Abstract：The arch foot of the initial support is a crucial component in the deformation control during the sequential excavation of soft rock tunnels. To address the issue of foot settlement control in the upper step of soft rock tunnels, this study first analyzed the settlement deformation mechanism of the arch foot and proposed an active control concept for foot settlement. Subsequently, the use of small-diameter prestressed feet-lock cables was suggested to control foot settlement. A second-generation support structure, combining steel-rib, steel mesh, shotcrete, and feet-lock pipes (cables) with both active and passive support functions, was established. The advantages of small-diameter prestressed feet-lock cables over traditional feet-lock pipes (bolts) were analyzed. Field tests verified the effectiveness of small-diameter prestressed feet-lock cables in controlling foot settlement of the initial support, and potential challenges in their future application were discussed comprehensively. The results indicated that: (1) The systematic bolts were generally short and ineffective in soft rock tunnels, leading to fewer installations and more focus on tunnel feet-lock pipes (bolts). (2) The upper step of the tunnel had limited space, making it difficult to install large-diameter feet-lock pipes, and increasing the number of small-diameter feet-lock pipes had limited control effect on foot settlement. (3) Small-diameter prestressed feet-lock cables provide suspension and active support functions for the arch foot of the initial support, offering significant advantages over feet-lock pipes (bolts) which rely on transverse bending stiffness to resist foot settlement deformation. (4) Prestressed feet-lock cables can also control foot convergence deformation of the initial support by adjusting installation angles and positions, showing promising application potential. (5) Foot deformation in sequential excavation of soft rock tunnels is persistent and sudden. For high strength and toughness structures, the concept of a third-generation support structure combining steel-rib, steel mesh, shotcrete, and feet-lock pipes (cables) is proposed, providing a direction for future research.
陈丽俊，陈建勋，郭会杰，张立鑫，孙鹏飞，罗 华. 软岩隧道拱脚沉降的主动控制理念与技术实现[J]. 岩石力学与工程学报, 2025, 44(6): 1466-1480.
CHEN Lijun, CHEN Jianxun, GUO Huijie, ZHANG Lixin, SUN Pengfei, LUO Hua. The concept and technological implementation of active control for foot settlement of soft rock tunnels. , 2025, 44(6): 1466-1480.
[1] 陈建勋，陈丽俊，罗彦斌，等. 大跨度绿泥石片岩隧道大变形机理与控制方法[J]. 交通运输工程学报，2021，21(2)：93–106.(CHEN Jianxun，CHEN Lijun，LUO Yanbin，et al. Mechanism and control method of large deformation for large-span chlorite schist tunnel[J]. Journal of Traffic and Transportation Engineering，2021，21(2)：93–106.(in Chinese))
[2] LIU W W，CHEN J X，CHEN L J，et al. A rational construction method and deformation control system of tunnelling in extremely soft and fractured chlorite schist medium[J]. Tunnelling and Underground Space Technology，2024，143(Jan.)：105472.1–105472.17.
