Soil Improvement Technology and Dynamic Control of a Large Diameter Shield in Sandy Cobble Strata

During the shield-based construction of a large-diameter subway tunnel crossing sandy cobble strata in the Chengdu region, a number of problems are encountered: the large particle size, high strength, loose structure of cobbles and boulders, difficulty in discharging slag and soil from the shield, and serious wear of the cutter head. It is necessary to adopt a dynamic control method to reduce material consumption using multiple groups of residue improvement experiments. Unlike other methods, we propose two improvement schemes and a dynamic control process in this paper. A dynamic control scheme combined with shield parameter feedback is proposed, using different proportions of modifiers to improve the sandy cobble strata.