Dynamic response of slopes in hilly regions of loess and analysis method for their seismic subsidence deformation
摘要
The hilly region of loess is prone to slope instability of seismic subsidence. Through the dynamic centrifugal model tests and the finite difference nonlinear dynamic analysis methods, the dynamic response and deformation mechanism of loess slopes under earthquakes are studied. The acceleration and displacement responses of the generalized loess slopes under earthquakes are explored. The empirical formula for the seismic subsidence coefficient of loess and the method for estimating the seismic subsidence of loess field are proposed based on the dynamic single shear tests, and they are also used to calculate the seismic subsidence of loess slopes. The results show that the loess slope has a magnification effect on the seismic loads, the acceleration magnification coefficient increases nonlinearly along the elevation, and the dynamic magnification effects of the slope surface are greater than those inside the slope. The seismic subsidence of the slope is closely related to the thickness of the soil layer. The seismic subsidence coefficient increases logarithmically with elevation. The failure form of loess slopes under earthquakes is the result of the two-way coupling of horizontal sliding deformation and vertical seismic subsidence deformation. The tensile fissures at the top of the slope and the dislocation fissures on the slope surface are widely developed, and the uneven settlement of the seismic subsidence leads to the formation of dislocation steps on the slope surface.