Present Status and Technology of the Shield Tunneling Method for Urban Railway System in Chengdu, China (2005-2019)
Shield tunnelling technology has significant advantages in urban areas, and it has become one of the most common tunnel excavation methods in the world. However, there are huge challenges for shield tunnelling in Chengdu, China, i.e., cobbles and boulders are difficult to smash, cutter tools wear severely, water-rich sand and gravel spew easily and soil conditioning is challenging. These challenges restrict the further development of the shield tunnel technology. This paper presents the recent challenges and developments in shield tunnelling technology in Chengdu, China, and proposes effective countermeasures for the gravel geological conditions. The results of this research are helpful for improving the shield tunnel technology in Chengdu and ensuring a smooth and safe construction.