ABSTRACT
The maximum pressure that can be exerted on the tunnel front of slurry shield TBM or on the grout of the lining is investigated for a tunnel in sand. There is quite a scatter in the ratio between the maximum pressure and the effective stress as a function of the liquid properties, the flow rate etc. However, comparing a field test with results of centrifuge tests and DEM (Discrete Element Calculations) it was possible to derive some trends. Hydraulic fracture of the soil can occur when the applied pressure on the liquid is more than 2 times the effective stress in a homogeneous soil.
