新型磁浮交通路基沉降变形现场监测及数值模拟

Field Monitoring and Numerical Analysis on Settlement of New type Maglev Subgrade

依托北京市中低速磁浮交通示范线,提出悬臂式挡土墙、U形槽、U形槽组合顶板3种适用于中低速磁浮交通的新型路基结构。该路基结构上承小型分节式承轨梁,下部采用旋喷桩或素混凝土桩进行地基处理,共同构成中低速磁浮交通新型路基及低置型承轨梁台结构系统。通过在代表性断面预埋单点沉降计、沉降观测标、土压力计,开展现场静力学试验。此外,建立三维有限元模型,验证地基处理、新型路基结构、承轨梁台结构的科学性及有效性,并揭示中低速磁浮交通路基结构静力学行为规律。研究结果表明,路基结构的总沉降值为2~5 mm,远低于规范要求。沉降主要发生在施工期间,静置期基本不发生沉降,并且路基压缩主要发生在复合地基加固区。

Based on a medium and low speed maglev demonstration line in Beijing, three new type roadbeds, including the cantilever retaining wall, U-type channel and U-type channel combined with plate, were proposed for the medium and low speed maglev. Small sectional type support-beams and jet grouting/unreinforced concrete piles constituted the critical technologies of the system design. Serval typical cross sections embedded with subsidence meters, settlement observation points and soil pressure gauges, were selected to conduct the statics experiments. In addition, three-dimensional finite element models were established to confirm the scientific and effectiveness of the foundation treatment, new type roadbed and sectional type support-beams. The results show that the total settlement of the roadbed ranges from 2 to 5 mm, which are far below the specification requirement;the settlement mainly occurs during the construction period, while no settlement has been found during the standing stage;the roadbed compression mainly occurs in the reinforced area of composite foundation.