Mechanical behavior of ground due to EPB shield TBM tunnel excavation passing through fractured zone

초록

Recently, tunneling with shield tunnel boring machine (TBM) is getting popular for the construction of cable tunnel in urban area. Mechanized tunneling method using shield TBM has various advantages such as minimization of ground settlement and prevention of vibration induced by blasting that should be accompanied by conventional tunneling. In Korea, earth pressure balance (EPB) type of shield TBM has been mainly used. Despite the popularity of shield TBM for cable tunnel construction, studies on the mechanical behavior of cable tunnel driven by shield TBM passing through the fracture zone are insufficient. Thus, in this study, three dimensional numerical modelling of EPB shield TBM is presented. And, the effect of fractured zone ahead of tunnel face on the mechanical behavior of composite ground consisted with soil, weathered soil, weathered rock and fractured zone is investigated. The critical orientation of fractured zone ahead of tunnel face is derived based on the results obtained from the 3-dimensional numerical analysis.