Research on the static and dynamic properties of the granite in Xinjiang Province Tianhu Area for the geological disposal of the high level radioactive waste

Based on the MTS815 Flex Test GT for the rock testing and SHPB (Split Hopkinson Pressure Bar), the static and dynamic properties of the granite in Xinjiang province Tianhu area have been studied deeply, which is a preselected area for the HLW (High Level radioactive Waste) geological disposal. For the granite in the borehole, the tension testing, uniaxial compression testing, dynamic tension testing, dynamic compression testing and the one dimension coupled static and dynamic loading testing have been carried out separately. Specifically, all the rock tested is from the same borehole under one same depth, i.e. 360 m, therefore, the testing results could be considered much more representative of the granite. The tension strength is about 11.75 MPa, and the uniaxial compression strength is 175 MPa or so, which is about 14 times than the tension strength. With the dynamic conditions, the dynamic tension strength is about 25 MPa∼35 MPa under the stress rate is 0.34∼0.51 × 10⁶ MPa/s. And the dynamic compression strength located in 138 MPa∼208 MPa under the strain rate is 80∼160/s. With the loading rate increases, the strength is also increase, whatever the tension strength or the compression strength, which shows the loading rate effect of the rock. Furthermore, the one dimension coupled static and dynamic tension loading testing has been carried out. It is found that with the precompression stress increase, the impact dynamic strength increases. It could reach maximum when the precompression stress is about 50% of the static tension strength. Meanwhile, with the precompression stress increase, the coupled static and dynamic strength increases obviously, especially it could reach about three times of the static precompression stress, and about one and half times of the dynamic strength. The testing results show that the failure model of the coupled static and dynamic loading is also tension failure, which is the same as the static tension and conventional dynamic loading test. Through a series of the testing above, rock in this area may be considered stable and this area could be a selected area for the HLW geo-disposal. However, the testing result is inadequate, and the other testing, for example, the seepage testing, the in site stress testing and other should be moved forward, not only in one borehole, but also in different kinds of borehole in diverse depth. Then, the rock in this area could be researched in detail, and the result and the theoretical knowledge could be applied to the blasting and excavation of the deep geoengineering and the HLW geo-disposal.