基于组合权重与灰色关联度分析法的地铁深基坑开挖稳定性评价

Stability Evaluation of Deep Foundation Pit of Metro Based on Grey Correlation Analysis with Combined Weights

伴随着城市的快速发展,地铁深基坑工程越来越多。在开挖过程中如何对其稳定性进行评价,是当前需要重点关注的问题。以成都地铁十七号线凤溪站深基坑支护开挖工程为依托,利用层次分析确定的主观权重与利用熵值法确定的客观权重计算获得组合权重,并与灰色关联度分析法相结合,通过现场数据采集并进行综合评判,客观评价地铁深基坑开挖的稳定性。结果表明,各监测项目对基坑稳定性的重要程度从大到小依次为桩顶水平位移(0.29)、地表沉降(0.24)、建筑物沉降(0.19)、桩顶沉降(0.18)、内支撑轴力(0.10),基坑稳定性综合评判结果等级为"非常好"。所建立的评价模型可为类似地铁深基坑开挖稳定性评价提供新的方法。

Because of many risk factors, the stability of deep foundation pit of metro is highly demanded during excavation. Especially in the water-rich gravel stratum and near the existing metro line, it is extremely necessary to make an accurate evaluation of the stability of foundation pit in excavation. The authors took Fengxi station deep foundation pit project of Chengdu Metro Line 17 as the research object, by using the combined weight obtained by using the subjective weight determined by AHP and the objective weight determined by entropy method with the grey correlation method, and objectively evaluated the stability of foundation pit in the excavation through the fuzzy comprehensive evaluation of the monitoring data of the sections around the foundation pit. The evaluation results show that the importance of foundation pit stability to each monitoring project from large to small is horizontal displacement of pile on the top(0.29), ground settlement(0.24), building settlement(0.19) settlement of pile on the top(0.18),and internal support axial force(0.10). The comprehensive evaluation result of the foundation pit stability is very good. The evaluation model can provide reference for the construction of deep foundation pit and risk control in Chengdu area.