Abstract: The hydro-mechanical (H-M) coupled numerical simulation was conducted for the prediction of the tunneling construction in water-rich areas using the earth pressure balance (EPB) shield. First, a zone state index (ZSI) was established based on the achievements of other scholars. Then, the yield approach index and failure approach index was unified to safety evaluation system (negative values mean failure), which achieved a complete expression of elastic, yield and failure states. By combining the strain-permeability equation with ZSI, the variable of permeability coefficient was calculated during the coupled process, which made up for the deficiency of permeability coefficient in FLAC3D seepage simulation. Taken the 202 section of Dalian Metro, Xianggong street station to Shahekou railway station, as an example, the H-M coupled numerical simulation was realized by using program in FISH language. The deformation and failure characteristics of excavation face and surrounding rock during tunnel excavation were analyzed. The stability of excavation face was further evaluated according to numerical results of ZSI. The results indicate that the proposed method can be used to well simulate and analyze the H-M coupling process, which are in good agreement with measured results.

Key words: hydro-mechanical coupling, shield tunnel, excavation face, zone state index, FLAC3D