不同赋存深度新疆天湖花岗岩的动态拉伸力学特性研究

基于SHPB装置，进行了高放废物地质处置新疆预选区天湖地段花岗岩的动态拉伸力学特性试验，试验所用岩芯均取自于同一钻孔的不同深度处（深度范围为350 m~580 m）。测试结果显示：该花岗岩在加载率处于105 MPa/s这一中高等加载率下，其动态拉伸强度一般在15 MPa~35 MPa。并且随着加载率的提高，无论哪一赋存深度的花岗岩样品，其动态拉伸强度均随之增大，这说明了花岗岩的率相关加载效应特性。此外，对该花岗岩冲击破坏后的形态进行了观测，发现其加载破坏模式呈现拉伸破坏，与静态拉伸加载下的劈裂破坏特征基本一致。进一步分析试验数据，认识到花岗岩样品其动态拉伸强度之所以随着深度会产生增大或者减小的现象，是因为深部岩石其自身的物理特性已经发生了变化，从而造成了岩石力学特性随之发生改变。其密度、孔隙度等均不相同，正是这些物性的差异导致了其力学特性的差别。该研究的试验数据与理论可支撑于深部地下工程的爆破开挖及高放废物的深地质处置。

RESEARCH ON DYNAMIC TENSION PROPERTY OF GRANITE AT DIFFERENT DEPTH IN TIANHU AREA OF XINJIANG AUTONOMOUS REGION

Based on the SHPB (Split Hopkinson Pressure Bar), the dynamic tension property of the granite at different depth in Tianhu area of Xinjiang Autonomous Region has been studied deeply, which is a preselected area for the HLW (High Level radioactive Waste) geological disposal. For the granite in the borehole, all the rock tested is from the same borehole at different depth, i.e. 350 m~580 m. Therefore, the testing results could be considered much more representative of the granite. Under the dynamic conditions, the dynamic tension strength is about 15 MPa~35 MPa when the stress rate is about 105 MPa/s. With the loading rate increases, the dynamic tension strength also increases, no matter at what depth, which shows the loading rate effect of the rock. Meanwhile, the testing results show that the failure model of the rock is also tension one, which is the same as the static tension test. Furthermore, the phenomenon that the dynamic tension strength increases or decreases with depth illuminates that the granite has been varied itself at different depth. The density and porosity have also been changed, presenting various mechanical property of the granite. And the result and the theoretical knowledge could be applied to the blasting and excavation of deep geo-engineering and HLW geo-disposal.