关键词: 预制裂隙, 砂岩, 能量转化, 渐进破坏, 特征参数

Abstract: In order to study the energy conversion characteristics and dip effect of fractured sandstone, the axial loading test was carried out. The energy conversion characteristics in process of the whole stress-strain were study, and the relations among the energy conversion, the progressive failure process and the dip of pre-existing crack were discussed. The test results showed that the energy conversion presented an obvious stage characteristic. Taking dissipation energy conversion rate as an example, it has experienced linear decline, slow decline, stable development, slow increase, and sudden increase near the peak stress, which was corresponding to the stages of full stress-strain curves, and the damage stress σcd determined by the dissipation energy conversion was in good agreement with the value determined by AE ringing count. As the dip of pre-existing crack increasing, the input energy, elastic strain energy and dissipated energy at σcd increased linearly, while they showed a relatively gentle increase trend at initiation stress σci and closure stress σcc. The energy conversion of the specimens with different pre-existing crack at σcd was relatively stable, which showed that there was little difference between the dissipation energy conversion rate at σcd and at σci, i.e. the energy parameters and conversion relationship at σcd could be used to characterize the evolution characteristics of rock deformation and fracture.