Research On Stability Of Reservoir Gravity Retaining Wall On Deep Earthy Slope

This paper aims at researching the stability of gravity retaining wall under condition of deep earthy bank slope, discussing the evaluation method and influence factors about stability of gravity retaining wall. In this basis, it proposes some optimization measures of foundation treatment which are suitable for gravity retaining wall structure. The major work and conclusions are as follows:(1) The paper discusses the influence law of gravity retaining wall stability through the factors:thickness of covering layer, soil strength parameters, change speed of reservoir water level and the seepage of groundwater etc. Example shows that:Gravity retaining wall has a most unfavorable level when the reservoir water level falls in the design of important project, we can use PL AXIS program automatically searching for the most unfavorable water level and minimum safety factor; The faster reservoir water level falls, the faster integral safety coefficient reduces, maxima seepage velocity appears below the phreatic surface of retaining wall structure near the reservoir water side. In addition, the overall safety coefficient which considers the excess pore water pressure is about 20% lower than without it, so we should pay attention to the control of excess pore water pressure in bank slope of retaining walls, to prevent the excess pore water pressure for accumulating.(2) The paper discusses the influence law of gravity retaining wall stability through the factors:thickness of covering layer, soil strength parameters, change speed of reservoir water level and the seepage of groundwater etc. Example shows that:Gravity retaining wall has a most unfavorable level when the reservoir water level falls in the design of important project, we can use PLAXIS program automatically searching for the most unfavorable water level and minimum safety factor; The faster reservoir water level falls, the faster integral safety coefficient reduces, maxima seepage velocity appears below the phreatic surface of retaining wall structure near the reservoir water side. In addition, the overall safety coefficient which considers the excess pore water pressure is about 20% lower than without it, so we should pay attention to the control of excess pore water pressure in bank slope of retaining walls, to prevent the excess pore water pressure for accumulating.(3) This paper investigates the stability of three treatment measures about retaining wall foundation:the change fill of ripped-rock, the change fill of ripped-rock +grille and low pile caps. Research shows that three measures are all the effective treatment methods of improving the stability of gravity retaining wall, the best treatment can be selected according to the construction condition and engineering economy in practice. To deep change fill ripped-rock foundation, its inside may have potential sliding surface, the depth of pile in the rock of low pile caps exist a critical value, the research results can provide basis for the engineering design.(4) Aiming at calculating poor drainage performance of earthy bank slope, the construction process of retaining wall foundation is simulated. The calculation of engineering examples shows that the excess pore water pressure and shear strength of soil, stable safety coefficient decreases gradually as the soil consolidation time increases, therefore attention should be paid to lengthen consolidation time appropriately in divisional construction so that the excess pore water pressure can be dissipated as possible. Conclusions can be provided the reference for organization of retaining wall foundation and the control of construction process.