Safety Study on Transmission Tower Based on Prediction of Surface Movement of Coal Caving Mining

To evaluate the influence of mining of Wujianfang coal field layout area on the safety of transmission tower, the surface movement was predicted by FLAC^3D numerical simulation and the optimized probability-integration method to obtain parameters. Based on comprehensive forecast results, ANSYS was used to study characteristics of the internal force and deformation of the transmission tower based on the composite surface deformation of caving mining, and evaluated its safety in terms of its structure and slope of cross-arm. Results show that, the surface movement predicted by the above two methods are close together and the comprehensive forecast results are reliable. The most subsidence of the ground is 1.86 m. The most horizontal movement is 524 mm from east to west. The most horizontal movement is 737.5 mm from north to south. The most axial tensile stress of the tower is 25.2 MPa, which does not exceed the allowable stress of Q235 steel. The structure of the tower is in a safe state. The incline of the cross-arm of the tower is as high as 29.5 ‰, and its value exceeds the limit of 10‰. Taking measures to control the surface movement and strengthen the monitoring of the deformation in mining process can ensure the safe operation of the transmission tower.