Research On Acceleration Amplification Effect Of Accumulation Slope Based On FLAC3D

In recent years,earthquake disasters have occurred frequently in mountainous areas of western China,which often induce large-scale landslide geological disasters.Due to the particularity of its material composition and structure,accumulation slope is prone to landslide under seismic load,which forms geological disasters.This kind of disaster accounts for a considerable proportion of seismic geological disasters in China,but there is still insufficient understanding of its acceleration amplification effect.Therefore,on the basis of summarizing the main progress of slope seismic response at home and abroad,this paper takes the acceleration amplification effect of common accumulation slope as the main line,and uses the mainstream geotechnical engineering analysis software FLAC3 D to study the acceleration response characteristics of accumulation slope and corresponding homogeneous soil slope and rock slope,and analyzes their differences,and further studies the influence of input seismic characteristics on the acceleration amplification effect of accumulation slope.The specific work and results are as follows:1.The numerical analysis models of piled slope,homogeneous soil slope and rock slope are established by FLAC3 D software,and the acceleration response distribution characteristics of slope surface,slope and bedrock under typical earthquake are studied.The results show that:(1)PGA amplification coefficient of homogeneous soil slope and homogeneous rock slope is basically consistent with nonlinear amplification along elevation.(2)The PGA amplification factor of accumulation slope increases greatly in the range of 1/3 near slope toe,and the latter2/3 elevation increases nonlinearly along elevation with significant amplification effect.The PGA amplification coefficients of each measuring point in the slope and each measuring point on the slope change along the elevation are completely different,and the amplification effects of different parts are significantly different,showing wavy changes.the amplification effect of slope shoulder appeared at the top of slope;The acceleration at the bedrock is amplified along the elevation,but it is significantly weaker than that of the sliding body.(3)The slope surface and inner material of the accumulation slope are the same as the homogeneous soil slope,and the bedrock material is the same as the homogeneous rock slope,but the overall amplification effect is homogeneous soil slope > accumulation slope > homogeneous rock slope.(4)When seismic wave propagates upward along the slope,there is obvious slope waveform conversion phenomenon.There are obvious differences between the spectrum components of the ground motion at each point on the slope and the input ground motion.2.The effects of input ground motion waveform,amplitude,frequency,initial motion direction and duration on acceleration response of accumulation slope are further studied,and the distribution characteristics of acceleration response on slope surface,slope and bedrock are analyzed.The results show that:(1)With the increase of input seismic amplitude,the amplification coefficient of accumulation slope decreases gradually;The amplification coefficient in the slope changes in wave shape;The amplification coefficient of bedrock PGA changes little.(2)Under the action of EL Centro waves with different frequencies,the amplification coefficient of stacked slope does not completely increase with the increase of predominant frequency.(3)Under the action of different seismic waves,the acceleration response of accumulation slope varies greatly.The amplification coefficient of Taft wave is the largest,followed by Kobe wave,and El Centro wave is the smallest.(4)The initial direction and duration of ground motion have little effect on the acceleration response of accumulation slope.