花岗岩动静态压剪复合加载实验研究

EXPERIMENTAL STUDY ON GRANITE UNDER COMBINED COMPRESSION-SHEAR DYNAMIC AND QUASI-STATIC LOADING

岩石为天然含有微裂纹微孔洞等缺陷的复杂介质,其在复杂应力状态,尤其是在压剪应力状态下的性能研究,对工程应用有着十分重要的意义.论文利用双斜面垫块改进现有装置对花岗岩进行了动静态下的压剪复合加载实验,其中静态实验基于MTS材料试验机,动态实验基于分离式Hopkinson压杆(以下简称SHPB),由此得到不同压剪载荷联合作用下花岗岩的静态和动态力学性能.通过改变倾斜端面的角度就能够得到岩石在不同压剪加载路径下的力学性能,由此可以得到岩石的静动态破坏面.结果表明:花岗岩的破坏强度具有明显的加载速率效应.此研究为探讨岩石在复杂应力状态下的力学性能提供了新的方法.

Rocks are natural complex medium with micro cracks, micro-holes and other defects. It is significant to study their performance under complex stress state, especially under combined compression- shear loading for their engineering applications. Quasi-static and dynamic experiments of granites under combined compression- shear loading were carried out by adding a set of double beveled device in MTS for quasi-static experiments and in Split Hopkinson Pressure Bar（SHPB） experimental devices for dynamic ex- periments. When changing the inclined angle of cushions, equivalent load-displacement curves of granite samples under different loading paths were obtained. By decoupling these curves, compression and shear properties of granite samples were discussed, respectively. Failure surfaces were further analyzed. The re- sults showed that failure strength of granite had obvious loading rate effects and compression-shear cou- pling effects. The technique was helpful for the study of the mechanical properties for rock under complex stress states.