在超大埋深软岩中修建隧道,由于地应力高、围岩软弱,常常导致隧道产生大变形灾害。采用超前中导洞应力释放技术释放部分地应力,可使围岩中高地应力场转变为低地应力场,降低正洞扩挖时围岩作用于支护结构上的力,从而减小隧道变形,保证支护结构的安全。本文以滇藏铁路丽香段哈巴雪山隧道为依托,分析中导洞不同超前距离工况下隧道的变形量、初期支护结构受力及围岩塑性区大小,提出中导洞合理超前距离,并通过现场监测对其应用效果进行分析。结果表明:中导洞超前距离为2倍中导洞洞径时,隧道变形及围岩塑性区较小,支护结构受力较为合理,且现场实测隧道变形平均可减小44.52%,初期支护结构围岩压力、钢筋应力及喷混应力平均降低32%、35%、31%。
When tunnels are built in super deep soft rock, due to high geo-stress and weak surrounding rock, large deformation disasters often occur in tunnels. The middle pilot tunnel stress release technology is used to release part of the crustal stress, which can transform the high-ground stress field in the surrounding rock into the low-ground stress field, reduce the stress of the surrounding rock on the support structure when the main tunnel is expanded, thus reducing the tunnel deformation and ensuring the safety of the support structure. Therefore, relying on the Haba Snow Mountain Large Deformation Tunnel in the Lixiang section of the Yunnan Tibet Railway, literature research, numerical simulation, and on-site tests are used to study the tunnel deformation, initial support structure stress, and distribution of the loose zone of the surrounding rock under different advance distance conditions of the middle pilot tunnel. Finally, a reasonable advance distance for the middle pilot tunnel was proposed, and its application effect was analyzed through on-site monitoring. The results show that when the leading distance of the middle pilot tunnel is twice the diameter of the middle pilot tunnel, the deformation and plastic zone of the tunnel and surrounding rock are relatively small, and the stress on the support structure is relatively reasonable. Moreover, the average deformation of the tunnel measured on site can be reduced by 44.52%. The initial support structure reduces the surrounding rock pressure, steel stress, and shotcrete stress by an average of 32%, 35%, and 31%.
[1] 洪开荣, 冯欢欢. 近 2 年我国隧道及地下工程发展与思考(2019—2020年) [J]. 隧道建设(中英文), 2021, 41(8): 1259. (Hong Kairong, Feng Huanhuan. Development and thinking of tunnels and underground engineering in China in recent 2 years (From 2019 to 2020)[J]. Tunnel Construction, 2021, 41(8): 1259. (in Chinese))
[2] 王永刚, 丁文其, 刘志强, 等. 木寨岭隧道大变形分级标准与支护时机研究[J]. 地下空间与工程学报, 2020, 16(4): 1116-1122. (Wang Yonggang, Ding Wenqi, Liu Zhiqiang, et al. Classification standard of large deformation and construction time of second lining in Muzhailing Tunnel [J]. Chinese Journal of Underground Space and Engineering, 2020, 16(4): 1116-1122. (in Chinese))
[3] 袁飞, 包崇超, 王猛, 等. 红层软岩隧洞大变形特征及控制措施研究[J]. 地下空间与工程学报, 2022, 18(增1): 332-340, 349. (Yuan Fei, Bao Chongchao, Wang Meng, et al. Study on large deformation characteristics and control measures of red-bed soft rock tunnel [J]. Chinese Journal of Underground Space and Engineering, 2022, 18(Supp.1): 332-340, 349. (in Chinese))
[4] Su Z M. Analysis ofinfluence to primary support forces by stress release in loess tunnel[J]. Advanced Materials Research, 2014, 859:153-156.
