Model Test Investigation of Rock-Fall Impaction to Cut-and-Cover Tunnel Arch Structure

On conditions of different weight，height, shape, slope gradient and the property of slope surface, the tunnel portal structure’s strain evoked by rock-fall impaction has been researched in laboratory by using a 1/30 scale similar model. The study shows that there is a simple linear relationship between the structure’s strain , the rock weight and the rockfall height when the slope gradient is specific and the slope surface is slippery and the multiple linear relationship between the structure’s strain , the rock weight and the rockfall height has been obtained. Effect of the shape of the rockfall and the property of slope surface on structure’s strain has been analyzed; The distribution characteristics of the structure’s strain of different parts of one cross-section and the same parts of different cross-sections has been comparative analyed.