无砟轨道格室加筋路基sandwich形结构服役性能演变机理与评价方法研究

无砟轨道格室加筋路基sandwich形结构要受到高周频列车动载与干湿循环效应的长期联合作用，中部夹层格室加筋级配碎石动态力学性能将发生演化，引起整体结构服役性能演变，给行车带来安全隐患。本项目运用理论与试验相结合的研究手段，开展无砟轨道格室加筋路基sandwich形结构在高周频动载和干湿循环下服役性能演变机理与评价方法研究，探明夹层格室加筋级配碎石动态力学性能劣化机制，提出其动力本构模型、累积变形演化状态判别准则和计算方法，建立其动态力学特性劣化评价与预测模型；剖析夹层动态力学性能劣化对无砟轨道格室加筋路基sandwich形结构服役性能演变的影响机制，揭示无砟轨道格室加筋路基sandwich形结构动力性能演变规律，建立其长期动力性能预测模型，提出反映车-轨-路系统服役状态的多层次动力指标控制阈值，构建其服役状态评价数学模型。研究成果可为该结构运营安全管理和养护维修提供理论依据与技术支撑。

The geocell-reinforced subgrade sandwich structure of ballastless track is subjected to the long-term combined effect of the dynamic train loads with high cycles and frequencies and the drying-wetting cycles. The dynamic mechanical properties of the geocell-reinforced graded crushed stone in the middle part of the sandwich structure would be evolved, resulting in the service performance evolution of the sandwich structure. It can bring about potential safety for traveling trains. Therefore, the evolution mechanism and evaluation method of service performance of the geocell-reinforced subgrade sandwich structure of ballastless track under the combined effect of the dynamic train loads with high cycles and frequencies and the drying-wetting cycles are investigated by using theoretical and experimental methods in this project. The deterioration mechanism of dynamic mechanical performance of the geocell-reinforced graded crushed stone is studied under the combined effect of the dynamic train loads with high cycles and frequencies and the drying-wetting cycles. A dynamic constitutive model, a calculation method and an evolution state criterion of cumulative deformation, a model for evaluating and predicting deterioration of dynamic mechanical properties are proposed for the geocell-reinforced graded crushed stone. Then the influence mechanism of the dynamic mechanical performance deterioration of the geocell-reinforced graded crushed stone in the interlayer on the service performance evolution of the sandwich structure are analyzed. The dynamic performance evolution rule of the geocell-reinforced subgrade sandwich structure of ballastless track is revealed. A prediction model of long-term dynamic performance is established for the sandwich structure. The control threshold values of multilevel dynamic indexes reflecting service state of vehicle-track-subgrade system are proposed. Then an evaluation mathematical model of service state of the geocell-reinforced subgrade sandwich structure of ballastless track is established based on the dynamic parameters of vehicle-track-subgrade system. The results obtained from the project could provide theoretical basis and technical support for the safety management and maintenance of the geocell-reinforced subgrade sandwich structure of ballastless track.