董 鹏， 李唱唱， 王正中， 刘 彪， 刘铨鸿， 马清瑞.引汉济渭二期高地下水位盾构隧洞渗流应力耦合研究Journal of Water Resources and Water Engineering[J].,2022,33(4):202-209
引汉济渭二期高地下水位盾构隧洞渗流应力耦合研究
Seepage-stress coupled simulation of shield tunnelling of the Hanjiang to Weihe River Valley Water Diversion Project Phase Ⅱ under high groundwater level
Bailuyuan tunnel is a part of the Hanjiang to Weihe River Valley Water Diversion Project Phase Ⅱ, which is characterized by its deepest buried depth and highest groundwater tale in the Loess Plateau area, the feasibility and safety of its shield tunnelling excavation are not clear. Thus, the section with the buried depth of 282.22 m in Bailuyuan tunnel was selected for the 3-D simulation of shield tunneling excavation using Mohr-Coulomb elastoplastic constitutive model and the stiffness migration method with the application of ABAQUS software. The variation of pore water pressure, stress deformation, plastic zone in surrounding rock and displacement of lining of the typical section during the excavation phase were analyzed emphatically. The results show that with the progress of the excavation, the pore pressure decreased first then steadily rose to a stable state. Excess pore water pressure occurred at the section which was 3.6 m away from the front edge of the shield tunnelling face because the section started to shrink, and its maximum value nearly reached 248.0 m. The deformation of the tunnel involved convergence around the tunnel, subsidence at the crown and heave at the invert. The stress, strain and radial displacement of the surrounding rock were symmetrically distributed. Since equivalent plastic strain mainly occurred within 3 m at the spring line of the tunnel but no obvious plastic zone above the invert, the most likely failure mode would be the collapse of surrounding rock at the sides of the tunnel. During the construction phase, the dominant stress of the lining both at the inner diameter and outer diameter was compressive stress, and its maximum value was 18.77 MPa; whereas tensile stress occurred at the crown and invert of the lining outer diameter, as well as the side wall of the lining hance, which was only about 0.85 MPa. Both stresses met the requirements of compressive bearing capacity and tensile strength for the lining. The results could provide a reference for the safe operation and disaster prevention of the Hanjiang to Weihe River Valley Water Diversion Project Phase Ⅱ.