ABSTRACT
As the growth of underground space development, dense urban infrastructure clusters confront challenging geological environments increasingly often. For instance, over-excavation or insufficient support has serious ramifications on existing tunnels. Understanding the interaction between the existing tunnel and a new tunnel ensures the safety of the infrastructures. This study utilized a centrifuge modeling test to investigate strain responses of an existing tunnel caused by the instability of a new tunnel, a trapdoor was dropped from 0 - 1.8 m (in prototype scale) with 100 g centrifugal acceleration. The trapdoor widths were 1, 2, 4, and 6 m. The tunnel exhibited predominant tensile forces near the center and pressure at the ends. The maximum tensile strain increased with the trapdoor width. The strain was 2.5 e-4 at 2 m and 6.5 e-4 at 6 m, which might cause concrete cracking.
