Studies on the Stress Distribution Features and Changing Rules of Surrounding Rock of Roadway under Isolated Coal Face

Abstract

With the development of society and the progress of science and technology, people’s living standard has been raised gradually. Behind these, it the development and utilization of energy. China is a large coal production country. Coal is the basic energy in China, and will be the major energy in the current decades and even in the coming decades. As coal is a non-renewable resource, plus the irrational exploitation in the first few years, a great deal of coal resources were wasted, which is contrary to the sustainable development strategy of the country. In recent years, to respond to national policies, vigorously promote sustainable development strategy, improve energy efficiency, major mining areas are enhancing the mining of residual coal, especially in isolated island state of coal. At present, there are some effective safety measures for mining coal under the condition of isolated island in China, but most of the safety research focuses on the mining face, but only a few studies focus on the safety of roadway. Through investigation, it is found that there are a series of problems in roadway driving and working face mining, such as strip wall and coal cannon. This seriously restricts the mining speed of isolated island working face, and always threatens the safety of workers. In this paper, the stress distribution characteristics of coal body under isolated island state are analyzed by numerical simulation. On the basis of this, the stress distribution characteristics of roadway surrounding rock and working face mining are analyzed, and the stress variation law is summarized. It is found that there exists a stress concentration zone in the coal pillar under the condition of isolated island. The stress concentration zone is mainly affected by the geological conditions of isolated island. There is a second stress concentration zone 7 m away from the side of the roadway, which is smaller than the stress concentration zone in the protected coal pillar, but the dynamic change is larger and the stress concentration zone moves with the advance of the working face because of the influence of mining in the working face. Therefore, in the aspect of maintaining the stability of roadway surrounding rock, the effective maintenance mode is determined according to the stress distribution characteristics and variation law of roadway surrounding rock under isolated island working face.