The differential settlement of short subgrade between two highway structures (bridges, tunnels, culverts, etc.) is significantly greater than that of the other subgrade for the insufficient compaction of short subgrade owing to limited construction site. This paper aims to establish the control criteria to prevent bump at bridge approach for differential settlement of short subgrade with oblique prestressed concrete overlying asphalt layer (AC + OPC) composite pavement. In this work, the short subgrade and AC + OPC composite pavement were defined. Meanwhile, the driving comfort was analysed and the control criteria for differential settlement of short subgrade with different lengths were obtained based on the driving comfort using the driving comfort test. Finally, the effects of different layer parameters on stress and deflection were investigated and the control criteria for differential settlement of short subgrade were established based on the void area beneath the slab using the finite element software ANSYS. Results show that the length of short subgrade between two highway structures is defined to be less than 200 m. The vehicle speed and longitudinal slope have significant effects on the vertical acceleration. The asphalt layer modulus, OPC layer thickness and modulus, base layer thickness and modulus, and foundation modulus have effects on the flexural stress and deflection, especially the OPC layer thickness. The relationship between the additional stress and void area beneath the slab is derived. In addition, the control criteria for differential settlement of short subgrade with different lengths are put forward based on the void area beneath the slab and driving comfort. The application of AC + OPC composite pavement can prevent bump at bridge approach of short subgrade effectively. The results of this paper can provide guidance for the application of AC + OPC composite pavement.

中文翻译：

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倾斜预应力混凝土斜交沥青层在短路基桥梁进洞中的研究

由于施工场地有限，短路基的压实不足，两个公路结构（桥梁，隧道，涵洞等）之间的短路基的差异沉降明显大于其他路基。本文旨在建立控制标准，以防止斜交加沥青混凝土（AC + OPC）复合路面短路基差异沉降时桥梁方法的突跳。在这项工作中，定义了短路基和AC + OPC复合路面。同时，对驾驶舒适性进行了分析，并通过驾驶舒适性测试，根据驾驶舒适性获得了不同长度短路基差异沉降的控制标准。最后，研究了不同层参数对应力和挠度的影响，并利用有限元软件ANSYS，基于平板下方的空隙面积，建立了短路基差异沉降的控制标准。结果表明，两个公路结构之间的短路基长度被定义为小于200 m。车速和纵向坡度对垂直加速度有重要影响。沥青层模量，OPC层厚度和模量，基础层厚度和模量以及基础模量对弯曲应力和挠度有影响，特别是对OPC层厚度有影响。得出了附加应力与平板下方空隙区域之间的关系。此外，根据板坯下面的空隙面积和行驶舒适性，提出了不同长度的短路基差异沉降控制标准。AC + OPC复合路面的应用可以有效地防止短路基桥梁引爆。本文的研究结果可为AC + OPC复合路面的应用提供指导。