Analysis Of Bearing Capacity Of Unsaturated Polluted Cohesive Foundation Soil

This paper studies unsaturated polluted clay,tests the soil water characteristic curve(SWCC) and fits SWCC model by the unsaturated soil consolidation test, analyzes the relationship between water volume content and matric suction, saturation and matric suction, and concludes the formula and curve.Through unsaturated polluted clay’s consolidated drained direct shear tests, it established bivariate model of unsaturated polluted clay’s shear strength about vertical normal stress and matric suction,draws the unsaturated soil shear failure surface. Using the relationship between water volume content and matric suction, saturation and matric suc tion in SWCC, it can conclude model formula between shear strength and water volume content, shear strength and saturation. In addition, paper analyzes the change of shear strength of unsaturated polluted clay.With the role of the matrix suction to cohesion, it evaluates the factors of unsaturated polluted clay’s ultimate bearing capacity in the actual situation. Comparing and calculating saturated and unsaturated ultimate bearing capacity of clay foundation in strip, round, square foundation, it is concluded that the matric suction contributes to the ultimate bearing capacity of unsaturated polluted clay sample. Plus, it concludes formulas and curves of the relationships between matric suction and ultimate bearing capacity, water volume content and ultimate bearing capacity. Plus, paper analyzes the change of ultimate bearing capacity of unsaturated polluted clay.Finally, this paper verifies the accuracy of analysis of the ultimate bearing capacity unsaturated soil by numerical simulation. Considering unsaturated and saturated states, it simulates ultimate bearing capacity of unsaturated polluted clay in strip, round, square foundation by FLAC3 D. Comparing the difference of ultimate bearing capacity in two conditions, it shows the contribution of matric suc tion to shear strength and verifies the accuracy of theoretical formula of the ultimate bearing capacity unsaturated soil.