Design Aid for the Verification of Resistance to Failure by Hydraulic Heave

For the determination of the required embedded length for the safety against hydraulic heave several approximate solutions exist. However, most of these solutions do not take into account the geometrical boundary conditions such as width B and length L of the excavation as well as the thickness of the aquifer S. Thus, values obtained by such simplified approximate solutions can easily lead to an unsafe design. For this reason investigations on the safety against hydraulic heave have been carried out at the Chair of Geotechnical Engineering at RWTH Aachen University. From the results of numerous calculations dimensionless design charts have been generated. With the help of these design charts the required embedded length T can be determined quite easily taking into account the difference of the ground water level H, the geometrical boundary conditions of the excavation and the unity weight of submerged soil γ’.