摘要
回弹模量是反映路基弹性支撑能力的重要指标,并受运营期间基质吸力变化的显著影响。通过3种压实黏土试样的土-水特征曲线试验和重复动三轴试验,研究了回弹模量与基质吸力的相关性,并基于非饱和土有效应力原理,提出了考虑吸力效应的回弹模量预估模型。结果表明:基质吸力与回弹模量之间具有较强的非线性相关性,可采用指数形式进行两者的拟合;含水率由最佳含水率-4%提升至最佳含水率+4%时,受基质吸力减小的影响,回弹模量降幅达到29.1%~39.0%;在土-水特征曲线过渡区,采用以饱和度表征的有效应力参数,可较好地反映基质吸力对于回弹模量的贡献,预估效果优于采用残余含水率或进气值相关的有效应力参数;在相同饱和度的情况下,黏粒含量越多、塑性指数越高,基质吸力对有效应力的贡献比例越小。
The resilient modulus （MR） used for characterization of subgrade elastic support performance is an important parameter significantly affected by matric suction after traffic opening. To investigate the correlation between resilient modulus and matric suction, soil-water characteristic curve （SWCC） and repeated load triaxial （RLT） tests for three kinds of compacted clay soils were conducted, and then the prediction model of resilient modulus considering the effect of matric suction was proposed based on effective stress theory of unsaturated soils. Test results show that the resilient modulus has a good non-linear relationship with matric suction, which can be presented by an exponential function. When the gravimetric moisture content increases from 4% below optimum water content （OMC） to 4% above OMC, MR decreases by 29.1%-39.0% resulting from reduction of matric suction. Within the transition zone at SWCC, the prediction model with effective stress factor related to the degree of saturation can explain the contribution of matric suction to resilient modulus, and the model has higher predicting accuracy compared with the models with effective stress factor dependent on residual water content or air-entry value. With the same degree of saturation, the contribution of matric suction to effective stress is less significant with higher clay particle content and plastic index.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第1期123-128,共6页
Rock and Soil Mechanics
基金
交通运输部建设科技项目(No.2013319223010
No.2015318822170)~~
关键词
黏土
回弹模量
基质吸力
有效应力原理
饱和度
clay soil
resilient modulus
matric suction
principle of effective stress
degree of saturation
