双环形内支撑在邻近地铁深基坑工程中的应用

Application of the Double-Circle Internal Support on a Deep Excavation near the Metro Alignment

以中海油(深圳)总部大厦基坑为例,介绍了深圳填海区邻近地铁的深基坑工程设计思路。该工程采用"咬合桩+双环形内支撑"的方案,借助PLAXIS软件对其围护支撑体系的受力机理和周边环境的变形规律进行了研究和探讨。通过数值计算与监测结果对比发现,双环形内支撑支护体系在节省工期的前提下,能较好地满足周边环境的高要求。

The internal support system has a wide applications in various deep excavation engineering projects. This paper presents the deep excavation support case history of the Shenzhen Headquarter Building of China National Offshore Oil Co. （CNO- OC）. The design approaches of deep excavation near the metro alignment are presented. The secant pile combined with the double-circle internal supporting system is adopted in this project. Using the popular geotechnical commercial software PLAX- IS, the mechanical behaviors and the deformation characteristics of the retaining structure and internal supports are thoroughly investigated. In comparison of the computational and the construction monitoring results, it is demonstrated that the design approach of the ＂double-circle internal supporting system＂ can not only meet the retaining structure safety requirements and cost effectiveness but also satisfy the demanding requirements of the adjacent surrounding structures and facilities.