[3] 赵亮亮，杨文波，潘文韬，等. 不同大变形等级的层状软岩隧道施工模型试验与数值模拟研究[J]. 岩石力学与工程学报，2024，43(2)：454–467.(ZHAO Liangliang，YANG Wenbo，PAN Wentao，et al. Study on model test and numerical simulation of layered soft rock tunnel construction with different large deformation grades[J]. Chinese Journal of Rock Mechanics and Engineering，2024，43(2)：454–467.(in Chinese))
[4] 李 峰. 高地应力构造破碎带隧道大变形灾变机制及控制技术研究[J]. 铁道科学与工程学报，2021，18(5)：1 222–1 230.(LI Feng. Study on the formation mechanism and large deformation control of tunnel in structural fracture zone with high in-situ stress[J]. Journal of Railway Science and Engineering，2021，18(5)：1 222–1 230.(in Chinese))
[5] 汪 波，李天斌，何 川，等. 强震区软岩隧道大变形破坏特征及其成因机制分析[J]. 岩石力学与工程学报，2012，31(5)：928–936.(WANG Bo，LI Tianbin，HE Chuan，et al. Analysis of failure properties and formatting mechanism of soft rock tunnel in meizoseismal areas[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(5)：928–936.(in Chinese))
[6] 陈丽俊，陈建勋，罗彦斌，等. 深埋大跨度绿泥石片岩隧道变形规律及合理预留变形量[J]. 中国公路学报，2021，34(6)：147–157.(CHEN Lijun，CHEN Jianxun，LUO Yanbin，et al. Deformation law and reasonable reserved deformation of deep large span chlorite schist tunnel[J]. China Journal of Highway and Transport，2021，34(6)：147–157.(in Chinese))
[7] 夏润禾，崔小鹏，周 泉. 复杂地质隧道衬砌变形分析与工程治理技术[J]. 铁道工程学报，2015，32(8)：66–72.(XIA Runhe，CUI Xiaopeng，ZHOU Quan. Analysis of tunnel lining deformation in complex geology and engineering control technology[J]. Journal of Railway Engineering Society，2015，32(8)：66–72.(in Chinese))
[8] 王 琳，杨 林，袁 青，等. 浅埋富水隧道施工大变形原因分析与应对措施[J]. 人民长江，2022，53(5)：162–167.(WANG Lin，YANG Lin，YUAN Qing，et al. Cause analysis and countermeasures of large deformation induced by shallow-buried tunnel construction under water-rich condition[J]. Yangtze River，2022，53(5)：162–167.(in Chinese))
[9] 王道远，刘 佳，张 逴，等. 高地应力深埋隧道断裂破碎带大变形控制方法现场试验研究[J]. 岩土工程学报，2020，42(4)：658–666.(WANG Daoyuan，LIU Jia，ZHANG Chuo，et al. Field tests on large deformation control method for surrounding rock of deep tunnel in fault zone with high geostress[J]. Chinese Journal of Geotechnical Engineering，2020，42(4)：658–666.(in Chinese))
[10] 杨建民，舒东利，张 涵，等. 软岩隧道初期支护沉降机理及其工程措施研究[J]. 隧道建设(中英文)，2018，38(4)：545–550.(YANG Jianmin，SHU Dongli，ZHANG Han，et al. Research on settlement mechanism of primary support of soft rock tunnel and its countermeasures[J]. Tunnel Construction，2018，38(4)：545–550.(in Chinese))
[11] 罗彦斌，陈建勋. 软弱围岩隧道锁脚锚杆受力特性及其力学计算模型[J]. 岩土工程学报，2013，35(8)：1 519–1 525.(LUO Yanbin，CHEN Jianxun. Mechanical characteristics and mechanical calculation model of tunnel feet-lock bolt in weak surrounding rock[J]. Chinese Journal of Geotechnical Engineering，2013，35(8)：1 519–1 525.(in Chinese))
[12] 陈丽俊，张运良，马震岳，等. 软岩隧洞锁脚锚杆–钢拱架联合承载分析[J]. 岩石力学与工程学报，2015，34 (1)：129–138.(CHEN Lijun，ZHANG Yunliang，MA Zhenyue，et al. Joint bearing analysis for feet-lock bolt and steel arch in weak rock tunnel[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(1)：129–138.(in Chinese))
[13] 陈丽俊，张运良，马震岳. 锁脚锚管合理打设角度的理论研究[J]. 岩石力学与工程学报，2015，34 (7)：1 334–1 344.(CHEN Lijun，ZHANG Yunliang，MA Zhenyue. Theoretical research on reasonable installation angle of feet-lock pipes[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(7)：1 334–1 344.(in Chinese))
[14] 陈丽俊，张运良. 锁脚锚管受力分析的双参数弹性地基梁模型[J]. 岩石力学与工程学报，2016，35(5)：989–999.(CHEN Lijun，ZHANG Yunliang. Double parameters elastic foundation beam model of feet-lock pipes[J]. Chinese Journal of Rock Mechanics and Engineering，2016，35(5)：989–999.(in Chinese))
[15] CHEN L J，ZHANG Y L，MA Z Y. Analytical approach for support mechanism of feet-lock pipe combined with steel frame in weak rock tunnels[J]. KSCE Journal of Civil Engineering，2016，20(7)：2 965– 2 980.
