Study On Formation Mechanism Of Xierguazi Reservoir Landslide And Treatment Structure In The Sichuan Maoergai Hydropower Station

Reservoir landslide in the construction of hydropower projects in a common geological disasters, when the landslide slip into the reservoir area may cause a relatively large impact, including reducing the capacity of threat to the dam safety. Xierguazi landslide is a large ancient landslide with a resurrection of the new landslide composed of the landslide stability will directly affect the safety of Ma Wo town and Bell tunnel. This paper uses the theories and methods of engineering geology and hydrogeology, rock mechanics, structural mechanics and numerical simulation to study the ancient landslide history of the causes of the resurrection of the course as well as analysis of new landslide prediction of the stability of the landslide prospects and associated works., combined with the structural mechanics analysis of the works of the new anti-slide structure, access to the following aspects of the research results as follows:1. The landslide area is located in the Maoergai station upstream, adjacent to Ma Wo town, Bell tunnel through the landslide area; the terrain is steep, overburden loose stone rubble piled soil, under the bedrock of metamorphic sandstone folder phyllitesegment and metamorphic quartz sandstone, landslide deformation of the sliding performance overlay slide; seismic intensity vii degree; the region without a regional fracture by secondary associated compression shear fault more than an extension of the shorter interlayer extrusionfracture zone and fault-based, and the other through the good jointed development, is a regional tectonic stability district; landslide spatial form of groundwater mainly pore diving for loose overburden, followed by bedrock fissure water, groundwater mainly bythe reservoir area the water supply, followed by rainfall recharge; the landslide area to the geological phenomenon mainly as landslides and reservoir banks and recycling.2. Ancient landslide as an irregular landslide, the leading edge and central slightly wider, the trailing edge is gradually converge, as posed by the armchair-like away from the heart rate of about0.54oval in the landslide whole plane; field research analysisand the process mechanism the Xierguazi of ancient landslide slip composite landslides, dumping large rock in space is a combination of bending shallow crack and deep slip of the Ministry of pressure-induced crack. According to the survey, landslide in the after edge of the site for decades has not been deformed, indicating that the ancient landslide in the back of the landslide has been stabilized state.3. The ancient Xierguazi landslide is in a stable state of water before and after the "5.12" Wenchuan earthquake, after long-term deposition of consolidation gravel soil piled weight new loose, coupled with the reservoir began filling with water, the water level reached about 2085m, the leading edge of the ancient landslide deformation slide. By use of FLAC3D Finite Element software simulate a landslide deformation sliding mechanism when the water level in the different libraries, from the simulation results, the performance of the landslide deformation mechanism of a tractor-goes style landslide result of joint action, slip band and the position of the sliding surface is located based coating interface. when the water level in the2105m, landslides will be completely destroyed.4. Landslide stability analysis of ancient landslides and new landslides in reservoirs of stagnant water, the operator of a sudden jump in the sudden drop of the stability evaluation under various conditions, overall instability of the ancient landslide the possibility of small, newThe resurrection District instability is very likely. New resurrection District instability after, the rear of the invading ancient landslide speculate landslide secondary disintegration of destabilization in the heavy rain and seismic conditions. Landslide surge into the water to form analysis, the safety of Ma Wo town is not much impact.5. The arc interval arranged in piles-the top of the pile with the Department of beam space anti-slide structure is the anti-slide pile curved interval arranged pile top set with tie beams to resist the landslide thrust a novel anti-slide structure. In this thesis, structural mechanics and geotechnical physical science works for the comprehensive analysis of the structure, the use of the Xierguazi landslide control engineering examples prove computational model of internal forces and displacement distribution is reasonable to do a comparative analysis with traditional cantilever anti-slide pile obtained a new type of anti-slide pile superiority in treating landslide.