Abstract: Chiseling operations in an operating tunnel lining defect treatment process have various disadvantages, such as low mechanization, high labor consumption and intensity, prolonged time-window occupation, discontinuous chiseling, and incomplete target-area coverage. To address these issues, existing pipeline layouts, application status of mechanized chiseling devices, and chiseling construction needs in railway tunnels are investigated and analyzed to propose a novel chiseling trolley that achieves continuous, circumferential, mechanized chiseling construction for tunnel lining. The proposed trolley integrates a multidegree-of-freedom robotic arm and a continuous milling and chiseling device to realize a novel continuous chiseling technique for tunnel lining, which can well fit the tunnel profile. The trolley exhibits various advantages, including automatic tracking and recovery of concrete debris, self-planning of chiseling paths with anticollision detection, and multiple emergency recovery mechanisms. The trolley is applied to the tunnel lining reinforcement construction of a railway quality improvement project. The application results indicate the following. (1) Compared with the existing pneumatic impact chiseling method, the proposed trolley enables continuous circumferential milling and chiseling of tunnel linings, along with automated dust and debris recovery. (2) Compared with traditional manual handheld electric hammer operations at scaffolds, the labor consumption can be reduced from 30－35 to 10－12 and the chiseling efficiency can be improved from 10 to 40 m²/h, construction efficiency is improved by more than two times that of traditional chiseling, with half the labor consumption.

Key words: operating railway tunnel, lining surface chiseling, chiseling trolley, continuous circumferential milling