车辆荷载作用下的黄土路堤结构体系受力与变形数值分析

Numerical Analysis of Force and Deformation of Loess Subgrade's Structure System under Vehicle Load

针对车辆动荷载作用下黄土地区公路结构体系受力与变形问题,运用有限元法对其进行了数值分析.将车辆荷载简化为车辆静载与正弦周期荷载相叠加的动态荷载,分析中考虑了道路的实际结构体系、车速以及路面平整度条件下的动轮载系数等主要因素的影响.分析结果表明:动应力在道路横向呈现"W"状分布,且在车轮两侧向外快速衰减;沿道路各结构层竖向,应力衰减相对较慢,当距路面3.4m时,最大动应力约为25kPa.路面与基层变形基本一致,且较小,其中路基及下部地基的变形占总变形90%以上.车辆移动速度为20m/s时,道路沿纵向整体最大变形量为6.0mm;超载状况下,路面的最大变形量为15.6mm,为标准轴载下的路面变形的2.5倍左右,这表明车辆超载是诱使道路产生病害的重要原因.

For structure force and deformation of highway in Loess Area under vehicles dynamic load, it is analyzed by using the Finite Element Method. The vehicle load is simplified as vehicle static and dynamic loads superimposed, and dynamic load are assumed to be sinusoidal cyclic load. The actual structure of the road system, vehicle speed, wheel load factor of pavement roughness condition and other major factors are considered in the analysis. The results show that dynamic stress in the horizontal road shows ＂W ＂ shape distribution, which decay quickly on both sides of the outside wheels. Along the vertical roads layer structure, the stress attenuation is relatively slow. When the distance is 3.4 m away from the pavement, the maximum dynamic stress is about 25 kPa. Pavement deformation is consistent with the primary, and the deformation is smaller. The deformation of the roadbed and subgrade is more than 90% of the total deformation. When the vehicle moves at 20 m/s, the overall maximum deformation of road along the longitudinal direction is 6.0 mm. the maximum deformation of the pavement is 15.6 mm under overload condition, which is about 2.5 times under the pavement deformation of standard load. This shows that overloading of vehicles is an important reason that induces disease of road.