Analysis on H & V shield behavior by the kinematic shield model

Mitsutaka SUGIMOTO

The construction project on °»Tachiaigawa rainwater discharge tube°… constructs a drainage shield tunnel to discharge all rainwater in Tachiai river to Keihin river. Due to the limitation of land use, such as, narrow river and exiting structures over the planned route of the tunnel, only the spiral excavation mode of the horizontal and vertical variation shield method (H&V shield) can construct the tunnel, of which the cross section enables the required amount to be discharged. However, this is the first application in practice except for a test execution.
Therefore, this study aims to grasp the H&V shield control method. Then the followings were carried out:
1) The shield operational parameters, such as, crease angle, copy cutter length and range, and jack force are obtained based on the geometric conditions;
2) The simulation of the H&V shield behavior is carried out by the shield kinematic model; and
3) The force acting at the connection point between the left body and the right body is calculated for shield design.
As a result, we found the followings:
1) In the horizontal curve section, the setting operational parameters, such as, crease angle, copy cutter length and range, are reasonable.
2) Jack thrust and jack moment, which are set from unbalanced force acting on the shield, are appropriate as initial values.
3) The analytical values of the shield behavior and shield trajectory matched the planned ones after a curtain correction on shield operating conditions.
4) It is considered that the tunnel can be constructed by H&V shield, under appropriate excavation management.

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