Seepage Analysis And Stability Study On The Slope Of A Dam Abutment Hydropower Project Zone Inn Impounding Period

Landslide treatment on the bank slope is the premise of the stable operation ofreservoir impounding period. At the same time, the reservoir water level fluctuationis a dominant factor affecting the water slope sliding failure. At present, technicalmeans of the reservoir water level fluctuation is lack of qualitative determination.Use it as research background, seepage analysis and stability research on the slopeof a abutment hydropower project zone in impounding period have great economicvalue and guiding significance for the prediction and control of reservoir landslide.Based on the saturated unsaturated seepage theory and the theory of limitequilibrium, the paper selected the right bank slope of DaGangshan as the researchobject to study the stability. The stability of the slope at bank side of reservoir can becalculated with finite element analysis program SEEP/W and slope stability analysissoftware SLOPE/W in the GEO-SLOPE software. It taught the change rule of thestability of the slope at bank side of reservoir In the transient seepage conditions.They are the main contents of the paper as follows:(1) It is about the analysis of the stability of rock slope in the environment ofrising and falling of water level, rainfall and earthquakes as well as the couplingeffect among them. The percolation mechanism of rock slope is different from thegeneral soil slope. The paper reaches a conclusion that the rise and fall of reservoirwater level, rainfall and earthquake have an effect on rock slope.(2) Based on the saturated unsaturated seepage theory, it is about the analysis ofseepage mechanism and seepage property of saturated and unsaturated rock mass. Inthe reservoir water level fluctuation conditions, it can draw a conclusion about rockmass seepage on the slope at bank side of reservoir. The reservoir water level risingand falling, the saturation line had concave and convex shapes. The reservoir waterlevel falling, the saturation line is convex. The rising and declining velocity hada relationship with sphere of influence on the saturation line and its shapes. At thesame time, it also provides basic seepage data for the rock mass stability analysisand landslide disaster prevention.(3) Based on the theory of limit equilibrium, rock slope stability analysis method is the second improved Morgenstern-Price method (half sine function).Modeling analysis on the right bank slope of DaGangshan is combined withconsideration on the dynamic of the seepage field and limit equilibrium analysis.When the reservoir water level is rising and falling, the paper researched the changelaw of the factor of safety. Below the elevation of1135m in water changes affectedzone and above the elevation of1135m, rainfall had different effects of stability andthe influence degree.(4) According to the reservoir water level fluctuation velocity, rock mass watersaturated softening coefficient and permeability coefficient, it can use differentcombinations of parameters, and then calculate factor of safety of the slope.Research showed the stability of the bank slope had a relationship with the differentcombinations of parameters. According to the factor of safety as to reservoir waterlevel fluctuation of sliding body, the paper determined the reservoir water levelfluctuation velocity in impounding period preliminarily.