摘要
研究目的：兰州地区的工程水文地质条件特殊，关于地铁深基坑的桩撑支护设计、施工监测及数值模拟研究尚属空白。本文以兰州地铁世纪大道站基坑为例对桩撑支护结构设计为例，对桩顶水平位移、桩体水平位移、内支撑轴力和地表沉降监测结果进行研究。研究结论：（1）基坑开挖初期，桩身呈向坑内变形的前倾型曲线，随着基坑的开挖和支撑的安装，桩身变形曲线逐渐向“）”形变化，最大水平位移发生的位置也随之下移，一般出现在桩体中部的4—10m范围，约为坑深的1／3—2／3；（2）基坑开挖过程中，实测圈梁水平位移一般为5～10mm，远小于规范30mm控制值；（3）桩底附近仍有少量位移，说明将支护桩嵌固段作为固定端的设计方法有待完善；（4）地表沉降和水平位移大小分布是对应的，基坑周边土体呈现沉降一隆起一沉降一隆起一沉降状态，最大地表沉降约位于基坑外侧1／3倍坑深处；（5）采用有限元软件ADINA模拟基坑开挖过程，将有限元计算值与实际监测结果进行对比，发现二者比较接近，发展变化趋势几乎一致，说明有限元分析的结果可靠，桩撑支护结构支护效果理想；（6）本研究成果可为类似深基坑工程的设计和施工提供借鉴。
Research purposes： With special engineering and hydrological geological conditions in Lanzhou, the research about pile -strut supporting design, construction monitoring and numerical simulation of subway deep foundation pit is still blank. In this paper, taking the pile - strut supporting structure design of Lanzhou Century Avenue Metro station excavation as the example, horizontal displacement of pile top, lateral displacement of piles, axial force of support and the surface subsidence monitoring results are studied. Research conclusions ： （ 1 ） The initial excavation, pile was forward curve deformation to the pit, with the excavation and support installation, curve of pile gradually to the deformation ＂ ） ＂ shape change, the position of maximum horizontal displacement occurred is also down. The maximum displacement of pile body generally appears in the middle part of the pile body 4 - 10 m range and about 1/3 to 2/3 of deep excavation. （2） During the process of excavation, measured horizontal displacement of ring beam is about 5 - 10 mm, and it is far less than 30 mm of specification control values. （3） There is still a small amount displacement near the bottom of the pile, the design methods supporting piles embedded solid segment as fixed end need to be improved. （4）Surface subsidence and horizontal displacement size distribution are mutually corresponding, soil around the pit present settlement - uplift - subsidence - uplift - settlement status, the maximum surface settlement located outside pit and approximately 1/3 times the depth of the pit. （5）Using the finite element software ADINA to simulate the process of foundation pit excavation, finite element calculation values are compared with the actual monitoring results, it is found that their values are close, development trends are almost the same, and the results of finite element analysis is reliable and the supporting effect of the pile - strut supporting structure is ideal. （6）It can provide a reference for the follow -up design and construction.
出处
《铁道工程学报》
EI
北大核心
2014年第1期82-88,共7页
Journal of Railway Engineering Society
基金
甘肃省自然科学基金资助项目(No.1208RJZA158)
甘肃省高等学校基本科研业务费资助项目
兰州理工大学红柳青年教师培养计划资助项目(No.Q201108)
关键词
地铁深基坑
桩撑支护结构
位移
支撑轴力
数值模拟
deep excavation of metro
pile - strut supporting structrue
displacement
axial force of support
numerical simulation
