The decision on which tunneling method to use is essentially based on the lithological characteristics of the crossed soil. Earth pressure balanced (EPB) shields are now the most widely used technology because they can operate in a much broader spectrum of lithological conditions and do not require expensive additional equipment. The soil permeability for EPB drives can reach either values of up to k  =  10−3 m/s for the most porous soils (BPNL Lyon-Turin) and/or it can come down to practically impermeable clay (Heathrow T5) (Langmaack and Feng, 2005). With EPB shields, the cohesive soil loosened by...

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