CN-121980645-A - Rock mass anisotropic continuous damage mechanical model construction method under true three-dimensional stress

CN121980645ACN 121980645 ACN121980645 ACN 121980645ACN-121980645-A

Abstract

The invention provides a method for constructing a rock mass anisotropic continuous damage mechanical model under true three-dimensional stress, which comprises the following steps of S1, determining a basic expression form of the damage mechanical model, wherein stress deformation of a rock mass material comprises elastic deformation and plastic deformation, S2, determining a damage factor and a structural surface influence factor, and S3, constructing a complete rock mass continuous damage mechanical model. According to the invention, based on a continuous damage mechanics theory, a rock mass continuous damage mechanics model capable of considering anisotropic damage characteristics under true three-dimensional stress is established, so that the model can reflect the damage accumulation evolution process of three main stress directions, meanwhile, the model can further reflect the influence rule of a structure on rock mass damage by establishing a relation between damage factors and structure surface, the established mechanics model is embedded into numerical simulation analysis software by using programming language, the anisotropic damage characteristics of the rock mass under the true three-dimensional stress of deep underground engineering are analyzed, and a basis is provided for underground engineering design and construction.

Inventors

GAO YAOHUI
LIU NING
WANG GANG
CHEN JUN
Zhong Daning

Assignees

中国电建集团华东勘测设计研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20251229

Claims (7)

1. The method for constructing the rock mass anisotropic continuous damage mechanical model under the true three-dimensional stress is characterized by comprising the following steps of: s1, determining a basic expression form of a damage mechanical model, wherein damage of a rock mass material is represented by plastic deformation, and stress deformation of the rock mass material comprises elastic deformation and plastic deformation, and the rock mass continuous damage model is shown in the following formula: ; In the formula, And The stress and strain are indicated as such, 、 And Respectively corresponding to the maximum principal stress, the intermediate principal stress and the stress in the direction of the minimum principal stress, 、 And Respectively corresponding to maximum principal stress Intermediate principal stress And minimum principal stress Is a strain of (2); as the damage factor, the value is in the range of 0 to 1, when When it means that the rock mass has not been damaged, when When the rock mass is completely damaged, macroscopic damage cracks are generated; S2, determining damage factors and structural surface influencing factors, wherein the damage factors define the damage degree evolution of each main stress direction of the rock mass and are divided into a complete rock and a rock containing the structural surface; S3, constructing a continuous damage mechanical model of the complete rock mass, wherein the continuous damage mechanical model is shown in the following formula: ; ; In the formula, Is elastic deformation and plastic deformation of the rock mass in the main stress direction, Is the elastic modulus of the rock mass in the main stress direction, In order for the damage factor to be a factor, Is in the shape of a structural surface, Is an equivalent plastic internal variable.
2. The method according to claim 1, wherein in step S1, stress of the rock mass material is measured It is equally possible to divide into two parts, one part for producing elastic deformation and the other part for producing plastic deformation, and the two parts act simultaneously, if expressed in mathematical expressions, in the form: ; In the formula, And Elastic stress and plastic stress respectively, and correspondingly generate elastic deformation and plastic deformation.
3. The method of claim 2, wherein the elastic stress is expressed in terms of generalized Hokko's Law: ; In the formula, Is the elastic modulus of the rock mass in the main stress direction, 、 And Respectively corresponding to maximum principal stress Intermediate principal stress And minimum principal stress Elastic modulus of (a); elastic deformation in the main stress direction of the rock mass; 、 And Respectively corresponding to maximum principal stress Intermediate principal stress And minimum principal stress Is formed by a spring.
4. The method of claim 2, wherein the plastic stress is such that a damage factor is introduced: ; In the formula, In order to fit the parameters of the model, 、 And Respectively corresponding to maximum principal stress Intermediate principal stress And minimum principal stress Fitting parameters of (a); In order for the damage factor to be a factor, 、 And Respectively corresponding to maximum principal stress Intermediate principal stress And minimum principal stress Is a damage factor of (2); Is the plastic deformation of the rock mass in the main stress direction, 、 And Respectively corresponding to maximum principal stress Intermediate principal stress And minimum principal stress Is formed by a plastic deformation of the steel sheet.
5. The method according to any one of claims 1-4, wherein the rock mass continuous damage model is: ; The determination of rock mass continuous damage mechanics model is mainly to damage factors Is determined; The evolution rule of the damage factors of the three main stress directions of the rock mass along with the plastic accumulation is not completely the same, and the damage factors of the rock mass are: ; In the formula, Is an equivalent plastic internal variable, and is characterized by that, Is a structural plane shape.
6. The method according to claim 1, wherein in step S2, the formula for the complete rock, i.e. the rock free structure surface, is reduced to: ; based on a large number of developed true triaxial test researches of complete rock, the expression is proposed as follows: ; ; ; ; in which a 1 、a 2 、a 3 、m 1 、m 2 、m 3 corresponds to the maximum principal stress Intermediate principal stress And minimum principal stress Fitting parameters of (a); The moment of stress of the rock mass; is at different stress moments Is equivalent to plastic internal variable of (1) In the time-course of which the first and second contact surfaces, I.e. when the rock mass does not generate plastic deformation, the rock mass is not damaged; when the rock mass enters the residual stage, the rock mass is completely damaged, and a macroscopic crack is generated, and the corresponding rock mass is stressed as residual stress Injury factor If the equivalent plastic internal variable corresponding to the moment of defining the residual stress is Then a relationship between three principal stress direction damage factors is established: ; ; In the formula, Is equivalent plastic internal variable corresponding to the residual stress moment, Residual stress of the rock mass; There is a special case that if the accuracy of the fit of the damage factor to the plastic deformation of the rock mass can be reduced to 95%, then the fitting parameters will become: the formula is: 。
7. the method according to claim 1, wherein in step S2, the structural face shape is considered for the rock mass, i.e. the rock interior contains the structural face The formula is as follows: ; ; ; based on a large number of true triaxial test researches of rock containing structural surface, the fitting parameters are found And structural plane shape The formula accords with the Gaussian distribution function relation, and is as follows: ; In the formula, 、b、c、d、 In order to fit the parameters of the model, Is in the shape of a structural surface.

