列车荷载作用下地裂缝与大角度斜交马蹄形地铁隧道动力相互作用研究

发布时间：2018-04-30 19:52

本文选题：地裂缝 + 列车荷载　；参考：《长安大学》2015年博士论文

【摘要】：西安城区的发展日新月异,伴随而来的交通拥堵问题也日渐突出。为缓解这一现状,西安市从2006年起,开始了地下铁道的建设。截止目前,西安已有地铁2号线、1号线两条线路先后完工并投入运营,地铁3号线已经开工建设并计划于明年建成通车,地铁4号线也处在开工前的准备阶段。由于地铁经过的路线中有大量地裂缝的存在,地铁建成运营后,在列车荷载作用下通过地裂缝地带的隧道能否保证列车的运营安全,呈现何种特点,这些都成为西安地铁建设中亟待解决的问题。本文以国家自然科学基金项目“地铁动荷载作用下的地层-地裂缝-隧道相互作用研究”为依托,以穿越地裂缝带的西安地铁项目为研究背景,设计并开展了地裂缝与地铁隧道大角度斜交的动力模型试验,结合数值模拟,对地裂缝与地铁隧道大角度斜交时在列车荷载作用下的动力特性进行了研究,取得的主要认识如下:(1)地铁行驶产生的振动在土层中各个方向传播时会有不同程度的衰减,地裂缝对地铁振动具有阻隔作用;(2)地裂缝附近隧道下方土层的振动要比上方土层强烈;地铁隧道的拱底部位相比拱腰和拱顶部位振动响应更强烈;(3)地裂缝未活动时,列车荷载所在位置的隧道下方土体的附加土压力较大;地裂缝上盘下降时,隧道上方的土体附加压力呈现上盘大、下盘小的分布规律,其余部位的土体呈现下盘大、上盘小的规律,其中位于下盘地裂缝附近的隧道底部附加土压力最大;(4)地裂缝未活动时,隧道底部与土体的接触附加压力较大;地裂缝上盘下降时,位于地裂缝附近的下盘隧道底部和上盘隧道顶部与土体的接触附加压力较大;(5)分段式隧道由于受到分段的影响,振动响应比整体式隧道强烈,单段长度越小此种现象越明显。分段式隧道对振动沿隧道纵向的传播相比整体式隧道具有更大的衰减作用。(6)车速越大,隧道及地层的振动响应越强烈,但振动在地层中传播时衰减的程度越大。(7)当地铁隧道与地裂缝大角度斜交时,在设计方面应该根据地裂缝的活动量来确定隧道结构。
[Abstract]:With the rapid development of Xi'an urban area, the traffic congestion problem is becoming more and more prominent. In order to alleviate this situation, Xi'an City from 2006, began the construction of subway. Up to now, Xi'an Metro Line 2 and Line 1 have been completed and put into operation. Subway Line 3 has started construction and is scheduled to be completed and opened to traffic next year, and Metro Line 4 is also in the preparatory stage before the start of construction. Due to the existence of a large number of ground cracks in the subway route, after the subway is built and operated, can the tunnel passing through the ground fissure zone under the train load ensure the safety of the train operation, and what kind of characteristics does it have? All these become the problems that need to be solved urgently in Xi'an subway construction. This paper is based on the National Natural Science Foundation project "study of Strata-ground fissure-Tunnel interaction under dynamic loads of Subway", and takes Xi'an Subway Project across the ground fissure Zone as the research background. The dynamic model test of large angle oblique intersection between ground fissure and subway tunnel is designed and carried out. Combined with numerical simulation, the dynamic characteristics of ground crack and subway tunnel with large angle skew under train load are studied. The main understanding obtained is as follows: (1) the vibration produced by the subway will attenuate in varying degrees when it propagates in all directions of the soil layer. Ground fissures have a barrier effect on subway vibration. The vibration of the soil layer below the tunnel near the ground fissure is stronger than that of the upper soil layer, and the vibration response of the arch bottom part of the subway tunnel is stronger than that of the arch waist part and the arch top part) when the ground fissure is not active, The additional earth pressure of the soil under the tunnel where the train load is located is larger; when the upper face of the ground fissure drops, the additional pressure of the soil above the tunnel presents the distribution law of the upper wall and the lower wall, and the soil in the rest of the tunnel presents the lower wall. The law of small upper face, in which the contact additional pressure between the bottom of the tunnel and the soil is larger when the ground fissure is not active, and when the upper face of the ground fissure falls, the maximum additional earth pressure at the bottom of the tunnel near the bottom of the ground fissure is not active. At the bottom of the tunnel and the top of the tunnel near the ground fissure, the contact additional pressure between the bottom of the tunnel and the soil is greater than that of the soil. (5) the vibration response of the segmented tunnel is stronger than that of the integral tunnel, and the smaller the length of the single section is, the more obvious this phenomenon is. The bigger the speed of segment tunnel is, the stronger the vibration response of tunnel and stratum is compared with that of integral tunnel. But the greater the attenuation degree of vibration propagates in the stratum, the more the tunnel structure should be determined according to the activity of ground fissures when the subway tunnel is inclined to the ground fissure at a large angle.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U451.3

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