The　TBM　tunneling　process　in　hard　rock　is　actually　a　rock　or　rock　mass　breakage　process,　which　determines　the　efficiency　of　tunnel　boring　machine　(TBM).　On　the　basis　of　the　rock　breakage　process,　a　rock　mass　conceptual　model　that　identifies　the　effect　of　rock　mass　properties　on　TBM　penetration　rate　is　proposed.　During　the　construction　of　T05　and　T06　tunnels　of　DTSS　project　in　Singapore,　a　comprehensive　program　was　performed　to　obtain　the　relevant　rock　mass　properties　and　TBM　performance　data.　A　database,　including　rock　mass　properties,　TBM　specifications　and　the　corresponding　TBM　performance,　was　established.　Combining　the　rock　mass　conceptual　model　for　evaluating　rock　mass　boreability　with　the　established　database,　a　statistical　prediction　model　of　TBM　penetration　rate　is　set　up　by　performing　a　nonlinear　regression　analysis.　The　parametric　studies　of　the　new　model　showed　that　the　rock　uniaxial　compressive　strength　and　the　volumetric　joint　count　have　predominantly　effects　on　the　penetration　rate.　These　results　showed　good　agreement　with　the　numerical　simulations.　The　model　limitations　were　also　discussed.　(C)　2008　Elsevier　Ltd.　All　rights　reserved.