Method for observing rock and soil sample shear band inclination angle evolution rules under two types of formation conditions

Abstract

The invention provides a method for observing rock and soil sample shear band inclination angle evolution rules under original and real-time formation conditions. The method includes acquiring a digital image, comprising speckle surfaces, of a sample by shooting devices under a loading condition; by a digital image correlation method, acquiring maximum shear strain fields of the sample under the original and real-time formation conditions; by an interpolation method, acquiring maximum shear strain fields good in smoothness in an area comprising measured shear bands; deleting redundant data according to roughly-estimated widths and inclination angles of the measured shear bands to acquire positions of all points on center lines of the measured shear bands, and acquiring inclination angles of planer shear bands and spatial shear bands by a fitting method. The method has the advantages that the rules that the shear band inclination angles evolve according to stress, strain and time under the original and real-time formation conditions can be acquired; automated, rapid and accurate measurement of the shear band inclination angles can be achieved; the method is suitable for measuring the inclination angles of plane inclination strain concentration bands and spatial shear planes of various materials.

Description

technical field [0001] The invention relates to a shear band measurement technology of rock and soil materials, in particular to a shear band dip angle measurement technology. Background technique [0002] In various geotechnical engineering practices, the sudden failure and instability of structures composed of geological materials (rock, soil, etc.) are widespread and often occur. For example, in the construction and operation of hydropower, railway, protection, and petroleum projects, disasters such as cavern rockbursts, collapses, and landslides may be encountered; in coal mining, rock bursts, coal and gas outbursts, and other disasters may be encountered. The occurrence of these disasters has seriously affected the healthy development of economic construction and energy industry, resulting in huge property losses and heavy casualties. In 1985, a landslide accident occurred at the Tianshengqiao No. 2 Hydropower Station, resulting in 48 deaths; in 2005, a gas explosion a...

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Problems solved by technology

[0013] In order to solve the problems of low measurement accuracy, low efficiency, and limited amount of data obtained in the existing sample shear band dip angle observation method (for a sample, only one shear band dip angle can be given), the present invention provides a A digital image correlation method based on the observation method of the dip angle evolution of the sample shear zone under two configuration conditions, using particle swarm optimization algorithm, Newton-Raphson iterative method, bicubic spline interpolation method, least squares fitting method , which realizes the measurement of the evolution law of the shear zone dip angle under two configuration conditions, improves the efficiency and accuracy of the measurement, and can obtain a wealth of data

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