78 Stability Analysis for Post-Office Building Landslide in Xingshan County, Three Gorges Reservoir Area

Post-office building landslide in Xingshan county is the slide of covering soils of Quaternary and strong weathering rockmass, which results from bending and topping deformation of the soft and steep rockmass caused by gravitational stresses. The prime deformation of the landslide happened in April 1994, and became worse in June. There are several transverse tension cracks with plumb dislocation in the ground. The longest one was 40m long and 3cm width. Some houses and theirs cement floor cracked. After the slide, some houses on the middle of landslide body were abandoned, anti-slide plies were used to control the landslide as an emergency measures. Heavy rain, domestic water seepage, and building load on the back are the essence inducement of its slide. After Three Gorges Reservoir restores water, the front of post-office building landslide will be immerged, and its stability will become further worse. The stability analysis with finite element method and block limit equilibrium method shows the deformable body will be instable and need treatment. Anti-sliding piles with surface drainage and revetment system have been advised to reinforce the landslide.