紧邻既有航站楼基坑工程降水设计及风险控制

Dewatering Design and risk Control of Foundation pit Adjacent to Existing Terminal Building

杭州萧山国际机场扩建基坑开挖项目紧邻现有的航站楼,其中大面积的深基坑开挖势必会影响到机场的正常运行。为了使机场在施工阶段正常运行,本工程采用压力平衡理论中的基坑大面积开挖公式,验证了基坑底板抗突涌稳定性,得到抗突涌稳定性安全系数为1.1。根据基坑内外止水帷幕设计深度的不同,制订真空疏干井布置方案,提出降水井井身设计要求。参照国家规范和浙江地区规范的验算要求,测算因降水引起的地面沉降量,并据此设计了风险控制方案。同时,在确保基坑施工安全的前提下,保证现有机场航站楼的不停航运行。

The foundation pit excavation project of Hangzhou Xiaoshan International Airport is adjacent to existing terminal building,and excavation of a large area of deep foundation pit will inevitably affect normal operation of the airport.In order to make the airport run continuously during construction stage,formula of large area excavation of foundation pit in theory of pressure balance is adopted to verify stability of foundation pit floor against inrush for this project,and safety coefficient of the stability against inrush is 1.1.According to different design depths of waterproof curtain inside and outside foundation pit,the layout plan of vacuum dredging well is formulated,and the design requirements of dewatering well are put forward.The ground settlement caused by precipitation is calculated according to checking requirements of National standard and Zhejiang standard,and risk control scheme is designed accordingly.At the same time,under the premise of ensuring the safety of foundation pit construction,the existing airport terminal non-stop operation is ensured.