摘要
以西安地铁隧道穿越骊山山前断裂为研究原型,分析了该断裂的活动特征,并基于近场区地震危险性分析结果,对断裂黏滑活动可能产生的地表最大垂直位错量进行了预测;运用数值模拟方法,研究了断裂错动造成地层与隧道的变形响应特征,并对分段隧道结构受损的临界位错量值进行了分析验证;计算了断裂活动的影响范围,确定了地铁隧道穿越断裂带的主要设防区域。研究结果表明,随着断裂位错量的增大,上盘地层的沉降响应表现较明显,上下盘地层的差异沉降区域集中在断裂带附近,并呈"倒三角"形状逐渐向两侧扩展;当断裂位错量大于20cm时,上下盘远离断裂带的地铁隧道差异沉降尤为严重;当上盘沉降量达到50cm时,相邻分段隧道产生拉张、位错破坏;基于隧道拱顶处地层的竖向位移变化特征,得到地铁隧道穿越该断裂带的最小纵向设防长度为上盘40m、下盘15m,经对比验证,数值模拟计算结果与现场勘察结论一致;最后提出了相应的设防建议措施。
Piedmont fracture of Mount Li that Xi^an metro tunnel pass through was taken as research prototype, and the activity characteristics were analyzed, and the biggest vertical displacement of the ground surface by the fault sticky slip activity was forecast based on the risk analysis results of earthquake in near field. T he responsive deformation and failure characteristics of stratum and subway tunnel caused by fracture dislocation were studied by using numerical simulation m e t h o d, and the critical dislocation amount of section tunnel structure damaged was analyzed and verified; the influence range of fracture activity were calculated, and the main fortification area of thesubway tunnel crossing the fault zone was determined. Research result shows that the settlement response of stratum on the hanging wall is more obvious with the increase of the amount of fracture dislocation, differential settlement areas of stratum between the hanging wall and foot wall are concentrate near the fracture zone, which extend to both sides taking on the shape of “inverted triangle” gradually. W h e n the amount of dislocation is greater than 20c m , the differential settlement of metro tunnel between the hanging wall and foot wall is particularly serious; the adjacent sectional tunnels appear tension and dislocation p h e nomena w h e n the dislocation of hanging wall is 50c m . Based on the changing characteristics of the stratum vertical displacement at the tunnel vault, the least longitudinal fortified lengths of subway tunnel passing through the fault zone are get, which are 40m on the hanging wall and 15m on the footwall. The experimental results are consistent with the field investigation results after contrasting and verifying. Finally, corresponding proposed measures for fortification are put forward.
出处
《工程地质学报》
CSCD
北大核心
2017年第6期1624-1632,共9页
Journal of Engineering Geology
基金
中国地质调查局项目(DD20160235)
国家重点基础研究发展计划(973计划)(2014CB744700)
国家自然科学基金项目(41772274)
中央高校基本科研业务费专项资金资助项目(310826174001)资助
关键词
断裂活动
地铁隧道
数值模拟
变形响应
设防长度
Fracture activity, Metro tunnel, Numerical simulation, Deformation response, Fortified length
