三类勘察场地地裂缝活动对地铁隧道的影响

发布时间：2018-03-19 22:04

本文选题：隧道工程　切入点：地铁隧道　出处：《交通运输工程学报》2017年02期 　论文类型：期刊论文

【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。
[Abstract]:Taking the ground fissures of the subway tunnel through three kinds of exploration sites in Xi'an as the research prototype, the characteristics of the ground fissures are analyzed, and the formation stress field caused by the different activity values of the ground fissures in the three kinds of sites are studied by using the numerical simulation method. The variation characteristics of failure region and displacement field are calculated, and the damage characteristics of subway tunnel structure caused by ground fissure zone activity are analyzed. The corresponding engineering countermeasures are put forward. The results show that the vertical stress of the strata on both sides of the ground is approximately antisymmetric due to the activity of the ground fracture, and the increment of the formation stress increases with the increase of the upper plate settlement. Based on the comprehensive analysis of the vertical stress variation characteristics of the subways at the arch top and the bottom of the tunnel, the main influence ranges of the upper and lower face of the ground fissures are 0 ~ 20 m and 0 ~ 15 m respectively, which are consistent with the results of the physical model test. Shear failure occurs in the area near the ground fissure, and the fracture gradually extends upward, finally forming a shear failure envelope line with an angle of 18 掳to the ground fissure, the range of which is the concentrated area of shear failure. The ground fissures cause displacement abrupt changes on both sides of the soil mass, forming two deformation areas similar to "active wedge", and the range of this area is gradually expanding, and the differential settlement of the downboard tunnel increases with the increase of fault momentum of the ground fissure. When the local crack activity reaches 20cm, it causes the integral subway tunnel to take the form of "S" failure, and to adapt to the large deformation caused by the ground fissure activity of three kinds of sites, It is suggested that the subway tunnel structure should be fortified with special deformed joints and flexible joints.
【作者单位】：长安大学地质工程与测绘学院;长安大学西部矿产资源与地质工程教育部重点实验室;亚利桑那大学工程学院;
【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)
【分类号】：U231.1;U452.11

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