基于FWD路表动态弯沉盆参数的路基模量评价研究

Evaluation Study on Subgrade Modulus Based on FWD Dynamic Deflection Basin Parameters

为客观地反映既有路基的承载能力状况,基于结构动力学基本理论,建立了沥青路面结构的动力有限元数值分析模型,分析了路基模量参数与路表动态弯沉盆参数指标的相关关系,据此构建了路基模量参数的预测分析模型,并探讨了层间非连续接触、路面横向开裂及刚性层深度等因素条件对路基模量预测结果的影响。结果表明:路表动态弯沉盆参数指标与路基模量之间具有良好的相关性,路基模量可由直接弯沉参数指标d9、形状参数指标F8以及结构层厚度联合确定;路面开裂及层间非连续接触行为对路基模量参数的预测结果没有影响;当路基内刚性层深度小于6 m时,路基模量预测分析结果明显偏大。研究结果为进一步推广FWD测试设备在路基结构性能评定中的广泛应用提供了技术保障。

To reflect the bearing ability condition of the existed subgrade,determining its modulus is a crucial task for highway engineers.The objective of this study was to establish a method to predict subgrade modulus of asphalt pavements and analyze its applicability.Firstly,Based on the basic theory of structure dynamics,the finite element model of the intact asphalt pavement was established to generate a synthetic database of surface dynamic deflection basin parameter（DBP）indicators.Secondly,the relationship between DBP indicators and subgrade modulus was discussed by the related coefficient,then the regression function for predicting subgrade modulus was established.Finally,the influence of the factors including transverse cracking,interface contact condition and rigid layer depth on the predicted results of subgrade modulus was performed.The analysis results demonstrate that the subgrade modulus can be predicted by the direct deflection indicator d9,shape indicator F8 and structure layer thickness and the predicted precision is satisfied.The transverse cracking and layer interface condition of pavement structure has few effect on the predicted results of subgrade modulus.Nevertheless,the rigid layer depth that is less than 6m will have the major impact on the predicted results of subgrade modulus.The research results provide a technology supports to popularize FWD testing technology applied in performing subgrade structure performance evaluation.