A New Construction Method of Rock Statistical Damage Constitutive Model

Abstract

The invention discloses a novel construction method of a rock statistical damage constitutive model and aims at providing the novel construction method of the rock statistical damage constitutive model. The novel construction method comprises the following steps: carrying out fitting on testing data by adopting a probability density function of infinitesimal strength distribution of the statistical damage constitutive model, so as to obtain a numerical value of the testing data; furthermore, representing a damage variable D; then representing a constitutive relation of a material and arrayingthree main stress on the material from big to small, wherein sigma1 is greater than or equal to sigma2 and the sigma2 is greater than or equal to sigma 3 and less than or equal to the sigma1; based ona Mohr-Coulomb criterion, obtaining an included angle theta between a damage slip plane and a plane suffered from the main stress sigma1, and obtaining positive stress on the slip plane; when the positive stress sigmatheta is greater than or equal to 0, obtaining a compression-shear stress state; when the positive stress sigmatheta is less than 0, obtaining a tensile-shear stress state; taking the positive stress as evidences for tensile-shear and compression-shear stressed states of rocks; finally, defining an infinitesimal strength distribution variable under a Mohr-Coulomb failure criterion as follows: a formula is shown in the description. By adopting the novel construction method, the fitting precision of an axial stress-strain curve can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of rock statistical methods, in particular to a new method for constructing a rock statistical damage constitutive model. Background technique [0002] Rock is a heterogeneous geological material with complex constitutive relations. Its research has always been an important aspect of rock mechanics and geotechnical engineering, and has been generally valued by engineering circles. The constitutive model is the foundation of geotechnical engineering mechanics calculation. Due to the unreasonable construction of the constitutive model, geotechnical engineering accidents, waste of mine resources and economic losses of geotechnical engineering often occur. Therefore, in-depth research on constitutive models is the basis for ensuring rational design, safe construction, and ensuring benefits of geotechnical engineering, and has important scientific research significance and engineering application value. [0003]...

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Problems solved by technology

[0008] Disadvantages of the prior art: (1) There is no distinction between the stress states of tensile shear and compressive shear in the process of rock damage and fracture

(2) There is a flaw in the mechanical mechanism of the effective normal stress definition of the internal section of the rock in the compression-shear damage state

(3) Using the Mohr-Coulomb failure criterion, the contact of the crack surface on the fracture slip surface is not considered to have the property of generating contact pressure

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