| Research of soil consolidation has been one of important issues in soil mechanics.The consolidation mechanism of unsaturated soil is very complex due to the existence of gas phase,and the consolidation characteristics of soils with different saturations vary greatly.The characteristics of excess pore gas pressure and excess pore water pressure produced by soil consolidation and its dissipation characteristics with time have been main contents of consolidation study of unsaturated soil.It is of great significance to study the generation laws of excess pore gas pressure and excess pore water pressure and to further study the consolidation characteristics of different saturations soils.Utilizing improved GDS triaxial apparatus,the law of initial pore pressure with different saturation is obtained through different saturation soil load tests.The relationship between saturation and permeability coefficient measured by soil seepage tests Based on Fredland's double parameters consolidation theory and the existing analytical solution of one-dimensional consolidation,a one-dimensional consolidation model of unsaturated soil is established.then the consolidation characteristics of soils with different saturation are analyzed while considering the influence of saturation on initial pore pressure and permeability coefficient respectively.The main contents of this paper are as follows:(1)Through the improvement of GDS triaxial test system,the precise measurement of water pressure in undrained condition is realized.Through iso-compression tests and axi-compression tests of unsaturated soil under different saturations and different stress paths,the laws of consolidation deformation,excess pore pressure,excess pore water pressure,volume change with time are obtained.and the change rule of excess pore pressure and excess pore water pressure with saturation is obtained when combined with the soil-water's characteristic curve.(2)One dimensional consolidation model of unsaturated soil with one side drainage and two sides drainage is established,Based on Fredland's one-dimensional consolidation theory and the existing analytical solution of unsaturated soil consolidation.combined with determination tests of initial pore pressure,the dissipation laws of excess pore pressure,excess pore water pressure and consolidation deformation under different saturation and drainage conditions are analyzed.(3)Through the relationship between saturation and permeability coefficient measured by soil seepage tests,under the conditions of single-sided and double-sided drainage,the consolidation deformation characteristics and consolidation time characteristics of soils with different saturation and different depth are analyzed respectively. |
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