The Key Construction Technology Study On The Heavy-Load Railway Tunnel In Soft-Hard Layer Stratum

Many factors need to be taken into account in tunnel construction, and the most foundamental one is geological environment due to its uncertainty and complexity. The casualty caused by tunnel construction is preminent. So choosing appropriate construction methods can guarantee the safety of tunnel structures and reduce the disturbance of surrounding rocks.For the engineering of Linxian Tunnel designed for heavy load transportation, it crosses soft-hard layer with shallow buried depth and large section, which will bring about extreme construction difficulties and safety risks. Combined with the difficulties and charateristics of tunnel design and construction methods associated with the geological analysis, research had been done on the basis of therotical analysis manily in the following aspescts:(1)According to the geological condition, the safty of tunnel structures under uneven pressure and the rock’s damage Pattern were analyzed, and also the key influencing factors;(2)Combined with the construction method, systematically on the feasibility of blasting control technology under different soft-hard layer were studied;①The minimum layer height between the soft-hard interface and tunnel vault when the interface beyond the tunnel were obtained;②The influence of blasting vibration on tunnel structures and surrounding rocks when the interface intersect the tunnel were analyzed;(3) The diseases of railway tunnel were studied and the possible reason were put forward; the numerical simulation technology of vehicle load were determined through therotical analysis; the long-term effects on tunnel and rocks were analyzed by simulation in FLAC3D; and the possible damage loci on the basis of fatigue theory were predicted.