关键词: 膨胀土, 胀缩变形, 干湿循环, 渗透性, 容许胀缩变形量

Abstract: Under the influence of atmospheric environment and underground water, expansive soil roadbed or slope in a certain depth will generate obvious dry shrinkage and wet swelling deformation, inducing obvious change of expansive soil permeability, which further induces the destruction of expansive soil roadbed or slope. In order to systematically study the change of swelling and shrinkage deformation and permeability of expansive soil under the action of wet-dry cycling and vertical load, the swell-shrink deformation and permeability test under the action of different loads and wet-dry cycling was carried out by the thermostatic pressure permeation consolidometer. The swelling-shrinkage deformation laws of expansive soil under different loads and wet-dry cycling were studied, and the variations of water permeability coefficient and gas permeability coefficient were determined. The research results can be used to determine the allowable swelling-shrinkage deformation and vertical load of expansive soil, the minimum protection depth and limited load of expansive soil roadbed or slope for optimizing the design of expansive soil roadbed or slope.

Key words: expansive soil；swelling-shrinkage deformation, wet-dry cycling, permeability, allowable swelling-shrinkage deformation