| Airports,roads and other engineering construction are carried out in the southwest of many mountainous areas.It is normal to open a road in the mountains and fill in the ditches first.In Guizhou,the unique topography and landforms exacerbate the complexity of regional geological space,forming a complex geological environment system as a whole.In view of the mutual feedback between engineering construction and geological system under such complex conditions,this paper takes the shangshikanggao fill landslide in Longli County as the research object to carry out the master’s thesis research.This paper mainly adopts the research method of combining geological prototype field investigation and geological process analysis.On the basis of collecting previous research data and field survey,this paper carries out regional geological survey and regional hydrological survey on shangshikan.Through the combination of engineering geological analysis method,field fine survey,geophysical exploration test,numerical simulation and other methods,The influencing factors and formation mechanism of shangshikan landslide are systematically studied.The main results and understandings of the research are summarized as follows:(1)Shangshikan landslide is located in shangshikan,Xima Town,Longli county.The landslide mass is artificial heaped gravelly soil and Quaternary clay.The south side of the landslide is bounded by the crack of artificial heaped carrier,the west side is bounded by the gully at the foot of the ridge line,and the north-east side is bounded by the residential houses and hardened roads above the Shikan.Due to the thick clay layer at the front edge of the landslide,the shear outlet is not obvious.The cracks are mainly developed at the residential houses and hardened roads at the northeast side,and the overall trend of the cracks is biased to the northwest,The maximum width is 0.55M and the maximum visible depth is 0.75m.The main sliding direction of the landslide is about 10°,the width is about 240m,the thickness of the sliding mass is about 11.8M,the overall scale is about 200000m~3,and the scale of the landslide is medium.(2)Through the comprehensive analysis of field investigation and geophysical exploration,it is concluded that the main controlling factor affecting the formation of landslide is groundwater.There is a groundwater drainage spring in the center of the filling area.At the initial stage of loading,no drainage measures were taken for the groundwater there,which led to the accumulation of groundwater in the slope,accelerated the creep of the filling slope,and finally led to the formation of landslide.(3)Combined with the numerical simulation results,the formation process of shangshikan landslide can be divided into two stages.The first is a stress concentration process in which the groundwater pressure plays a major role in the landslide start-up area,and the hydrostatic pressure and excess pore water pressure play a promoting role.Finally,the stress is concentrated in the lower mudstone and gravelly clay area,so that the groundwater not only dissipates towards the karst cave and the remaining coal mining roadway,but also continuously infiltrates and softens the potential slip surface,and provides the stacking area with the thrust caused by the relatively high hydrostatic pressure brought by the start-up area at the infiltrating place;The second is that the groundwater softens the potential slip surface.The"floating"acts as the upper soil mass,and the high hydrostatic pressure brought by the start-up area generates the slip stage.(4)Through the study of the formation causes of shangshikan landslide,it is concluded that for the landslide with blocked groundwater discharge channel,the internal groundwater level changes sharply,driving the landslide to accelerate creep.In the process of promoting the deformation and failure of the landslide,the existence of the lower weak foundation often causes the deformation and failure process of this kind of landslide to be controlled by the surge of hydrostatic pressure,that is,the excess pore water pressure,which belongs to the excess pore water pressure driven landslide. |
