基坑施工对地铁隧道影响的数值试验研究

NUMERICAL TESTS FOR THE INFLUENCE OF FOUNDATION PIT ON SUBWAY TUNNEL

为进一步研究基坑施工对地铁隧道的影响规律,文中分别建立了邻近和上跨两种位置关系的数值试验模型,分析了不同水平距离、隧道埋深、基坑加固、围护结构厚度等影响因素下基坑开挖对隧道变形的影响,总结了隧道位移变化规律。研究表明隧道位移与基坑邻近隧道的水平距离近似线性关系;隧道埋深对隧道水平和竖向位移变化影响不同;基坑加固对邻近隧道位移的改善程度与基坑和隧道的相对位置关系有关;围护结构厚度与隧道位移成线性关系,增加围护厚度可控制隧道位移;基坑上跨时,隧道与基坑水平和竖向距离对上部隧道位移存在明显影响,隧道越靠中心,水平位移越小,竖向位移越大。

In order to further study the impact of foundation pit construction on subway tunnels,two numerical ex⁃perimental models are established for the adjacent and upper span positions.The effects of foundation pit excavation on tunnel deformation are analysed under different horizontal distances,tunnel burial depth,foundation pit reinforce⁃ment,and enclosure structure thickness.The displacement variation of tunnels is summarized,indicating that there is an approximate linear relationship between tunnel displacement and the horizontal distance of adjacent tunnels to the foundation pit.The influence of tunnel burial depth on the horizontal and vertical displacement changes of the tunnel is different.The degree of improvement in displacement of adjacent tunnels by soil reinforcement is related to the relative position relationship between the foundation pit and the tunnel.The thickness of the enclosure structure is linearly related to the tunnel displacement,and increasing the enclosure thickness can control the tunnel displace⁃ment.When the foundation pit is crossed,the horizontal and vertical distance between the tunnel and the foundation pit has a significant impact on the displacement of the upper tunnel.The closer the tunnel is to the centre,the small⁃er the horizontal displacement and the larger the vertical displacement.