煤层群下行开采煤柱应力传递规律

Strata behaviors analysis of stage coal pillar in Tong Xin mine caused by repeated mining

为研究煤层群开采过程中遗留煤柱应力传递规律,防治下煤层开采中上部煤柱应力传递形成应力集中引起的矿井动力灾害.采用理论研究与数值模拟的方法对煤柱的应力传递规律进行研究.应用土力学原理对集中应力和线性应力在岩体中垂直近似传递规律公式进行推导;运用FLAC3D软件对同忻矿8104工作面区段煤柱应力状态及上覆侏罗系煤柱应力传递规律进行数值模拟,对不同宽度以及不同应力场条件下煤柱应力传递规律进行分析.研究发现,煤柱应力垂直传递受到自身宽度、埋深、采高和煤层倾角的影响,同时还受下部采空区的影响.8104工作面准备完成后煤柱所受应力较高,工作面前方应力升高区近100 m,工作面推进到550 m时矿压显现较严重,对工作面安全作业威胁较大,煤柱应力升高主要是由上部采空区煤柱应力传递及采空区悬顶面积过大所引起.

In order to study the law of left coal pillar stress transfer in coal seam group mining and prevent mine dynamic disasters caused by the coal pillars stress concentration when the coal seam below coal pillar is mined, theoretical research and numerical simulation methods were used. This paper applied the principle of soil mechanics to deduce the vertical transfer law of linear and concentrated stress in rock mass. FLAC^3D software was used to analysis the stress transfer law of section coal pillar in 8104 working face and overlying Jurassic coal seam in Tong Xin mine. Stress transfer law with different coal pillar width and field stress condition was analyzed. Results show that the stress vertical transfer in pillar is not only affected by itself and floor integrity, but also affected by similar degree of the physical and mechanical properties of lower coal strata and adjacent layers. Stress in coal pillar is very high when 8104 working face is just prepared and the rising stress area in front of working face is nearly 100 m. when working face advancing to 550 m, strata behaviors becomes more obviously, seriously threat the safety of workers. Higher stress in coal pillar is caused by the upper coal pillar stress transfer and great area of goaf roof hanging.