Application Ranges of EPB Shield TBM in Weathered Granite Soil: A Laboratory Scale Study

Soil conditioning is a key factor in increasing tunnel face stability and extraction efficiency of excavated soil when excavating tunnels using an earth pressure balance (EPB) shield boring machine (TBM). Weathered granite soil, which abundant the Korean Peninsula (also Japan, Hong Kong, Singapore), has different characteristics than sand clay; it also particle-crushing characteristics. Conditioning agents were mixed with weathered soils individual particle-size gradations, three (workability, permeability, compressibility) evaluated to find optimal method. The lower upper bounds water content that are needed for well-functioning EPB TBM proposed. Through trial-and-error experimental analysis, was confirmed foam only possible controlled within allowable range, is, between bounds; exceeded bound, solidification along foam. By taking advantage feasible adopt even extremely coarse cohesionless by polymer slurries Finally, application ranges proposed; newly proposed wider expanded coarser zones compared those so far.