Study on Gas Enrichment Mechanism of Coal Seam Influenced by Vertical Stress on Mountainous Region Condition

Xiaojie Yang,Feng Zhang,Chaowen Hu,Shuhua Sun,Bo Cheng,Jianning Liu,Ruifeng Huang,Chen Miao

doi:10.1155/2020/8822384

Abstract

The controlling effect of vertical stress of mountainous region on gas occurrence of the coal seam below it has always been ignored. In order to clearly express its influence mechanism, the change laws of depth, stress, and permeability of coal seam pressurised by the overlying mountain were studied based on the Winkler elastic foundation beam theory and seepage theory in the paper. At the same time, the enrichment mechanism of the coal seam pressurised by the overlying mountain was analyzed. The results showed the following: (1) There was a significantly strong correlation between the stress, permeability change rule of the coal seam, burial depth, and surface elevation under such condition. (2) Under the action of the vertical pressure of the mountain, the stress and permeability distribution of the coal seam showed significant nonlinear characteristics. The stress was the greatest under the peak, and the permeability was the smallest. (3) The initial gas content value was controlled by the permeability and the stress of the coal seam in the situation. Moreover, the field practice showed that under the action of vertical pressure of the mountain, the evaluation law of gas content was coupling with the surface elevation of the overlying mountain. In addition, the gas emission change law during the excavation of the driving face also showed the same characteristics. The results might be of great significance for the development and utilization of coal-bed gas and the safe exploitation of coal resources.

Highlights

Academic Editor: chen miao e controlling effect of vertical stress of mountainous region on gas occurrence of the coal seam below it has always been ignored
For ground stress increases with the increase in burial depth, the permeability of the coal seam decreases gradually [13,14,15] and the gas content of the coal body increases as burial depth of coal seam increases [16,17,18]. e influence mechanism of burial depth on gas content can be expressed as follows according to the above investigations: the permeability of the coal seam is controlled directly by the stress associated with burial depth, which has strong correlation with gas flow
Based on the Winkler elastic foundation beam theory, seepage theory, and the method of field observation, the change rules of stress and permeability of the coal seam pressurised by the overlying mountain were studied. en, the relationship between burial depth, stress, permeability, and gas content was analyzed

Summary

Introduction

Academic Editor: chen miao e controlling effect of vertical stress of mountainous region on gas occurrence of the coal seam below it has always been ignored. E results showed the following: (1) ere was a significantly strong correlation between the stress, permeability change rule of the coal seam, burial depth, and surface elevation under such condition. E influence mechanism of burial depth on gas content can be expressed as follows according to the above investigations: the permeability of the coal seam is controlled directly by the stress associated with burial depth, which has strong correlation with gas flow. It implies that the high ground stress and low permeability might induce gas enrichment of the coal seam in complex coalforming and geology movement process. E aim of the investigation here was to analyze the inner mechanism of mountainous topography to gas enrichment

Methods

Results

Conclusion