In this paper

the finite element models are established for typical kinds of electricity transmission tower.The anti-deformation performances of single foundation and composite foundation with different thickness protection plate are studied with numerical simulation.The study indicates that

compared to the single foundation

the horizontal displacements of supports and the stresses of the upper structure are distinctly decreased by the composite foundation.The study also indicates that

the improvement of anti-deformation performance by increasing thickness of protection plate played an important role only in a limited range

the feasible minimum thickness of the plate is about 1/45-1/35 of the distance between two supports.As a result

the study lends a support to the improvement of the foundation design method for the transmission tower in the subsidence area.