Stabilization on 1000 kv UHV Transmission Tower Foundation Influenced by Underground Coal Mining in Mountainous Areas

Abstract

This paper presents a case study of stabilization of a transmission tower foundation influenced by underground coal mining on mountains. The tower foundation is built on land that is going to be mined, and it belongs to a 1000 kV UHV (ultra high voltage) transmission line in Shanxi province. Considering the synergistic effects between rock and transmission tower foundation, the transmission tower foundation deformation and the potential dangerous situations were calculated by using FLAC3D code numerical simulation. The comparison of results by numerical and analytical calculation was conducted as well. According to simulation results, the tower foundation deformation is dominated by the effect of coal mining rather than rock slope sliding. The potential moving track of tower foundation surface points is incomplete “C” shape in adverse slope situation. The modified reinforced concrete slab foundation combined with protection panel and length-adjustable anchor bolts is recommended in this paper. The UHV tower foundation construction followed the recommended method was completed in 2015. Further field monitoring data show that the modified tower foundation can be suggested to guarantee the safety of transmission tower during coal seam mining.