Seepage Shear Test Of Granite Residual Soil And Study On Influence Of Rainfall And Water Level Change On Reservoir Slope Stability

The residual soil of granite is mainly distributed in the southeast coastal areas with abundant rainfall in China.The residual characteristics of granite residues are greatly affected by weathering and engineering geological environment.The number of slope engineering and foundation pit engineering in southeast coastal areas is large and its working condition-The types are different,and various working conditions are affected by factors such as groundwater,rainfall,and reservoir water level changes.The study of the permeability characteristics of residual soil is of great significance.The slope instability in different endangered conditions accounts for a large proportion,so the study of reservoir slope stability is particularly meaningful.In this paper,the granite residual soil obtained from the coastal area of Xiamen was taken as a sample,and it was pulverized and air-dried to re-saturate into a saturated sample.The SLB-1 stress-strain triaxial shear permeameter and other instruments were used to study the different seepage and seepage of the granite residual soil.The influence of different conditions on the permeability and the attenuation of the shear strength of granite residual soil under the effect of seepage flow,and the numerical simulation software is applied to study the influence of rainfall and water level decline on the stability of reservoir slope.The main research contents are as follows:1.Through the constant water head triaxial seepage test,according to the test results,the influence of different initial pore ratio,osmotic pressure,confining pressure and prnncipal stress difference on the permeability coefficient was investigated.2.Through the constant flow triaxial permeability test,based on the test results,the influence of different initial pore ratio,flow velocity,confining pressure and principal stress difference on the permeability coefficient was investigated.3.By comparing the results of two test modes of constant water head triaxial seepage test and constant flow triaxial permeability test,the influence law of seepage flow mode on permeability coefficient under three equal conditions is studied.4.Through the constant water head seepage shear test,according to the test results,the influence of osmotic pressure on stress-strain relationship,peak strength and shear strength parameters was investigated.5Through the KO consolidation shear test and the constant flow seepage shear test,and the comparison with the constant water head seepage shear test results,the influence of confining pressure on the stress-strain relationship and peak strength under different shear modes is investigated.6.Based on the data obtained from the series of permeation tests of granite residual soil,the geoporous engineering software of Geostudio was used to establish the seepage characteristics and stability calculation model of granite residual reservoir slope under different rainfall conditions and different water level change modes.The model calculates the parameters and the setting of the boundary conditions.7.The effects of rainfall intensity and rainfall duration on the seepage field of granite residual reservoir slope and the safety and stability of slope are simulated.8.The simulation of the water level fluctuation and water level change speed on the seepage field of the granite residual soil slope and the safety and stability of the slope are simulated.9.The simulation of the variation of the seepage field of the granite residual soil slope and the safety and stability of the slope during the continuous decline of the reservoir water level under the condition of rainfall and water level changes.