Abstract:Abstract : Research purposes : Aim at the problems of the slipping stability of wing wall tunnel portal by the strip method,which leads to the result excessively conservatism because neglecting the integrity of tunnel portal and the friction of soils, the integral method was put forward in this paper by regarding the portal as integral structure. Considered the interaction between the various parts of the portal and the friction effect of lateral earth pressure surrounding side wall, the slij^ force and stabilizing force acted on the portal was calculated by the integral method, then the factor of the slipping stability was analyzed. Research conclusions :(1) The slipping stability factor obtained in the integral method is larger than the strip method' and the former is about 1.2 ?1.5 times of the latter. ( 2 ) Sometimes the slipping stability factor obtained in the strip method cannot attain the standard values for some reliable structures,which indicates that the strip method is excessively conservative and necessary to improve. (3) The integral method can be applied in the slipping stability design of wing wall tunnel portal in the engineering practice, and the result is reliable. Under the premise of ensuring safety, the integral method is more economical than the strip method.