为了研究深部地下资源开发过程中矿岩破裂的能耗效应,通过利用自行研制的岩石动静组合加载试验机,对细砂岩进行了2个系列的三维动静组合加载试验。即固定围压改变轴向静压和固定轴向静压改变围压的冲击试验。试验结果表明:在固定围压条件下.随着轴向静压增加.砂岩试件破坏所消耗的动载荷能量密度逐渐降低;当轴向静压在对应的常规三轴抗压强度的70%以上,消耗的动载荷能量密度变为负值(岩石试件释放能量);轴向静压再进一步加大,负值逐渐接近0,但始终在0以下。在轴向静压不变且较小的条件下,随着围压增大,岩石试件破坏所消耗的动载荷能量密度值一直在增大;但当轴向静压较大且在对应的常规三轴抗压强度的70%以上时,岩石试件在受到动力扰动后失去原平衡。能够白行破坏.并释放多余的能量。
By means of the improved SHPB with axial pre-pressure and confining pressure, a series of experiments on sandstone were carried out to investigate the energy consumption in rock fracturing during the course of deep underground resources exploitation. In the experiments, the cylindrical sandstone specimens were subjected to the static-dynamic coupling loads with fixed confining pressure or fixed axial static pressure. Under fixed confining pressures; the dynamic load energy densities consumed by the breakage of the sandstone specimens decrease gradually with the increase of axial static pressures. When the axial static stress is above 70% of the corresponding static tri-axial compressive strength, the dynamic load energy density consumed is below 0, namely, the sandstone specimens release energy. With the further increase of the axial static stress, the negative dynamic load energy density consumed approaches gradually to 0 and keeps below 0. If the axial static stress fixed is low, the dynamic load energy density consumed by the sandstone specimens increases continuously with the increase of the confining pressure. When the axial static stress fixed is great and above 70; of the corresponding static tri-axial compressive strength, the sandstone specimen can be fractured by itself and release the rest energy after losing the former balance by dynamic disturbance.