| With the sustainable development of the economy,the construction of major national infrastructure is being carried out on a large scale across the country,and many high-speed railways,highways,and power transmission and distribution projects are being newly built or double-track construction,during which engineering blasting technology is widely used.Large-scale infrastructure construction often overlaps and overlaps with the safe space of the operating facilities,and because the seismic effect of blasting has a great impact on the bearing capacity and stability of the structure,the safety and reliability of the structure under the action of blasting seismic waves is a key issue that must be solved in the engineering blasting community.Accordingly,the vibration response dynamics of high-voltage line towers under blasting conditions and their safety criteria are studied.Firstly,a simplified mechanical model of the tower line system is established,and then an approximate theoretical calculation method for the dynamic response of the transmission tower line system is derived.Next,ANSYS is used to conduct finite element modeling and structural dynamic analysis of the transmission tower line system,study its inherent characteristics,and analyze the influence of the three elements of blasting vibration on the vibration response dynamic behavior of high-voltage line tower,and finally establish a safety criterion.The content is detailed below:(1)By reducing the transmission tower to a cantilever beam and the transmission line equivalent to a mass spring,a two-wire continuum mechanical model of one tower and two lines was established.Then,an approximate theoretical calculation method for the dynamic response of the tower line system under blasting excitation is derived,and the three elements of blasting vibration,namely amplitude,frequency and holding time,are reflected in the theoretical calculation.(2)A finite element model of the transmission tower line system was developed using ANSYS.Then,the modal analysis of the single tower and transmission tower line systems is carried out to understand the inherent characteristics of the structure.According to the results,it is found that the transmission line has a significant impact on the dynamic characteristics of the transmission tower,and the role of the transmission line cannot be ignored when analyzing the dynamic analysis of the transmission tower line system,and the quality and stiffness of the transmission line need to be considered.(3)Varying the magnitude of the amplitude,frequency and duration of the blast seismic wave,ANSYS performed transient dynamic analysis of the tower line system under different blasting seismic waves.According to the results,the three elements of blasting vibration have a significant impact on the seismic response amplitude of the transmission tower system.In addition,MATLAB is used to calculate the dynamic response of tower line system under blasting excitation,and compare and analyze with the numerical simulation results,which verifies the effectiveness of the derived approximate theoretical calculation method of transmission tower line system.(4)The safety criterion of the transmission tower line system under the stimulation of blasting vibration is: when the amplitude of the input blasting seismic wave is smaller,the shorter the duration,and the farther the frequency is from the natural frequency of the structure,the smaller the dynamic response amplitude of the structure and the safer the structure will be.In addition,in order to prevent the collapse and damage of the transmission tower line system studied in this paper,it is necessary to ensure that the vibration velocity at the bottom node 225 of the transmission tower cannot exceed 0.52m/s. |
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