Study On Physical And Mechanical Properties Of Frozen Soil In Suzhou Subway

The artificial freezing method would be used in parts of subway interconnecting roads of Suzhou subway Line 1 as an auxiliary technique. For now there are no experimental research data about physical and mechanical behavior of frozen soil in Suzhou. And reference the parameters of other areas will bring many uncertainties to the construction. By the typical soil of Suzhou Subway, coeifficient of thermal conductivity,frozen temperature,uniaxial compressive strength, tensile strength, frost heaving ratio and thaw-settelment coefficient had been studied deeply. And there also had many quantitative analyses. The research results will provide important parameters for designing and guiding of the frozen construction in Suzhou subway. The primary work and study achievements are as followed.1) Based on the clay, silty clay, silt and silty sand,we analysised the physical and mechanical properties of coeifficient of thermal conductivity and frozen temperature between original and thawing siol.In which coeifficient of thermal conductivity and frozen temperature increased with water content. By increasing the dry density, the coeifficient of thermal conductivity also growed,but the frozen temperature did not Changed significantly.2) Through instantaneous uniaxial compressive and tensile strength tests between original and thawing siol of the typical soil in Suzhou,we summarized the variation of basic parameters with various factors.When the temperature decreased and the ater content increased, the instantaneous uniaxial compressive and tensile strength linearly growed. The influence by dry density did not define.3) By the test device which self developed,we made many tests on frost heaving ratio and thaw-settelment of different soils.Then we concluded the influence rules with water content and dry density.They will provide valuable reference to design on wall thickness and the thawing of the freeze-thaw.4) Based on the existed data, we made various prediction models of the parameters by BP neural network. Meanwhile we made normalized data tables of physical and mechanical parameters,and they will Service for designing and construction on artificial freezing method in Suzhou subway.