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含水量对路基的回弹模量有显著的影响,而回弹模量是水泥混凝土路面板应力和路面弯沉的重要影响因素。为克服采用线弹性当量回弹模量进行路面结构分析带来的偏差,通过对粉土三轴试验数据拟合,获得了不同含水量下应力相关的非线性回弹模量参数。推导了精确的一致切线刚度矩阵,利用Abaqus用户材料子程序UMAT对应力相关的回弹模量模型进行有限元实现。基于路基-路面协调变形,建立三维有限元分析模型,调用移植的回弹模量模型对典型的水泥混凝土路面结构进行结构分析,获取路基土在不同含水量下的路面结构的应力应变响应,结合水泥混凝土路面的疲劳寿命关系分析路基土含水量对混凝土路面疲劳寿命的影响。研究结果表明:路基土含水量从最佳含水量-3%增加到最佳含水量+3%,回弹模量相应显著减小,路面顶面最大弯沉增加,路面板的板底最大拉应力增加,路面结构的疲劳寿命减少。
Water content has a significant effect on the rebound modulus of the roadbed, while the elastic modulus is an important factor affecting the stress and pavement deflection of the cement concrete pavement. In order to overcome the deviation caused by pavement structure analysis using linear elastic equivalent modulus of elasticity, stress-related nonlinear resilience modulus parameters under different water contents were obtained by fitting triaxial test data of silt. The exact uniform tangent stiffness matrix is deduced and the finite element method is applied to the Abaqus user material subroutine UMAT. Based on the coordinated deformation of subgrade and pavement, a three-dimensional finite element model was established, and the model of rebound modulus was used to analyze the typical cement concrete pavement structure. The stress and strain response of the subgrade soil under different water contents were obtained. Influence of Water Content of Subgrade Soil on Fatigue Life of Concrete Pavement. The results show that the subgrade soil moisture content increases from the optimum water content of 3% to the optimum water content of + 3%, the springback modulus decreases significantly, the maximum deflection of the road surface increases, Increased stress reduces the fatigue life of the pavement structure.