基坑施工对地铁隧道影响的模拟分析

Numerical modeling analysis of influence on metro tunnels due to excavation of foundation pit

文章以宁波轨道交通某区间隧道旁基坑开挖为实际背景开展模拟探究,分析了地铁隧道位移和应力的变化规律,探讨了隧道--基坑水平净距、隧道埋深、基坑地连墙厚度、基坑钢筋混凝土支撑的尺寸、基坑坑底是否加固等因素对地铁隧道的影响。结果表明:随基坑开挖深度的增大,隧道位移和应力的最大值均呈增大趋势;各影响因素中,隧道--基坑水平净距和隧道埋深对隧道位移和应力影响较大;地铁隧道控制保护,应重点考虑基坑--隧道水平净距、隧道埋深及基坑开挖深度等因素。

In the engineering background of foundation pit which is next to Ningbo rail transit＇s tunnels, numerical simulation study was carried out. The variations of metro tunnel displacement and stress were analyzed. Then the influences of horizontal clearance between metro tunnel and foundation pit, tunnel depth, thickness of underground continuous wall, size of reinforced concrete brace and foundation bottom consolidation on metro tunnel were explored. The results show that the maximum of tunnel displacement and stress increases with the increase of excavation depth. The horizontal clearance between metro tunnel and foundation pit and the tunnel depth have a great influence on tunnel displacement and stress. In metro tunnel control and protection, horizontal clearance between metro tunnel and foundation pit, tunnel depth and foundation pit excavation depth should be mainly considered.