动静荷载分离思路下高铁基床累积变形计算方法

高铁循环列车动荷载作用下,基床累积变形不仅与列车安全运营密切相关,同时对指导线路服役期精细化维修管理意义重大,而目前基床累积变形分析存在途径偏少、精度偏低等问题。为探索适合高铁基床累积变形分析方法,依托沪宁城际铁路路基工程背景,基于动、静荷载引起动变形(沉降)的新思路,将运营期沉降数据推算工后沉降与建设期沉降数据推算工后沉降差值(推算法),以及运营期沉降与静载计算固结沉降差值(估算法)作为列车动载引起的累积变形,由此提出一种由实测数据推算与估算基床累积变形的新途径,并将该方法用到实例分析中。结果表明:推算与估算获取累积变形随时间发展规律吻合,均呈快速-缓慢-稳定3阶段特征,估算结果一致性好于推算;基床累积变形在铁路运营前3年基本达到稳定,量值控制在3.5 mm以内;数值模型验证了"推算与估算"方法可行。

Calculation Method of Cumulative Deformation of the Bed of High-speed Railway Based on Dynamic and Static Load Separation

Under the dynamic load of high-speed cyclic train, the cumulative deformation of the road bed is not only closely related to the safe operation of the train, but also important to guide the refined maintenance management. At present, there are few approaches to analyze the cumulative deformation of the bed, and the accuracy is low. In order to explore a suitable deformation analysis method, this paper, with reference to the subgrade engineering project of Shanghai-Nanjing intercity railway and based on the idea that the dynamic deformation(settling) is caused by dynamic and static loads, puts forward a new method to calculate and estimate the accumulative deformation of the bed with measured data by taking the difference value(calculate method) between post-construction settlement after calculation of settlement data during operation period and construction period, and the difference value(estimation method) between consolidation settlement and static load calculation consolidation settlement as the cumulative deformation caused by train dynamic load. This method has been used in case analysis. The research results show that the cumulative deformation obtained by calculation and estimation is consistent with the development law of time and characterized by the three stages of fast, slow and stable. The consistency of the estimation results is better than that of the calculation. The cumulative deformation of the bed becomes primarily stable in the first three years of railway operation, and the value is controlled within 3.5 mm. The numerical model verifies that the"calculation and estimation" method is feasible.