地震前，震中区周围应力场发生转向，由正应力区变为负应力区，同时正应力的量值逐渐增大。
The stress field of periphery of the epicentral region transformed from positive stress into negative stress, and the value of the positive stress increased gradually before the earthquakes.
分析研究表明导致立井壁破坏的主要原因是井壁负摩擦力和温度应力。
The main causes of shaft wall fracture contain the reverse friction force and the temperature stress.
试验结果表明，在温度水平一定的条件下，砂岩的孔隙度随有效应力的增加而呈负指数规律减小；
The test results show that the porosity of sandstone decrease with the increasing effective stress at the fixed temperature level, following the law of negative exponent.
应用推荐