Static&Dynamic Analysis To A Slope Stability Of Hydroelectric Power Station In Jinsha River Valley

With the implementation of the country’s western development strategy and theentire social economic development to the demand for energy, a number of largehydropower stations in the Jinsha River have been constructing. These waterconservancy and hydropower project play an important role on the ease of nationalenergy shortage, and sustainable development of the country`s economy. The safety ofreservoir landslides especially landslides near the hydropower will reduce whenimpound, so it is urgent to analysis the stability of these landslides after impoundment;at the same time, earthquake frequently happen in Southwest China, to analysis thestability of landslides under earthquake is also important. In this paper, an ancientlandslide of some hydropower station in Jinsha River Valley both under Static&Dynamicstation was analyzed.Progress has been made in the following areas:1. Literatures`referring and analyzing.In the first chapter, this paper sum up the progress that have been made in domesticand forging countries at the area of static&dynamic research o f landslide, and made abrief review, combined with the writer`s subject, the paper point out some criticalproblems need to be solved.2. Collect geological data and carry out field survey of the ancient landslide.First, by collecting the geological data, we master follow information: natural andgeographic profile of the landslide, topography, geological structure, slope structure andengineering geological characteristics of the landslide; then combined with these data, afield geological survey was conducted. With above works, an analysis of mechanicalformation was taken. It’s indicate that because there is a soft layer in the landslide andthe gradient is sharp, the landslide begin to creep slip under the enormous pressure, andthen a slide zone formed. At certain factors (such as heavy rain, earthquakes, etc.), ahigh-speed landslide happened.3. Carried out in-situ tests.In-situ tests mainly include two parts: with improve equipment to carry out in sitularge-scale direct shear test; in situ density test. Firstly, this paper introduces the basicprinciples of these two tests and the arrangement of the test s place. Then the paperdiscusses how to carry out these two tests and how to process the data in detail. For insitu large-scale direct shear test that stress–displacement curve appears irregularsection, a careful analysis conducted. It indicates that the amount of stone and gravelparticle size in the sample is the main reason that caused this phenomenon, and give theconclusion that “small stones make small rolling, and big stones make large rolling”summed up small fluctuations in gravel, gravel large fluctuations conclusion. The paper lists all physical and mechanical parameters of the slide body and slide zone by in-situtests at the last part of this chapter4. Static stability analysis of the landslide.With limit equilibrium method and elastic-plastic finite element method, the paperanalysis the stability of the landslide when the reservoir water level in375m naturalcondition,431m construction of water storage condition, as well as600m the nor malreservoir water condition. Limit equilibrium method assess the overall stability of thelandslide, and the safety factors calculated by software showed that at this threeconditions the overall stability of the landslide is and it is less likely the landslide willslide along the slip zone. Elastic-plastic finite element method calculates and gets theinformation of stress and strain, displacement, and elastic-plastic field. With theseinformation, the paper analysis the integral stability of the landslide. Using the strengthreduction method, the paper gets the most dangerous sliding surface and its safety factor.5. Dynamic stability analysis of the landslide.This chapter contains two parts: pseudo-static analysis and dynamic finite elementanalysis.Based on the fortification intensity of reservoir dam that Kh=0.18,pseudo-static analysis was carried out to analysis the integral stability of the landslide,and the factors of safety calculated by the software indicate that at the condition ofreservoir level of375m and431m, the landslide was in short term safe; but at thecondition of reservoir level of600m, the ancient landslide will move along the slidezone, so we must pay attention to it. By using the dynamic finite element method，weconduct dynamic stability analysis. Seismic wave of Wenchuan with maximumacceleration of77.4cm/s2was input through artificial boundary and adopting viscousartificial boundary to absorb reflect wave. The seismic response of the landslide own bytime-integration method indicate that at three conditions, horizontal and verticaldisplacement happened in the landslide; with the reservoir water lev el rise，plastic zoneincrease in the landslide, but continuous plastic zone does not come being; From thebedrock to the top of the slope, acceleration increase at first, and then decrease at theslide zone, then increase till the maximum in the middle of slide body, then decrease.