Abstract:

The present criteria for the soil reinforcement during EPB shields’ launching and arrival construction in soft ground adopted in China are mainly based on Japanese experience, i.e., the length of the soil reinforcement for the shield launching is 6m, the length of the soil reinforcement for the shield arrival is 3.5m and the strength of the soil reinforcement ranges from 0.8MPa to 1.5MPa. Due to the fact that the normal strength of the reinforced soil is higher than 1.5MPa, the authors, based on the construction experience in the job site, suggest that the reasonable length of the soil reinforcement for the launching and arrival of shield machines under normal conditions should be 3.5m. On basis of the special features of sand ground, the authors recommend the reinforcement patterning for shield arrivals in sand ground. Furthermore, the authors, on basis of the waterproofing purpose of the reinforced soil and the construction methods adopted in the job site, suggest that the existing soil reinforcement criteria should be modified.

Key words: shield construction  , soil reinforcement reinforcement criteria discussion