Remote-control technology performance for excavation with pneumatic caisson in soft ground

The pneumatic caisson method is applicable to various ground conditions and has competitive advantages in deep excavations. However, in the conventional pneumatic caisson, workers are at risks of suffering from decompression sickness because of long-duration exposure to the hyperbaric environment. Furthermore, the construction cost of the conventional pneumatic caisson is fairly high owing to the inefficiency and labor redundancy. To address these issues, an automatic construction system for the pneumatic caisson, which enables unmanned excavations based on a remote-control technology, has been developed. This system mainly comprises a remotely operated excavator, a vertical screw conveyor for continuous soil discharge, and an integrated real-time monitoring system. Additionally, a program named “NPC (new pneumatic caisson) Manager” is adopted for the comprehensive analysis of real-time monitoring data. This paper describes the details of this system and its execution process, in which all the work of excavation and removal of soil is completed remotely by workers on the ground. Moreover, an application in a tunnel shaft in soft ground, as well as an analysis of its monitoring results, is also presented.