抄録
Because of the increased variety of construction conditions the technology of Shield excavation has made remarkable progress in recent years. Consequently we are always trying to improve our construction technique by designing our Shield Machines and creating our construction plan based on a careful analysis of prior investigations with the best technology available in the market. However at Tsudaka sewerage trunk main construction project (Stage 1) in Okayama city, the excavation progress of the shield machine was slowed down markedly by the appearance of solid rock which was much stiffer than we expected based on the results shown in our prior investigation. Under those circumstances, we remodeled our shield machine as much as possible until at last we succeeded in improving our daily progress. This report will describe the difference in the geological features of the rock from what we expected and that which we actually encountered, and will explain the points and effects of remodeling of the shield machine
