Investigation On Mechanism And Control Measures Of Yepo Village Collapse In Lintong District Of Xi'an

The Yepo Village Collapse is located in Yepo Village of Lintong District,Xi'an,Shaanxi Province.The research area is about 13km from the center of Lintong District and about50km from downtown Xi'an.Since 2013,due to extreme weather and human engineering activities,the research area has repeatedly collapsed,seriously threatening the lives and property of local residents.Therefore,investigating the mechanism of the problem can provide strong support for the prevention and control of loess collapses.Through the field investigation,laboratory test and numerical simulation,combined with the regional geological survey data,the formation mechanism and influencing factors of the Yepo Village Collapse in Lintong District were analyzed.The numerical simulation and kinematics related theoretical knowledge were used to investigate the mechanism of motion and the scope of impact of the Yepo Village Collapse.And the control measure of the loess collapses combining with landscape design was proposed.Following results have been achieved in this paper:1.Aiming at the Yepo Village Collapse in Lintong District,the morphological characteristics,structural features and deformation and failure characteristics were described.2.The Yepo Village collapse is affected by lots of factors,among which the internal factors are caused by the characteristics of the loess itself—the collapsibility and the shape of the slope.The external factors include vegetation,rainfall,earthquake and human engineering activities.3.Based on field survey data and measured sections,the geological model of the Yepo Village collapse was established.The 2D-Block discrete element software was used to simulate the extent of the impact after the collapse under the natural condition,the heavy rain condition,the seismic condition and the heavy rain condition combined with seismic condition.By analyzing the numerical simulation results,the maximum sliding distances of the collapsed bodies under the natural condition,the heavy rain condition,the seismic condition,the heavy rain condition combined with seismic condition are 27.10m,36.54m,41.41m and 55.80mrespectively,and the impact ranges are 2152.25m~2,3336.68m~2,3786.31m~2and 5133.63m~2 respectively.The actual impact of the collapse is between the simulation results of the natural condition and the simulation results of the heavy rain condition.The motion mechanism of the"lead edge fracture deformation-collapse body slip-collapse body accumulation"of the Yepo Village Collapse is proposed,and the characteristics of the collapse bodies at each stage are explained.The formation mechanism under three states is proposed:the mechanism of collapse under the engineering activity state,the mechanism of collapse caused by climatic factors and the mechanism of collapse of earthquake state.After comprehensive analysis of the formation mechanism of the Yepo Village Collapse,the formation mechanism under the condition of engineering activity is dominant.4.Two prevention and control measures were proposed for the collapse of the Yepo group:traditional treatment engineering measures and treatment measures combined with landscape design,comparing two prevention measures,and the treatment measures combined with landscape design are more environmentally friendly and more visually comfortable.And it meets the development requirements of ecological civilization.