Tunnels　constructed　in　loose　deposits　with　low　strength　and　complex　composition　are　usually　subjected　to　asymmetrical　stresses　at　the　entrance　and　exit.　The　secondary　tunnel　lining　is　prone　to　excessive　deformation,　cracking,　or　even　collapse,　seriously　affecting　the　safety　of　tunnel　construction　and　operation.　In　this　paper,　a　large　shallow　highway　tunnel　in　loose　deposits　is　used　as　an　example　to　study　the　cracking　mechanism　of　secondary　lining.　Triaxial　consolidated-drained　shear　tests　are　carried　out　on　large　remolded　specimens　to　obtain　the　mechanical　parameters　of　the　surrounding　soil.　Three-dimensional　numerical　modeling　is　conducted　based　on　the　field　monitoring　data　to　simulate　the　process　of　tunnel　construction　and　to　analyze　the　mechanical　mechanism　of　cracking　in　the　secondary　lining.　It　is　shown　that　even　with　the　30　m　advance　pipe　roof　at　the　tunnel　entrance,　the　apparent　difference　in　stiffness　between　the　retaining　wall　and　the　surrounding　soil　results　in　an　obvious　stress　concentration　at　the　spring　of　the　secondary　lining　near　the　end　of　the　retaining　wall,　due　to　the　effect　of　highly　asymmetrical　stresses.　In　addition,　loose　deposits　are　very　sensitive　to　construction　disturbances.　Large　horizontal　deformation　towards　the　lower　topography　occurs　during　tunnel　construction.　With　increasing　overburden　depth,　the　stress　concentration　at　the　spring　level　and　the　horizontal　deformation　in　the　secondary　lining　increases,　which　are　the　main　reasons　for　cracking　in　the　secondary　lining.　These　findings　can　be　useful　for　tunnel　design　and　construction　in　the　similar　type　of　loose　deposits.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.