| The excavation of tunnel will produce a different degree of disturbance and destruction to the surrounding soil, also makes the ground movement,and thus causes the subsidence of the earth's surface. It will lead to some bad effect to the surrounding environment. The effect of excavation of railway tunnel to the nearby high voltage power transmission tower and the corresponding construction control is one of unique issue which need to be study and solve. This thesis use theoretical analysis,field surveys and numerical simulation to study the issues which caused by excavation of railway tunnel to nearby 60 KV high-voltage power transmission tower which relying on the reconstructed railways in Fujian Nanping Expansion project Qianshan tunnel NLZQ-II bid section,The following is the main research contents and conclusions :(i) The analysis of stratum deformation and the surface subsidence caused by tunnel construction are discussed and the surface structure may damaged because of the tunnel construction.Also conducted a towering structure foundation deformation calculation and the analysis of control parameters.(ii) Conducted engineering excavation method and determine the selection of the construction technology on the basis of tunnel construction risk analysis also studied the tunnel construction and the mutual influence between the adjacent transmission tower which is based on the surface in the process of tunnel construction and the foundation settlement observation and analysis,such put forward reinforcement technique measures to tower foundation.(iii) Near the high voltage transmission tower of surface subsidence observation and analysis show that the ground subsidence appeared the tunnel axis as the center of the "middle big two small" trough which is caused by tunnel construction;the surface subsidence where the high-voltage transmission tower located is small; the influence of tunnel construction on nearby transmission tower is mainly showed the uneven settlement and the tower tilted. But tower foundation's maximum settlement and differential settlement are within the control range since the tunnel construction did not affect stability of transmission tower structure and operation safety.(iv) Established numerical simulation of tunnel excavation model which is underpass the transmission tower,the numerical analysis results show that export period of transmission tower will tilt to one side of the tunnel in the process of tunnel excavation,but the inclination, uneven settlement values of foundation as well as the maximum settlement are within the scope of the specification requirements.It conclude that the tunnel construction will not impact the safety of the transmission tower operation.(v) By comparison with the results of numerical analysis and field observation data,we can conclude that the former data is smaller,but the difference between them is very small.Both of them show that the surface subsidence of the high voltage transmission tower to the tunnel construction affection is small and the tunnel construction have some influence to the tower.But it will not impact the structure stability and safety of the transmission tower operation.In consideration of safety,so it is recommended that a certain reinforcement measures need to be taken for high voltage transmission tower. |
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