输电铁塔开孔复合板基础抗地表变形性能研究

发布时间：2018-04-19 11:32

本文选题：采动区 + 输电铁塔　；参考：《中国矿业大学》2015年硕士论文

【摘要】：随着我国变输煤为输电能源战略的提出,大量输电线路不可避免要经过煤矿采动沉陷区。采动区地表沉陷会影响输电线路安全,目前已有相关输电铁塔结构的保护措施,开孔复合防护板基础作为具有良好经济性和环保性的基础形式目前已有应用,但关于其抗变形性能尚未展开相应的研究,因此对采用开孔防护板基础的输电铁塔抗地表变形性能的研究具有重要的意义。研制了“输电铁塔地表水平变形大型模拟试验装置”,以典型220k V输电铁塔为研究对象,进行了独立基础和开孔复合板基础输电铁塔及基础、地基协同作用局部相似模型试验。分析了铁塔结构在地表变形影响下,结构杆件应力变化与支座变形值之间的规律,获得了开孔复合防护板基础中应力变化与地表水平拉伸变形之间的规律;比较了水平地表变形下,独立基础和开孔复合板基础的输电塔架的抗变形性能,分析了开孔复合防护板基础抗地表变形的有效性;同时对比分析了模型试验与数值模拟之间的符合程度,验证了数值模拟结果的可靠性。以典型220k V输电铁塔为研究对象,利用ANSYS程序,建立了有限元模型。分析了单独地表变形(11种典型工况)和复合地表变形(6种典型工况)下输电铁塔结构的破坏形态、杆件受力和变形的影响规律,得到了铁塔支座位移极限值,为采动区输电铁塔安全性评价提供参考。针对典型220k V输电铁塔,建立了输电铁塔、基础、地基的协同作用有限元模型,研究了输电铁塔不同基础(独立基础、复合防护板基础、开孔复合板基础)的抗变形性能,得到了典型地表变形(拉伸变形、压缩变形、正曲率变形、负曲率变形)作用下的表层土体变形、地基土应力(基础下土体应力)和基底应力、铁塔支座位移及上部结构内力的变化规律。研究结果表明,复合防护板基础和开孔复合板基础较独立基础均具有显著的抗地表变形能力,且开孔复合板基础较复合防护板基础抗地表变形能力基本相同。同时对开孔复合板基础进行抗变形优化分析,分析研究了开孔复合板的厚度对输电铁塔及地基、基础整体结构抗地表变形性能的影响。研究结果表明,典型铁塔的开孔复合板基础板厚可取为铁塔根开的1/30~1/20。同时,分析了不同地基土对开孔复合板抗变形性能的影响,结果表明土质越硬开孔复合板基础的防护作用越弱,在土质较硬的地基上建塔,应适当加大开孔复合板的板厚。
[Abstract]:With the strategy of transforming coal transportation into transmission energy, a large number of transmission lines will inevitably pass through the coal mining subsidence area.The ground subsidence in mining area will affect the safety of transmission line. At present, there are some protective measures for transmission tower structure, and the composite protection plate foundation with open hole has been applied as a foundation form with good economic and environmental protection at present.However, the research on the anti-deformation performance of transmission tower has not been carried out, so it is of great significance to study the anti-deformation performance of transmission tower based on open-hole protective plate.A large scale simulation test device for horizontal deformation of transmission tower surface is developed. Taking the typical 220kV transmission tower as the research object, the local similarity model test of independent foundation and perforated composite plate foundation transmission tower and its foundation is carried out.Under the influence of surface deformation, the law between stress change and support deformation value of steel tower structure is analyzed, and the law between stress change and horizontal tensile deformation of ground surface in composite plate foundation with open hole is obtained.The anti-deformation performance of transmission tower with independent foundation and open-hole composite plate foundation under horizontal surface deformation is compared, and the effectiveness of anti-ground deformation of open-hole composite plate foundation is analyzed.At the same time, the consistency between the model test and the numerical simulation is compared and analyzed, and the reliability of the numerical simulation results is verified.Taking the typical 220 kV transmission tower as the research object, the finite element model is established by using ANSYS program.In this paper, the failure patterns of transmission tower structure under 11 typical conditions of single surface deformation and 6 typical working conditions of composite ground deformation are analyzed, and the influence of stress and deformation on the members of the transmission tower are analyzed, and the limit values of the displacement of the tower support are obtained.It provides reference for safety evaluation of transmission tower in mining area.Based on the typical 220kV transmission tower, a finite element model of cooperative action of transmission tower, foundation and foundation is established, and the anti-deformation performance of different foundations (independent foundation, composite protective plate foundation, perforated composite plate foundation) of transmission tower is studied.The deformation of the surface soil, the stress of the ground soil (the stress of the soil under the foundation) and the stress of the base are obtained under the action of the typical surface deformation (tensile deformation, compression deformation, positive curvature deformation, negative curvature deformation).The change law of the displacement of the tower support and the internal force of the superstructure.The results show that the composite plate foundation and the perforated composite plate foundation have significant anti-ground deformation ability compared with the independent foundation, and the anti-surface deformation ability of the open-hole composite plate foundation is basically the same as that of the composite protective plate foundation.At the same time, the anti-deformation optimization analysis of the open-hole composite plate foundation is carried out, and the influence of the thickness of the perforated composite plate on the anti-ground deformation performance of the transmission tower and foundation is studied.The results show that the thickness of the open hole composite plate foundation of typical iron tower is 1 / 30 / 1 / 20 of that of the root of the tower.At the same time, the influence of different foundation soil on the anti-deformation performance of perforated composite plate is analyzed. The results show that the harder the soil quality is, the weaker the protective effect of the composite plate foundation is, and the thicker the plate thickness should be when the tower is built on the hard soil foundation.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU433;TM753

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