Mechanism of wet shotcrete interacting with rock in support systems

In order to have a good understanding of the behavior of wet shotcrete as a support element interacting with the rock mass, mechanism of wet shotcrete interacting with rock in support systems was analyzed through theoretical, numerical study and analytical analysis. A new model of distribution of rock stress state after wet shotcrete was applied, which includes shotcrete layer, composite layer, strengthening layer, plastic layer and elastic layer, and a full illustration of the rock mass stress state was given after shotcrete interacting with rock mass. At the same time, numerical analysis with FLAC gives a stress distribution along the monitor line, respectively, at the sidewall and roof of the tunnel. The displacement obviously decreases with the depth of rock, the tangential stress for tunnel supported by shotcrete is lower than that without shotcrete, and radial stress for tunnel supported by shotcrete is higher than that without shotcrete. It has been demonstrated by AIRY’S stress function, which gives a reasonable solution. Finally, the application of wet shotcrete in Jinfeng Gold Mine shows that the displacement of tunnel decreases obviously in sidewall and roof.