地铁隧道侧穿邻近建筑中隔离桩的应用研究

以某地铁隧道侧穿5层砖混结构房屋工程为背景,为研究隔离桩在隧道侧穿邻近建筑物工程中的隔离效果及影响因素,通过多组有限元数值模拟,并结合现场监测数据,分别研究隔离桩的桩长、位置,隧道埋深以及隧道与建筑物的距离等因素对隔离效果的影响。研究结果:隔离桩对因隧道开挖产生的滑动区土体有较好的隔断作用;隔离桩嵌入滑裂面以下的深度是隔离桩控制效果的重要影响因素,建议嵌入深度不小于4 m;隔离桩与隧道或建筑物距离的改变对隔离桩控制效果的影响较小;当建筑物与隧道的水平距离小于2倍隧道埋深或当隧道埋深小于2倍隧道洞径时,隔离桩的控制效果较为明显;对于工程地质条件较差或邻近建筑物沉降控制要求较为严格的工程中,当建筑物与隧道水平距离小于1.5倍隧道埋深,且隧道埋深小于2倍洞径时,建议设置隔离桩对邻近建筑进行保护。

Study on Application of Shelter Piles Where Subway Tunnel Passing Sideway Nearby Buildings

With reference to a subway tunnel passing sideway a five-story brick masonry building and based on groups of numerical simulations and in-situ monitoring data,this paper studies the isolation effect and influence factors of shelter piles in projects where tunnels passing sideway buildings,and in particular,analyzes the isolation effect of shelter piles with the influence of pile length and position,tunnel depth,distance between tunnel and building. The research results show that shelter piles have good effect to obstruct the soil in slide zone caused by the tunnel excavation; the depth of shelter piles imbedded in slip surface is an important factor to reflect the controlling effect of shelter piles,and it is advised that the embedding depth of the shelter piles should not less than 4m; the change of the distance between shelter piles and buildings has less influence on the controlling effect; when the horizontal distance between building and tunnel is less than twice of the burial depth of tunnel or the burial depth of tunnel is less than twice of the diameter of tunnel,the shelter piles have relatively good controlling effect;for projects with poor engineering geological condition and strict settlement control standard of adjacent buildings,shelter piles are recommended to protect the nearby buildings,where the horizontal distance between building and tunnel is less than 1. 5 times of the burial depth and the burial depth of tunnel is less than twice of tunnel diameter.