Study On Mechanic Model Of Transmission Line Steel Tower And Interaction Mechanism Of Tower-line System Located At Mining Area

Connection slippage and joint flexibility of tower are widely regarded as major influencing factors for its mechanic performance. As the improvement of tendency to underground resource and space development, mechanic model of transmission line steel tower and interaction mechanism of tower-line system is great significant to the realiability of superstructure and availability of underground resource.For one bolt and two bolts connection joint, load-displacement curve, slippage mechanism of bolt connection and failure mode of bolt joint were studied by using slippage performance test, and axial stiffness of member with slippage was presented.Based on the concept of fuzzy membership, using spring to achieve fuzzy rotation angle of joint through its flexible displacement, element stiffness matrix of space flexible beam was derived and the relationship between fuzzy rotation and spring stiffness was provided. Introduced the axial stiffness reduction coefficient, the source code on space flexible joint model with slippage (SFJS) was programmed using MATLAB and perform numerical analysis to obtain the axial force of legs and diagonals of JJ3-type transmission line steel tower. The numerical results compared fairly well with full-scale test results and verify the reliability of space flexible joint model with slippage which can solve the internal force distribution of bar of transmission line steel tower and more accurately than traditional space frame model. The SFJS provide theoretical foundation for the design, calculation and protection of transmission line steel tower located at mining area.Dynamic surface deformations were predicted using Mining Subsidence Prediction System (MSPS). Three-dimensional finite element model of tower-line system was built and perform study on stress and sag of conductor and lightning conductor, internal force of steel bar, bearing reaction and comprehensive displacement at tower top. Finally, interaction mechanism of tower-line system was provided. For three types relationship between workface tunneling direction and line, safety evaluation was conducted and give correspondent evaluation index. Based on workface layout principles, deviation rectification and strengthening reformation for existed tower-line system and design suggestion for newly-built tower-line system were presented.