开挖方案对紧邻地铁深基坑施工风险影响分析

Effects of Excavation Sequences on the Construction Risk of Super-deep Foundation Pit Adjacent to Metro Tunnels

以上海地区某紧邻地铁枢纽的超深基坑作为分析对象,着重讨论不同开挖方案对紧邻地铁的超深基坑施工风险的影响,以土体和支护墙体的位移以及基坑稳定性等作为考察的主要指标。采用模糊综合评判法对该基坑工程进行施工风险分析,并将基坑自身风险和周边的环境风险作为整体来考虑,从风险定量的方面来比较不同开挖方案的差异。分析结果表明,对于复杂的基坑工程,选择合理的开挖方案非常重要,可以明显地降低施工风险。

A super-deep foundation pit adjacent to metro tunnels is treated as the analytic object. This paper focuses on the effects of different excavation sequences on the ultra-deep foundation pit construction adjacent to the metro tunnels. Displacements of soil and retaining structures and the stability of foundation are considered as the main factors index. Fuzzy comprehensive evaluation method is adopted to analyze the construction risk of deep excavation. The risks of foundation and surrounding environment are taken into consideration as a whole system. The difference of different excavation sequences is analyzed with quantitative risk analysis. The results show that it is important to choose a reasonable excavation sequences for complex excavation which can reduce the risk of construction obviously.