水泥改良高液限黏土动态回弹模量试验研究

Experimental study of dynamic resilient modulus of cement-improved high liquid limit clay

利用动三轴试验,研究了水泥改良高液限黏土动态回弹模量的影响因素及其变化规律。研究表明,动态回弹模量随围压、压实度和水泥含量的提高而增大,随循环偏应力和含水率的增大而减小。为分析动态回弹模量的应力依赖性,研究采用了双因素方差分析。分析表明,偏应力与围压均对动态回弹模量有显著性影响,但偏应力的影响更为显著。鉴于动态回弹模量是偏应力和体应力的函数,在分析现有动态回弹模量本构模型适应性的基础上,采用偏应力和体应力为变量的3参数复合模型对试验数据进行回归分析,结果表明,所选模型具有较高的决定系数,证明所选模型具有较高的合理性与可靠性。研究获得了不同含水率、压实度和水泥剂量下水泥改良高液限黏土的动态回弹模量预估模型,为基于动力学的路面结构设计提供了参数。

In order to investigate the factors which affect the cement improved high liquid limit clay dynamic resilient modulus and their variation laws,a series of dynamic resilient modulus tests were carried out by conducting dynamic-triaxial tests.The study demonstrated that dynamic resilient modulus values rise with the increase of confining stress,compaction degree and cement content,decrease with the increase of circular deviator stress and moisture content.To accomplish the purpose of analysis the relationships between deviator stress,bulk stress and dynamic resilient modulus,the dual-factor analysis of variance was utilized.The analysis demonstrated that both the deviator stress and bulk stress have significant effects on the dynamic resilient modulus.However,the deviator stress has more significant effects.Considering that dynamic resilient modulus is a function of deviator stress and bulk stress,with a brief analysis of adaptability of the present dynamic resilient modulus constitutive models,the three-parameters compound constitutive model which reflects the effect of bulk stress and deviator stress was utilized for experimental data regression analysis.A high coefficient of determination shows that the model which reflects the effect of bulk stress and deviator stress is accurate and credible.The prediction models used for different compaction degrees,moisture contents and cement contents were achieved;and they can provide parameters for the pavement design based on dynamic method.