but the existing contact model lacks consideration of rock cracks, and various simulation methods for considering the cracks, which are proposed by researchers, have certain limitations. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides a microcrack connecting force deducing method based on a graph neural network, which constructs a rock model containing microcracks through a crack contact model containing connecting substances and effectively simulates the complete mechanical behavior of the rock in the uniaxial loading process. (II) technical scheme The invention aims to realize the aim by adopting the following technical scheme that the microcrack connection force breaking method based on the graph neural network specifically comprises the following steps: S1, simulating two side crack surfaces through two conceptual surfaces with the length of 2R, wherein the sizes and the positions of connecting substances in the cracks are randomly distributed, and the acting force of a single connecting substance on the crack surfaces is as follows Wherein subscripts n and s represent the normal and tangential directions of the crack surface, respectively, the crack surface receives a resultant force of: Wherein N is the number of connecting substances, the angle mark L represents the connecting substance, and the distance from the connecting substance to the center of the crack is L i, so that the resultant moment applied by all the connecting substances to the crack surface is: Wherein, the So there are: S2, setting the effective modulus of the connecting substance as E i, wherein the rigidity of the connecting substance is as follows: Wherein A i is the effective area of the binding substance, L i is the effective length of the binding substance, In order to act on the normal force of the joining substance,For normal deformation of the joint material due to force, but for simplicity of calculation, a special stiffness concept is defined without considering the cell area with reference to the parallel bonding model: Then there are: Wherein, the For tangential stiffness, k * is the stiffness ratio, and the force of the ith connecting substance on the crack surface is calculated as follows: In the formula, In order to act on the tangential force of the connecting substance,Is the relative displacement of the crack surface at the connecting material; s3, setting the rigidity of the cementing surface as The cementing surface force is: In the formula, Is the relative displacement of the cementing surface at the center; therefore, there are: The solution can be obtained: And (3) the same principle: S4, when the included angle of the crack surface is theta b, the relation between the relative displacement of each connecting substance and the relative displacement of the crack center is as follows: Wherein, the A distance from the connecting material to the center of the crack surface; similarly, since the incl