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| 1 | Behavior of noncircular tunnels excavated in stratified rock masses-Case of underground coal mines显示文摘The amount of tunnels excavated along stratified/sedimentary rock masses in Quangninh coal mine area,Vietnam, is gradually increasing. Rock mass in Quangninh is characterized by beddings between rock layers. The behavior of stratified rock masses surrounding the tunnels depends on both the intact rock and the beddings between rock layers. The main characteristics of stratified rock masses that need to be considered are their heterogeneity and anisotropy. Depending on the dip angle of rock layers, movements and failure zones developed surrounding the tunnels can be asymmetrical over the vertical axis of tunnel. This asymmetry causes adverse behaviors of the tunnel structures. The objective of this study is to highlight convergences and yielded zones developed in rock masses surrounding noncircular tunnels in Quangninh coal mine area using a finite element method. The presence of bedding joints is explicitly simulated. The numerical results indicated that with the increase in dip angle of bedding joints, the stress asymmetry over the tunnel vertical axis increases. It gradually leads to an asymmetry of the failure zone surrounding the tunnel. An increase of rock mass quality means a decrease of rock mass sensitivity to the discontinuities. In addition,a dip angle of the bedding joints of approximately 45° could be considered as the critical angle at which the rock mass mechanism changes between sliding and bending. | Ngoc Anh Do Daniel Dias Van Diep Dinh Tien Tung Tran Van Canh Dao Viet Doan Dao Phuc Nhan Nguyen | 2019 | Journal of Rock Mechanics and Geotechnical Engineering2019，11，1： | 9 |
| 2 | 不同岩层倾角深埋硬岩隧道围岩开挖变形研究显示文摘研究目的:深埋硬岩顺层构造由于其分层特性和结构形式的特点决定了在这样的地质环境中开挖隧道,其围岩受力之后的变形和破坏具有一定的特殊性.本文以拟建某高铁黄草隧道为例,就深埋隧道顺层硬岩组合围岩在不同岩层倾角下的开挖损伤变形开展数值模拟分析评价,主要研究不同岩层倾角下的隧道围岩变形、围岩屈服渐进性及稳定性,并给出强度折减至极限状态时硬岩组合隧道围岩的变形破坏模式.研究结论:(1)随着岩层倾角的增大,顺层硬岩组合隧道主变形从岩层弯曲变形逐渐向顺层滑移变形转变,倾角增大至一定程度时(>75°),垂直层面局部位移相对较大,在滑移变形为主的基础上弯曲变形程度加大;(2)硬岩组合的开挖引起洞室周边一定范围内的围岩发生屈服,岩层倾角变化导致围岩屈服区范围大小发生改变,倾角为30°时屈服范围最大,以此为界减小或增大倾角,屈服区均表现为不同程度的减小趋势;(3)岩层倾角存在界限值,硬岩组合黄草隧道为40°,小于或大于该值稳定安全系数均减小,10°~75°区间内稳定安全系数变化幅度最高达17%;(4)强度折减条件下,围岩破坏模式略有变化,表现为:倾角≤30°时,垂直于层面方向的位移量和破坏范围大,围岩以层裂(弯曲折断)破坏模式为主;当倾角>60°时,顺层面方向破裂范围大,但垂直层面破坏优先启动;(5)本研究成果对促进该高铁的顺利建设和今后类似工程的建设有着理论指导意义和工程价值. | 赖天文 雷浩 刘志强 李德武 | 2020 | 铁道工程学报2020，37，7： | 5 |
| 3 | 浅埋偏压隧道变形特征及施工方案优化显示文摘为研究隧道洞口浅埋偏压段的变形特征,采取现场隧道变形监测和围岩室内三轴率敏性试验相结合,建立隧道围岩的弹黏塑性本构模型.通过有限元软件ABAQUS的UMAT子程序开展了隧道变形三维弹黏塑性数值分析,探讨了隧道在三种开挖工法下的拱顶沉降、水平收敛位移、围岩最小主应力及围岩塑性区分布规律,以此确立合理有效的施工工法.研究结果表明:预留核心土法、三台阶法以及上下台阶法这三种施工工法引起的地表沉降,其深埋侧分别是浅埋侧的2.01,1.48,1.83倍,边墙两侧最小主应力则分别相差0.11,0.29,0.05 MPa,表明偏压隧道的应力场和位移场在开挖支护过程中呈现出不对称分布的特点;选出适宜的施工工法为上下台阶法,采用此工法可以使拱顶沉降及地表沉降减少11.7%~22.1%,而且在施工过程中支护结构受力最为合理,有利于偏压隧道的长期稳定. | 王智超 徐伟 张学兵 沈明燕 旷杜敏 | 2017 | 湘潭大学自然科学学报2017，39，3： | 5 |
