水泥混凝土路面临界荷位研究

基于Winkler弹性地基模型假设,结合多轴化、重载化的交通运载趋势,考虑不同温度梯度对水泥混凝土路面受力情况的影响,对各种车型位于不同荷载作用位置时的水泥混凝土路面受力状态进行有限元分析,确定不同荷载应力与温度应力耦合作用下水泥混凝土路面的临界荷位,为采用不同设计标准的各种设计方法提出选取临界荷位的合理建议。结果表明,若以板中荷载疲劳应力破坏为设计标准,当水泥混凝土路面处于正温度梯度或零温度梯度时,其临界荷位为车辆载重轴作用于纵缝边缘中部位置;当水泥混凝土路面处于负温度梯度时,临界荷位为车辆相邻两轴作用于同一块路面板的前后两端位置;若以板角挠度破坏为设计标准,无论水泥混凝土路面处于何种温度梯度,临界荷位均为载重轴作用于靠近角隅的板边横缝边缘。

Research on Critical Loading Position of Cement Concrete Pavement

Based on the Winkler elastic foundation model assumption,combined with the tendency of multiaxle heavy-duty trucks,considered the effect of different temperature gradients on the stress condition of cement concrete pavement,the finite element method was employed to analyse the stress state of cement concrete pavement under the circumstance that some common types of axle loads were exerted on different positions of the pavement.The critical loading position of cement concrete pavement was found out in the coupling effect of load stress and temperature stress,and the reasonable suggestions of selecting critical loading position for adopting different design methods with distinct design indicators were proposed.The results show that(1) if the fatigue stress damage of concrete slab midpoint is selected as the design indicator,when the pavement is in positive or zero temperature gradient,the critical loading position is at the midpoint of the longitudinal edge of the slab where the load axle exerted on;(2) when the pavement is in negative temperature gradient,the critical loading position is at both sides of the concrete slab where adjacent axles of a vehicle exerted on;and(3) if the deflection damage of concrete slab corner is selected as the design indicator,whatever the temperature gradient the slab is in,the critical loading position will be at the horizontal joint edge near slab corner where the load axle exerted on.