Anisotropy evaluation method for rock structural surface shear strength

Abstract

The invention discloses an anisotropy evaluation method for rock structural surface shear strength. The method comprises the following steps that: S1: obtaining the rock structural surface outline curve models of different shearing directions; S2: on the basis of the one-side PSD (Power Spectral Density)* of the rock structural surface, calculating the comprehensive power index Pf of each frequency ingredient which forms the rock structural surface for the roughness contribution of the rock structural surface; S3: calculating a corrected gradient mean square root Z2<*>; S4: on the basis of thecomprehensive power index Pf and the gradient mean square root Z2<*>, calculating the roughness parameter PZ of the rock structural surface; and S5: calculating the shear strength in different sheardirections of the rock structural surface. By use of the method, on the basis of the power spectral density, the contribution of each frequency ingredient which forms the rock structural surface for the roughness of the rock structural surface and the anisotropy characteristic of the roughness of the rock structural surface are analyzed, and therefore, the anisotropy of the shear strength of the rock structural surface can be more comprehensively subjected to quantitative evaluation.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering, in particular to a method for evaluating the shear strength anisotropy of rock structure planes based on power spectral density. Background technique [0002] The rock mass is composed of structural planes and structural bodies. The shear strength of structural planes is much lower than that of structural bodies. Therefore, the shear strength of structural planes is usually the controlling factor for the stability of engineering rock mass. At the same time, due to the obvious anisotropy of the shear strength of the rock structural plane, accurate and reasonable evaluation of the shear strength of the rock structural plane in different shear directions is helpful to find the most dangerous sliding direction of engineering rock masses such as slopes. Then the stability of engineering rock mass can be reasonably evaluated. [0003] Among the many factors affecting the shear behavio...

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Problems solved by technology

However, the test inverse method is the inverse process of the shear strength estimation of the JRC-JCS shear strength model, which is limited in engineering practice; the statistical parameter method and the fractal geometry method are often based on a single shape parameter index for the roughness of the structural surface evaluation, it is difficult to comprehensively measure the morphology characteristics of structural surfaces, which makes it difficult to obtain uniform and reliable roughness evaluation results. The obtained structure surface roughness evaluation results are often inconsistent with the size order of the selected parameters, and there are conflicting phenomena.

[0006] The contour curve of the rock discontinuity plane in nature can be regarded as a series of sine or cosine curve frequency components with different frequencies and amplitudes superimposed. At present, there is no quantitative analysis of the composition in the method for quantitatively determining the roughness of the rock discontinuity plane. The contribution of each frequency of the structural surface profile curve to the overall structural surface roughness leads to inconsistencies and contradictions between the obtained structural surface roughness evaluation results and the adopted parameter indicators, and the obtained structural surface roughness evaluation results are accurate. poor reliability and low reliability, which leads to unreasonable evaluation of the shear properties of the structural surface

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