Study on parameters of articulated design of tunnel lining under reverse fault dislocation

Based on the fault crossing situation of Xianglu mountain tunnel of water diversion project in central Yunnan province, the axial mechanical response of the lining was calculated by FEM. It was found that the influence of the fault movement on the lining is concentrated on 30 m in each side of the fault plane. The segment length and the width of the flexible joints of the articulated design were determined tentatively based on the distribution of the bending moment along the axial direction. The orthogonal test was conducted to investigate the influencing degree of the main factors and their different levels on the internal force of lining. Finally, the optimal combination for articulated design was obtained by range analysis. The results showed that the articulated design is an effective measure to accommodate the displacement of fault dislocation by the deformation. Moreover, the internal force of lining can be significantly reduced. The maximum reduction of bending moment, shear force and axial force are over 80%. Aiming at flexible material, the advantages and disadvantages of fiber-plastic concrete and high-performance foam concrete in strength and permeability were compared. It was concluded that the fiber-plastic concrete with a certain elastic modulus, good impermeability and higher tensile strength can be used as a flexible material for articulated design. The general regularity of this paper can provide some reference for the design of tunneling across fault zone. © 2018, Science Press. All right reserved.