Visual experimental study on suffusion in double-layered soil under different retention ratios
Geological structure significantly influences the evolution of suffusion in alluvium foundations,and then may affects the safety of dams.However,the present studies mainly focus on the internal instability and hydraulic conditions initiating suffusion of the internally unstable soils,and the influence of geological structure is neglected.A series of transparent suffusion tests on double-layered foundation were carried out by a new suffusion visualization apparatus based on planar laser induced fluorescence technology.In the double-layered foundation,the upper and lower soil layers serve as filter and base soil,respectively.The influence of retention ratio of double-layered soil on the evolution of suffusion was investigated.The results indicate that the upper soil layer has a remarkable influence on the critical hydraulic gradients at the initiation of suffusion and at blowout.The critical hydraulic gradients decrease with the increase of the retention ratio.The retention ratio significantly influences the fine particle migration and failure modes.If the retention ratio is less than or equal to 5,the eroded fine particles from the lower soil layer were clogged at the interface,and eventually induces tensile failure;if the retention ratio is larger than 5,the upper soil layer can't effectively protect the lower soil layer,the fine particles from the lower soil layer were eroded into the upper soil layer,and then pass through the layer,and eventually induce suffusion failure.A new filter criterion for the internally unstable base soils was proposed,and then it was validated by the experimental results presented in reference.
万方数据
维普
