| With the rapid development of infrastructure and mine construction in China,more and more projects such as open-pit mining use blasting technology for construction.Once the slope is unstable under the action of blasting vibration,it will bring disastrous consequences to the engineering construction and the peopleundefineds property safety.Based on the blasting vibration geological hazard test project in the mining area of Lv Liang mountainous area,based on the previous investigation data,this paper has a certain understanding of the geological situation of the study area,and analyzes the slope structure of the slope according to the field investigation.The deformation characteristics and deformation-failure signs,the engineering geological conditions of the study area and the basic characteristics of typical blasting cracked slopes are grasped,and the geological structure model of the slope under blasting vibration load is established,and a large number of laboratory tests are carried out.The material composition,structural characteristics,basic physical and mechanical properties and dynamic parameters of rock and soil are obtained.Finally,the dynamic response law and stability of slope under blasting vibration are analyzed by numerical simulation.The main findings are as follows:(1)The typical cases of geological disasters induced by blasting vibration load in the surrounding towns of Lv Liang mountainous area were investigated on the spot.The basic geological situation of blasting cracked slope in Beizhuang Village,Lingshi County,and the slope body structure were mastered.The characteristics of deformation and signs of deformation failure are investigated and the potential failure modes of slopes are analyzed.(2)In this paper,uniaxial compression tests and triaxial compression tests are carried out on Permian Shihezi Pshite sandstone in slope bedrock area.The static strength and dynamic strength of rock mass under different conditions are compared and analyzed,and the peak strength of rock mass under different vibration frequencies is studied.The change of mechanical parameters of rock mass such as residual strain,cohesion(C)and angle of internal friction(?)is used to analyze the damage to slope rock mass caused by blasting seismic wave with relatively low frequency.(3)The Hopkinson compression bar test was carried out on the Permian Shihezi Pshite sandstone in the slope bedrock area.The mechanical properties of the rock materials under the condition of high strain rate were studied.The stress and strain of the specimen at the medium and high strain rate were measured by this test.The relationship between strain rate and dynamic strength.Finally,the damage characteristics of rock subjected to high frequency and high amplitude shock wave and the damage degree of rock under different loading conditions are studied from two angles of energy and wave velocity.(4)Scanning electron microscope(SEM)tests were carried out on sandstone samples destroyed after cyclic load test and Hopkinson compression bar test.The phenomena of crystal failure were observed from a microscopic point of view,which was compared with macroscopic failure phenomenon.The failure modes of crystals under different stress conditions are studied,so that the mechanism of rock and soil failure is analyzed more comprehensively and accurately.(5)According to the geological prototype obtained by field investigation and using GeoStudio numerical simulation software,the slope dynamic calculation model is established to calculate the slope stability coefficient under different blasting dynamic loads.The relationship between slope failure and vibration intensity and vibration frequency is obtained,and then continuous blasting dynamic loads are applied to the slope.Through the change of slope stability coefficient,the change of plastic zone and the change of stress and strain in different parts of slope,To reflect the cumulative damage of the slope under the action of multiple blasting vibration. |
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