Study On Ground Deformation And Wind Resistant Performance Of 110kV Transmission Tower In Mining Subsidence Area

There are regional differences in supply and demand of electric energy in our country. Along with "coal for electricity transmission", "west-east power transmission" and other energy policy execute deeply in our country, more and more pithead power plant construct in the major coal producing areas. It cause a lot of HV and UHV transmission lines over mining subsidence area inevitably. Coal mining subsidence and wind load are potential great danger for the safe operation of the electric transmission line. Therefore, in order to make sure the transmission structure is on the safe side and the transmission lines run safety, to carry out the research ground deformation resistance and wind resistance comprehensive performance of transmission tower in mining subsidence area has important significance.Test apparatus of support displacement loading and wind loading at tower model were manufactured and the model experiment of transmission tower supporting displacement loading was conducted. The failure patterns of transmission tower under the action of the ground horizontal deformation were obtained. The influence laws of ground horizontal deformation for internal force and deformation of transmission tower were analysed. The influence law of wind load for ground deformation resistance of transmission tower was studied and the reliability of the finite element simulation verified. Test and finite element analysis results show that it has adverse effects of the wind load on ground deformation resistance of the transmission tower and the bigger of the wind load the more unfavourable.The finite element model of 1B-ZM3 transmission tower was established using ANSYS software. The influence laws of different ground deformation for internal force, deformation and failure pattern of transmission tower were studied. The ground deformation including 11 kinds of single ground deformation conditions and 10 kinds of composite ground deformation conditions. The values of ultimate support displacement under different ground deformation were obtained. It provide the reference for the safety evaluation of the transmission tower under the action of ground deformation.The whole finite element model of the transmission tower, foundation and ground was established. Take the deformation and stress of ground soil and the displacement and maximum stress of upper tower structure as comparative objects, ground deformation resistance of independent foundation and composite protective plate foundation were researched. The influence laws of protective plate thickness for stress and deformation of upper tower structure was analysed and the reasonable thickness value of protective plate was proposed. The results show that the composite protective plate foundation has better protection effect for the upper tower structure relative to the independent foundation and the protection effect increases with the increase of palte thickness, but its protection growth slowing when the thickness increases to a certain value. The reasonable values of plate thickness of 1B-ZM3 transmission tower should be between 200 millimeters and 300 millimeters, it bout the one-tenth to one-twentieth of long root.Wind-resistant performance of transmission tower in mining subsidence area was studied. After bearing different ground deformation, the failure pattern, wind-resistant ultimate load-carrying capacity and extreme wind speed of transmission tower under the action of wind load were obtained. The influence laws of ground deformation for wind-resistant performance of transmission tower was studied. Prediction models of wind-resistant ultimate load-carrying capacity and extreme wind speed of transmission tower in mining subsidence area were put forward. It provide the reference for the safety evaluation of the transmission tower under the action of wind load in mining subsidence area. The results show that wind-resistant ultimate load-carrying capacity of transmission tower decreases with the increase of the ground deformation values. The greater of ground deformation values, the more obvious of the change of decreasing range.