In this study, the stress and strain variations of an existing tunnel according to adjacent tunnel excavation have been evaluated via laboratory model testing. Since the tunnel has been a typical structure under the plain strain condition, the laboratory model tests were conducted using carbon rods which represents a weathered rock geometry. The stress and strain (deformation and rotation) variations of an existing tunnel model due to adjacent ground relaxation have been assessed with embedded load transducers and particle image velocimetry (PIV) analysis. Different vertical and horizontal spacing conditions between the ground relaxation (tunneling) point and the existing tunnel location were considered. The simultaneous load and PIV analyses data clearly verifies the acceptable construction guide for adjacent tunneling in weathered rock stratum.
