柔性基层在重载道路补强中的可行性分析

Feasibility analysis of flexible base in strengthening of overloading road

路面结构组成中,基层类型是影响道路使用性能重要因素。柔性基层与半刚性基层是道路基层的2种基本类型。长期使用实践证明了占据着主导地位的半刚性基层不可忽视的一些缺点,尤其在道路补强中更体现出容易开裂的缺陷。当旧路需要加铺补强层时,在旧沥青路面上加铺半刚性基层,旧路面的裂缝会反射上来,在重载作用下,新路面可能比原来损坏的更快,设计合理的柔性基层是解决重载交通下车辙问题最经济有效的途径之一。为了从理论上进一步确定重载道路补强时合理的基层类型,文中通过建立具有不同基层类型的2种典型道路结构,定义了对应的材料模型和物理模型,运用ABAQUS有限元软件计算了重载交通条件下2种不同基层结构的力学特性。计算表明,在重轴载作用下,半刚性基层结构的受拉区范围大于柔性基层,会使相应的结构层更容易产生疲劳开裂现象;计算结果显示,重载作用下,柔性基层处于受压状态,具有较好的疲劳性能,可以有效减少沥青路面结构中的应力集中现象,能更好地延缓路面反射裂缝的发生。该有限元分析结果从力学角度证明了柔性基层作为重载交通道路的补强层是一个很好的选择,也为柔性基层在重载道路补强中的应用提供了理论依据。

The basic type is a very important factor affecting road use performance. Flexible base and semi-rigid base are two basic types of road base. Semi-rigid base in our country has been dominant in the new road. However,the use of long-term process also proved its some disadvantages cannot be ignored;especially in strengthening road show more easily crack defects. Research has shown that when the old road needs to placing the reinforcing layer,in the old asphalt overlay on semi-rigid base,and the old pavement cracks can reflex,under the effect of overloading,the new pavement may be faster than the original damage. Have to study and put forward reasonable design of flexible base is to address the issue of overload transportation rutting under one of the most economic and efficient way. In order to theoretically determine the reasonable basic type under overloading road,In this paper,through the establishment of different basic types of two typical road structure,defines the corresponding material model and physical model,overloading traffic is calculated using the ABAQUS finite element software under the condition of different mechanical properties of the basic structure. Calculation shows that under the heavy axle load,the tension zone of semi-rigid base structure is more than the flexible base,can make the structure of the corresponding layer more prone to fatigue cracking phenomenon; Flexible base is in compression state,and it has good fatigue performance. It can effectively reduce the stress concentration phenomenon in asphalt pavement structure,to delay the onset of reflection cracks. Therefore,from the angle of mechanics analysis,flexible base is a good choice for reinforcing layer of heavy traffic road,and also provides a theoretical basis for application of flexible base in strengthening of overloading road.