The anti-deformation performance of composite foundation of transmission tower in mining subsidence area

To improve the design method of foundation of transmission tower in mining subsidence area, and considering the interactions of transmission tower, ground and foundation, this paper presents a contrast research on the anti-deformation performance of two types of foundation (i.e. independent foundation and composite foundation with protecting apron) by finite element simulation. For valid simulation, we put forward the methods and principles of simplifying foundation and sand cushion. The research results indicate that, if the ground deforms in patterns of negative curvature, tension or compression, the structure stress and the horizontal support displacement of transmission tower can be reduced by 25% and 40% respectively by using composite foundation compared with independent foundation. If the ground deforms in pattern of positive curvature, the tower can be also protected by using the composite foundation instead of the independent ones, but the effect is less than that in the former three deformation patterns. The research findings provide the basis for improving the design method of transmission tower foundation in mining subsidence area.