Tunnel deformation monitoring based on laser distance measuring and vision assistant

摘要

Full Face Rock Tunnel Boring Machine (TBM) has been applied in many underground tunnel projects. During the operation, the safety of the TBM is one of the major concerns in the construction project. One of the major safety concerns is the deformation of the tunnel. Minor tunnel deformation may cause additional delay of the operation due to rock cleaning and equipment replacement, whilst major deformation may jam the TBM or even endanger personnel safety. Hence a tunnel deformation monitoring system is needed during the operation of the TBM to deal with the problem of lacking of adaptability to geological conditions. In this paper, a visual assisted tunnel deformation measurement system is presented to automatically measure the deformation of the tunnel by using marked targets on the surrounding rock of the tunnel. The system mainly consists of a camera, a laser displacement sensor and a Pan-Tilt. The targets is marked by fluorescent coating and extracted by threshold segmentation method. Target is aimed using window tracing. The three dimensional coordinate of target point is calculated by using the principal of polar coordinates. A experiment platform is set up to verify the feasibility of the system. The experiment results show that the error of relative distance between two targets is smaller than 2mm within measuring range. The system can provide a high precision automatic measurement of the TBM tunnel.