停采后覆岩及地表下沉率随时间变化实验分析

Analysis of subsidence ratio of strata and surface varying with time after mining stop by experiment

根据实验结果分析了开采停止后覆岩及地表下沉率随时间变化过程。下沉率随着开采面积的增大而增大,在采动过程中,从煤层顶板到地表的下沉率由大变小,当达到充分开采后,地表和岩层的下沉率基本趋近为一常数。根据下沉率随时间变化的特点,建立了其相应的函数形式,最后根据动态下沉率推导出动态下沉值的计算公式。

According to the experiment results, the subsidence ratio of strata and surface varying with time is analyzed. The subsidence ratio enlarges with the extracting area increasing. When the extraction area is small (sub critical extraction), the difference of subsidence ratio between upper and below strata is large, and the subsidence ratio of below strata is bigger. With the extraction area increasing, the difference varies little, and when the area reaches critical or supercritical extraction , the subsidence ratio of surface and rock seam is almost the same. And the ratio changing rule is also revealed. Then a function is established, and dynamic subsidence formula is deduced by dynamic subsidence ratio.