This　paper　presents　a　study　on　the　mechanical　behavior　in　a　long　pipe　roof　during　excavation　of　a　shallow　bias　highway　tunnel　in　loose　deposits.　The　mechanical　parameters　of　the　surrounding　soil　were　obtained　by　triaxial　consolidated-drained　shear　tests　on　large　reconstituted　specimens.　Three-dimensional　numerical　modeling　was　conducted　to　simulate　the　tunnel　construction　process.　Six　typical　construction　stages　were　simulated　to　analyze　the　effects　of　tunnel　support　elements,　topographic　and　geological　conditions　on　the　mechanical　behavior　of　the　pipe　roof.　The　modeling　results　revealed　the　variation　of　force　and　bending　moment　distribution　in　the　pipe　roof　during　excavation.　Three　main　conclusions　were　drawn:　(1)　for　the　shallow　and　asymmetrically　loaded　tunnel　buried　in　loose　deposits,　a　pipe　roof　at　the　entrance　can　effectively　reduce　the　stresses　and　asymmetric　loading　between　the　tunnel　support　elements　and　enhance　the　tunnel　safety　during　construction;　(2)　because　of　asymmetrical　stresses,　the　umbrella　arch　could　shoulder　much　of　the　axial　force　of　the　pipe　roof　and　the　protection　arch　could　reduce　the　force　on　the　pipe　roof　effectively;　(3)　influenced　by　the　asymmetric　topography,　the　maximum　force　and　bending　moment　in　the　pipe　roof　occurred　mainly　in　the　upper　right　tunnel　heading.　As　the　stiffness　of　the　retaining　wall,　protection　arch,　umbrella　arch,　and　the　surrounding　loose　deposits　were　different,　the　force　and　bending　moment　distribution　in　the　pipe　roof　was　highly　non-uniform　during　excavation.　The　simulation　results　should　be　significant　both　for　the　pipe　roof　design　and　the　construction　of　other　tunnels　in　similar　geologic　conditions.