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为揭示隧道底部脱空与结构纵向变形之间的对应关系,模型试验以西安地铁隧道穿越地裂缝带为研究背景,采用圆形地铁隧道结构,研究了在不同地裂缝剖面活动特征下的隧道纵向应变变化规律及其垂直位移。试验结果表明,随着错位量增加,隧道底部脱空区域扩展过程可分为3个阶段:共同变形阶段、临界脱空阶段和脱空发展阶段。针对地裂缝的不同剖面活动形式,隧道结构内部应力将出现很大差异,建议在施工中对应不同地裂缝带采取不同的施工方案。通过监控,结合模型试验的应力应变发展变化规律,可判断结构底部脱空的发展趋势,为西安地铁穿越地裂缝带的结构设计和安全运行提供重要的参考依据。
In order to reveal the correspondence between the tunnel bottom emptying and the longitudinal deformation of the structure, the model test is based on the study of Xi’an subway tunnel crossing the ground fissure zone. By using the circular subway tunnel structure, Strain changes and its vertical displacement. The experimental results show that with the increase of dislocation, the expansion process at the bottom of the tunnel can be divided into three stages: common deformation stage, critical emptying stage and emptying stage. In view of the different forms of ground fissures, the internal stress of the tunnel structure will be greatly different. It is suggested to adopt different construction schemes corresponding to different ground fissures in the construction. By monitoring and combining with the rule of stress and strain of model test, the development trend of void at the bottom of structure can be judged, which provides an important reference for the structural design and safe operation of Xi’an metro through the ground fissure zone.