Study on Modified PCHeave Model for Weakly Sensitive Soils to Frost Heave Considering Void Ratio
In response to the strict compaction requirements for high-speed railway subgrade filling and airport filling projects in severe cold regions,and lack of systematic theoretical analysis on the frost heave effects of weakly sensitive soils considering void ratio,a modified PCHeave model considering void ratio was established based on the relationship among pore ratio,permeability coefficient and unfrozen water content of weakly sensitive soils by combining theoretical and empirical analysis.Based on this model,the relationship between void ratio and frost heave,freezing depth and freezing rate was analyzed,and the experimental comparison was carried out.The results show that there is a good linear relationship between pore ratio and unfrozen water content of soils with weak sensitivity to frost heave.The frost heave and frost heave rate of weakly sensitive soil increase first before decreasing with the void ratio,that is,there is a most unfavorable void ratio that maximizes the frost heave and frost heave rate.However,the freezing depth of weakly sensi-tive soil to frost heave increases with the increase of pore ratio.If only the effect of void ratio on saturation permeability coefficient is considered,both the frost heave and frost heave rate increase significantly with the pore ratio.If only the effect of void on unfrozen water content is considered,both the frost heave amount and the frost heave rate decrease with the void ratio,but with minor decrease range.Weakly sensitive soils to frost heave,which are generally considered to not produce significant frost heave,can also produce large frost heave at a certain porosity ratio level.Therefore,it is more reasonable to both consider the influence of porosity ratio on saturation permeability coefficient and unfrozen water con-tent.The change of void ratio cannot be ignored in the frost heaving of weakly sensitive soil.The comparison with the freezing tests shows that this model can better describe the effect of void ratio on frost heaving of weakly sensitive soil.
void ratiosaturated hydraulic conductivityunfrozen water contentweak frost susceptibility soilsfrost heave
万方数据
维普
