复杂地层条件下深基坑施工对下卧地铁隧道结构影响研究

发布时间：2019-05-28 04:59

【摘要】：近年来,地铁在当今社会中的位置越来越不可替代。由于大量的地铁隧道结构错综复杂的穿梭于城市之中,使得其地下空间的结构尤为复杂,因此给地铁结构上覆的基坑施工工作带来很大的难题,稍有不慎,就会引起地铁结构的破坏等严重的工程事故。为保证工程安全,对复杂地层条件下深基坑施工对下卧地铁结构影响的研究工作尤为重要。本文依托西安地铁1号线mP河东站与长乐坡站之间的东环广场建设工程,借助土工离心试验和数值模拟两种手段,重点对东环广场深基坑开挖及基坑底部桩基加载对隧道结构位移及力学性质的影响进行研究。通过研究得出以下结论:1.在基坑开挖过程中,隧道结构的应力、压力以及横竖向位移受到较为明显的影响。隧道周围应力、压力均呈现出减小趋势,且隧道顶部变化最为显著。分析隧道横竖向位移数据可知,隧道竖向位移变化量大于横向位移变化,隧道整体表现为被“拉长”的趋势。2.随着基坑底部桩基加载的进行,隧道结构的应力、压力及隧道横竖向位移增加量均较小。隧道底部压力及应力增加量大于隧道顶部,隧道两侧应力及压力增加量大致相同。分析隧道横竖向位移可知,竖向位移变化最大处为隧道顶部,水平位移变化最大处为隧道外侧。3.桩基加载过程中,双线隧道内侧距离桩基最近的隧道截面处压力、应力以及水平位移变化值相对于隧道其他截面较大。且隧道末端远离桩基处应力变化量小于桩基处隧道中部应力受到桩基加载的影响。4.在深基坑施工过程中,基坑开挖对隧道结构各因素的影响程度明显大于桩基加载对隧道结构的影响。
[Abstract]:In recent years, the position of subway in today's society is more and more irreplaceable. Because a large number of subway tunnel structures shuttle intricate through the city, the structure of its underground space is particularly complex, so it brings great problems to the construction of foundation pit overlying subway structure, which is a little careless. It will cause serious engineering accidents such as the damage of subway structure. In order to ensure the safety of the project, it is particularly important to study the influence of deep foundation pit construction on the structure of lying subway under the condition of complex strata. Based on the construction project of Donghuan Square between mP Hedong Station and Changle Slope Station of Xi'an Metro Line 1, with the help of geotechnical centrifugal test and numerical simulation, this paper relies on the construction project of Donghuan Square between Hedong Station and Changle Slope Station of Xi'an Metro Line 1. The influence of excavation of deep foundation pit of Donghuan Square and loading of pile foundation at the bottom of foundation pit on the displacement and mechanical properties of tunnel structure is studied in detail. Through the study, the following conclusions are drawn: 1. In the process of foundation pit excavation, the stress, pressure and transverse and vertical displacement of tunnel structure are obviously affected. The stress and pressure around the tunnel show a decreasing trend, and the change of the top of the tunnel is the most significant. By analyzing the horizontal and vertical displacement data of the tunnel, it can be seen that the variation of the vertical displacement of the tunnel is larger than that of the transverse displacement, and the overall trend of the tunnel is "elongated". 2. With the loading of pile foundation at the bottom of foundation pit, the increase of stress, pressure and transverse and vertical displacement of tunnel structure is small. The increase of pressure and stress at the bottom of the tunnel is larger than that at the top of the tunnel, and the increase of stress and pressure on both sides of the tunnel is about the same. Through the analysis of the horizontal and vertical displacement of the tunnel, it can be seen that the maximum variation of the vertical displacement is at the top of the tunnel, and the maximum change of the horizontal displacement is on the outside of the tunnel. In the process of pile foundation loading, the pressure, stress and horizontal displacement of the tunnel section closest to the pile foundation on the inside of the double-line tunnel are larger than those of the other sections of the tunnel. And the stress variation at the end of the tunnel far from the pile foundation is less than that at the middle of the tunnel affected by the loading of the pile foundation. 4. In the process of deep foundation pit construction, the influence of foundation pit excavation on each factor of tunnel structure is obviously greater than that of pile foundation loading on tunnel structure.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451;TU753

【共引文献】