| The access road for Jinping Hydropower Station starts from Anming River bridge of theManshuiwan Town in the east,crossing Maoniu Mountain,arriving Mofanggou（beside theYalong River）.T he road is a crestlength of57.15km w ith com plex geologicalconditions andstrong physical geologic function, which is belong to easy-happening area of natural geologicalhazard. After catastrophic rainstorm on August30,2010, mang sliding cracks appearedsignificantly in the subgrade of Lizhuang Road on both sides of the culvert on the K48+755section;on August31, mang cracks were found in the road surface, shoulder retaining wall,cutting retaining walls;the sliding traces were also found evidently in Lawo rural road. Becauseof the landslide formation, local residents are so panic that they aggregated and surrounded tobreak the traffics. The stabilityof the landslide relates to the safety of the dedicated highwayprojects; relating to the safety of lives and property of more than20local residents; relating to thesocial harmony and stability.According to field investigation, more than20cracks were discoveryed in the natural slopeand rural road; cracking,broken plates,sinkwere found on the pavemen;dumping, sink, tearingwere grown in the shoulder wall and cut slope wall.From the dedicated road stake K48+722toK48+800between elevation from1695m to1777m,deformation and fracture of the signs are veryobvious and landslide boundaries are very clear in the study area.In this paper, follow the guiding ideology of "geological process mechanism analysis andquantitative evaluation ", aiming at K48+722～800landslide section, summarizes the instabilitymode, analyzes the formation mechanism and stability evaluation of the main access to thefollowing conclusions:(1) Site mapping catalog and physical and mechanical nature of the test (including field,indoor test) on the basis of a detailed analysis of slope deformation and failure characteristics ofthe evolution of history, combined with the structure of the landslide, engineering geology andenvironmental conditions, and conceptual understanding of the evolution of landslidedeformation.(2) Assume that rainfall in the initial conditions, simulate and analysis on the slope body ofthe seepage field with the use of2D finite element (GEO-SEEP Software);simulate and analysisof three-dimensional differential (FLAC3D Software), respectively, on the slope area of thestress field in the situation before excavation and after excavation, the distribution of strain fieldsand failure zones features;deepen the understanding of landslide deformation and failure characteristics,especially its potential instability range and deformation of the development trend.(3) Landslide failure characteristics and the deformation and failure mechanisms analysis,qualitative analysis and evaluation of landslide stability, after the landslide stability coefficient ofsensitivity analysis and parameter selection,using the limit equilibrium analysis of the transfercoefficient method and the simplified BISHIP method to quantify the stability of calculation andanalysis review of stable status quo in order to inverse the strength parameters of the supportbefore,emergency treatment,the permanent support of three conditions, natural, earthquakes,torrential rain, the stability factor accounting for the three conditions, followed by the"emergency treatment","permanent support" measures the effect of contrast.(4) The landslide on section K48+722～800ofthe access road for Jinping is a small shallowresidual slope plot landslide;continuous (strong) under the influence of various internal andexternal forces, but factors-in particular the slope of the micro-landforms, rainfall is a majorcause ofand prerequisites, and the mechanism is "Continuous heavy rainfall infiltration-soilsoftening with saturated water-increasing in weight load-reducing shear strength-slow creeppingof slope-gave birth to the sliding surface-instability and failure. |
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