Centrifuge model test of tunnel face reinforcement by bolting

Typical auxiliary bolting methods were tested using centrifugal models with sandy ground to confirm their strengthening effects on tunnel faces. Face bolting, vertical pre-reinforcement bolting and forepoling were tested separately, in various arrangements. Also, the experimental results were compared with the analytical results by the Distinct Element Method (DEM). Experimental results demonstrate that each bolting technique has an optimum length and arrangement to perform effectively. DEM modeling with a staggered block pattern was used to stimulate the failure states observed in the experiment. The effect of the bolting obtained from the experimental results was also confirmed by numerical simulations. (C) 2003 Elsevier Science Ltd. All rights reserved.