油页岩采场围岩垂直应力时空演化规律试验研究

为研究油页岩采场围岩垂直应力的时空演化规律,以龙口某矿油页岩开采为原型,铺设了相似材料模拟试验模型,对油页岩采面回采过程中及开采后采场围岩中的垂直应力进行了连续监测,通过对垂直应力数据进行整理和分析,得到了采场围岩支承压力的峰值、影响范围及垂直应力的时空分布变化特征。结果表明,采空区冒落矸石可充分参与承载覆岩压力,并减小支承压力影响范围及压力峰值;开采过程中支承压力影响范围及峰值均先增大,随后减小,再增大;油页岩上层采后随时间推移,采空区底板的垂直应力不断升高,但采空区边界处底板的垂直应力增加不明显;两侧边界岩柱上的垂直应力在采后10 d内增幅较大,之后的30 d内增幅减小,采场围岩垂直应力在不同空间位置随时间的变化反映了采空区不同的压实程度。

Experimental study of time-space evolution law of vertical stress in surrounding rock of oil shale mining stope

To study the time-space evolution of vertical stress in surrounding rock in oil shale mining stope, according to the original size of the stope in Longkou colliery, a similar material simulation test model was built, then the model was mining to simulating the field mining. During and after the process of mining, the vertical stress of surrounding rock in the stope was continuously monitored. After processing and analyzing the the vertical stress data, some useful indexes were obtained such as the abutment pressure peak value and its influence area, time-space distribution and changing characteristics of vertical stress. It turns out that the falling rock blocks in the gob can participate in bearing strata pressure and can decrease the abutment pressure peak value and is influence area, during the mining process, these two indexes both go up first, then decrease and hold, at last increase. With the passage of time after mining, the vertical stress in the gob floor has a continuous rise except the gob corners. The vertical stress on the boundary rock pillars has a slight increase during 10 days after mining, whose growing rate was small, then during the following 30 days, the growing rate decrease which means the vertical stress comes to a instable value. And the change of vertical stress at different time and space site reflects the various compaction degree of the gob.