Abstract:
This report is the case of ground improvement work using V-JET method in widening work of a Tozai Line Minamisunamachi Station. If the hole is drilled in the upper part of the station building, there is a risk of the station building rebounding due to a reduction in the overload from excavation. Therefore, the ground under the station building before the excavation was improved within the station building. In order to make ground improvement from the station building, it was necessary to make it possible to move within the station building such as platforms by setting the head below 1.8 m, the weight less than 1.0 t, and to solve the problem of machine movement by human power and platform resistance. We also focused on reducing the viscosity of the sludge so that the sludge was not blocked by the guide hole and the track was not raised. By using a small machine, smooth construction was realized from the method that could not be constructed until now, and the use of the mix materials did not destroy the track due to obstruction of sludge and did not hinder subway business the construction was completed. Key words: Jet grounding, V-JET method, viscosity of the sludge, small machine