预制裂隙红砂岩在冲击荷载作用下的动力特性

Dynamic characteristics of red sandstone under impact load

红砂岩是南方地区普遍存在的泥状胶结结构土,为研究其在冲击荷载作用下的动力特性,本文采用理论分析和落锤试验相结合的方法,开展了节理砂岩和完整砂岩的冲击动力试验。结果表明:砂岩加载速率和卸载速率近似相等,节理砂岩达到峰值强度后存在短暂的蠕变现象;当冲击能较小且岩石较质密时,加载中后期位移会出现轻微反弹,反弹位移随落锤质量的增加而减小;节理的存在使得加速度时程曲线出现两个峰值,砂岩破坏被分为两次峰值加速度前后明显的两段;根据能量守恒原理,验证了裂隙岩体破坏时吸收的能量小于完整岩体吸收的能量。本试验研究可为红砂岩类围岩硐室的稳定性控制提供理论依据。

Red sandstone is a kind of clayey cementitious structural soil that commonly found in the southern region,in order to study its dynamic characteristics under impact load,the impact dynamic tests of fractured sandstone and intact sandstone are carried out by combining theoretical analysis and drop hammer test.The test results show that the loading rate and unloading rate of the red sandstone are approximately the same,and there is short creep after the joint rock reaches the peak intensity.When the impact energy is small and the rock is dense,the mid-to-late displacement will rebound slightly,and the rebound displacement will decrease with the increase of the weight of the hammer.There are two spikes in the acceleration curve during the acceleration,and the sandstone damage is divided into two periods of apparent peak acceleration before and after.According to the principle of energy conservation,it is proved that the energy absorbed by fractured rock mass is less than that absorbed by intact rock mass.It is hoped that the results of this experiment can provide references for the construction of red sandstone rock foundation.