Study On The Stability Of Transmission Tower-Foundation System Under Strong Wind Load

With the rapid development of economy,more and more excavation works are being carried out.Near the tower foundation excavation stability of reservoirs should be paid more attention to.The unloading of soil caused by excavation of the reservoir will cause the stability of transmission tower foundation.In this paper,a practical transmission tower project is taken as the background to systematically investigate the stability of transmission tower near the excavation,with considering of the effect of strong wind,from the aspects of excavation spacing,excavation form,wind direction,and rainfall.A three-dimensional finite element model of a transmission tower is first constructed by a nonlinear finite element method.And further an analytical model of a transmission tower-line system is established.A simulation study of the true dimensions and real load conditions of transmission lines is carried out.The field measurement of the dynamic characteristics of transmission tower is executed in this paper,and the vibration frequency and damping ratio of the transmission tower are identified and compared with the theoretical results.The measured results are in good agreement with the theoretical results,indicating that the finite element model established in this paper is correspond with the actual situation,and the finite element model can be used as a model of structural response analysis under the following soil excavation and strong wind action.Multiple soil excavation methods and loading conditions is set up in detail in this paper to study the influence of the excavation form on the stability of the transmission tower foundation under the action of strong wind.The influence of excavation clearance on the stability of transmission tower foundation is explored by changing the spacing of excavation to find the most unfavorable excavation condition.The results indicate that the danger of the excavation scheme on both sides is the greatest,and the smaller the excavation net distance,the worse the stability of the transmission tower foundation.In view of the actual service environment of transmission tower line system,the effect of wind and rain coupling effect on the stability of transmission tower foundation is studied in this paper.In this paper,the service capacity of transmission tower foundation under different wind speed,wind direction and rainfall intensity is studied in this paper,and the basic disaster assessment system of transmission tower under wind and rain coupling field is set up.The dynamic and static analysis of transmission tower foundation is carried out through in-depth study in this paper.The effects of dynamic wind loads and static wind loads on the stability of transmission tower foundation are studied respectively.The study shows that the simulation of static wind load under the strong wind of transmission towers meets the reliability requirements of the stability study of transmission tower foundation under strong wind.