地铁隧道相交地裂缝的破坏特征及结构抗裂设计  

Failure characteristics of ground fissures in metro tunnel intersection and structural anti-crack design

作　　者：孟振江[1,2] 彭建兵[1,2] 黄强兵[1,2] 邓亚虹[1,2] 范仲杰 

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]长安大学西部矿产资源与地质工程教育部重点实验室,陕西西安710054

出　　处：《长安大学学报（自然科学版）》2016年第6期88-97,共10页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(41372327);国家自然科学基金面上项目(41372328);国家重点基础研究发展计划(973)项目(2014CB744700);中央高校基本科研业务费专项资金项目(310826151046);京津冀地区地面沉降地裂缝调查及地质环境监测项目(DD20160235)

摘　　要：地裂缝是西安典型的地质灾害,对地铁建设造成很大威胁,引起了社会各界的广泛关注。进行地裂缝活动引起地铁隧道的变形破坏特征研究,尤其是针对性地研究地裂缝与地铁隧道在空间交汇处的运移特点及隧道结构的抗裂设计参数具有重要的理论和现实意义。在分析西安地裂缝基本特征的基础上,以地铁5号线隧道工程穿越地裂缝情况为具体研究背景,详细论述了与隧道相交处地裂缝的发育特征,揭示了地裂缝活动造成的地表及剖面上的破坏特点,并分析了现阶段沿线地裂缝的活动速率,确定了在空间上隧道与地裂缝的实际交汇位置。根据地裂缝年活动速率监测资料,对地铁设计使用期内隧道与地裂缝交汇处的最大垂直位移量进行了预测,并在此基础上结合地裂缝与隧道的夹角及其倾角,根据空间几何关系换算得出隧道结构三维抗裂预留位移参数,最后通过数值模拟分析对分段隧道扩大断面的适应性进行了验证。研究结果表明:与地铁斜交的地裂缝活动会引起相邻分段隧道结构产生竖向位错、横向扭曲及轴向拉伸等变形破坏;上盘隧道净空量满足预留设计要求;该研究成果可为在地裂缝活动环境下西安地铁隧道的结构设防措施提供参考与指导。Ground fissure is a kind of typical geological disaster in Xi＇an,which poses a serious threat on Xi＇an metro tunnel construction,causing the extensive concern of society from all walks of life.Study of ground fissure activity caused deformation and failure characteristics of metro tunnel,especially targeted research on migration characteristics of the intersection at ground fissure and subway tunnel in space and tunnel structure anti-cracking design parameters,has important theoretical and practical significance.Based on analysis of the essential characteristicsof ground fissures in Xi＇an,taking Xi＇an metro tunnel of line 5passing through ground fissures as research background,the developmental characteristics connected with tunnel were discussed in detail,failure characteristics of plane and profile caused by ground fissures near the metro line were revealed,activity rate at this stage were analyzed,and locations of the actual space intersected between tunnel and ground cracks were determinate.According to monitoring data of activity rate of ground fissures,the top vertical displacements of ground fissure were predicted in metro＇s designed operation period.Three-dimensional reserved displacements were obtained according to conversion of the geometrical relationship combined with the included angle and dip angle.At last the adaptability of enlarged section tunnel was numerical simulated.The results show that ground fissure activity oblique crossing with tunnel can make the adjacent section deforms,including vertical dislocation,horizontal distortion and axial tensile deformation.And the reserved clearance of upper plate of tunnel meets the requirement of design.The conclusions can provide references and guidance for fortification measures of Xi＇an metro tunnel structure under the active environment of ground fissures.

关 键 词：隧道工程 西安地铁 地裂缝 活动特征 隧道结构 预留位移 

分 类 号：U452[建筑科学—桥梁与隧道工程]