Wedge stability in the roof of a non-circular tunnel

摘要

A closed-form solution is presented for the calculation of the stability of a wedge in the roof of a tunnel. The stability of the wedge is investigated using a two-stage relaxation procedure. A polynomial function is used to fit the horizontal induced stress along the axis of the noncircular tunnel based on the numerical results. The effect of the ratio K of the horizontal to vertical in situ stress on the internal horizontal force is investigated. The influences of the normal and shear stiffness and the far field stress on the stability of the wedge are investigated. The results indicate that the stiffness and far field stress have significant effect on the stability of the wedge.