| 4 | Study on calculation of rock pressure for ultra-shallow tunnel in poor surrounding rock and its tunneling procedure显示文摘A computational method of rock pressure applied to an ultra-shallow tunnel is presented by key block theory, and its mathematical formula is proposed according to a mechanical tunnel model with super-shallow depth.Theoretical analysis shows that the tunnel is subject to asymmetric rock pressure due to oblique topography. The rock pressure applied to the tunnel crown and sidewall is closely related to the surrounding rock bulk density, tunnel size, depth and angle of oblique ground slope. The rock pressure applied to the tunnel crown is much greater than that to the sidewalls, and the load applied to the left sidewall is also greater than that to the right sidewall. Meanwhile, the safety of the lining for an ultra-shallow tunnel in strata with inclined surface is affected by rock pressure and tunnel support parameters. Steel pipe grouting from ground surface is used to consolidate the unfavorable surrounding rock before tunnel excavation, and the reinforcing scope is proposed according to the analysis of the asymmetric load induced by tunnel excavation in weak rock with inclined ground surface. The tunneling procedure of bench cut method with pipe roof protection is still discussed and carried out in this paper according to the special geological condition. The method and tunneling procedure have been successfully utilized to design and drive a real expressway tunnel. The practice in building the super-shallow tunnelhas proved the feasibility of the calculation method and tunneling procedure presented in this paper. | Xiaojun Zhou Jinghe Wang Bentao Lin | 2014 | Journal of Modern Transportation2014，22，1： | 4 |
| 5 | 地质顺层偏压隧道锚杆支护参数优化及施工技术研究显示文摘地质顺层偏压隧道稳定性与非对称控制技术一直是工程界和学术界关注的关键科学问题.依托武汉至十堰高速铁路大坡岭隧道,采用现场岩体结构面产状现场量测和离散元数值模拟相结合的方法,研究地质顺层偏压隧道力学响应、非连续变形特征,优化锚杆支护设计参数.研究表明:各层岩体均相当于独立的处于受弯剪状态悬臂梁,结构面产生易剪切滑移或张开;锚杆支护可以提高节理面法向刚度和剪切刚度,从而增强节理面的抗变形能力和抗剪切强度;通过数值模拟优化,提出非对称锚杆支护方案,可节约钢筋50%以上,锚杆打设方向尽量与节理成大角度相交.研究成果可为今后类似地质顺层偏压隧道稳定性评价和锚杆支护优化提供参考. | 杨晓辉 | 2020 | 铁道建筑技术2020，，9： | 3 |
| 6 | 泥岩节理对泥砂岩互层隧道初期支护结构受力变形的影响显示文摘为探明泥沙岩互层隧道开挖中泥岩节理对隧道初期支护结构受力变形的影响,依托香山隧道施工开展了相关现场监测,分析了初期支护的收敛变形特征,并借助离散元软件3DEC,研究了不同岩层倾向、不同层理厚度及不同层理角度下初期支护的受力变形规律。结果表明,顺倾及反倾层状围岩在垂直于岩层节理的拱肩位置所产生的弯矩及位移较大,锚杆所受轴力较强,初期支护易在拱肩位置产生开裂破坏;随着围岩层理厚度的增加,初期支护结构拱肩位置的变形及弯矩均逐渐减小,初期支护破坏形式趋向于无节理岩体;随着岩层层理角度的增加,初支结构最大弯矩呈先增大后减小的趋势,且由拱腰向拱肩位置转移。对于泥沙岩互层隧道,可根据岩层节理对垂直于节理一侧的拱肩位置进行加固处理,以减小隧道收敛变形,保证施工安全。 | 李军 王永刚 郑军 尉敏 马晓博 高鑫 | 2023 | 公路2023，68，11： | 1 |
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