有轨电车路基板-疏桩基础长期沉降现场实测与数值分析

Monitoring and Numerical Study of Long-Term Settlement of Track Bed with Sparse Pile Foundation for Tram

摘要:

有轨电车路基板?疏桩基础的目的在于避免长期轮压循环荷载造成软土路基显著沉降。为掌握其长期沉降特性，基于南方某实际有轨电车工程开展长达两年的工后沉降监测。结果表明：在运行初期路基沉降发展迅速，运营约一年后沉降速率变缓并于两年后趋于稳定，且绝对沉降量远小于容许值。该研究又基于土体累积应变显式模型提出了黏土中路基板?疏桩基础的长期循环累积沉降等效有限元分析方法，经与监测值对比验证其合理性，并采用等效有限元探讨路基板?疏桩基础的承载力机理。

Abstract:

The track bed with sparse pile foundation was developed to avoid the excessive settlement of track beds due to long-term cyclic wheel-pressure. To understand the settlement development， a two-year monitoring of an actual tram project in a southern city in China was reported. The results reveal that the settlement of the track bed increased rapidly in the initial stage. The settlement gradually reduced after around one year and tends to be stable after two years. Moreover， based on the explicit cumulative strain model， an equivalent finite element method is proposed for predicting the long-term cumulative settlement of the track bed with sparse pile foundation. A good agreement between the monitored and calculated results demonstrates the rationality. Furthermore， discussions on the bearing mechanism of the track bed with sparse pile foundation are presented.