Method for constructing failure criterion of rock under triaxial compression condition

Abstract

The invention discloses a method for constructing a failure criterion of rock under a triaxial compression condition. The method comprises the following steps: S1, aiming at the problems of the linearMohr-Coulomb criterion that the peak intensity of a low-confining-pressure section is overestimated, and nonlinear characteristics of rock failure in a high-confining-pressure section cannot be characterized, constructing a new intermediate variable shown in the specification by virtue of the Mohr-Coulomb criterion and an internal friction angle phi; S2, establishing a reasonable function expression of the intermediate variable X changing along with confining pressure sigma 3 based on theoretical analysis and test result analysis; S3, substituting the intermediate variable into the Mohr-Coulomb criterion, and obtaining a new empirical failure criterion expression for rock conventional triaxial compression analysis through parameter replacement; and S4, verifying the established criterionby adopting test data of various rocks, and proving the superiority of the established criterion by comparing the established criterion with the existing five common criteria.

Description

technical field [0001] The invention belongs to the research field of failure criteria of rocks under conventional triaxial compression stress state, and in particular relates to a construction method of failure criteria of rocks under triaxial compression conditions. Background technique [0002] With the increase of engineering activities in the world, the study of rock failure behavior under complex geological conditions has attracted more and more attention. Among them, the evaluation of rock failure criteria is crucial to geotechnical engineering practice. Typically, there are many forms of failure criteria, including stress failure criteria, energy failure criteria, and strain failure criteria, among which the stress failure criterion is the most commonly used criterion in the field of rock engineering. Therefore, it is of great practical significance to study the stress failure criterion of rocks for the safe and economical design of geotechnical engineering structur...

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Problems solved by technology

[0009] S1. In view of the problem that the linear Mohr-Coulomb criterion overestimates the peak strength of the low confining pressure section and cannot characterize the nonlinear characteristics of rock failure in the high confining pressure section, a new intermediate variable is constructed based on the Mohr-Coulomb criterion and the internal friction angle φ

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