Abstract
In order to excavate a shallow tunnel in sandy ground, it is necessary to stabilize the ground surrounding the opening and prevent a surface settlement. For the purpose, an appropriate prereinforcement should be applied to improve the ground conditions. However, it has not been fully clarified an effect and a reinforcing mechanism of the prereinforcement method. In this paper, a series of model tests was performed on sandy ground to investigate the reinforcing mechanism of prereinforcement method using steel bolts. It was found the following from the model tests.
(1) The reinforcing mechanism of bolting reinforcement is the restraint of deformation of ground by the frictional force generated between the soil and steel bolt placed in the ground.
(2) If the bolts were placed in the direction of the minimum principal strain, the effect of preventing the deformation is most effective.
