落石对缓冲土层的冲击力及冲击深度理论与试验研究OA北大核心CSTPCD

To elucidate the applicability and feasibility of the calculation methods for impact force and impact depth of falling rocks based on Hertz contact theory,as well as the determination method for the reinforcement coefficient of buffering soil layers,full-scale model tests,inversion analysis,and mathematical statistics methods were employed.The falling rock impact tests were carried out,involving cubic rock and conical rock with a spherical top,each with a volume of approximately 1 m3 and a weight of about 2 t.They were dropped from heights ranging from 1 to 10 m onto buffering soil layers with thicknesses of 0.5-2 m.Then,the reinforcement coefficient of buffering sand layers was determined,and theoretical and test results for impact force and impact depth of falling rocks were comparatively analyzed.The research conclusions are as follows:Based on inversion analysis of the test results,it is recommended that the reinforcement coefficient of buffering sand layers within the 99.7%confidence interval should range from 0.25 GN/m5/2 to 10.00 GN/m5/2.The theoretically calculated average impact force of cubic rock is 140%larger than the test value,while that of conical rock with a spherical top is 21%larger than the test value.The theoretically calculated average impact depth of cubic rock is 112%larger than the test value,while that of conical rock with a spherical top is 5%larger than the test value.Within the 99.7%confidence interval of the reinforcement coefficient,the range of calculated impact force and impact depth of rock can encompass 100%of the test results.Under the same conditions,the test value of the impact depth of conical rock with a spherical top is greater than that of cubic rock.The impact depth increases with the increase in the thickness of the buffering layer,while the variability in the impact force of falling rocks shows no significant correlation with the rock shape and buffering layer thickness.