【摘要】 根据砂岩单轴刚性加载试验情况,声发射信号在屈服点(即稳定破裂和非稳定破裂分界点)处存在激增现象,同时分界点处所对应的应变约为峰值强度对应应变值的74.6%左右。从加载历时来看,在非稳定破裂阶段存在较长的耗时。岩石脆性破坏前声发射信息存在"准平静期",而平静期的历时与峰值强度对应的历时比的平均值约为8%。以声发射信息为损伤测度进行了加载过程中的损伤值计算。屈服点处损伤值呈现出显著增长;应力-应变曲线峰后拐点处的损伤值大于0.9。峰值强度前,损伤值曲线呈现为下凹型;峰后阶段,呈现为上凸型,强度峰值位置为曲线拐点。更多还原

【Abstract】 Accroding to uniaxial rigid loading tests of sandstone,the acoustic emmission(AE) signals present sharp increase characteristics in the yield point,and the strain value corresponding to the yield point is about 74.6% of that in the peaking state.Meanwhile,the time consuming in the unsteady loading stage is relatively long,while the AE signals exit the quasi-quiet stage before the brittle failure of rock samples,and the avearege value of the duration ratio between the durations associated to quiet stage and peaking state respectively is about 8%.In addition,the damage values during the loading process are calculated based on AE information.The results show that there is a rapid growth in the yield point,and the damage value in the inflection point of stress-stain curve in the post-peak is more than 0.9.Moreover,the shape of damage-time curve before the peaking state is concave,while the curve in the post-peak shows the convex type,and the peak value locates in the inflection point of the curve.更多还原