干湿循环下红黏土回弹模量对路面结构影响

Influence of red clay elastic modulus on pavement structure under drying-wetting cycles

利用室内承载板法分析干湿循环作用下压实红黏土回弹模量变化规律,以壳牌设计软件BISAR3.0为计算工具,计算了干湿循环下红黏土回弹模量对路面结构的力学特性影响。结果表明:压实红黏土回弹模量值随干湿循环次数的增加而衰减,其中第1次衰减很大,经过3~5次干湿循环作用后,回弹模量基本都在10~15 MPa。面层层底弯拉应力、应变随红黏土土基回弹模量的减小而减小,基层、底基层层底拉应力、应变随红黏土土基回弹模量的减小而增加。底基层层底弯拉应力、应变与红黏土土基回弹模量的关系可用对数来拟合。结构层厚度随红黏土土基回弹模量的减小而增大,经第1次干湿循环其结构层厚度增加19.32%,当回弹模量稳定后其厚度增加21.59%。

The elastic modulus change of compressed red clay under drying-wetting cycles was analyzed by the laboratory bearing plate method.The influence of the elastic modulus of red clay on the mechanical properties of pavement structure under drying-wetting cycles was calculated by using BISAR3.0.The results show that the elastic modulus of the compressed red clay is attenuated with the increase of the number of drying-wetting cycles,and the first attenuation is large.After 3~5 drying-wetting cycles,the elastic modulus basically falls into 10~15 MPa range.The bending stress,strain and shear stress of the bottom of the surface course are reduced with the decrease of the elastic modulus of the red clay.The tensile stress,strain and shear stress of the base course and its bottom increase with the decrease of the elastic modulus of the red clay.The relationship between the bending stress of the bottom of the base course,strain,shear stress and the elastic modulus of the red clay soil base can be fitted with a logarithm.The thickness of the structural course increases with the decrease of the elastic modulus of the red clay soil.The thickness of the structural course is increased by 19.32%after the first drying-wetting cycle and by 21.59%when the elastic modulus become stable.