非线性温度梯度作用下水泥混凝土路面力学分析

Mechanical Analysis of Cement Concrete Pavement on Nonlinear Temperature Profile

为合理评价水泥路面温度沿深度方向的非均匀性分布对水泥混凝土板的应力和变形的影响,利用有限元软件模拟非线性温度梯度荷载;为分析不同程度非线性温度梯度对板的应力响应引入了非线性温度分布指数.研究结果表明:以线性温度梯度计算非线性温度梯度应力时,正温度梯度的应力偏大,负温度梯度的应力偏小.非线性温度梯度时板的变形和线性温度梯度板产生的变形则基本相同.负非线性温度梯度分布时:随着板厚和板弹性模量的增加,非线性温度梯度对板顶的应力影响增大;增加地基反应模量可以减小非线性温度梯度影响.并通过大量数据回归分析得出负温度梯度时板顶下最大应力计算公式.

To evaluate the deformation and stress distribution of cement-concrete pavement under no-u- niform temperature distribution along the depth direction, finite element analysis method was used in this research to simulate nonlinear temperature gradient load, and the nonlinear temperature distribution index was adopted to represent the degree of nonlinear distribution and to evaluate its effect on stress distribu- tion. Models with different nonlinear temperature index parameters were constructed. The results indicate that, although the deformation caused by linear temperature gradient models was almost identical with that from nonlinear temperature gradient models, the linear temperature gradient models have overestimated bottom-up stresses and underestimated top-down stresses. When the nonlinear temperature gradient is negative, the influence of nonlinear temperature gradient on slab stress increases with the increase of slab thickness and elastic modulus. Besides, the effect of nonlinear temperature gradient is reduced with the in- crease of the base reaction module. What is more, based on the regression analysis of a large database, the formula of maximum tensile stress of the slab top was obtained.