低速冲击下平行节理岩石能量传递及动力学特性

Energy Transfer Rules and Mechanical Characteristics of Rock with Parallel Joints under Low-velocity Impact

用水泥砂浆材料模拟岩样并人工形成节理裂隙,通过分离式霍普金森压杆(SHPB)实验,研究不同节理间距试件在相似冲击速度下的能量传递规律、强度特征和破坏形态,进而探究冲击速度对双平行节理试件能量传递及破坏形态的影响规律.试验结果表明,相似低速冲击下,节理间距影响类岩石试件中反射波能量、透射波能量、耗散波能量的占比,节理间距越大,破碎块度越小;平行节理试件的各能量传递规律与冲击速度密切相关,能量耗散比可表征试件的宏观破坏特征;损伤变量d与冲击速度呈弱幂函数增加关系,满足d=e(-0.148-0.0101/(v-3.103)),试件破坏时的损伤值约0.72.研究结果为地下工程多节理裂隙软岩的开挖支护及稳定性研究提供参考.

In order to study the energy transfer law of simulated rock containing parallel joints under impact loading,cement mortar meterial was used to simulate rock the ratio of mortar and plaster was adjusted to make the joints.With the help of the disconnect-type SHPB equipment,the rule of energy transfer,strength characteristics,and failure mode of specimens with different joint spacings under the similar impact velocity were studied.The experimental results showed that,in the condition of the same low-velocity impact,the proportion of reflected wave energy,transmitted wave energy and dissipative wave energy were affected by the jointed spacing.The larger the jointed spacing was,the smaller the fragmentation was.The energy transfer law of the two parallel cracks with 18 mm gap of simulated rock specimens was closely related to the impact velocity,and the energy dissipation ratio can characterize the macroscopic failure characteristics.Damage variable with the impact speeds presents an increase weak power function relationship,where d stands for damage variable and v stands for impact speeds in this formula,and the damage value of the specimen is about 0.72.The results of this study provides a reference for the analysis of the excavation supporting and stability controling of multi jointed soft rock under underground engineering.