关键词: 深水基坑, 锁口钢管桩, 锁口处理, 设计与计算

Abstract: The pile cap of 888#pier of Beichen Bridge has large foundation pit depth,complex geological conditions and great difference in soil thickness around the pit.Due to the tight construction period,combined with a variety of factors for analysis,the large diameter locking steel pipe pile cofferdam scheme is finally selected.The locking form of steel pipe pile is optimized,and the locking form of square pipe and I-beam is adopted.At the same time,in order to prevent water seepage in deep pits,fiber bag grouting measures are adopted in the locking mouth.In addition,in order to obtain the actual working state of the cofferdam,the simulative calculation of the main structure of the cofferdam was carried out using the Venus Foundation pit software.The calculation results show that the stress,displacement and stability of the cofferdam structure all meet the requirements.The deformation is highly consistent with the calculated value,indicating that the calculation of the cofferdam is accurate and reliable.Construction practice shows that the optimized lock form combined with the lock grouting measures has a good water stop effect during the support of the 11mdeep water foundation pit,which ensures the smooth operation of the foundation pit bottom sealing and the construction of the bearing platform.