Abstract: In association with the conformal transformation method of plane elastic complex function,the analyticalsolutions of stress and displacement for a non-circular lined tunnel subjected to in-situ stress and internal water pressure are derived. The support delay and the full contact between surrounding rock-mass and lining are taken into consideration. The power series method is used to simplify the calculation process. With a horseshoe tunnel as an example,the analytical solutions are verified by numerical results. Furthermore,the tangential stresses along the excavation boundary and the inner and outer boundaries of the lining,as well as the contact stresses along the interface of the lining-surrounding rock mass are calculated. Besides,the stress distributions of the surrounding rock mass and the lining under different lateral pressure coefficients,displacement release coefficients and internal water pressures are discussed. The results show that the analytical solution is in good agreement with the numerical solution,and the displacement release coefficient and internal water pressure have significant influence on the stress distributions of the lining and surrounding rock mass. Great values of displacement release coefficient and internal water pressure will give rise to tensile stress along the inner boundary of the lining.

Key words: non-circular tunnel, support delay, conformal transformation, hydrostatic pressure, stress and displacement analysis, analytical solution