基于差异化设计的相邻轻重载车道内部竖向剪应力分析

结合高速公路拓宽改建工程案例,基于有限元计算技术,对既有高速公路沥青路面结构进行不同交通工况的力学响应分析,根据计算结果提出了上中面层实行材料性能差异的车道差异化路面结构设计方案；分析设计年限内临近的轻载与重载车道之间形成的路面内部上中面层竖向界面及其下层竖直面上的剪应力,研究接触状态和荷载作用位置对剪应力的影响规律及剪切破坏的可能性。结果表明,荷载作用位置不同时,界面及下层竖直面的产生的剪应力分布规律也不同,荷载位于重载车道中央时剪应力随着深度增大在逐渐增大,最大值出现在半刚性材料底基层层底；而位于界面顶部时,剪应力随路面深度的增加逐渐减小,最大值出现在路表,且可产生导致剪切破坏的较大剪应力,但因荷载继续作用于界面的几率较小,因而界面处实际不会产生剪切破坏,反而是轮迹带处产生剪切破坏几乎成为必然。

Vertical shear stress analysis of adjacent light and heavy loading lanes based on differential design

Combined with the case of expressway widening and reconstruction project, based on the finite element calculation technology, the mechanical response analysis of the existing asphalt pavement structure of expressway under different traffic conditions was carried out. According to the calculation results the differential pavement structure design scheme with different material properties on the upper and middle surface layers was proposed. The shear stress of the vertical interface in the upper and middle surface layer and the vertical surface of the lower layer formed between the adjacent light-load and heavy-load lanes within the design period are analyzed. And the influence law of the contact state and the position of load on the shear stress and the possibility of shear failure are studied. The results show that the shear stress distribution law of interface and lower vertical surface is different when the load position is different. When the load is located in the center of the heavy-load roadway, the shear stress increases gradually with the increase of pavement depth, and the maximum value appears at the bottom of the semi-rigid material base layer. However, at the top of the interface, the shear stress gradually decreases with the increase of pavement depth, and the maximum value appears on the pavement surface, which can produce a large shear stress leading to shear failure. However, the probability of the load continuing to act on the top of the interface is small, so the shear failure at the interface will not actually occur, but the shear failure at the track zone is almost inevitable.