Limits to foundation displacement of an extra high voltage transmission tower in a mining subsidence area

Abstract

Given the background of a transmission tower erected on a particular mining subsidence area, we used finite element modeling to analyze the anti-deformation performance of transmission towers under a number of different load conditions, including horizontal foundation displacement, uneven vertical downward displacement, wind loads and icing conditions. The results show that the failure in stability of a single steel angle iron represents the limit of the tower given ground deformation. We calculated the corresponding limits of foundation displacements. The results indicate that compression displacement of the foundation is more dangerous than tension displacement. Under complex foundation displacement conditions, horizontal foundation displacement is a key factor leading to failure in the stability of towers. Under conditions of compression or tension displacement of the foundation, wind load becomes the key factor. Towers do not fail when foundation displacements are smaller than 1% (under tension) or 0.5% (under horizontal compression or single foundation subsidence) of the distance between two supports.