西安地铁2号线面临的技术挑战（地裂缝）

西安地铁2号线是西安的第一条地铁线路，它穿过了13条地裂缝中的10条，西安地裂缝是在西安正断层纽的基础上发育起来的，地裂缝的变形具有不可抗拒性和巨大的破坏性，会给隧道结构带来致命的危害，地裂缝引起的隧道结构破坏模式有两种：拉张一挤压破坏型和直接剪断破坏型。通过分析地裂缝的活动特征，估算出2号线沿线地裂缝的最大垂直位移量及百年变形量，分别阐述明挖法、浅埋暗挖法的结构处理方案，地裂缝处理的接头方案，地裂缝处的结构防水等技术措施。

Technical Measures for Xi'an Subway Line 2 to Traverse Ground Fissures

Xi'an subway Line 2 is the first subway line in Xi'an which passes through ten of the thirteen ground fissures in the city.This paper introduces the causes of the formation of ground fissures and their effect on subway Line 2.There are two modes of damage to tunnel structures caused by fissures:tension-squeeze mode and direct shear mode.Maximum vertical displacements and one hundred years' deformations of the ground fissures along Line 2 are estimated by analyzing the activities of ground fissures.Options of structural treatment for open-cut and bored excavation,options for joint treatment at ground fissures,technical measures of structural waterproofing at ground fissures are put forward.