Hydraulic heave - new design formula for the embedded length

摘要

To determine the embedded length of a building pit wall which is required for the safety against hydraulic heave flow nets can be evaluated. This procedure usually requires an iterative process including several extensive 3D ground water flow calculations. Hence, a couple of approximate solutions have been developed. However, these solutions can lead to unsafe results as they do not consider fundamental boundary conditions. Thus dimensionless design charts have been generated based on numerical flow calculations. The design charts enable the quick and easy determination of the required embedded length considering different boundary conditions (e.g. width and length of construction pit, thickness of aquifer, unity weight of soil, anisotropy, soil stratification) and the safety level according to Eurocode 7-1 and to the German National Annex DIN 1054 respectively. In addition to the design charts an overall formula for various soil and boundary conditions for the design in homogenous, isotropic soil has been developed.