北京地铁车站深基坑地表变形特性研究  

RESEARCH ON CHARACTERISTICS OF GROUND SURFACE DEFORMATION DURING DEEP EXCAVATION IN BEIJING SUBWAY

作　　者：李淑[1] 张顶立[1] 房倩[1] 卢伟[2] 

机构地区：[1]北京交通大学隧道及地下工程教育部工程研究中心,北京100044 [2]中国科学院大气物理研究所东亚区域气候–环境重点实验室,北京100029

出　　处：《岩石力学与工程学报》2012年第1期189-198,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2010CB732102);国家自然科学基金青年基金项目(51108020)

摘　　要：为明确北京地区地铁车站深基坑开挖引起的地表变形规律,对北京地铁30个明挖车站的现场实测数据进行统计分析,并将分析结果与国内外类似工程进行对比。研究表明:(1)北京地铁车站深基坑开挖引起的地表变形最终表现为"凹槽形"。最大沉降发生在拆除坑底以上1～2道支撑时,距基坑侧壁10～15 m。(2)地表最大沉降值随开挖深度的增大而增大,随插入比的增大而减小,为(0.034%～0.316%)H,平均值为0.1%H。(3)地表最终变形值小于最大变形值。75%的测点最终沉降为0～20 mm,沉降大于30 mm的测点很少,仅占1.93%。(4)基坑开挖在引起地表沉降的同时还会导致地面隆起,但隆起值随开挖深度的加大而减小,最终的隆起量和隆起测点数较小。(5)基坑变形具有明显的时空效应:各测点的沉降速率随时间的推移、开挖深度的加大、尤其是排水固结的开始而逐渐加大,但随着内部结构的施作完成,变形逐渐趋于稳定;长边中点处变形值最大,边角处变形值最小,距坑壁30 m以外变形微小。该研究成果可为北京及其他地区类似工程的设计和施工提供参考,对防止基坑事故、避免资源浪费具有重要意义。In order to clarify the law of ground surface deformation due to deep excavation in Beijing, a database of 30 case histories of field monitoring on Beijing subway stations is analyzed; and the results are compared with worldwide case histories. Research shows that： （1） The final pattern of ground surface deformation is ＂groove shape＂ the maximum settlement is located at distances of about 10 to 15 m from the wall and occurs when the 1st to 2nd supports above the bottom are removed. （2） The maximum values of settlement, which range from 0.034%H to 0.316%H with a mean value of about 0.1%H, increases with the increase of H and decreases with the increase of insertion ratio. （3） The final values of deformation are less than the maximum ones. 75% of values of the monitoring points range from 0 to 20 ram, only 1.93% of that are larger than 30 ram. （4） Excavation can also lead to a small amount of ground upheaval; but the values of upheaval decrease with increasing excavation depth,and become very small finally. （5） Foundation pit deformation has obvious temporal and spatial effects; the settling rate increases gradually with time passing, excavation depth increasing, especially when drainage starts and the consolidation appears; but since the completion of the internal structure, deformation become stable. Values of deformation from transverse sections near the center of the excavations are largest and those from sections near the corners are the least. The settlement influence zone reaches to a distance of about 30 m from the excavation. The result can provide valuable references for the design and construction of similar projects in Beijing and other areas; it has great significance for preventing the foundation pit accident and avoiding the waste of resources.

关 键 词：土力学 北京地铁 深基坑 地表变形特性 现场实测 

分 类 号：TU44[建筑科学—岩土工程]