深季冻区碳酸盐渍土累积塑性变形研究

Study on cumulative plastic deformation of saline-alkali soil of deep frozen season area under cyclic loading

为研究深季冻区碳酸盐渍土地区路基的长期沉降问题,利用动静态三轴测试系统开展了循环加载试验,得到了不同振动频率f、压实度k和循环应力σ_(d)—下碳酸钠盐渍土重塑土样的累积塑性变形曲线。结果表明,随着荷载频率的增加,加载前期累积塑性应变的增长速率和累积塑性变形先增加后减小;累积塑性变形与压实度的关系并不总是负相关的;循环应力σ_(d)对累积塑性变形有显著影响,循环应力σ_(d)越大,土样的累积塑性变形越大;Monismith指数模型可以很好地预测冻融后碳酸盐渍土的累积塑性变形。

In order to study the long-term settlement of subgrade in saline-alkali soil of deep frozen season area,a series of cyclic loading tests were carried out by using the dynamic and static triaxial test system.The cumulative plastic deformation curves of remolded samples of saline-alkali soil under different vibra­tion frequencies f,compacting degree k and cyclic stressσ_(d)were obtained.The results show that with the increase of loading frequency,the growth rate of cumulative plastic strain and cumulative plastic deforma­tion rise firstly and then decrease in the early loading stage.The relationship between cumulative plastic deformation and compaction degree is not always negatively correlated.Cyclic stress has a significant effect on the cumulative plastic deformation,and the greater the cyclic stress is,the greater the cumula­tive plastic deformation is.Monismith index model can perfectly predict the cumulative plastic deforma­tion of saline-alkali soil under freeing-thawing.