Method for determining widths of partition coal pillars at slope based on creep test of coal sample

Abstract

The invention provides a method for determining the widths of partition coal pillars at a slope based on the creep test of a coal sample. The method comprises the following steps: acquiring a coal sample and determining the time of one stoping; with the time of one stoping as destroy time of the coal sample on a testing machine, setting normal stresses of different grades, setting horizontal stresses by using the Cheng' step loading method, carrying out creep fracture test on the coal sample within the time of one stoping, acquiring a creep stress-strain curve of the coal sample and a series of shear fracture strength data under the action of the normal stresses of different grades, and recording target time strength of the coal sample; subjecting the target time strength under the action of the normal stresses of different grades to fitting and determining the cohesive force and internal friction angle of the coal sample according to a fitting curve and Mohr' strength equation; setting the width range of the coal pillars, and simulating the vertical stress field distribution rule and plastic failure zone distribution rule of the coal pillars under the conditions of different coal pillar widths by using FLAC3D software according to the determined cohesive force and internal friction angle of the coal sample; and carrying out contrastive analysis so as to obtain the proper width range of the coal pillars.

Description

technical field [0001] The invention belongs to the technical field of coal mining, and in particular relates to a method for determining the width of a coal pillar isolated from a slope based on a coal sample creep experiment. Background technique [0002] After years of mining in my country's open-pit mines, a large number of coal mine sidewalls are left behind. Due to the high stripping ratio of the mining area or the limitation of mining technical conditions, this part of the pressed coal often has to be abandoned. Using end-side shearer coal mining technology to recover end-side pressed coal can achieve good economic results and improve the recovery rate of coal resources. Although end-side shearers have been widely used abroad, limited by the production level of technical equipment, the use of end-side shearers is rarely seen in China. Domestic scholars have done a lot of theoretical work for the promotion and use of end-side shearers in China, and studied the applica...

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Problems solved by technology

Even so, the research content is based on foreign actual production experience and theoretical formulas, and its mining parameters are not necessarily applicable to my country's special engineering geological environment, and there is no systematic research on the width of the isolated coal pillars on the slope, and many issues still need to be investigated. practice test

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