Overview
Visual monitoring of the progress of concrete filling and compaction at the crown area in a tunnel lining is generally impossible because all inspection windows and bulkhead forms are closed. This situation may result in void generation at the upper part of the crown area due to remaining air or bleeding water. In order to solve this problem, we have developed an ultra-thin sheet sensor "Juten Mieruka" in collaboration with Munekata Industrial Machinery Co., Ltd., which can be attached to the waterproof sheet in the upper part of the crown area. The main feature of this system is its ultra-thin design, flexibility, and ability to monitor a wide range of filling and compaction conditions at once. This makes it possible to visualize the casting status.