EPBM excavates in gravel stratum

whose ground water level is high. The soil excavated in chamber has big permeability coefficients

and is poor in flow ability. It is difficult to apply the support earth pressure to the working face due to the permeation of groundwater. Soil conditioning is a way of adjusting the soil condition in pressure chamber and increasing support earth pressure

which can decrease the permeability and increase the flow ability. The three-dimensional fast Lagrangian differential finite element method which can reflect the large strain of material is utilized to study the contribution of soil conditioning to face stability. The relationship between soil permeability decreasing and support pressures is analyzed. Some results from simulation are given for controlling face pressure.