Loess is characterized by significant anisotropy,high permeability and wet sinkability.In this paper,the ani-sotropy and deformation characteristics of in-situ loess in the project area were investigated by physical properties test,consolidation compression,wet sink test and triaxial shear test of in-situ loess based on Coke Bay loess tunnel project.Using numerical simulation finite element software,the settlement deformation trend in the construction of loess tunnel was compared and analyzed under the conditions of different excavation methods,different lengths of o-verrunning small conduits,different lengths of locking foot anchor tubes and surface grouting.The results show that:1)there are obvious differences between the mechanical indexes of loess in vertical and horizontal directions,and the natural compression modulus in vertical direction is smaller than that in horizontal direction;2)considering various factors,it is recommended to use two-step and five-step construction method assisted by 4.5 m of overrun-ning small conduit and 5 m of locking foot anchor pipe;3)the protective effect of surface grouting on settlement de-formation of tunnel and oil pipeline is not obvious.
维普
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