考虑蠕变的邻近地铁隧道深基坑开挖工序优化  

Deep Foundation Pit Excavation Procedure Optimization Considering Creep Deformation on Nearby Metro Tunnel

作　　者：刘继强[1] 李元海[2] 林志斌[2] 桂常林[2] 

机构地区：[1]北京交通大学,北京100044 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《铁道工程学报》2014年第9期108-114,共7页Journal of Railway Engineering Society

基　　金：国家自然科学基金项目(51174197)

摘　　要：研究目的：针对现有软土地层邻近地铁深基坑开挖工序研究没有考虑软土的流变特性且缺乏系统性的情况，以深圳地铁11号线前海湾车站为工程背景，通过考虑淤泥地层的蠕变特性，模拟研究基坑不同横向、纵向分块和竖向分层开挖对基坑和邻近地铁隧道的变形影响，以期为前海湾站基坑的开挖工序选择提供理论依据。研究结论：（1）当基坑水平向只横向分块时，应先开挖远离隧道一侧的基坑土体；（2）基坑竖向分层开挖、只纵向或横向分块开挖时，桩最大水平位移与分块数呈指数关系；水平方向不分块时，竖向分层开挖厚度控制在1．5—2n3之间可使基坑靠近隧道一侧桩体最终变形值减小9％；（3）在分块数相同且不改变支撑架设的条件下，基坑横向分块且远离隧道一侧先开挖的效果最好，其次为横向和竖向都分块，最后为纵向分块；（4）研究结果对前海湾车站基坑以及类似深基坑工程的施工具有指导意义。Research purposes： The existing researches about excavating procedures of deep foundation pit on nearby metro tunnel in soft formation are lack of systematicness, and creep characteristics of soft clay are not usually taken into consideration. This paper takes Qianhaiwan station of Metro Line 11 in Shengzhen as engineering background and considers creep characteristics in sludge formation. The influence of step excavation in the transversal, longitudinal and vertical directions on the deformation of foundation pit and nearby subway tunnel are simulated, which may be expected to provide theoretical basis for choosing foundation pit excavation procedure of Qianhaiwan station. Research conclusions： （ 1 ） The segment far away from tunnel should be excavated firstly when only transversal step excavation was undertaken along the horizontal direction of foundation pit. （2）The maximum horizontal displacement of the piles show exponential relations with the number of segments when step excavation of foundation pit was undertaken in vertical and transversal or longitudinal. If thickness of every step excavation was limited in 1.5 -2 m, the horizontaldisplacement of the pile near tunnel can be reduced about 9 percent when there is no horizontal step excavation. （3） Transversal step excavation with segments far from tunnel excavated firstly was found to be the best step excavation method under the same condition of step number and support, and longitudinal and transversal step excavation followed while longitudinal step excavation was the last. （4） The research results have guiding significance for foundation pit of Qianhaiwan station and similar projects.

关 键 词：蠕变 开挖工序 数值模拟 

分 类 号：TB657[一般工业技术—制冷工程]