柔性路面结构层模量梯度控制与论证

Control and Verification of Modulus Gradient of Flexible Pavement Structural Layers

为了从理论及实践上验证结构层模量梯度控制的必要性及合理取值范围,以对结构受力影响最为显著的模量比为研究切入点,选取层间不完全连续接触,利用壳牌路面设计软件Bisar3.0全面计算模量比变化时柔性路面的力学响应,将模量比的影响定量化。在力学分析的基础上,以推荐的柔性结构铺筑实体工程进行性能跟踪验证,采用FWD检测方法实测关键层位模量比。结果表明:模量比从8增大到14时,沥青层最大拉应变与结构最大弯拉应力均随之增大,同时面层剪应力随之减小;对柔性结构的弯拉应力与剪应力水平实行双控,控制级配基层模量在合理范围内取相对高限值,可使结构受力较均衡;通过广州实体工程进行现场模量检测及长期性能观测的印证,建议控制柔性基层与面层的模量比为8~10。

In order to verify the necessity and reasonable value range of controlling modulus gradient of structural layers from theory and practice, from the perspective of the modulus ratio affecting stress of structure most obviously, setting interlayer binding condition as not fully continuous, the mechanical response of flexible pavement is comprehensively calculated by using shell designing software Bisar3.0, and the effect of modulus ratio is quantified. On the basis of mechanical analysis, the performance of the pavement project using recommended flexible structure is verified, and the modulus ratio of key layers is tested by FWD method. The result shows that （3） when the modulus ratio changed from 8 to 14, the maximum tensile strain of asphalt layer and the maximum flexible stress of the structure both showed the trend of increasing, while the shear stress of surface decreased; （4） controlling both flexible stress and shear stress of the flexible structure together and taking higher threshold of modulus of control graded base layer in proper scale is good for structure to keep mechanical balancing. By making modulus test on site and long-term behavior measurement and verification on practical engineering of Guangzhou, it is suggested to control the modulus ratio of structural layers at the scale from 8 to 10.