[16] CHEN L J，CHEN J X，LI Y，et al. Performance of tunnel feet-lock pipe(TFP) in sharing vertical foundation load[J]. KSCE Journal of Civil Engineering，2021，25：1 086–1 094.
[17] 陈丽俊，陈建勋，罗彦斌，等. 黄土地层锁脚锚管横向地基反力系数[J]. 交通运输工程学报，2021，21(4)：106–115.(CHEN Lijun，CHEN Jianxun，LUO Yanbin，et al. Lateral foundation reaction coefficient of feet-lock pipe in loess stratum[J]. Journal of Traffic and Transportation Engineering，2021，21(4)：106–115.(in Chinese))
[18] 陈建勋，陈丽俊，罗彦斌，等. 软岩隧道锁脚锚管应变现场测试及对拱脚的约束作用研究[J]. 中国公路学报，2023，36(11)：218–230.(CHEN Jianxun，CHEN Lijun，LUO Yanbin，et al. On-site testing of strain of feet-lock pipe and its restraining effect on tunnel feet in soft rock[J]. China Journal of Highway and Transport，2023，36(11)：218–230.(in Chinese))
[19] 陈丽俊，陈建勋，郭会杰，等. 软岩隧道初期支护拱脚收敛变形控制新方法[J]. 中国公路学报，2025，待刊.(CHEN Lijun，CHEN Jianxun，GUO Huijie，et al. A new method for controlling convergence deformation at arch feet of initial support in soft rock tunnels[J]. China Journal of Highway and Transport，2025，to be pressed.(in Chinese))
[20] 石 州，罗彦斌，陈建勋，等. 软弱围岩隧道锁脚锚管力学特性现场模拟试验[J]. 公路交通科技，2021，38(7)：96–106.(SHI Zhou，LUO Yanbin，CHEN Jianxun，et al. Field simulation test on mechanical characteristics of feet-lock anchor pipes for soft surrounding rock tunnel[J]. Journal of Highway and Transportation Research and Development，2021，38(7)：96–106.(in Chinese))
[21] 罗彦斌，陈建勋，杨东辉，等. 隧道锁脚锚管受力测试方法试验研究[J]. 隧道建设(中英文)，2016，36(12)：1 435–1 441.(LUO Yanbin，CHEN Jianxun，YANG Donghui，et al. Experimental study of testing technologies for stress of tunnel foot locking bolts[J]. Tunnel Construction，2016，36(12)：1 435–1 441.(in Chinese))
[22] LUO Y B，DIAO P S，CHEN J X，et al. New method of monitoring tunnel feet-lock pipe(TFP) mechanics using fiber bragg grating (FBG)[J]. Journal of Testing and Evaluation，2020，48(4)：1–18.
