冻融循环对非饱和粉质粘土SWCC及强度的影响

Effect of Freeze-thaw Cycle on SWCC and Strength of Unsaturated Silty Clay

为研究季冻区非饱和粉质黏土在冻融条件下的土水特征曲线及强度的变化,对季冻区非饱和粉质粘土的SWCC(土水特征曲线)和强度进行了测量,观察了冻融循环次数及冻结负温对非饱和路基粉质黏土土水特征曲线及强度的影响。研究表明:非饱和粉质黏土的土水特征曲线用Gardner模型进行拟合效果良好;土水特征曲线受冻融循环次数和冻结负温的影响较大,其强度随冻融循环次数的增加呈先减小后趋于稳定的趋势,冻融一次以后其强度降低最为明显,并且冻结负温为-10℃时其粘聚力损伤值最大。由基质吸力引起的累计粘聚力损伤值随冻融循环次数增加呈线性增加,随冻结负温减小成指数型增加。

To investigate the influence of freezing-thawing conditions on the soil-water characteristics and strength of unsaturated silty clay in the seasonal frozen soil area.The soil-water characteristic curve of unsaturated silty clay for the seasonal frozen area was measured to observe the influence of different freeze-thaw cycles and different negative freezing temperatures on the soil-water characteristic curve and strength of unsaturated silty clay.The results show that the Gardner model can obtain good fitting results by fitting the soil-water characteristic curve of unsaturated silty clay.The unsaturated soil-water characteristic curve is greatly affected by the number of freezingthawing cycles and freezing negative temperature.Along with the increase in the number of freeze-thaw circulation on its strength decreases before stabilizing trend,the intensity of freeze-thaw decreased most obviously after one time,and freeze the negative temperature was minus 10℃when the cohesive force of lower is most obvious.The cumulative cohesive damage caused by matric suction increases linearly with the number of freeze-thaw cycles and exponentially with the decrease of negative freezing temperature.