Investigation and analysis of the tower collapse accident and the impact of rainstorm and flood in Gucheng on 6 August 2012

Based on the field investigation methods, the damage severity and flood inundation area at the scene of a collapse accident for the No.170 tower on the 500 kV Shiyan-Xiangfan circuit in Gucheng County on 6 August 2012 were investigated and analyzed. Then the hydrological and meteorological conditions in the disaster period as well as the reservoirs, river channels and physical geography in the disaster area were investigated and arranged using data analysis methods. We calculated the extreme values of water level, discharge, precipitation and other factors, and simulated the flood path and the depth and context of flood inundation by a two-dimensional hydrodynamic model, to assess the cause of the tower collapse event. The results show that the tower collapse event induced by rainstorm is obviously characterized by the disaster chain effects. Due to the local heavy rainfall inducing mountain torrents and the middle and small river floods, both the inflow peak discharge of Tankou reservoir and the peak dischar