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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2025 Vol.26 No.8 P.787-800
Dynamic response of the ground beneath a high-speed railway based on typical upper Shanghai clays involving water table change
Abstract: A rising water table increases soil water content, reduces soil strength, and amplifies vibrations under identical train loads, thereby posing greater risks to train operations. To investigate this phenomenon, we used a 2.5D finite element (FE) model of a coupled vehicle–embankment–ground system based on Biot’s theory. The ground properties were derived from a typical soil profile of the Yangtze River basin, using geological data from Shanghai, China. The findings indicate that a rise in the water table leads to increased dynamic displacements of both the track and the ground. This amplification effect extends beyond the depth of the water table, impacting the entire embankment–foundation cross-section, and intensifies with higher train speeds. However, the water table rise has a limited impact on the critical speed of trains and dominant frequency contents. The dynamic response of the embankment is more significantly affected by water table rises within the subgrade than by those within the ground. When the water table rises into the subgrade, significant excess pore pressure is generated inside the embankment, causing a substantial drop in effective stress. As a result, the stress path of the soil elements in the subgrade approaches the Mohr-Coulomb failure line, increasing the likelihood of soil failure.
Key words: Dynamic response; Excess pore pressures; Water table rise; High-speed train; 2.5D finite element (FE) model
机构:1福州大学,土木工程学院,中国福州,350108;2南安普顿大学,声学与振动研究所,英国南安普顿,SO17 1BJ;3浙江大学,软弱土与环境土工教育部重点实验室,中国杭州,310058
目的:本研究旨在探讨地下水水位抬升对车辆-路基-地基系统动力响应的影响。研究主要聚焦于水位抬升如何改变路基和地基在列车荷载下的振动位移、有效应力和超静孔压,并分析水位抬升高度和列车运行速度对路基-地基动力响应及路基失稳风险的具体影响。
创新点:1.调研和收集了大量上海的地质信息和数据,建立了具有代表性的上海典型地层和水位抬升模型;2.建立了多层多相介质的2.5维有限元模型,并获得了不同地下水位条件下的动力响应。
方法:1.通过文献调研,建立上海典型地层;2.基于Biot理论建立多相介质动力问题的2.5维有限元求解方法,并通过改变单元参数,实现水位抬升的模拟;3.围绕列车速度和水位抬升高度进行数值模拟,揭示水位抬升对路基-地基动力响应的影响。
结论:1.水位抬升使得路基-地基的振动强度增大,且这种振动强度的放大作用并不是局限在水位变化的深度范围内,而是会导致整个路基和地基断面的振动增大,并且这种全断面式的振动放大效应随着列车速度的提高而增强。2.上海典型地层上建造的高速铁路,其临界速度大约为85 m/s;水位抬升虽然显著增加了位移响应,但对临界速度的影响很小。3.水位抬升使得路基和地基频域内的响应幅值增大,特别是当水位抬升至路基时,幅值增加最为显著。4.水位抬升不仅加剧了土体的变形,还会使饱和土体内出现超静孔压,使有效应力减小;这会导致土单元上的剪应力与有效应力比值增大,进一步造成显著的土体变形;当水位抬升至路基内部时,路基内部出现显著的超静孔压,导致有效应力大幅下降,使路基内土单元的应力路径向破坏线靠近,因此不利于路基的稳定。
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DOI:
10.1631/jzus.A2400345
CLC number:
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On-line Access:
2025-08-27
Received:
2024-07-16
Revision Accepted:
2024-11-26
Crosschecked:
2025-08-28