Examination of load when constructing it acting on shield machine tail

Mitsutaka SUGIMOTO

It is confirmed that the kinematic shield model can express actual shield behaviors through the previous researches.
The ground water leakage accident through segments were occurred at the sharp curved tunnel alignment due to the tunneling execution loads on segments, which comes from the decrease of tail clearance and the compression of tail grease. To make clear its influence on segments, it is necessary to develop the model, which can represent the force acting on tail from segments accurately. Therefore, this research aims to make clear the mechanism of the interaction between shield and segments. In this research, the detail model of the load acting on segments by flow resistance of grease and each wire brush was developed, and the influence of these loads on shield behavior was examined qualitatively.
As a result, The followings were concluded.
1)The model of the loads by flow resistance of grease and each wire brush including the effect of hardened grout material inside tail was developed.
2)The simulation on shield behavior was carried out by using the measured data during the slurry type articulated shield excavation at the shape curve alignment. As a result, the simulated shield machine behavior has a good agreement with the observed one. This demonstrates the validity of the newly improved shield kinematics model.
3)It was confirmed that the model can represent the change of jack thrust when shield tail passes at a segment with enlarged diameter.
Then, this shield kinematics model enable us to evaluate the execution loads on segment move accurately.