无砟轨道沥青混凝土支承层准静态设计方法

Quasi-static Design Method of Asphalt Concrete Bearing Layer of Ballastless Track

沥青混凝土铺装轨道结构中,沥青混凝土支承层的厚度设计目前以经验为主。本文建立了轨道板在均布荷载作用下的层状弹性体系理论模型,应用有限元分析和实测数据验证了理论模型的有效性,提出以沥青混凝土层层底拉应变、路基面竖向应力、路基面竖向位移为关键设计指标的沥青混凝土支承层厚度准静态设计方法,并进行了实例设计。结果表明:理论分析结果相比有限元计算结果偏于保守,两者都在实测数据取值范围内;理论模型修正后可用于无砟轨道沥青混凝土支承层的厚度设计;设计指标的阈值可控制设计层的最小适宜厚度。

The thickness design of the asphalt concrete bearing layer in asphalt concrete paved track structure is mainly based on experience. In this paper,assuming the track slab under uniform load,the theoretical model of layered elastic system was established,and the finite element analysis and the measured data were used for verification. Then,the quasi-static design method for the thickness of asphalt concrete bearing layer was proposed,in which bottom strain of asphalt concrete layer,vertical stress of subgrade surface and vertical displacement of subgrade surface are key design indexes,and a design example was given. The results show that the theoretical analysis results are more conservative than the finite element calculation results,both of which are in the range of measured data. The modified theoretical model can be used for the thickness design of the asphalt concrete bearing layer,and the threshold values of design indexes can control the minimum suitable thickness of design layer.