Research On Evolution Mechanism And Controlling Techniques For Long Jiayan Multi-stage Landslide

Multi-stage landslide generally has the characteristics of large scale, high hazard degree, complex evolution mechanism and difficult to control; In the control design often ignore the evolution process of landslide in space and time, so it is difficult to obtain satisfactory control measures,This paper takes the Long Jiayan landslide in Yanhe county Guizhou province as the supported engineering,by the research methodology of field investigation, field monitoring and numerical simulation, focusing on studies formation mechanism, Finally, using the idea of synthetical measures put forward effective measures. The main results of research as follows:(1) Long Jiayan landslide is a large scale tractive ancient landslide caused by excavation of roadbed under heavy rainfall,the excavation of roadbed landslide is the main factors of instability,its has been divided into three zones in the space base on the main crack coalescence; according to the landslide evolution sequence of the forming process its divided into four stages and two stages by deformation process in time, Finally,detailed analysis the landslide of the process stability-sliding-stability.(2) Taking synthetical measures to analysis stability of the landslide, and considering the effects of landslide spatial form and type U cross sections of the force, finally, determining the anti-slide pile+surface and the underground drainage as the main control program.(3) According to the characteristics of the anti-slide pile in deep displacement monitoring data, concluding 3 methods of inverse analysis for pile body stress.the deflection differential equation and difference equation can be used to monitor the data in parabola shape, anti-slide pile is elastic pile; the approximate solution method of material mechanics is applied to monitor the data in radial shape, anti-slide pile is rigid pile.(4) By using FLAC3 D to simulate the stability of the landslide under different conditions,When excavate the roadbed to design 's elevation the landslide will sliding, the first level landslide is key governance and middle part of the cross section of the landslide is the most important; the effect of impose the beam on the h type anti-slide pile to improve the strength of support structure is bad, And the anchor cable is applied to the beam is worse than of the pile.