Mechanical Responses of Single-Pressure Arch-Shaped Open Tunnel Structure under Rockfall Impaction
-
摘要: 为进一步了解结构受力情况,为明洞结构设计提供依据,采用动力有限元方法,对客运专线双线单压式拱形明洞落石冲击下结构力学响应进行了研究.首先,以竖直下落冲击为基本工况,从落石与洞顶回填土的相互作用及运动轨迹入手,分析了结构的应力、应变、应变率、位移、速度、加速度等作用效应响应;其次,根据落石、回填土及结构间能量的转化与传递规律,结合结构及基底应力响应,阐述了回填土和混凝土填充材料对落石冲击的缓冲和对结构的保护作用机理,以及边墙形式对基底及仰拱受力的影响;最后进行了45斜向冲击响应分析并与基本工况进行了对比.研究结果表明:所设计的明洞结构可以承受竖向700 kJ的落石冲击能量,拱顶、拱肩及墙身内侧和耳墙墙址等部位是相对受力不利位置,回填方式和直墙式拱墙形式有待进一步研究优化;冲击引起的结构应变率响应介于110-3~110-2 s-1,与地震引起的响应范围相同;在本研究工况下,45斜向冲击作用效应总体上小于竖直冲击.Abstract: To learn the stress state and provide a design basis for open tunnel structures, the mechanical response of a single-pressure arch-shaped open tunnel structure on a double-line passenger dedicated line is analyzed using dynamic finite element method. Firstly, regarding the vertical drop impaction as the basic condition, interactions between rockfall and backfill soil on the tunnel top, as well as the motion trajectory of rock-fall, are analyzed to study responses of the tunnel structure in terms of stress, strain, strain rate, displacement, velocity and acceleration. Secondly, according to the law of energy conversion and transmission among rockfall, concrete backfill materials and tunnel structure, the mechanisms of backfill soils acting as buffering cushions and concrete-filled materials as structure protection to rockfall impaction are explained through stress responses of the side wall and ground basement, and influences of the structural form of the side wall on the mechanical performance of the ground basement and the inverted arch of open tunnel are also discussed. Finally, the dynamic responses of the tunnel structure under 45 oblique rockfall impaction are analyzed and compared with those in the basic condition. The results show that the designed open tunnel can bear 700 kJ vertical impaction energy of rockfall while substructures such as apex of arch, spandrel, inner side of the arch wall and corner of the ear wall are relatively weak parts in bearing the stress; thus the way of backfill and the structural form of the side wall in the open tunnel need to be further optimized. Strain rates of the open tunnel structure caused by rockfall impaction are found limited in the range of 10-3~10-2 s-1, which is the same as that caused by earthquake. Under the condition of this research, the effect on the open tunnel structure from oblique rockfall impaction is generally less than that from vertical drop impaction.
-
Key words:
- rock-fall impaction /
- arch-shaped open tunnel /
- backfill soil /
- dynamic finite element
-
王玉锁,杨国柱. 隧道洞口段危岩落石风险评估[J]. 现代隧道技术,2010,47(6): 33-39. WANG Yusuo, YANG Guozhu. Rockfall risk assessment for a tunnel portal section[J]. Modern Tunneling Technology, 2010, 47(6): 33-39. 王玉锁. 高速铁路隧道洞口段危岩落石运动轨迹及冲击特性研究[J]. 学术动态,2011(2): 16-21. 王全才,王兰生,李宗有,等. 都汶路恢复重建中的主要地震次生山地灾害与明洞工程[J]. 山地学报,2011,29(3): 356-361. WANG Quancai, WANG Lansheng, LI Zongyou, et al. Open tunnel engineering and secondary disasters of earthquake in the post-earthquake reconstruction projects along Duwen Road[J]. Journal of Mountain Science, 2011, 29(3): 356-361. 中华人民共和国交通部. JTG D702004公路隧道设计规范[S]. 北京:人民交通出版社,2004. 中华人民共和国铁道部. TB10032005 铁路隧道设计规范[S]. 北京:中国铁道出版社,2005. 铁道第二勘测设计院. 铁路工程设计技术手册:隧道[M]. 北京:中国铁道出版社,1999: 142-145. 张慧玲,唐辉,唐元峰,等. 高速铁路护桥棚洞结构:中国,ZL 2011 2 0212046.1[P]. 2012-05-23. MOUGIN J P, PERROTIN P, MOMMESSIN M, et al. Rock fall impact on reinforced concrete slab: an experimental approach[J]. International Journal of Impact Engineering, 2005, 31(2): 169-183. DELHOMME F, MOMMESSIN M, MOUGIN J P, et al. Behavior of a structurally dissipating rock-shed: experimental analysis and study of punching effects[J]. International Journal of Solids and Structures, 2005, 42(14): 4204-4219. RONCO C, OGGERI C, PEILA D. Design of reinforced ground embankments used for rockfall protection[J]. Natural Hazards Earth System Science, 2009, 9(4): 1189-1199. KISHI N, KONNO H, IKEDA K, et al. Prototype impact tests on ultimate impact resistance of PC rock-sheds[J]. International Journal of Impact Engineering, 2002, 27(9): 969-985. 何思明,沈均,吴永. 滚石冲击荷载下棚洞结构动力响应[J]. 岩土力学,2011,32(3): 781-788. HE Siming, SHEN Jun, WU Yong. Rock shed dynamic response to impact of rock-fall[J]. Rock and Soil Mechanics, 2011, 32(3): 781-788. 王玉锁,李俊杰,李正辉,等. 落石冲击力评定的离散元颗粒流数值模拟研究[J]. 西南交通大学学报,2016,51(1): 22-29. WANG Yusuo, LI Junjie, LI Zhenghui, et al. Assessment of rockfall impact force by particle flow code numerical simulation based on discrete element model[J]. Journal of Southwest Jiaotong University, 2016, 51(1): 22-29. 王琦,王玉锁,耿萍. 橡胶缓冲垫层保护下棚洞结构落石冲击力学响应研究[J]. 铁道建筑,2017(2): 64-67. WANG Qi, WANG Yusuo, GENG Ping. Research on mechanical response of tunnel shed with protective rubber cushion subjected to impact of rockfall[J]. Railway Engineering, 2017(2): 64-67. WANG Yusuo,TANG Jianhui,YAN Tao, et al. Model test investigation of rock-fall impaction to cut-and-cover tunnel arch structure[J]. Applied Mechanics and Materials, 2011, 90-93: 2492-2499. 程选生,杜永峰. 正交各向异性钢筋混凝土板结构弹性常数的确定[J]. 四川建筑科学研究,2006,32(5): 30-33. CHENG Xuesheng, DU Yongfeng. Confirm of elasticity cofficient about or thotropic plates of reinforced concrete[J]. Sichuan Building Science, 2006, 32(5): 30-33. 曾廉. 明洞顶设计荷载的研究[J]. 铁路标准设计通讯,1974(7): 3-17. ZENG Lian. Research on designing load on top of open cut tunnel[J]. Railway Standard Design Communication, 1974(7): 3-17. 李敏. 材料的率相关性对钢筋混凝土结构动力性能的影响[D]. 大连:大连理工大学,2011. 高原. 混凝土动力强度与静力强度的关系探讨[D]. 北京:清华大学,2008. 中华人民共和国住房和城乡建设部.GB 500102010 混凝土结构设计规范[S]. 北京:中国建筑工业出版社,2010.
点击查看大图
计量
- 文章访问数: 493
- HTML全文浏览量: 68
- PDF下载量: 187
- 被引次数: 0