Abstract
The mechanical effect of the interaction between the shotcreting and the ground is studied from a view point of the tunnel support stability. A serial set of rigid bars jointed through the bending springs are adopted for a model of the lining while the constant coefficient of subgrade reaction is assumed for the ground. A lot of parametric numerical analyses are done by changing the width of shotcreting, the coefficient of the lateral earth pressure, the overburden and the shape of tunnel section. It is shown that the subgrade reaction is essential for the tunnel stability and that even a thin shotcrete lining supports the surrounding ground if an adequate amount of the subgrade reaction is expected.