[23] 康红普. 我国煤矿巷道围岩控制技术发展70年及展望[J]. 岩石力学与工程学报，2021，40(1)：1–30.(KANG Hongpu. Seventy years development and prospects of strata control technologies for coal mine roadways in China[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(1)：1–30.(in Chinese))
[24] 李沿宗，尤显明，赵 爽. 极高地应力软岩隧道贯通段变形控制方案研究——以兰渝铁路木寨岭隧道为例[J]. 隧道建设(中英文)，2017，37(9)：1 146–1 152.(LI Yanzong，YOU Xianming，ZHAO Shuang. Study of deformation control scheme of break through section of soft rock Muzhailing tunnel on Lanzhou-Chongqing railway with extremely high ground stress[J]. Tunnel Construction，2017，37(9)：1 146–1 152.(in Chinese))
[25] 李 干. 深埋薄层板岩隧道变形机理及高预紧恒阻锚索控制技术研究[博士学位论文][D]. 北京：中国矿业大学(北京)，2019.(LI Gan. Deformation mechanism of deep-buried thin-bedded slate tunnel and control technology of high pre-tightening constant resistance anchor cable[Ph. D. Thesis][D]. Beijing：China University of Mining and Technology(Beijing)，2019.(in Chinese))
[26] 陶志刚，罗森林，李梦楠，等. 层状板岩隧道大变形控制参数优化数值模拟分析及现场试验[J]. 岩石力学与工程学报，2020，39(3)：491–506.(TAO Zhigang，LUO Senlin，LI Mengnan，et al. Optimization of large deformation control parameters of layered slate tunnels based on numerical simulation and field test[J]. Chinese Journal of Rock Mechanics and Engineering，2020，39(3)：491–506.(in Chinese))
[27] 陶志刚，任树林，王丰年，等. 高地应力软岩隧道围岩大变形NPR锚索控制方法研究[J]. 隧道建设(中英文)，2020，40(增2)：82–92.(TAO Zhigang，REN Shulin，WANG Fengnian，et al. Research on NPR anchor cable support scheme for large deformation of surrounding rock in high-ground stress soft sock tunnel[J]. Tunnel Construction，2020，40(Supp.2)：82–92.(in Chinese))
[28] ZHANG B，TAO Z G，QIAO X B，et al. Study on large deformation mechanism and control technology of layered carbonaceous slate in deep tunnels[J]. Bulletin of Engineering Geology and the Environment，2024，83：1–22.
[29] SUN X M，JIANG M，MIAO C Y，et al. Study on large deformation and failure mechanism of deep buried stratified slate tunnel and control strategy of high constant resistance anchor cable[J]. Engineering failure analysis，2023，144：1–22.
[30] 汪 波，喻 炜，訾 信，等. 软岩大变形隧道不同支护模式的合理性探讨——以木寨岭公路隧道为例[J]. 隧道建设(中英文)，2023，43(1)：36–47.(WANG Bo，YU Wei，ZI Xin，et al. Rationality of various support types of Muzhailing highway tunnel in soft rocks with large deformation[J]. Tunnel Construction，2023，43(1)：36–47.(in Chinese))
[31] 张立鑫，陈丽俊，陈建勋，等. 单斜构造软硬互层围岩隧道变形特征及控制对策[J]. 建筑科学与工程学报，2021，38(6)：186–196. (ZHANG Lixin，CHEN Lijun，CHEN Jianxun，et al. Deformation characteristics and treatment measures of tunnels in soft and hard interbedded surrounding rock with tilted stratum[J]. Journal of Architecture and Civil Engineering，2021，38(6)：186–196.(in Chinese))
[32] 郭会杰，陈丽俊，张立鑫，等. 软岩公路隧道紧急停车带变截面段变形特征及加固方法[J]. 科学技术与工程，2022，22(35)：15 765–15 774.(GUO Huijie，CHEN Lijun，ZHANG Lixin，et al. Deformation characteristics and reinforcement methods in variable cross-section at emergency parking belt in soft rock mass highway tunnel[J]. Science Technology and Engineering，2022，22(35)：15 765–15 774.(in Chinese))
