动态反演方法进行路面结构性能衰减分析的可行性

    Feasibility of Dynamic Backcalculation on Pavement Performance Reduction Analysis

    • 摘要: 为对沥青路面结构性能衰减演化分析提供参考,以不同基层类型的沥青路面结构作为研究对象,分析动态反演方法在路面结构性能衰减研究中的可行性. 首先,收集了实验路段2010年和2015年的实测弯沉数据,采用动态和静态方法进行路面力学参数反演,分析反演结果在服役期的变化趋势. 其中,动态方法采用谱单元法进行沥青路面动态黏弹分析,以弯沉时程曲线构造力学参数优化目标函数,得到沥青层的复数模量和其他结构层的弹性模量. 静态方法以层状弹性理论作为正分析方法,以弯沉盆进行反演得到各结构层的弹性模量. 继而采用动态反演力学参数进行移动荷载作用下的路面分析,计算了基层层底和沥青层层中的应力、应变等力学响应,分析了力学响应随服役时间的变化. 结果表明:静态反演结果表现出较大的波动性,2015年的静态反演结果甚至大于2010年的结果; 动态反演结果比静态反演结果更加稳定,参数变化趋势可以客观描述路面结构性能的衰减,而且与基于动态反演参数的路面力学响应变化趋势具有合理的一致性. 动态反演方法可以充分利用实测弯沉信息,有效避免模量窜层引起的静态反演结果误差,为路面结构性能衰减演化分析提供了便利和途径.

       

      Abstract: To provide a reference for the reduction analysis of pavement performance, an asphalt pavement with different base types was taken as research object in this study to evaluate the feasibility of the dynamic backcalculation in pavement performance reduction. The field deflection measured at 2010 and 2015 was backcalculated by using dynamic and static approaches to study the various tendencies of the layer property during the service life. The spectral element method was adopted in the dynamic approach to conduct dynamic viscoelastic analysis and the deflection time-history was used to construct the optimization objective function. The complex modulus of asphalt layer and the elastic modulus for other layers were obtained. The layered elastic theory was adopted as forward analysis engine in the static method, and the deflection basin as constrain in the optimization process, and the elastic moduli for all layers were obtained. The dynamic backcalculated layer property was employed for pavement analysis under moving vehicles. The strainress at the bottom of the layer and the vertical strain at the mid depth of the asphalt layer were calculated to study the various tendencies of response within service life. Result shows that the layer property from static approach is fluctuant, and the result of 2015 is even greater than that of 2010. The dynamic backcalculated layer property is more stable, and its tendency can objectively characterize the pavement performance reduction. The analyzed response based on dynamic backcalculated layer property shows reasonable variation and it is consistent with the layer property. The deflection time-history can provide more constrains in optimization process, which can be efficient to avoid the error of static approach due to the modulus compensating phenomenon. The research provides an efficient and convenient routine for pavement performance reduction analysis.

       

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