Slope Seismic Survey Of Wenchuan Earthquake And Monitoring Research In Qingchuan County

Earthquake is the main cause of slope unstability, collapse, landslides and mudslides. China is located to the two most active belt of the world, geohazard induced by earthquake frequently."5.12"Wenchuan earthquake caused tens of thousands of geohazard, resulted in great damage and loss. So through the development of slope ground motion response survey and monitoring research have important theoretical and practical significance.This article through on site investigation to Wenchuan earthquake geohazard, establish ground motion response monitoring station and the numerical model of seismic slope, systematically studied the factor of slope topography, slope lithology composition and epicenter position which influence of slope deformation and failure under seismic load. Analysis the mechanism of seismic forces, discusses the slope deformation mechanism and failure mode under seismic load. Research found that slope seismic has the following rules:(1) Wenchuan earthquake secondary geohazard of Qingchuan county main development nearby seismogenic fault and central fault, vertical direction of seismogenic fault and central fault when it is in 1-2km range, geohazard is concentrated,but geohazard quickly reduce when beyond the range.(2) Earthquake geological hazards main occurs in slope top, slope break position and mountain spur, and show the unique dynamics characteristics of shatter-buckling failure, mass ejection, debris flow.(3) Hard rock slope usually happen collapse geological hazards,but soft rock and soil slope main development landslide; The epicenter area slope that soft rock(down) hard-rockeasy(up) easy happening mass ejection phenomenon.(4) The seismic dynamic response of slope is greater when aspect is the same as seismic wave propagation direction than contrary situation, that is beipo effect.(5) Earthquake monitoring reveal that:under seismic load's effect, seismic response of slope is not monotone increase, but has great relationship with the slope's landform, slope body structure and lithologic association.(6) Numerical simulation study show that: under seismic load's, whether a horizontal or vertical direction, the dynamic response extent of the slope manifested as from internal of the slope to surface, dynamic response increases gradually and reached maximum when it reach to slope surface.