Description

Rock mass anisotropic continuous damage mechanical model construction method under true three-dimensional stress Technical Field The invention belongs to the field of underground engineering, and particularly relates to a method for constructing a rock mass anisotropic continuous damage mechanical model under true three-dimensional stress. Background With the gradual exhaustion of superficial space and resources, the demands for space and resources are increasingly prominent towards the deep part of the earth, and underground engineering layers exceeding kilometers of burial depth emerge endlessly. Compared with the conventional three-dimensional stress of the superficial engineering) Deep underground engineering shows remarkable true three-dimensional stress) Intermediate principal stress [ ]) The effect will cause rock mass damage to exhibit a strong anisotropy, i.e. the degree of damage in the three principal stress directions is different, the elastoplastic deformations in the three principal stress directions are mutually unequal in the rock mass mechanical model, whereas under the conventional three-way stress of the superficial engineering, the elastoplastic deformations in the rock mass intermediate principal stress direction and the minimum principal stress direction are equal, for which reason the rock mass anisotropic damage characteristics in the deep true three-way stress environment are critical for the optimization of the deep engineering layout and support design, in particular the hole axis selection of the deep engineering and the quantitative characterization of the overall damage. With the increase of stress of the rock mass, irreversible deformation can occur, namely damage is generated, and the rock mass is instable and damaged when the damage is increased to a certain degree. The continuous damage model is an effective means for describing the accumulated evolution of damage, mainly relates to weakening of material rigidity and anisotropic enhancement, and actually describes the whole process of cracking and expanding of microcracks in a rock body to penetration. The damage factor is a critical parameter in continuous damage models. Disclosure of Invention The invention aims to solve the problems, and provides a method for constructing a rock mass anisotropic continuous damage mechanical model under true three-dimensional stress. For this purpose, the above object of the present invention is achieved by the following technical solutions: a rock mass anisotropic continuous damage mechanical model construction method under true three-dimensional stress comprises the following steps: s1, determining a basic expression form of a damage mechanical model, wherein damage of a rock mass material is represented by plastic deformation, and stress deformation of the rock mass material comprises elastic deformation and plastic deformation, and the rock mass continuous damage model is shown in the following formula: ; In the formula, AndThe stress and strain are indicated as such,、AndRespectively corresponding to the maximum principal stress, the intermediate principal stress and the stress in the direction of the minimum principal stress,、AndRespectively corresponding to maximum principal stressIntermediate principal stressAnd minimum principal stressIs a strain of (2); as the damage factor, the value is in the range of 0 to 1, when When it means that the rock mass has not been damaged, whenWhen the rock mass is completely damaged, macroscopic damage cracks are generated; S2, determining damage factors and structural surface influencing factors, wherein the damage factors define the damage degree evolution of each main stress direction of the rock mass and are divided into a complete rock and a rock containing the structural surface; S3, constructing a continuous damage mechanical model of the complete rock mass, wherein the continuous damage mechanical model is shown in the following formula: ; ; In the formula, Is elastic deformation and plastic deformation of the rock mass in the main stress direction,Is the elastic modulus of the rock mass in the main stress direction,In order for the damage factor to be a factor,Is in the shape of a structural surface,Is an equivalent plastic internal variable. The invention can also adopt or combine the following technical proposal when adopting the technical proposal: As a preferable technical scheme of the invention, in the step S1, the stress of the rock mass material It is equally possible to divide into two parts, one part for producing elastic deformation and the other part for producing plastic deformation, and the two parts act simultaneously, if expressed in mathematical expressions, in the form: ; In the formula, AndElastic stress and plastic stress respectively, and correspondingly generate elastic deformation and plastic deformation. As a preferable technical scheme of the invention, the elastic stress is expressed by adopting generalized Hokko'