Study On The Key Technologies For Tunnel Construction In Shallow-buried And Crumbly Strata

With the constant progress of the society, to construct the resource-saving andenvironment-friendly engineering has become the dominant ideology, so as to implementscientific outlook on development and sustainable development. The tunnel engineering keepan increasingly high proportion in highway projects as the tunnel has some advantages onovercoming the terrain obstacles, saving land resource, making project comfortably to nature,and reducing ecological damage. For replacing the high slope and deep excavation, thenumber of the tunnel engineering in shallow-buried and crumbly strata is increasing sharply.And so, the study on the key technologies for tunnel construction in shallow-buried andcrumbly strata becomes one of the engineering problems demanding prompt solution.Base on the Guojiachuan No.2tunnel engineering on Gao (Ping)-Ling (Chuan) Highwayin Shanxi Province and the traffic science and technology projects “Study on the criticaltreatment technology for highway tunnels traversing crumbly strata and mined-out area” ofShanxi department of transportation, the paper mainly study the key technologies for tunnelconstruction in shallow-buried and crumbly strata by theoretical analysis, numericalsimulation and field measurement methods.(1) The combined lining support method was presented for solving the problems ofprimary support large deformation in tunnel entrance excavation in shallow-buried andcrumbly strata, on the base of the primary support deformation mechanism analysis bymonitoring measurement, theoretical calculation and numerical simulation. The combinedlining support method was proved to be significantly effective through the comparison ofmonitoring data.(2) For control the primary support deformation of the tunnel in shallow-buried andcrumbly strata, the triple breadth invert construction method was presented after analyzingand comparing the characteristics of the different invert construction methods. The goodapplication effect of this method was proved through a systemic and deep analysis for thecharacteristic, as well the contrast of numerical simulation and on-site monitoring.(3) For the tunnel engineering in shallow-buried and crumbly strata, the paper alsosummarized and analyzed the primary support deformation mechanism, the strengthening and emergency response plan, the treatment scheme for invading lining boundary, as well theadvantages and disadvantages of the treatment measures. This provides a reference for dealingthe primary support large deformation of the Guojiachuan No.2tunnel.(4) On the base of analyzing the influencing factors of tunnel collapse in shallow-buriedand crumbly strata, the paper presented some collapse prevention methods. At the same time,the dealing methods for the small collapse, large collapse and collapse at the entrance sectionwere put forward according to the collapse size and position. At last, the reasonable collapsetreatment methods for the Guojiachuan No.2tunnel were developed, that ensure the tunnelwas constructed successfully.