摘要
隧道穿越富水软弱地层时易发生开挖面滑塌失稳破坏,为此,本文以郑万高铁巴东隧道为工程依托、以巴东组紫红泥岩为研究对象,开展系列室内试验,揭示泥岩遇水软化的力学特征。综合考虑围岩节理发育及施工扰动等因素的影响,基于Hoek-Brown强度准则将室内试验获取的完整岩体的强度参数转化为现场岩体参数,并采用两相单质点流固耦合物质点法(MPM)对隧道开挖面滑塌失稳大变形全过程进行模拟,并结合现场评价超前帷幕注浆预加固措施的有效性。研究结果表明:开挖面滑塌失稳过程可大致分为开挖面隆起变形、开挖面局部失稳及滑塌体加速运动、滑塌体稳定这3个主要阶段。随着开挖面前方滑塌体的加速运动,围岩的渗流场发生明显的变化,渗水形态呈“漏斗状”,水流向开挖面“缺口”汇集;滑塌体稳定后呈锥体状堆积,滑塌体坡脚与开挖面的距离约25 m,与现场滑塌体最终形态较吻合。采取超前帷幕注浆预加固措施后围岩稳定性较好,确保了隧道施工安全顺利推进。流固耦合物质点法可动态再现地下水渗流作用下软弱地层隧道滑塌失稳破坏全过程,可为类似工程研究提供参考。
The excavation face is susceptible to instability and collapse when tunnels traverse water-rich soft strata.Based on the Badong Tunnel of the Zhengzhou—Wanzhou high-speed railway,series laboratory tests on the purple-red mudstone series of the Badong formation were conducted to examine the mechanical characteristics of mudstone softening upon contact with groundwater.Considering the influences of rock mass joint development and construction disturbances,the strength parameters of the intact rock mass obtained from laboratory tests were converted to the field rock mass parameters based on the Hoek-Brown strength criterion.The two-phase singlepoint coupled material point method(MPM)was employed to simulate the large deformation collapse process of the tunnel face.The effectiveness of advanced curtain grouting pre-reinforcement measures was assessed in conjunction with the on-site assessment.The results show that the entire collapse process of the tunnel face can be roughly divided into three main stages:the uplift deformation stage of the tunnel face,the local tunnel face instability and the accelerated movement stage of the collapse rock mass,and stabilization stage of the collapsed soil masses.As the collapse advances,notable changes occur in the seepage field of the surrounding rock,resulting in a funnel-shaped water seepage pattern with water flowing towards the'gap'in the tunnel face.Following stabilization,the collapsed rock mass accumulates in a cone shape,with the collapsed body located approximately 25 m away from the tunnel face,closely resembling the final pattern observed at the actual site.The implementation of advanced curtain grouting pre-reinforcement measures significantly improves the stability of surrounding rock,ensuring the safe and smooth progress of tunnel construction.Moreover,the two-phase coupled MPM method can dynamically replicate the entire process of tunnel face collapse and large deformation failure in weak strata subjected to groundwater seepage,providing reference for similar projects.
作者
吕敬康
阳军生
郑响凑
汤宇
谢亦朋
梁雄
LÜJingkang;YANG Junsheng;ZHENG Xiangcou;TANG Yu;XIE Yipeng;LIANG Xiong(School of Civil Engineering,Central South University,Changsha 410075,China;The First Engineering Co.Ltd.,China Railway No.5 Group,Changsha 410117,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第4期1418-1432,共15页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(U1934211,52308425)
博士后国际交流计划引进项目(YJ20220219)
中国博士后科学基金资助项目(2023TQ0382)
中南大学中央高校基本科研业务费专项资金资助项目(2024ZZTS0753)。
关键词
巴东组泥岩
大变形失稳
流固耦合物质点法
帷幕注浆
Badong formation mudstone
large deformation instability
coupled material point method
curtain grouting
