不同湿度粘性路基土动态回弹预估研究

研究以滤纸法测量了粘性路基土基质吸力，获得了土水特性曲线。通过动三轴试验，研究了不同含水量下粘性路基土动态回弹模量，并于试验后以滤纸法测量土样的基质吸力，并探讨了粘性路基土动态回弹模量与基质吸力的关系。研究表明，粘性路基土动态回弹模量随循环偏应力和含水量的增大而减小，随基质吸力的增大而增大。鉴于动态回弹模量是偏应力和体应力的函数，在现有偏应力和体应力为变量的三参数复合模型基础上引人基质吸力的影响，进而提出综合反映湿度和应力状态的动态回弹模量预估模型。通过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，证明所选综合考虑应力和湿度影响的模型具有较高的合理性与可靠性。模型的建立，不仅为南方多雨地区评价路基土在环境和交通荷载作用下长期性能提供了依据，也为基于动力学的路面结构设计提供了参数。

Study on Prediction Model of Dynamic Resilient Modulus of Cohesive Subgrade Soils Considering under Different Moisture

The matric suctions were measured by the filter paper method, and the parameters of soil-water characteristic curve equations were obtained. In order to investigate the effect of moisture con- tent on cohesive subgrade soils dynamic resilient modulus, a series dynamic resilient modulus tests were carried out by conducting dynamic-triaxial tests. Based on the matric suctions measured by the filter pa- per method, the relationship between dynamic resilient modulus and matric suctions were analyzed. The study demonstrated that dynamic resilient modulus values decrease with the increase of circular deviator stress and moisture content, in reverse of matric suctions. Considering that dynamic resilient modulus is a function of deviator stress and bulk stress, based on the present three-parameters compound constitutive model which reflects the effect of bulk stress and deviator stress, the effect of matric suctions which could indirectly reflect the effect of moisture content were introduced. And then the prediction model incorpora- ting the effect of stress and moisture for cohesive subgrade soils was established. The model was utilized for experimental data regression analysis, a high coefficient of determination shows that the model is accu- rate and credible. The prediction models not only can evaluate the long-term performance of subgrade soil in Southern China＇s rainy areas, but also can provide parameters for the pavement design based on dy- namic method.