Analysis On Revival Formation Mechanism And Hazard Of Ximi Landslide In Heihui River Reservoir Area Of Xiaowan Hydropower Station

Introduction of the author: Wang Tao, male, was born in October,1986whosetutor was Professor Deng Hui. He graduated from Chengdu University of Technologyin geotechnical Engineering major and was granted the Master Degree in June,2012.The landslide is a multiple geological disaster. It is widely distributed around theglobe and the hazard is very serious. It is not only a threat to people’s lives andproperty but also restricting the construction and operation of large-scale projects.Therefore, it is important to strengthen the study of the landslide disaster in thedisaster mitigation projects.Ximi Landslide is located in Ximida Village Xinhua Country, the right bank of Ximiriver which is on the right bank tributary of the Heihui River, and it’s huge and widelyaffected and is bounded by Ximi River. It is about1100m long,650m wide, and about2700×10~4m~3of volume. about13km away from Xiaowan hydropower station, Thefailure does not directly threaten the safety of buildings. However, the landslide maybe caused by the surge and blocking river, about the hub building safety havedifferent degrees of impact, mainly displays in: first, the sliding body at a certainspeed to slide into the reservoir, is bound to create a certain height of surge, and thedam, hydraulic structures to produce certain effect; secondly, landslide damming ofriver once the formation of "two dam", resulting in tail water uplift of undergroundpowerhouse, will cause a great threat to. Therefore, to study the deformation failuremode stability conditions and reasonably predict the hazard has importantsignificance.This paper mainly focuses on Ximi yuanzi Landslide. By the integrated use ofthe analysis of geological history, the limit equilibrium method and the numericalanalysis method, based on the research of the area’s natural geographical andgeological background, the basic characteristics and genetic mechanism is researched,the stability and evolution mode is evaluated. And based on it, the danger is furtherassessed and the probable surge events caused by the landslide is analyzed andforecasted by use of empirical formulas and theoretical calculations. The results showthat:(1) The analysis of the dimensional finite element shows that the distribution ofthe overall stability stress comply with the general law of which in the landslide.Significant concentration of maximum shear stress occurs in the leading andfollowing edge slip band. The slide is basically stable on working condition of “nature” but might fail in condition of “rainstorm” or when the reservoir water levelchanges.(2) Based on the analysis of its field survey results and finite element analysis ofsimulated data, the deformation and failure mode is “traction-slipping mode”(3) Comprehensive analysis,This thesis also did the systematic analysis,caculation and estimate of the stability after sluice. As the fatalness estimate, it alsoanalysed the stress and distortion character through3d finite element softwareFLAC3Dnumerical simulation. And with the above conclusions and simulated resultsresults are compared to achieve mutual checking analyzed the effect. Based on thislandslide destroying forms and failure analysis and research on the scale, identified inthe event the whole sliding landslide from the special circumstances, the wavesgenerated happened height and whether plugging river two problems based oncalculation and analysis,thus depriving harmful evaluation.(4) The surge calculation shows that on the most affecting working condition of“rainstorm and reservoir water” the surge result of local failure is29.5m and of whichthe overall failure is48.6m. But it will not be a threat because the hub buildings andthe residential areas are at a relatively high position. And the swell harm can beneglected. Results show that the minimum volume the landslide needs to block theriver is135.98×10~4m~3, and of which the local failure is588.1320×10~4m~3, which willblock the river. At the same time, the volume of overall failure of the slope is2500×10~4m~3, which will also cause the river-blocking.(5) On working condition of “rainstorm and reservoir water”, the slope willthreaten the lives and property of the residents living on it. The suggestion is torelocate the residents to safe areas to avoid the landslide harm. Inspections should bestrengthened and warning signs should be set up. Once in danger the appropriatemeasures should be taken immediately.