冲击作用下节理岩体应力波波速衰减规律研究

Attenuation Law of Stress Wave Velocity in Jointed Rock Mass under Impact Loading

为探究冲击荷载下节理岩体中应力波波速衰减规律,用水泥砂浆梁状结构模拟岩体,填充黏土层模拟软弱薄夹层,采用自行设计的摆锤冲击装置作为动力源进行冲击加载试验.研究了节理存在与否、节理数量和厚度对冲击荷载下节理岩体应力波衰减规律的影响,并利用特征线法和位移不连续模型推导节理面对应力波衰减的影响.结果表明:随着距离增大,振动衰减速度减慢,呈现出近端衰减快,远端衰减慢的规律;梁状结构表面的振动响应与节理厚度、数量呈负相关;节理引起的振动响应差异随节理数量的增加逐渐降低;理论的峰值和变化规律与试验结果吻合.通过分析节理对应力波波速衰减规律的影响,为日后实际工程作业中减小对周边建筑物的安全风险提供一定的参考.

To explore the stress wave velocity attenuation law of jointed rock mass under impact load,cement mortar beam structure was used as the working medium to simulate the rock mass,clay layer was filled to simulate the weak thin interlayer at the joint position,and a simple pendulum impact device was used as the power source to carry out a series of impact load tests.The influences of existence of joints,number of joints and thickness of joints on stress wave attenuation law of jointed rock mass under impact load were studied.The attenuation law of stress wave in jointed rock mass was analyzed,and the effect of jointed rock mass on stress wave attenuation was deduced by using characteristic line method and displacement discontinuity model.The results are as follows.With the increase of the distance,the vibration attenuation slows down,showing a law of fast attenuation near the impact point,slow attenuation away from the impact point.The vibration response of beam structure surface is negatively correlated with joint thickness and number.With the increase of the number of joints,the difference of vibration response caused by joints decreases gradually.The theoretical peak value and variation rule agree well with the experimental results.By analyzing the influence of joints on stress wave attenuation law,it can provide some reference for reducing the safety risk of surrounding buildings in practical engineering operation in the future.