Hydraulic heave: new findings

The contribution presents the results of investigations for the verification of hydraulic heave for excavations in front of walls with small embedment in the ground and with filter layers at the excavation side of the wall. For this case numerical groundwater flow computations show that there are significant vertical flow components below the wall which have to be considered in the verification of hydraulic heave. Based on the flow computation a procedure is presented to calculate the required height of the filter depending on the distance to the wall. This is compared with commonly used approaches. Furthermore, on the basis of this procedure, the integration of safety factors in accordance with DIN 1054 and of friction forces within the filter are explained.