平顶直墙浅埋暗挖施工对地表沉降的影响分析

发布时间：2018-05-31 03:38

本文选题：平顶直墙 + 浅埋暗挖　；参考：《北京工业大学》2014年硕士论文

【摘要】：平顶直墙结构受顶部因缺乏拱效应,在开挖过程中易造成地表沉降值过大,甚至产生坍塌事故。因此,研究平顶直墙浅埋暗挖隧道施工对于地表沉降的影响,采取有效措施减小变形,以使道路等不至造成损害,是城市地铁建设面临的重要任务,并具有重要施工指导意义。本文将以地铁14号线大瓦窑站出入口的暗挖工程为依托,对砂卵石地层平顶直墙暗挖施工引起的地表沉降情况进行研究,系统分析地表沉降的监测结果,结合有限元理论研究暗挖施工对地表沉降的影响规律,确定主要影响因素,并进一步对平顶直墙暗挖施工工法进行优化,寻求科学合理的地表沉降控制措施。在介绍浅埋暗挖工艺的基础上,从采用的施工法、隧道的埋深(隧道覆土的厚度)、覆土或围岩的岩性和质量、隧道的截面形式、隧道衬砌的刚度和施工速度、后注浆的质量和注浆压力、施工降水等方面分析影响沉降的因素;以北京地铁五号线某区间隧道工程的平顶直墙暗挖段作为工程依托,利用有限元计算,分析导洞暗挖宽度、导洞暗挖高度、导洞埋深、导洞壁厚及导洞周围土体加固效果对地表沉降的影响;依托实际工程对导洞开挖引起的地表沉降进行了有限元分析和监测分析,并将两种方法所得数据进行对比分析。研究结果表明,地表沉降值随着导洞宽度、高度的增大而增大,随着导洞埋深、壁厚、周围加固土体弹性模量的增大而减小。导洞宽度对地表沉降的影响可以分为三个区域,即明显区、微弱区、显著区,在选择洞口开挖宽度时,为控制地表沉降的同时兼顾施工便利性,可在导洞宽度对地表沉降影响的微弱区选择;超过一定高度的导洞需要采取一定的加固措施,防止地面沉降过大;当导洞埋深较小,要注意采取防护措施,防止对地表的影响过大;增加导洞的壁厚,可以较为有效地控制地表路面的沉降,当壁厚增加的一定的程度时,一味的增加导洞壁厚,对控制地表沉降影响相当小。
[Abstract]:Due to the lack of arch effect at the top of the flat top and straight wall structure, it is easy to cause excessive surface subsidence and even collapse in the process of excavation. Therefore, it is important to study the effect of shallow buried tunnel construction on the surface settlement of flat top straight wall, and take effective measures to reduce the deformation so as to make the road do not cause damage. It is the importance of urban subway construction. The task is of great significance for construction. This paper will study the surface subsidence caused by the dark excavation of the flat top straight wall of the sand gravel stratum, based on the dark excavation project of the entrance of the great tile station of the subway line 14, and systematically analyze the monitoring results of the surface subsidence, and study the influence of the underground excavation on the ground settlement with the finite element theory. Law, determine the main influencing factors, and further optimize the excavation method of flat top straight wall, seek scientific and reasonable control measures of surface subsidence. On the basis of shallow buried excavation technology, the construction method, buried depth of tunnel (the thickness of tunnel overlying soil), the lithology and quality of overlying soil or surrounding rock, section form of tunnel, tunnel The stiffness and construction speed of the lining, the quality and the grouting pressure of the post grouting, the construction precipitation and so on are used to analyze the factors that affect the settlement. Based on the underground excavation section of the flat top straight wall of a tunnel project in Beijing metro line five, the length of the excavation width, the depth of the guide hole, the depth of the guide hole, the thickness of the guide hole and the guide wall are analyzed by the finite element calculation. The effect of soil reinforcement effect on the surface subsidence around the cave; based on the actual engineering, the finite element analysis and monitoring analysis are carried out on the ground subsidence caused by the tunnel excavation, and the data obtained by the two methods are compared and analyzed. The results show that the surface subsidence value increases with the width of the guide hole, the height increase, and the depth of the tunnel and the thickness of the wall. The influence of the elastic modulus of the surrounding soil decreases. The influence of the width of the guide hole on the surface subsidence can be divided into three regions, that is, the obvious area, the weak area and the significant area. In the choice of the width of the tunnel opening, the settlement of the ground surface is controlled and the convenience is taken into consideration, and the influence of the width of the guide hole on the surface settlement can be selected; It is necessary to take some reinforcement measures to prevent the ground settlement too large. When the depth of the guide hole is small, it is necessary to take precautions to prevent the oversize of the surface, and to increase the wall thickness of the guide hole, which can effectively control the settlement of the surface of the surface of the surface, and increase the thickness of the guide hole when the wall thickness increases. The influence of surface subsidence is rather small.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U231.3;TU433

【参考文献】