Test method for influence of coalbed methane extraction on coal seam roof deformation under non-uniformly distributed load

Abstract

The invention discloses a test method for the influence of coalbed methane extraction on coal seam roof deformation under non-uniformly distributed load. The test method comprises the steps that a test device is manufactured, specifically, the test device comprises a concave-shaped sealed cavity and a transparent box, a test-piece placement cavity is formed in the recess part of the sealed cavity,a front pressing plate is provided with a front pressing rod, side pressing plates are arranged on the left, right and rear sides of the test-piece placement cavity, ventilation holes are formed in the head ends of the side pressing plates, the side pressing plates are provided with side pressing rods, upper pressing plates are arranged above upper base plates front and rear in a closing mode, the upper plates are provided with upper pressing rods, and a structure of which spherical balls are installed between two clamping plates is applied to the end heads of the upper pressing rods; pulverized coal is prepared; a coal briquette test-piece is prepared; the coal briquette test-piece and extraction tubes are installed; triaxial stress is applied; gas pressure is applied; a test is performed; other tests in the same group are performed, and the number of the extraction tubes is changed; and test data are arranged. Triaxial real simulation tests of the coalbed methane extraction and thecoal seam roof deformation under the non-uniformly distributed load are carried out.

Description

technical field [0001] The invention belongs to the technical field of coal mine safety, and in particular relates to a method for testing the deformation of a coal seam roof affected by coal seam gas extraction under the action of non-uniformly distributed loads. Background technique [0002] Energy is the foundation and driving force of modernization, and energy supply and security are related to the overall situation of my country's modernization drive. In the national "Energy Development Strategic Action Plan (2014-2020)", it is pointed out that the production increase and clean and efficient utilization of conventional fossil fuels should be accelerated. In 2019, total coal consumption will be controlled at about 4.2 billion tons, shale gas production will strive to exceed 30 billion cubic meters, and coalbed methane production will strive to reach 30 billion cubic meters. [0003] In the process of coalbed methane extraction, due to the change of the effective stress ...

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Problems solved by technology

[0004] At present, domestic and foreign scholars have mostly focused on the field research on the influence of coalbed methane extraction on the deformation of the coal seam roof under the action of non-uniform loads, and there are few laboratory tests and theoretical studies. Under the triaxial stress state, coalbed methane extraction affects the coal seam roof deformation under the action of non-uniform load, so as to study the influence of coalbed methane extraction on coal deformation and permeability under the true triaxial stress state

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