Study On The Kinematical Model And Its Application For Landslide Movement

The prediction of sliding distance for the potential landslide seems quite important to effectively assess the potential risk of landslides disasters, which is able to provide the basis of geological hazard assessment. The prediction is still in the stage of statistics and empirical formula. And There is no model to be widely applicable to simulate landslide motion in China.Loess landslides constitute a large proportion of landslide disasters in China. According to the characteristics of loess landslides kinematics, loess landslides are divided into four styles:quick collapse landslides, rapid slide-flow, rapid long run-out landslides and slow transitional landslides. Quick collapse landslides with small scale, steep slip surfaces, short run-out distance, usually happen in loess slope near residential place, which are induced by man-made excavation and river erosion. Rapid slide-flow is a prominent geological hazard which starts as a loess landslide in the source area, but quickly changes to a flow moving down along a gully to the outlet. And the run-out distance is controlled by the length of the gully. Rapid long run-out landslides often occur on the sides of loess platforms, and travel with long distance and high speed on the saturated sand gravel layer covering the first terrace between the toe of the loess slope and the river. Slow transitional landslides generally take place along impermeable red clay or bed rock with large scale and short distance.On the basis of landslide motive model proposed by K. Sassa, the three-dimension and tow dimension movement formulas are derived in this paper, two-dimension motive simulation program is compiled at the same time. Yanlian loess slow transitional landslide in Yanan City, Shaanxi Province is a case study by adopting different residual friction angle as the sliding friction angle in the two-dimension motive simulation. The result shows the run-out distance and the accumulation form were both very close to reality.The typical case of rapid slide-flow Huaxian Gaoloucun slide-flow and the typical case of rapid long run-out landslides Dongfeng slide are respectively simulated by using the three-dimension motion software LS-RAPID. Depending on the structure, saturated condition, grain crushing susceptibility of the loess of different sliding zoon and traveling path, different effective residual friction angle and shear resistance at the steady state in the completely undrained condition are determined by making reference to residual shear strength parameters from repeated direct shear test of saturated loess, and different accumulation possibility of excess pore pressure is also estimated, and these parameters were used in the simulation. The simulation results of areal prediction show a good correspondence to the deposit distribution of the actual landslides.The motive model proposed by K. Sassa is successfully used to predict the sliding distance of loess landslides in this paper, which provides a applicable theoretical method for such landslide risk assessment.