Slope Seismic Response Of Lushan County Earthquake And Aftershocks Monitoring Research

Earthquake is an important factor leading to slope instability, induced collapses,landslides, mudslides. As the most active life two seismic zone, frequent secondarydisasters caused by earthquake in china."4.20" Lushan earthquake evoked a lot oflandslides hazards, caused tremendous damage and loss. Therefore, the vibrationresponse of investigation and study of Lushan earthquake aftershock monitoring inslope land has important theoretical and practical significance.Based on the Lushan County secondary mountain hazards site survey, combinedwith aerial images of remote sensing interpretation and the establishment of seismicrespond stations means to the real-time monitoring of aftershocks, systematic studyof the characteristics of secondary geological hazards in Lushan County, furtherdiscusses the mechanisms and modes of deformation and failure of slope underearthquake. The main conclusions are as follows:(1) After the earthquake the salient features of the study area, the geologicaldisasters of slope distribution in the area is that in Space along the seismogenic faultsdistribution flocks (band) on both sides and along the River and its tributarieslinearly distributed on both sides, mostly occurred in Longmen-Yuxi, Yuxi-Baosheng, Baosheng, Taiping, and add two stone (double Shek KIP), Ling Guancanyon the five gorge section, along the upper slope and Canyon terrain turning partsdevelopment, spur is focused on slope slope, slope break and free part,(2) of secondary mountain hazards in small collapse and shallow landslide. Thefield investigation found, secondary mountain hazards mainly developed in theelevation of500～1500m,20～50°slope slope, and mainly developed in theslope high above H/2position, area landslide developed on seismic wave has asignificant amplification effect parts, such as: slope by slow steep terrain turning partsetc.. In the slope lithology, geological hazards mainly developed in soft and hard rockstrata combination, sandstone and shale interbed formation, concentrated near theseismogenic fault central fault belt, perpendicular to the seismogenic fault or thecentral fault belt direction in the range of3km, greater than6km geological disaster israpidly reduced, in the range of15～19km and rebounded significantly, if to increase the distance gradually decreased. The landslide mass concentration distribution in thestream400m distance away, but the landslide density is not high. In the range of1.2～1.4km landslide quantity are few, but the high density. The distribution has certainback slope effect and direction effect.(3) By monitoring the aftershock and comprehensive analysis reveals that,velocity, aftershocks reveal: degree of response acceleration increased with elevation,slope under earthquake, nonlinearly. The maximum slope seismic site response in themountain slope break, thin ridges and landscapes more prominent position.Topographic control on slope seismic response relative to the elevation factors withina certain range, the amplification effect is more obvious.(4) Different form slope acceleration amplification factor, speed and horizontaldisplacement values are increases with the increase of the high of slope height, slopeseismic dynamic response degree convex> straight; different slope high accelerationamplification coefficient, velocity and displacement distribution induced by A. WhenQuaternary overburden reaches a certain thickness on the slopes, has a more distinctthan the average bedrock ground motion amplification effect.(5) Venue near the Epicenter, vertical peak acceleration has a more significantamplification, as far away from the amplification was significantly lower. Shockresponse is an important factor influencing the amplification effect of slopes. Seismicwaves in slope in the direction of propagation and the slope has amplification effect toa certain relationship: When the aspect is consistent with the seismic wavepropagation direction the extent Seismic response of slopes is greater than its opposite.Slope seismic response has a great relationship between vibration frequency by itself,Slope will Selective enlarge the seismic wave in a frequency range.(6) In seismic wave comes, the slope will occurs resonance phenomenon whenseismic waves at frequencies close to its own,lead to the extent of its dynamicresponse dramatic increasing. The LuShan seismic dynamic response of theaftershocks of the monitoring frequency values mainly within10Hz. The frequencyrange of Slopes under seismic combined effect and control by the earthquake and eachslope Characterize, resonance in the range of0.1～0.3s cycle.