砂卵石地层地下水对盾构隧道影响的离散元流固耦合分析

发布时间：2018-12-25 15:40

【摘要】：为探明砂卵石地层中地下水对盾构隧道衬砌上的土压力以及地层变形的影响,以成都地铁2号线为依托,采用颗粒流方法,从细观角度模拟分析地下水对盾构隧道衬砌荷载分布以及地层扰动的规律,研究盾构隧道动态施工过程中及后期稳定后的水、土压力分布。研究表明:考虑地下水工况时的衬砌荷载小于不考虑地下水的工况,开挖后地下水位越高,衬砌荷载越小;地下水分布影响隧道开挖后洞周应力重分布,拱顶处受到的影响最大,拱肩处受到的影响最小;盾构隧道开挖后,拱顶上方存在一定范围的松动区,在松动区上方一定范围形成坍落拱,起到承载作用,同时将上方土荷载有效地传递到洞周两侧。考虑地下水时,由于有效应力减小,地层变形相应减小,地层受盾构施工扰动的影响减弱。
[Abstract]:In order to find out the influence of underground water on the earth pressure and formation deformation of shield tunnel lining in sand pebble formation, the particle flow method is adopted based on Chengdu Metro Line 2. In this paper, the distribution of underground water load on shield tunnel lining and the regularity of formation disturbance are simulated and analyzed from the view of meso, and the distribution of water and earth pressure during and after the dynamic construction of shield tunnel is studied. The results show that the lining load is smaller than that without groundwater, and the higher the groundwater level is after excavation, the smaller the lining load is. The distribution of groundwater affects the stress redistribution around the tunnel after excavation, the influence on the arch is the biggest, and the influence on the arch shoulder is the least. After the shield tunnel is excavated, there is a certain range of loose area above the arch roof, and the collapse arch is formed in a certain range above the loose zone, which plays a bearing role. At the same time, the above earth load is effectively transferred to both sides of the tunnel. When groundwater is considered, due to the decrease of effective stress, the formation deformation is correspondingly reduced, and the formation is weakened by the disturbance of shield construction.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家重点基础研究发展计划(973)项目(2010CB732105) 国家科技支撑计划(2013BAB10B02,2013BAB10B04)
【分类号】：U455.43

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