| The Bazhong Huangshipan reservoir is located at Enyang River middle reaches,which is a tributary of the Ba River.Huangjiaoshu ancient landslide is located in the Huangshipan reservoir area,at the left riverside of Enyang River.It is about 390 meters long and 290 meters wide,entire unstable area of about 101 southand square meters,average thickness of accumulation about 19 meters,the volume of about 1 million 920 thousand cubic meters,and the sliding direction is 182 deg.New surface cracks generated after the Wenchuan earthquake,expanding and opening in the rainy season.The new deformation direction of deformable body is 244 deg,the length of about 350 m,width of 190 m,entire area of about 48 southand square meters,the average thickness of about 9m,and the deformation amount is about 430 southand cubic meters.Under the condition of heavy rain,the deformable body of the landslide has obvious deformation,so it is necessary to analyze the stability of this landslide when reservoir operation.Predicting the damming height if it is failure has an essential significance on guarantee the normal operation of the reservoir and the disaster prevention and mitigation.Based on the investigation of Huangjiaoshu ancient landslide,I accessed information and analyzed the engineering geological conditions of landslide and formation and reactivation mechanism as well as influence factors of deformation of leading edge deformation.I also summarized the mechanism of groundwater effect on deformable body of this landslide,and I have researched the value method about the mechanical parameters of slip soil.Its stability is analyzed and evaluated through GEO-Studio software,with the damming height after its failure has been predicted by empirical method and particle flow software which is called PFC2 D.Finally,this paper analyzes the harm and influence to Huangshipan reservoir and the whole area,which caused by blocking river of Huangjiaoshu landslide.Providing a reference significance for forecast of blocking river by detritus landslide in red beds of East Sichuan Province.Through the study of this paper,the main conclusions are as follows:(1)Huangjiaoshu landslide is an ancient landslide which had repeated slip,and its differences of the substance of landslide accumulation are large.The occurrence of slip surface is about 182?9 deg,and the deformation direction of deformable body is about 244 deg,the potential sliding surface is located above that of the ancient.The main influence factors which leading the deformable body at the front of landslide are expansibility of soil,slope structure,rainfall,river side erosion,human engineering activities and eaarthquake.(2)The change of the water content of the rock and soil mass in the deformable body is caused by reservoir water level fluctuation,which cause the drop of mechanical strength parameters of slip soil.Hydrostatic pressure and dynamic water pressure as well as excess pore water pressure have a direct influence on the matrix suction and the friction force on the slip zone.(3)The ancient landslide is stable in all circumstances,but the deformable body will fail when the reservoir water level 1 meter increases per day and 1meter decreases per day as well as 13 meters decreases per day.It will not destruct overall,but each part fail in some certain orders.(4)When the reservoir water level 13 meters decreases per day,the damming height is 353 meters caused by failure of part ?b of the deformable body,which predicted through the PFC2 D particle flow method.It is not impeding the current completely,but completely blocking the original river.(5)Water lateral erosion strength on the right bank will increase after the deformable body failing.Reservoir bank reconstruction and progressive failure will cause new landslides,which will cause completely blocking river.Leading upstream backwater flooded,downstream cutoff,swells,outburst flood,slope reconstruction,blocking river again,pollution of water resource and a series of secondary disasters and environmental effects. |
PDF Full Text Request