Facebolts are frequently used in order to reinforce the ground ahead of the cutting face. They are especially effective for tunnelling in poor conditions due to ground squeezing. According to our centrifuge model tests and parametric studies with numerical analysis method, it demonstrated that bonding strength was influential on failure pattern and ground movement. We subsequently developed new facebolts with checkered steel surface which can present much larger bonding strength. Furthermore, this paper describes an actual employment of these newbolts to a tunnel with strongly weathered breccia.

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