A three-dimensional dynamic numerical simulation model of loess slopes was established with FLAC3D program

the dynamic response laws and the influence of parameters of ground motion on the responses of slopes under earthquakes were analyzed.It is shown that the input seismic waves are affected by vertical and surface amplification of the slopes;with increase of amplitude and frequency of input seismic wave

the amplification factors of PGA at monitoring points on slope surface display a pattern of three segments of increase

decrease and increase as the height of slope increases;amplification factors of PGV and PGD increase with the amplitude and frequencys increasing;while these factors are less affected by the duration;slope displacement increases obviously with duration increasing;the location and the shape of the maximum shear-strain increment region under the action of strong earthquake show that the failure pattern of homogeneous loess slopes under earthquakes is still the instability along a potential sliding surface

similar to that under static condition.Results can help further reveal the failure mechanism of loess slope under earthquake and give a reference to seismic design of slope in loess regions and to disaster prevention and reduction.