摘要
以地铁隧道穿越西安三类勘察场地的地裂缝为研究原型,分析了地裂缝的发育特征;运用数值模拟方法,研究了三类场地地裂缝不同活动量值引起的地层应力场、破坏区域和位移场的变化特征,计算了地裂缝的影响区域范围,解析了地裂缝带活动对地铁隧道结构产生的破坏特征,并提出了相应的工程对策。研究结果表明:地裂缝活动造成其两侧地层的竖向应力呈近似反对称的分布形态,地层应力的变化增量随上盘沉降的增加而增大;通过综合分析位于地铁隧道拱顶和拱底埋深处地层的竖向应力变化特征,得到三类场地地裂缝上盘和下盘的主要影响范围分别为0~20m和0~15m,经对比验证,与物理模型试验结果一致;下盘靠近地裂缝的区域发生剪切破坏,且破裂逐渐向上扩展,最终形成一条与地裂缝呈18°夹角的剪切破坏包线,其中间包含的范围为剪切破坏的集中区域;地裂缝活动导致两侧土体发生位移突变,形成2个类似"活动楔体"的变形区域,且该区域范围逐渐扩大;上、下盘隧道的差异沉降随着地裂缝错动量的增加而增大,当地裂缝活动量达到20cm时,造成整体式地铁隧道呈"S"破坏形态;为适应三类场地地裂缝活动引起的大变形,建议地铁隧道结构采用分段设置特殊变形缝加柔性接头处理等措施进行设防。
The ground fissures of Xi’an third-class surveying site that metro tunnels pass through were taken as research prototype, their development characteristics were analyzed. The variation characteristics of stress fields, failure zones and displacement fields caused by the different dislocation amounts of ground fissures in third-class surveying site were studied by using numerical simulation method, and the influence areas of fissure activity were calculated. The failure characteristics of metro tunnel structure caused by fissure activity were analyzed, and the corresponding engineering measures were proposed. Research result shows that the vertical stresses on both sides of ground layers present approximate anti-symmetric forms caused by ground fissure activity, and the mutative increments of stresses increase with the increase of hanging wall settlement. Based on comprehensively analyzing the variation characteristics of vertical stresses at the positions of vault and arch bottom of subway tunnel, the main influence ranges of hanging wall and footwall of ground fissure are 0-20 m and 0-15 m, respectively, which is consistent with the result of physical model test by contrasting verification. The footwall occurs shear failure near the ground fissure, the rupture spreads up gradually, a shear failure envelope line with 18° angle relative to the ground fissure forms, and the middle section is concentrated area of shear failure. The fissure activity leads to the displacement mutation of soils on its both sides, two deformation areas similar to active wedge forms, and expand gradually. The differential settlement amounts of metro tunnel on the hanging wall and footwall increase with the displacement increase of ground fissures. When the displacement of ground fissure is 20 cm, the deformation of integral metro tunnel is S-shape. In order to meet the large deformation caused by the activity of ground fissures in third-class surveying site, the special deformation gap-flexible joint treatment measure is proposed to fortify the structure of metro tunnel. 3 tabs, 14 figs, 29 refs.
作者
孟振江
彭建兵
黄强兵
邓亚虹
赵林浩
邢燕
MENG Zhen-jiang PENG Jian-bing HUANG Qiang-bing DENG Ya-hong ZHAO Lin-hao XING Yan(School of Geological Engineering and Geomatics, Chang＇an University, Xi＇an 710054, Shaanxi, China Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education, Chang＇an University, Xi＇an 710054, Shaanxi, China College of Engineering, University of Arizona, Tucson 85721, Arizona, USA)
出处
《交通运输工程学报》
EI
CSCD
北大核心
2017年第2期41-51,共11页
Journal of Traffic and Transportation Engineering
基金
国家973计划项目(2014CB744700)
中国地质调查局地质调查项目(DD20160235)
国家自然科学基金项目(41372327
41372328)
中央高校基本科研业务费专项资金项目(310826174001)
关键词
隧道工程
地铁隧道
数值模拟
三类勘察场地
地裂缝
结构设防
tunnel engineering
metro tunnel
numerical simulation
third-class surveying ground
ground fissure
structure fortification
