A method for determining long-term rock strength parameters based on steady-state rheological rate intersection

Abstract

The invention discloses a steady rheology rate cross point-based determination method of rock long-time strength parameters. The steady rheology rate cross point-based determination method comprises following steps: rock core samples are processed to be standard cylindrical samples; the standard cylindrical samples are subjected to triaxial rheological mechanical property test; two steady rheology rate curves are obtained via fitting based on axial rheological rate and volume rheological rate of steady rheology period; and quantitative determine of rock long-time strength parameters is realized based on the cross points of the axial rheological rate curve and the volume rheological rate curve. According to the steady rheology rate cross point-based determination method, the axial rheological rate curve and the volume rheological rate curve obtained via rock rheological mechanical property test result calculation are compared; rock long-time strength parameters are determined based on critical values of rock compression deformation and volume expansion, wherein the critical values are represented by the cross points of the two steady rheology rate curves; a problem that inflection points are not clear in rock samples with unobvious rheological behaviors in conventional stress-strain isochronous curve cluster method and steady rheology rate method is solved; and the steady rheology rate cross point-based determination method possesses reference value in accurate evaluation of rock long-time stability.

Description

technical field [0001] The invention relates to the field of rock mechanics and engineering, in particular to a method for determining long-term rock strength parameters. Background technique [0002] The determination of long-term strength is an important aspect of long-term stability and safety analysis of rock engineering, and has very important engineering background and significance. According to the actual requirements of different projects, the understanding of the long-term strength of rocks is also quite different. A more accepted definition of long-term rock strength is that the rock undergoes rheological phenomena under long-term constant external loads; when the external load is greater than or equal to a certain value, the rheological deformation of the rock will continue to increase and eventually fail. ; When the external load is less than a certain value, the rheological deformation rate of the rock will gradually decrease with time, and the rheological defo...

AI Technical Summary

Problems solved by technology

The inflection point method widely used at present is to randomly select any one of the axial, circumferential or volume rheological rate curves for visual inspection of the sudden change point, so it is more random and inaccurate

In addition, the inflection point of the initial straight line section of the curve and the later curve section is relatively obvious, but if the rheological properties of the rock are not obvious, the inflection point of the curve is relatively blurred, and it is difficult to obtain it directly visually, and the effect is not good

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