Discrete element analysis of a cross-river tunnel under random vibration levels induced by trains operating during the flood season
Floods result in many problems, which may include damage to cross-river tunnels. The cross-river tunnel, as a new style of transportation, deserves a large amount of attention. In this paper, a large-scale cross-river tunnel model is proposed based on discrete element method (DEM). Micro parameters used in the model are calibrated by proposing a triaxial numerical model. Different in situ strata, high water pressures of normal flood-water levels and random vibration levels induced by running trains are taken into account to evaluate the dynamic characteristics of a high-stress tunnel in deformation and stress analysis. The results show that the upper half of the tunnel, including the concrete lining and the surroundings, is at higher risk than the lower half. Vibration waves transferring into the surroundings undergo an amplification process. The particles of the surroundings at the vault of the tunnel separate and move downward and then reassemble during the dynamic vibrations. The vibration levels, represented by particle accelerations, are lower under flood conditions than those under normal conditions. As train speed increases, the acceleration of the track and particles in the foundation increases, accompanied by a decrease in deformation.
Key wordsDiscrete element method (DEM) Cross-river tunnel Water pressure Metro train operation Random vibration level Acceleration
采用离散元方法进行数值仿真。1. 基于室内三轴试验和离散元数值拟合得到土层的各细观参数;2. 采用不同接触模型对隧道内钢轨、轨枕、管片以及周边岩土体进行建模;3. 将地铁随机振动荷载施加在钢轨上,对管片及周边岩土体不同区域内颗粒的受力及变形进行监测并分析。
1. 位于隧道上半部分的周边岩土体颗粒振动偏大;2. 随着距离的增大,振动波在周边岩土体内先放大后减小;3. 汛期水位条件下地铁行车荷载对管片和周边岩土体的振动影响较小,但是对隧道变形影响较大。
关键词离散元方法 越江地铁隧道 水压力 地铁行车荷载
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- Dinis Ferreira PA, 2010. Modeling and Prediction of the Dynamic Behavior of Railway Infrastructures at Very High Speeds. PhD Thesis, Technical University of Lisbon, Lisbon, Portugal.Google Scholar
- Gao WL, Yang MS, Zhao BM, 2012. Seismic response analysis of large span tunnel across the river under earthquake. Highway, 5:344–349 (in Chinese).Google Scholar
- Itasca (Itasca Consulting Group, Inc.), 2008. PFC Particle FOW Code, Version 4.0. Itasca, Minneapolis, USA.Google Scholar
- Kouroussis G, Conti C, Verlinden O, 2012. Efficiency of resilient wheels on the alleviation of railway ground vibrations. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 226(4):381–396. https://doi.org/10.1177/0954409711429210 CrossRefGoogle Scholar
- Ling XZ, Chen SJ, Zhu ZY, et al., 2010. Field monitoring on the train-induced vibration response of track structure in the Beiluhe permafrost region along Qinghai-Tibet railway in China. Cold Regions Science & Technology, 60(1): 75–83. https://doi.org/10.1016/j.coldregions.2009.08.005 CrossRefGoogle Scholar
- Lu JF, Zhang CW, Jian P, 2017. Meso-structure parameters of discrete element method of sand pebble surrounding rock particles in different dense degrees. Proceedings of the 7th International Conference on Discrete Element Methods, p.871–879. https://doi.org/10.1007/978-981-10-1926-5_91 CrossRefGoogle Scholar
- Xiong C, 2014. Technical characteristics and innovation of the cross-Yangtze river tunnel of Wuhan subway line No. 2. Railway Survey and Design, 3:1–7 (in Chinese).Google Scholar
- Zhang S, Xia Y, Ma G, et al., 2013. Reconnaissance and construction key issues for the cross-river tunnel of Wuhan subway line No. 2. Chinese Journal of Underground Space and Engineering, 9(4):914–918 (in Chinese).Google Scholar