(1. Shenzhen Geotechnical Investigation and Surveying Institute Co.，Ltd.，Shenzhen，Guangdong 518028，China；
2. School of Mechanics and Architecture Engineering，China University of Mining and Technology，Beijing 100083，China)
Abstract：In the construction of the extra-deep foundation pit of Shenzhen Ping?an Financial Center，the maximum excavated depth is over 30 m and the minimum distance to metro structures is just 5.3 m. Some of the super-large digging piles will be constructed subsequently with the top opening diameter of 9.5 m. The maximum depth for piles construction is 68 m below the ground surface. Therefore，it is key to consider and control the settlement of metro structures during the pile construction. Based on the actual construction conditions，the three-dimensional numerical simulation method was used for analysis of digging piles construction. Hereby，a series of significant countermeasures were proposed and performed before pile constructions to reduce the excessive settlement，such as high-pressure jet grouting and curtain grouting according to geological conditions. The settlement values monitored increased slightly and matched well with the predicted results after the completion of digging piles，which indicates a better controlling of metro structure deformation contributed by the effective countermeasures.
2012, Vol. 31 
