Stress Analysis And Experimental Study Of Foundation Settlement For 110kV Transmission Tower

With the development of power networks,the accidents of the deformation,slope or even collapse frequently occur in transmission towers,which are caused by the foundation subsidence of the special regions such as exploitation areas,river shoal,hillside land.According to the key members stress characteristics of foundation settlement,inclination,sideslip conditions under the wind load or the ice load,the installation position of strain monitoring sensor is determined,and the stress characteristics are tested and verified,which has great engineering significance to timely find the tower long-term operation fault point.Firstly,a finite element model of 110 kV tower analysis model is established,with the stress characteristics of the operating conditions and the deformation of the actual bar structure considered,the nonlinear static analysis is carried out for above accidents based on the calculation formula of tower structure load.Secondly,according to the analysis of the working conditions above,the relations between the maximum equivalent stress and the settlement value of the key members are obtained,where the yield stress is also obtained by using the strength theory of material mechanics,then the displacement thresholds of foundation settlement,inclination,sideslip are determined,respectively.The results show that the maximum equivalent stress of the key rods increases linearly with the increase of settlement and sideslip displacement,and the inclination increases nonlinearly.For the same external loads,the displacement threshold of the inclination is largest,the foundation settlement is smallest.Meanwhile,when the single or three foundation settlements occur,whose key members firstly exceed the yield stress and cause dangers under different working conditions.Finally,based on the settlement stress analysis of the tower,a stress monitoring and morphological identification system of transmission tower is presented in this paper,which can collect the key members stress real-time information by the monitoring terminal strain sensing unit and find the force of the bar long-term running fault point.Besides,based on the 110 kV condition monitoring test platform,the results are analyzed and verified by using the resistance strain gauge.During the test,for one thing,the displacement of the tower is solved by introducing the ultra-thin hydraulic jack,which was sample and easily implement.For another,by installing the resistance strain gauges on foundation settlement,inclination,sideslip corresponding to key element position,the distributed multi point measurement method is used to achieve stress measurement under various working conditions,which is convenient to evaluate the overall condition of the tower.The relevant research results have reference significance for foundation righting,correction,on-line monitoring and fault warning of the 110 kV transmission tower.