浅埋薄基岩煤层快速推进工作面矿压显现规律研究

Study on Strata Behaviors of Coal Seam with Shallow Mining Depth and Thin Bedrock in the Process of Rapid Mining Velocity

基于神东矿区1-2#煤层的赋存条件和开采技术条件,采用FLAC3D数值模拟方法,研究浅埋薄基岩回采工作面快速推进过程中的矿压显现规律,为工作面支架阻力确定和岩层控制提供依据。结果表明,随着推进速度的增加,顶板压力呈现减小趋势;推进速度越快,工作面前方应力集中程度越高,峰值应力距工作面距离越小,应力集中影响范围呈减小趋势;推进速度不同时煤层上部的薄基岩和厚松散层破断都直接波及地表,地表下沉量明显高于相同条件下的正常采深煤层工作面;浅埋采场上覆松散层变形移动过程中难以形成承载结构,荷载估算时不能采用传统的普氏压力拱理论。

In order to provide the basis for the support resistance calculation and strata control of mining face with the shallow mining depth and thin bedrock,based on the engineering geological conditions and mining conditions of the 1-2# coal seam in Shendong Mining Area,the FLAC3D numerical simulations was applied to study the mine strata pressure behavior laws in the process of rapid mining velocity. Results show that the roof pressure trends to decrease as the mining velocity increases. The faster the mining velocity,the higher concentration degree at the front working face is,and the shorter the distance from the peak stress is. The distance between the face and the location of the peak abutment pressure also decreases. The zone of stress concentration tends to decrease. The roof breaking of coal seam with shallow mining depth and thin bedrock and thick unconsol-idated layers directly affects the surface at the different mining velocity. The surface subsidence is obviously higher than the normal mining deep coal seam face at the same conditions;It is difficult to form bearing structure in the process of the overlying thick unconsolidated layers movement of shallow coal stope. Therefore,the load estimation of thick unconsolidated layers can′t be made by the traditional Pu′s compressive arch theory.