中文摘要：

以西安地铁工程为背景,对穿越地裂缝带的地铁隧道在地裂缝活动时的变形特征进行了研究.在此基础上,对穿越地裂缝带的整体式地铁隧道的监测部位和监测方法提出了建议.通过对整体式大型物理模型试验结果的分析,认为当地裂缝活动时,在靠近地裂缝下盘3H范围内的隧道变形量较大,变形使下盘隧道顶部受拉,底部受压.位于上盘的隧道在全长范围内都有变形,并在隧道底部产生部分脱空现象,脱空区的长度与隧道的埋深、长度、土与隧道的刚度比等因素有关.当变形或脱空区长度超过隧道的允许变形值时,将引起隧道顶部混凝土的开裂,引发漏水等不良现象,影响隧道的安全运营.在对试验成果分析的基础上,提出整体式地铁隧道的安全监测内容应包括：1）地裂缝两侧隧道的相对垂直位错 2）隧道底部脱空区的长度 3）隧道结构的应力变化幅度.针对上述变形特征及监测内容,提出了监测点的合理布置范围及采用的监测方法.

英文摘要：

This paper is inclined to present its research results of investigation and analysis of the engineering background of Xi＇ an subway tunnel system, particularly, of the deformational features of the subway tunnel parts that cross the ground fissures belt still in activities. And, then, based on the research results, we have checked the monitoring sites and put forward the well-designed monitoring and protective measures to guarantee the tunnel safety. The results of our investigation also show that, while the ground fissures were in activi- ties, maximum deformation in the tunnel would occur within the range of 3H near the ground fissure on the foot-wall, which is likely to lead to a strong pressure and compression at the bottom of the fissure zone. At the same time, deformations would also come about within the whole range of the tunnel system along the hanging parts of the wall of the ground fissure in some places at the bottom. The length of such void zones may have something to do with the burial depth, the longitudinal length of the tunnel, and/or the stiffness ratio of soil and tunnel. When the deformation of the tunnel or the length of the void zone between the tunnel and the soil exceed the tolerable limitations, the concrete at the top of the tunnel are likely to get cracked down and lead to some adverse disasters, such as leaking and collapse, which may endanger the traffic safety of the whole subway system. Based on the analysis of the above testing results, we have worked out the entire tunnel-safety monitoring items as follows： （1） Relatively vertical dislocation of tunnels on both sides of the ground fissure; （2） The length of the void beneath the subway tunnel; （3） The stress variation scope of the tunnel structure. In view of the deformation characteristics and monitoring necessities, we have proposed a set of reasonable monitoring methods and the corresponding monitoring mea- sures to prevent and protect from unexpected traffic accidents.