Abstract: When the tunnel crosses fractured zone and faults, overlarge tunnel structural deformation and even collapse often occur. As a result, the onsite monitoring data of a deepburied tunnel lining crossing fractured zone in southwest China are analyzed. And based on numerical simulation experiments, the laws of tunnel crown settlement and peripheral convergence are studied, and comparison is made between the two laws. The results show: (1) Uneven settlement occurs to the transition zone between Grade Ⅳ and Ⅴ surrounding rocks, and the settlement of Grade Ⅴ surrounding rock is 15 mm larger than that of Grade Ⅳ surrounding rock. (2) The settlement of tunnel crown is about 1.25~1.75 times of the peripheral convergent displacement, which indicates that the sensitivity of the tunnel crown to the uneven settlement is greater than peripheral area, and the tunnel crown is the weak part of the tunnel structure. Based on the selfdeveloped twoway sliding physical model box, the deformation properties of lining under the condition of uneven settlement are studied. The study results show that the tunnel lining deformation under uneven settlement can be roughly divided into five stages, i.e. elastic strain stage, soil compactionattitude adjustment stage, plastic strain stage, soil recompactionattitude adjustment stage, and fracture failure stage; the tunnel crown axial deformation of each section is about 1.75~2.45 times of the peripheral convergence, which also shows that the sensitivity of the tunnel crown to environmental variation is greater than that of peripheral convergence, and monitoring and protection should be carried out for tunnel crown. 

Key words: tunnel, fractured zone, deformation properties, insitu monitoring, model test, numerical simulation