Technology of Slurry Shield Pebble Bed Pressurized into the Tank

Abstract

In the shield project, crossing through the permeable, collapsing and unstable pebble layers has been the critical and difficult point of construction. Oujiang shield tunnel was 834.5 m long, it was mainly crossing through the formation of medium sand bed, pebble bed and andesitic porphyrite. Among them, the pebble bed was more than 300 meters long, the largest pebble grain size was 450 mm, 60% of pebble grain size was more than 150 mm, its proportion was more than 90%. For the tool pan break ribs large grain size pebble was hard to be broken, with the increase of the excavation length, the large grain size pebble was cumulated step by step, the tool pan torque increases and stuck tool occurs, pressurizing the pebble into the tank was needed for tool pan cleaning in the tank. In Oujiang Shield Project, by the improvement of technology of pressurizing into the tank, it ensures the smooth excavation of 300 long pebble beds. It provides technical reference for pebble bed pressurizing into the tank for the slurry shield projects.