THE STUDY OF GOAF INFLUENCE ON THE STABILITY OF TRANSMISSION LINE BASED ON THREE-DIMENSIONAL NUMERICAL SIMULATION ANALYSIS

In order to study the relationships between goaf collapse caused by underground coal-mining and the safety of buildingsandsurface deformation, we analyzed the deformation of pylon foundation affecting by different mine goaf due to different mining methods, as well as the stability of adjacentslope in an area. This area is located in the district of Z149#~Z154# transmission line, which is based on the 750kV power transmission project. A MIDAS numerical simulation software is used to establish a three-dimensional analysis model and two working conditions are simulated in this paper, some conclusions are obtained as follows:(1) under the existing working conditions, the goaf mainly affected the tower of 149# and the tower of 150#, and the simulation results show thatbetween the tower of 149# and the tower of 150#,vertical displacement have its peakat 0.7259m, which is in consonance with the actual observation of the maximum surface settlement of 0.65m, showing that the simulation results can approximately reflect the actual deformation results; exploitation can cause 149#, 150# and 151# tower' foundation uneven settlement, the maximum difference in settlement between towel foots reachto 0.0091m, which is in accordance with the measured value of 150# tower with its maximum difference in settlement is 0.0085m, and likewise, the simulation results suit actual results well; and the least favorable profiles only appear in slopes in the vicinity between the 149# tower and 150# tower, but no continuous slip surface is formed, and no slope instability would be formed.(2) Under the final working condition, all the already formedgoaf in this field have impacts on pylon foundations, and compared with the existing working conditions, the vertical displacementsof each towel display an increasing trend; the mining-caused maximum settlement in tower foots could reach as high as 0.0120m, and tower of 150#, 151# and 152# produced an oversized subsidence difference, so strengthened monitoring should be warranted; although slopes near the tower are all influencedby mining activities, there are not continuous slip surface formed, as a result, no slope instability would occur. This paper can provide technical support and reference for the safe operation and control of the transmission line and other related structures which are located in the goaf areas.