case study: influence of artificial mountain construction with isolation piles on underpass tunnels

This paper presents a case study of an artificial mountain construction in zhengzhou, china. two roads under the designed artificial mountain had to be transformed into tunnels to make sure the normal operation of traffic. in this project, isolation piles were installed to control the horizontal displacement of the tunnels. to evaluate the deformation behavior of tunnels with isolation piles, the field monitoring data were obtained and analyzed. then, a flac3d model was built and the simulation result of tunnel horizontal displacement was compared to the field data. field monitoring data show that the settlement of the tunnels was greatly influenced by the distance between the tunnels and the main mountain. the crosswise differential settlement of tunnels was dominated by the height difference among mountains. the isolation piles have a significant effect on the horizontal displacement of the tunnels, which reduce the horizontal displacement by more than 40%. however, the pile-tunnel spacing has little effect on the horizontal displacement of the tunnels. these results could be reference for similar projects in future.