Wind-Induced Responses Of Long Span Transmission Tower Considering Pile-Soil-Structure Interaction

With the rapid development of the electric power industry,overhead transmission lines are developing towards the direction of ultra-high voltage,extra-long span and towering.The interaction between soil,foundation and transmission towers cannot be ignored.In this paper,the tower with 385 m height is taken as the research object.The wind-induced response of the transmission tower considering the pile-soil-structure interaction is studied through theoretical analysis,finite element calculation and aeroelastic model wind tunnel test.The details are as follows:(1)In order to study the pile-soil interaction,a single pile-soil solid element model and a single pile-soil spring element model were established.After considered three single pile-soil spring element simulation methods and compared with a pile foundation calculation software,we determined that the p-y method results are the most reasonable among the three methods.The pile group-soil solid element model was established,and we obtained the pile group effect coefficient by comparing it with the single pile-soil solid element model.The pile group effect coefficient of the pile group arrangement scheme of 6 times 5 in this paper is about 0.42.(2)In order to study the influence of the substructure on the mechanical characteristics of the transmission tower,a bottom-clamped model and an integrated model including the substructure were established,and the response analysis under the action of self-weight and horizontal wind was carried out.It was found that the base bending moment of the integrated model was bigger than the bottom-clamped model.Carried out the wind-induced pulsation response calculation,it was found that the results of the time-domain method and the frequency-domain method are very close,and the top displacement and acceleration of the integrated model were slightly larger than the bottom-clamped model.The influence of different soil surface heights on the calculation results of the integrated model was studied,and it was found that the lower the soil surface height,the softer the structure and the greater the wind-induced pulsation response.(3)The aeroelastic model wind tunnel test of the bottom-clamped model was carried out,the model of the transmission tower was made by the discrete stiffness method.The displacement of the transmission tower model was measured by a non-contact displacement video measuring instrument,and compared with the finite element results.It was found that the aeroelastic model wind tunnel test results of the downwind were in good agreement with the finite element results.(4)The aeroelastic model wind tunnel test considering the integrated model of the substructure was carried out,the bottom spring was used to simplify the integrated model.The simplified transmission tower model at the bottom was designed and produced,different soil surface height conditions were realized by changing the bottom spring,and the wind tunnel test results of the aeroelastic model were compared with the finite element results.The results showed that the wind tunnel test results of the aeroelastic model based on the simplified model were in good agreement with the finite element;and the smaller the spring stiffness of the simplified model at the bottom,the greater the displacement and acceleration response of the tower top.