Study On The Genetic Mechanism And Stability Of The High-speed Loess Slope In The Loess Plateau In Northern Shaanxi

In China, northern ShaanXi loess plateau is very wide, the landslide occurs frequently,while the rainy season comes. Some landslide’s declining rate is extremely high, people haveno time to avoid them, and their damage is very serious. Therefore, at present, it’s a complexand key problem for the geological workers in our country to study the cause of the landslidemechanism and stability in the region.In this paper, the authors measured Yongning Production Plant’s6th then turn waterstation landslide in Zhidan as an example. Firstly, basing on the field investigation and survey,as well as the geotechnical tests, the paper discussed the geological environment conditions ofthe water station landslide, including the meteorology, the hydrology and so on. Furthermore,it expounded the characteristics of its morphology, structure and deformation and damage,accordingly, the landslide was a new passage-type and high-speed loess landslide. To deeplydiscuss and compare the internal and external factors which promote the landslide’s forming,and by using the Analytic Hierarchy Process (AHP), we have evaluated the sensitivity of thelandslide’s inducing factors, then hold the idea that among the various factors which causingthe high-speed loess landslide, the most active factor is the rainfall. Studying on the hazards’ssensitivity sequence, which can provide a reference for similar high-speed loess landslide’sprevention and early warning in Loess Plateau region. Secondly, Basing on the throughoutkinetic mechanism of high-speed landslide by Mr. Hu Guangtao, the paper conducted apreliminary study on the kinetic mechanism of the water station landslide, respectively, fromthree aspects, which are "vigorous beginning","high-speed traveling","decelerating ending",to reveal the water station landslide’s high-speed sliding mechanism. The paper also took aevolution analysis for the water station landslide’s formation process, and divided the waterstations landslide’s formation process into five steps, that is “Strata’formation Period”,“Freesurface’s formation Period”,“Cracks widen Period”,“Slip surface through Period”,“Landslide occurrence and termination Period”. Furthermore, using SEEP/W module ofGeo-Studio software to simulate and analysis water station landslide’s seepage which underthe rainfall conditions, and got the transient changes of the pore water pressure in the rampbody, and then brought the mechanisms that rainfall-induced the landslip’s deformation andfailure to light. Finally, basing on the limit equilibrium theory and the finite element strengthreduction theory, this paper carried on calculations and numerical simulation for the waterstation landslip’s stability, obtained the stability factor for the landslip under the conditions ofnatural and saturated, revealed influences saturated condition’s influences for the landslip’s displacement, stress, strain,and so on, then also made analogies and summaries between theresults of the two methods.Research results of this study can provide the basis for the engineering treatment designof water station landslide, at the same time, it can offer a reference for similar high-speedloess landslide’s early warning, mitigation and research in Loess Plateau region, has a certainpractical value.