In practice there are different processes which are used to support excavations and to maintain the groundwater level in excavations which go down to this level. In urban areas the diaphragm wall is frequently used to protect the excavation and as underground water packing against groundwater flowing in from the side. In addition, the lowering of groundwater is necessary using a well point within the excavation. A new foundation trench sheeting has been developed by the author of this paper. This new method is an improvement on the diaphragm wall by which not only is the earth shored up, but the lowering of the groundwater within the excavation can also be carried out. In accordance with the function of this method, we refer to the new type of foundation trench sheeting as drainage walling. This drainage walling is manufactured in a similar way to the diaphragm wall. We have observed drainage walling on building sites which differ greatly from each other. The results of our observations are intended to demonstrate the advantages and also the problems involved in this new process to the planning and project engineers
