基于路基动态回弹模量的水泥混凝土路面动力响应分析

Dynamic Response Analysis of Cement Concrete Pavement Based on Dynamic Resilient Modulus of Subgrade

路基回弹模量是路面结构设计的重要参数。为切实体现路基土回弹模量的应力相关性,克服简化的线弹性当量回弹模量带来的偏差,研究采用综合考虑体应力和八面体剪应力影响的动态回弹模量模型。基于广义胡克定律,从理论上严格推导了该动态回弹模量模型在三维应力状态下的精确一致切线刚度矩阵。通过编写用户自定义材料子程序(UMAT)将动态回弹模量模型移植到ABAQUS中,成功实现了应用动态回弹模量进行结构分析的目标。通过建立应用动态回弹模量本构模型的典型水泥混凝土路基路面结构三维有限元模型,全面研究了载荷对路基路面动力响应的影响,分析了不同行车速度、不同轴重和轴型下路基路面变形特征和应力分布规律。同时确定了车轮与路面共振时的行车速度和重载交通条件下路基工作区深度,研究成果为实际的路基路面设计提供了参考。

The resilient modulus of subgrade is an important design parameter of pavement structure.In order to effectively reflect the stress correlation of the resilient modulus and eliminate the deviation caused by the simplified linear elastic equivalent resilient modulus,the dynamic resilient modulus model with the influence of the body stress and octahedral shear stress is considered.Based on the generalized Hooke law,the accurate consistent tangent stiffness matrix of dynamic resilient modulus under three dimensional stress state is theoretically derived.The model is implanted into ABAQUS for structural analysis by compiling the user material subroutine(UMAT).Combined with the accurate consistent tangent stiffness matrix of dynamic resilient modulus,the 3 Dfinite element dynamic analysis model using dynamic resilient modulus for typical cement concrete pavement is established.A study is conducted to get the deformation characteristics and stress distribution of subgrade and pavement under various load parameters,such as load magnitude,distribution,period on the dynamic response of pavements subjected to moving loads.The driving speed of the resonance between the wheel and the road is determined.Meanwhile,the work area depth of subgrade under the condition of overloading transportation is determined.Research findings can provide reference for the subgrade and pavement design in practice.