The purpose of cofferdam is to isolate the application area from the outside soil and / or water. There is usually no need to drain water completely, which is not possible in some cases, but water must be taken into account in the calculation.
For the basement structural designer should be sheet piling
cofferdam and permanent structure combined to consider. The use of sheet pilings as a permanent structural wall can greatly reduce the duration and cost, and the wall can be designed to withstand the vertical load. Adequate seepage Control can be achieved with a suitable sealing system.
For the surface sedimentation control requirements of the region should be considered more stringent reverse method. The purpose of this is to displace the top of the pile prior to excavation by the support of the ground, and to eliminate the additional displacement of the lateral earth pressure Transmitted to the main structure after the temporary support is removed.
There are two basic types of sheet piling cofferdam, the most common of which are single row cofferdam, but for large scale or deep excavation engineering and ocean engineering, double cofferdam or gravity type cold-formed steel plate Pile cofferdam is more suitable.