基于旧路病害的混凝土薄层加铺结构力学分析

Mechanical analysis of concrete thin layer overlay structure based on old pavement disease

为了更加科学合理地进行旧水泥路面加铺混凝土薄层罩面路面结构设计,充分考虑加铺过程中旧路面病害状况,利用MATLAB进行旧路面病害的识别及坐标位置的提取,借助有限元软件分析不同程度病害(裂缝损害、坑槽、修补、基层脱空)状况下路面加铺结构的应力状态,实现病害信息与有限元模型的联动,进一步探讨旧水泥混凝土路面进行薄层加铺时存在病害作用下的力学响应规律。结果表明:加铺层层底以压应力为主,旧路面层层底以拉应力为主;对于同等程度的裂缝病害,直接加铺后各层层底最大荷载应力值相比修补加铺分别高出72.75%、43.53%;旧路面层层底应力值最小时的坑槽长宽比为2∶1,加铺薄层层底应力值则随着坑槽长宽比的增大逐渐降低;基层脱空会明显改变旧路面层层底的受力状态,正方形为脱空部分与旧路面层的最不利接触面。

The uncertainty of old pavement diseases in the process of overlay was fully considered in order to carry out more scientific and reasonable design of old cement pavement with concrete thin-layer overlay pavement structure.The stress state of the pavement overlay structure under different degrees of diseases(crack damage,potholes,repairs,base layer voids)was analyzed using finite element software.Moreover,MATLAB was used to identify the diseases and extract the coordinate positions to realize the linkage between the disease information and finite element model.Based on the disease information and the finite element model,the mechanical response law of the old cement concrete pavement under the action of the disease was further discussed.The results show that the compressive stress is dominant at the bottom of the pavement layers and the tensile stress is dominant at the bottom of the old pavement layers.For the same degree of cracking,the maximum load stress value at the bottom of each layer after direct paving is 72.75%and 43.53%higher than that of the repaired paving.The pit aspect ratio is 2∶1 when the stress value at the bottom of the old pavement layer is smallest,and the stress value at the bottom of the thin pavement layer decreases gradually with the increase of the pit aspect ratio.The subgrade debris will significantly change the force state of the bottom of the old pavement layer,and the square is found to be the most unfavorable contact surface between the voids part and the old pavement layer.