New hydro-mechanical tunnel excavation method using an abrasive waterjet system

Abstract

Tunnel excavations in urban areas are highly restricted by the need to control the blasting vibration level and obtain rapid excavation. A new tunnel excavation method using an abrasive waterjet (AWJ) system assisted by mechanical excavation tools is now under development for efficiently creating tunnels and underground spaces, such as generating a continuous free surface on the tunnel's perimeter. This artificial continuous free surface can increase the efficiency of the excavation rate and even enhance the excavation rate at various free surface conditions. In this study, an in-situ experimental test was performed to verify the free surface effects on excavation performance. A continuous free surface is generated using an abrasive waterjet system. Mechanical excavation tools (drilling jumbo or hydraulic rock breaker) are utilized to excavate the remaining tunnel face. According to the in-situ experimental results, we expect that this new tunnel excavation method can be effectively utilized as baseline data for establishing new alternative tunneling methods in various construction locations, such as short tunnels near urban areas, utility tunnels, and shafts