摘要
以新建宝鸡至兰州客运专线的朱家山隧道为背景,开展了软弱围岩断层破碎带条件下特长铁路隧道试验段的2组现场试验,完成了拱顶下沉、水平收敛、围岩压力、初期支护喷射混凝土应力、钢架受力、初支与二衬间压力及二衬混凝土应力等项目的现场测试,并对测试结果进行了详细分析.结果表明:在施工工法及支护参数基本一致的条件下,变质砂岩中隧道变形及受力要大于千枚岩;试验断面隧道变形超过控制标准,需调整施工方案并辅以相应的变形控制措施;围岩压力及初期支护应力受台阶施工影响明显,拱墙二次衬砌施工后,测值趋于稳定;初支承担了部分荷载,使得二衬受力减小;部分位置喷射混凝土出现了受拉开裂现象,部分钢架应力接近材料容许应力,二衬混凝土应力在容许范围内.研究结论以期为类似工程提供借鉴与参考.
Based on the engineering practice of Zhujiashan tunnel of a new-built passenger transport line from Baoji to Lanzhou, two groups of field experiments on broken surrounding rock zone in super long railway tunnel are carried out. The test includes crown settlement, convergence displacement, surrounding rock pressure,concrete stress and steel frame stress of primary support, pressure between primary support and secondary lining, and concrete stress of secondary lining. Results of the test are： Firstly, with the approximately coincident construction method and support parameters, tunnel deformation and stress of metasandstone is larger than that of phyllite. Secondly, tunnel deformation of two test sections is larger than relevant standard; therefore,construction scheme should be adjusted with corresponding measures. Thirdly, rock pressure and stress of primary support are obviously affected by step construction. After construction of secondary lining of arch wall,rock pressure and stress of primary support begin to stabilize. Fourthly, certain load is undertaken by primary support and stress of secondary support will be reduced. Finally, concrete of some places cracks under tension.Besides, stress of some steel frames is near allowable stress. The conclusions presented can be used for reference in design, construction and site monitoring of similar tunnels in the future.
出处
《江西理工大学学报》
CAS
2017年第3期20-29,共10页
Journal of Jiangxi University of Science and Technology
关键词
特长铁路隧道
软弱围岩破碎带
试验段
变形
应力
现场测试
super long railway tunnel
broken surrounding rock zone
test section
deformation
stress
in-situ monitoring
