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

Abstract

The invention discloses a method for determining the long-term strength parameters of rock based on the tangent line of the steady-state rheological rate. Through the steady-state rheological rate curve with 0° to 90° as the angle interval, the steady-state rheological rate of the rock is determined every 10°. Draw a tangent line to the curve to obtain the interval formed by the intersections of each tangent line and the horizontal axis, and select the interval with the smallest interval range and the inflection point of the steady-state rheological rate, then the deviatoric stress value of this interval is the rock long-term strength parameter interval; The invention introduces the interval formed by the intersection of the tangent line of the steady-state rheological rate curve and the X-axis, and determines the long-term strength parameter interval of the rock where the inflection point is located by controlling the angle between the tangent line, which can overcome the traditional stress-strain isochronous curve cluster method and the steady-state rheological rate method have the problem of fuzzy inflection points in rock samples with inconspicuous rheological properties. The specific interval value of the long-term rock strength parameter can be quantitatively determined through the tangent line, and the long-term rock strength can be represented by the interval between the tangent line and the coordinate axis. The range of parameters.

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 long-term strength of rock is the focus of rock engineering long-term stability research, which has very important engineering background and significance. 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 deformation will gradually converge, and the rock will not crack; the critical value of this stress level can be called the long-term strength of the rock. Theoretically, l...

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, when the stress-strain isochronous curve cluster method is obvious in rock rheological properties, the inflection points of the initial straight line segment and the later curve segment are more obvious, but if the rock rheological properties are not obvious, the curve inflection point is relatively vague. Difficult to get directly visually, the effect is not good

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