【作者】 张华林；

【导师】 阳军生；

【作者基本信息】 中南大学 ， 土木工程， 2012， 博士

【摘要】 由于地域特点和走廊条件的限制,常常遇到高压输电铁塔位于隧道上方或在隧道上方附近的情况。自立式高压输电铁塔作为一种高耸空间结构,具有刚度较小、塔基相互独立、对基础沉降差敏感等特点。隧道邻近或者下穿既有高压输电铁塔施工时,极易导致铁塔基础发生不均匀沉降,严重时可致铁塔倒塌,危及电力线路的正常运行和生命财产安全,这不仅会造成重大的经济损失,而且会造成及其严重的社会影响。本文以李家冲隧道下穿500kV高压输电铁塔为工程依托,采用数值分析和现场测试相结合的研究手段,在分析隧道施工对上覆高压输电铁塔影响的基础上,重点针对李家冲隧道与500kV高压输电铁塔的具体条件,研究施工方案和技术措施,以及分析应用效果。主要研究成果和结论如下：1、以铁塔最大应力达到钢材设计抗压强度为基准,针对典型的不同高度自立式高压输电铁塔,提出了塔基倾斜和铁塔倾斜的允许值。2、研究了铁塔位置、隧道洞径、隧道埋深、铁塔型号和铁塔外荷载等因素对上方输电铁塔因隧道施工所引起的变形的影响。比较了隧道施工对不同位置铁塔的影响规律,并对影响范围进行了分区。通过对比计算,获得了不同洞径和不同埋深的隧道施工对铁塔的影响规律,获得了隧道施工对不同高度铁塔的影响规律,获得了铁塔处于不同外荷载时隧道施工对铁塔的影响规律。3、针对李家冲隧道下穿高压输电铁塔的工程实例,分析了隧道施工可能导致的铁塔损害情况。对比分析了几种施工风险处治方案的优缺点,建议对李家冲隧道下穿高压输电铁塔时采用框架梁加固铁塔基础方案来规避施工风险。通过数值模拟方法分析了该处治方案的有效性,并通过现场测试方法验证了该处治方案的可行性。4、分析表明,采用框架梁加固铁塔基础,将铁塔基础联为一体,增加了四个塔基的整体抗变形能力,有效减小了四个铁塔塔基的不均匀沉降和相邻塔基之间的水平位移差,同时降低了铁塔上杆件的应力增量,降低了施工风险。5、通过对李家冲隧道下穿高压输电铁塔的长期观测,得到隧道开挖过程中洞内变形、地表沉降以及铁塔位移和应力变化规律。李家冲三车道大跨度隧道成功下穿高压输电铁塔的工程实践表明,施工过程中所采用的风险处治方案和隧道施工方法是合理的,为类似隧道下穿高耸构筑物提供了类比和参考。更多还原

【Abstract】 Due to the region characteristic and the constraint of transmission line corridor, high-voltage transmission tower is often located right at the top of tunnel or near the top of the tunnel. Free-standing high-voltage transmission tower, as a towering space structure, has less rigidity. The foundations of tower are independent of each other. Tower is very sensitive to the settlement difference between two adjacent foundations. When tunnel constructed under or nearby the high-voltage transmission tower, the tunnel construction is easily result in uneven settlement of tower foundations. Serious uneven settlement may cause tower collapse. The collapse of tower may endanger the normal operation of the power lines, and it will not only cause significant economic losses, and can cause serious social influence.Lijiachong tunnel underneath500kV high-voltage transmission tower is used as engineering example. The numerical analysis and real-time monitoring are used as research methods. The influence of tunnel construction on transmission tower is analyzed. Based on the specific conditions of the Lijiachong tunnel and500kV transmission tower, the construction scheme and technical measures are studied, and the application effect is analyzed. The main research results and conclusions are as follows:1. The maximum stress of tower to the design compressive strength of steel is used as benchmark. The allowable value of foundation tilt and tower tilt are put forward, for typical free-standing high-voltage transmission towers with different height.2. The influence factors of the location of tower, diameter of tunnel, depth of tunnel, type of tower and external load of tower are studied, for the influence of tunnel construction on transmission tower. The influence of tunnel construction to towers at different position is compared, and the scope of influence is divided into several areas. By comparing calculation, the influence law of tunnel construction on tower is obtained, when the tunnel have different diameter and different deep, and when the tower have different external load. The influence law of tunnel construction on different height towers is obtained. 3. According to engineering example of Lijiachong tunnel under the high-voltage transmission tower, the damage to tower by the tunnel construction is analyzed. The advantages and disadvantages of several treatment plan of construction risk are compared. The construction scheme using the frame beams to reinforce the foundations of tower to avoid the risk of is suggested. The effectiveness of the treatment scheme is analyzed by numerical simulation method, and the feasibility of the treatment plan is proved by field test method.4. Analysis showed that the overall ability to resistance deformation is increased to the foundations of tower by using the frame beams to reinforce the foundations of tower and the independent foundations are connected as a whole. The uneven settlement and the difference of horizontal displacement of foundations are reduced effectively, at the same time, the stress increment of tower member and construction risk is reduced.5. Through the long-term monitoring of the construction of Lijiachong tunnel under the tower, the law of the deformation of tunnel, ground settlement, displacement and stress of tower is obtained. The engineering practice, which Lijiachong three lanes large-span tunnel under the high-voltage transmission tower constructed successfully, shows that the risk treatment plan and tunnel construction method are reasonable. The success engineering example provides analogy and reference to similar tunnel under tall buildings.更多还原