地铁车站基坑支护变形特性研究

Study on Deformation Characteristics of Foundation Pit Support of Subway Station

以某地铁车站基坑为研究对象,通过室内模型试验,分析了地铁车站施工过程中支护结构水平位移规律,并对比三种不同排数工况下支护结构变形,获得了排桩排数对支护结构变形的影响。研究表明,沿着基坑深度方向,桩身位移总体呈增大趋势。具体的,基坑左边缘排桩在小荷载下呈现先减小后增大趋势,在大荷载下呈现先增大后减小趋势;基坑中间部位排桩都呈现先缓慢增大后加速增大的趋势;基坑右边缘排桩在小荷载下加速增大,在大荷载下平缓增大。在距基坑顶部1/6位置,沿着基坑从左到右的方向,桩身位移呈先增大后平稳的趋势;在距基坑顶部1/2位置,沿着基坑从左到右的方向,桩身位移首先增大,随后减小,最终趋于平缓。在距基坑底部1/6位置,沿着基坑从左到右的方向,桩身位移呈先增大后减小的趋势。桩身位移峰值随着地面荷载增大呈曲线型。排桩排数越少,桩身位移峰值变化幅度越大。

Taking the foundation pit of a subway station as the research object,through the indoor model test,the horizontal displacement law of the supporting structure during the construction of the subway station is analyzed,and the deformation of the supporting structure under three different row conditions is compared,and the influence of the number of row piles on the deformation of the supporting structure is obtained.The research shows that the pile displacement increases along the depth of the foundation pit.Specifically,the row piles at the left edge of the foundation pit decrease first and then increase under small load,and increase first and then decrease under large load;The row piles in the middle of the foundation pit increase slowly and then accelerate;The row piles at the right edge of the foundation pit increase rapidly under small load and gently under large load.At the position 1/6 away from the top of the foundation pit,along the direction from left to right of the foundation pit,the pile displacement increases first and then becomes stable;At the position 1/2 away from the top of the foundation pit,along the left to right direction of the foundation pit,the pile displacement first increases,then decreases,and finally tends to be flat.At the position 1/6 away from the bottom of the foundation pit,the displacement of the pile body increases first and then decreases along the direction from left to right of the foundation pit.The peak value of pile displacement shows a curve with the increase of ground load.The smaller the number of rows of piles,the greater the variation range of the peak displacement of pile body.