ANALYSIS OF COLLAPSE DISPOSAL AND ITS EFFECT AT GUANKOUYA HIGHWAY TUNNEL

Owing to continuous rainstorm and fractured surrounding rock, collapse of tunnel was broken out in the cross-section YK73+955～YK73+925. Based on the analysis of field engineering geology and construction condition, ahead ductile grouting method was recommended and applied to pre-treat the surrounding rock. In order to test consolidation effect, two measurement cross sections were set up at the collapse zone. Measurement results of convergence and vault displacement show that the tunnel collapse zone was well strengthened by the ahead ductile grouting method.