Seepage field force is calculated to reflect the force effect of seepage flow field. Relationship equation of stress-damage-seepage is built to consider the effect of stress and damage on seepage flow field. Combined with 3-dimension elastoplastic-damage finite element analysis of rock mass

stress-damage-seepage coupling analysis model of large-scale underground surrounding rock is established. The difficulties of solving the model mainly lay on elastoplasticity of rock material

damage

free surface boundary of seepage flow

escaping surface boundary of seepage flow

interaction of stress-damage-seepage

etc. Considering the difficulties

the sequential iteration method is proposed to solve the difficulties by several sequential iterations; and nice calculation result is obtained. The method is used to analyze the large-scale underground caverns of a hydropower station

and a series of useful conclusion is made.