The unsaturated permeability coefficient is the basis of seepage analysis and hydraulic-mechanical coupling research of unsaturated expansive mudstone soil,which is of great significance to engineering construction and disease prevention.As an example,the micro-expansive mudstone broken soil of Hami region in Xinjiang is processed into four remodeled samples with various initial dry density.The soil-water characteristic curve is measured by pressure plate method and filter paper method,and the saturation permeability coefficient is measured by variable head tests.Then,the one-dimensional soil column seepage test under constant-volume conditions is carried out by a self-developed soil column seepage test device.The applicability of wetting front advance method and transient profile method are explored,so as to obtain the unsaturated permeability curves of soils with different initial dry densities,and the Childs and Collis-Geroge(CCG)permeability coefficient prediction model is modified based on the test values.The results show that the matric suction of Xinjiang Hami micro-expansion mudstone broken soil ranges from 1-105 kPa,and the permeability coefficient ranges from 10-9-10-4 cm·s-1.The larger the initial dry density of soil sample,the smaller the proportion of macropores,and the more obvious the seepage resistance.The CCG permeability coefficient prediction model can better reflect the development trend of the soil permeability curve,but it is gradually far away from the true soil permeability curve with the increase of suction.The modified CCG permeability coefficient prediction model can reflect the development of soil permeability curves at different initial dry densities.
关键词
高速铁路/膨胀泥岩/瞬态剖面法/土-水特征曲线/渗透系数/CCG渗透系数预测模型
Key words
High-speed railway/Expansive mudstone/Instantaneous profile method/Soil-water characteristic curve/Permeability coefficient/Childs and Collis-Geroge penetration model
维普
万方数据