[5] 赵勇. 隧道软弱围岩变形机制与控制技术研究[D]. 北京: 北京交通大学, 2012. (Zhao Yong Research on deformation mechanism and control technology of weak surrounding rock in tunnels [D] Beijing: Beijing Jiaotong University, 2012. (in Chinese))
[6] 夏才初, 金天垚, 徐晨, 等. 软岩隧道超前导洞应力释放力学机制及适用性[J]. 隧道建设(中英文), 2020,40(增2): 1-9. (Xia Caichu, Jin Tianyao, Xu Chen, et al. Mechanical mechanism and applicability of stress release for pilot heading in soft rock tunnel[J]. Tunnel Con-struction, 2020,40(Supp.2): 1-9. (in Chinese))
[7] 祁和刚, 于健浩. 深部高应力区段煤柱留设合理性及综合卸荷技术[J]. 煤炭学报, 2018, 43(12): 3257-3264. (Qi Hegang, Yu Jianhao. Rationality and comprehensive unloading technology of deep high stress section coal pillars[J]. Journal of China Coal Society, 2018, 43(12): 3257-3264. (in Chinese))
[8] 高攀, 张文新, 邹翀. 超前大钻孔应力释放方法在高地应力软岩隧道中的应用效果分析[J]. 隧道建设, 2013, 33(10): 820-825. (Gao Pan, Zhang Wenxin, Zou Chong. An Analysis on the effect of stress releasing by drilling in advance large-diameter boreholes: A Case study on high stress field soft rock tunnel[J]. Tunnel Construction, 2013, 33(10): 820-825. (in Chinese))
[9] 刘建国. 下导洞超前施工技术在大断面山岭硬岩隧道中的应用[J]. 现代隧道技术, 2009, 46(6): 102-105, 112. (Liu Jianguo. Advance bottom heading technology applied in hard rock mountain tunnels with large cross-section[J]. Modern Tunnelling Technology, 2009, 46(6): 102-105, 112. (in Chinese))
[10] 李廷春. 毛羽山隧道高地应力软岩大变形施工控制技术[J]. 现代隧道技术, 2011, 48(2): 59-67. (Li Tingchun. Large deformation control technology for Maoyushan Tunnnel in soft rock under high in-situ stresses[J]. Modern Tunnelling Technology, 2011, 48(2): 59-67. (in Chinese))
[11] 郭小雄, 刘艳青, 马伟斌. 高地应力软岩隧道超前导洞法施工围岩变形预释放规律分析[J]. 铁道建筑, 2011(12): 86-88. (Guo Xiaoxiong, Liu Yanqing, Ma Weibin. Analysis of pre release law of surrounding rock deformation during construction of high ground stress soft rock tunnel with ahead pilot tunnel method[J]. Railway Engineering, 2011(12): 86-88. (in Chinese))
[12] 周宗青, 李术才, 李利平, 等. 导洞超前开挖施工性态空间效应分析[J]. 岩石力学与工程学报, 2014(增1): 2611. (Zhou Zongqing, Li Shucai, Li Liping, et al. Analysis of spatial effects of advanced excavation construction behavior in pilot tunnels [J]. Chinese Journal of Rock Mechanics and Engineering, 2014(Supp.1): 2611. (in Chinese))
[13] 张梅, 徐双永, 张民庆, 等. 高应力软岩隧道超前导洞法应力释放试验研究[J]. 现代隧道技术, 2013, 50(4): 68-75, 83. (Zhang Mei, Xu Shuangyong, Zhang Minqing, et al. Experimental study of stress release using a pilot heading for a highly stressed soft—rock tunnel[J]. Modern Tunnelling Technology, 2013, 50(4): 68-75, 83. (in Chinese))
[14] 闫鑫. 高地应力软岩隧道超前应力释放变形控制机理及技术研究[D]. 北京: 中国铁道科学研究院, 2012. (Yan Xin. Research on deformation control mechanism and technology of advanced stress release in high ground stress soft rock tunnel [D] Beijing: China Academy of Railway Sciences, 2012 (in Chinese))
[15] 张宝瑾, 谭忠盛, 卫鹏, 等. 超大埋深软岩隧道超前中导洞合理断面尺寸及应力峰值转移机制[J]. 科学技术与工程, 2024, 24(17): 7334-7341. (Zhang Baojin, Tan Zhongsheng, Wei Peng, et al. Reasonable cross section size and stress peak transfer mechanism of middle pilot tunnel in super deep buried soft rock tunnel [J]. Science Technology and Engineering, 2024, 24(17): 7334-7341. (in Chinese))
[16] 王桂林, 陈瑶, 何晓樟. 软岩的损伤西原流变模型及FLAC3D实现[J]. 地下空间与工程学报, 2022, 18(1): 50-56. (Wang Guilin, Chen Yao, He Xiaozhang. Nishihara rheological model of soft rock considering damage and FLAC3D Implementation[J]. Chinese Journal of Underground Space and Engineering, 2022, 18(1): 50-56. (in Chinese))
[17] Lu R, Wei W, Shang K, et al.Stability analysis of jointed rock slope by strength reduction technique considering ubiquitous joint model[J]. Advances in Civil Engineering, 2020(1): 8862243.
[18] Guo X P, Jiang A N, Liu X. Back-analysis of parameters of jointed surrounding rock of metro station based on random forest algorithm optimized by cuckoo search algorithm[J]. Advances in Materials Science and Engineering, 2022, 1: 1718773.
[19] Leng X L, Wang C, Sheng Q, et al. An Enhanced ubiquitous-joint model for a rock mass with conjugate joints and its application on excavation simulation of large underground caverns[J]. Frontiers in Earth Science, 2021, 9: 744900.
[20] Yadav P. Numerical investigation of squeezing in underground hard rock mines[J]. Rock Mechanics and Rock Engineering, 2019, 52(4): 1211-1229.