[33] 陈伟祥，张立鑫，陈丽俊，等. 小孔径预应力锚索合理支护参数研究[J]. 公路，2023，68(9)：443–451.(CHEN Weixiang，ZHANG Lixin，CHEN Lijun，et al. Research on reasonable support parameters of small-diameter prestressed anchor cables[J]. Highway，2023，68(9)：443–451.(in Chinese))
[34] 陈丽俊，陈建勋，郭汇杰，等. 小孔径预应力锚索对软岩隧道围岩的加固效应[J]. 中国公路学报，2025，38(1)：224–237.(CHEN Lijun，CHEN Jianxun，GUO Huijie，et al. Reinforcement effect of small-diameter prestressed anchor cables on surrounding rock of soft rock tunnels[J]. China Journal of Highway and Transport，2025，38(1)：224–237.(in Chinese))
[35] 王万平，李建斐，晏鹏博，等. 基于主动支护的木寨岭隧道高地应力软岩大变形预应力锚索支护设计实践[J]. 隧道建设(中英文)，2023，43(增1)：313–322.(WANG Wanping，LI Jianfei，YAN Pengbo，et al. Design practice of prestressed anchor cable support technology for soft rock with extremely high geostress and large deformation in Muzhailing tunnel[J]. Tunnel Construction，2023，43(Supp.1)：313–322.(in Chinese))
[36] 陈洲频，郭新新，于家武，等. 软岩隧道高强预应力锚索快速支护技术研究——以木寨岭公路隧道为例[J]. 隧道建设(中英文)，2024，44(8)：1 669–1 678.(CHEN Zhoupin，GUO Xinxin，YU Jiawu，et al. Rapid support technology for high-strength prestressed anchor cables in soft rock tunnels：a case study of Muzhailing highway tunnel[J]. Tunnel Construction，2024，44(8)：1 669–1 678.(in Chinese))
[37] SINGH B，GOEL R K，JETHWA J L，et al. Support pressure assessment in arched underground openings through poor rock masses[J]. Engineering Geology，1997，48(1/2)：59–81.
[38] 汪 波，王振宇，郭新新，等. 软岩隧道中基于快速预应力锚固支护的变形控制技术[J]. 中国公路学报，2021，34(3)：171–182. (WANG Bo，WANG Zhenyu，GUO Xinxin，et al. Deformation control technology based on fast prestressed anchor support in soft rock tunnel[J]. China Journal of Highway and Transport，2021，34(3)：171–182.(in Chinese))
[39] 郭新新，汪 波，刘锦超，等. 软岩隧道锚固系统预紧力匹配性设计方法与实践[J]. 铁道科学与工程学报，2023，20(2)：651–660. (GUO Xinxin，WANG Bo，LIU Jinchao，et al. Design method and practice of pre-tightening matching for anchorage system of soft rock tunnel[J]. Journal of Railway Science and Engineering，2023，20(2)：651–660.(in Chinese))
[40] 钟官峰，张子洋，汪 波，等. 浸水条件下树脂锚索锚固性能劣化试验研究[J]. 防灾减灾工程学报，2024，44(3)：568–578.(ZHONG Guanfeng，ZHANG Ziyang，WANG Bo，et al. Experimental study on the deterioration of anchoring performance ofresin anchor cable under water immersion condition[J]. Journal of Disaster Prevention and Mitigation Engineering，2024，44(3)：568–578.(in Chinese))
[41] 肖明清. 隧道支护结构设计总安全系数法[M]. 北京：人民交通出版社，2020：245–252.(XIAO Mingqing. Total safety factor method of tunnel support structure design[M]. Beijing：China Communications Press，2020：245–252.(in Chinese))
[42] 陈建勋，姜久纯，王梦恕. 黄土隧道网喷支护结构中锚杆的作用[J].中国公路学报，2007，(3)：71–75.(CHEN Jianxun，JIANG Jiuchun，WANG Mengshu. Function of rock bolt of lattice girder and shotcrete support structure in loess tunnel[J]. China Journal of Highway and Transport，2007，(3)：71–75. (in Chinese))
[43] 陈建勋. 软弱地层隧道初期支护技术：钢架喷网锁脚锚杆组合结构[M]. 北京：科学出版社，2011：25–64.(CHEN Jianxun. Tunnel support structure made up of steel frame and shotcrete and steel mesh and feet-lock rock bolt[M]. Beijing：Science Press，2011：25–64.(in Chinese))
[44] 何满潮，任树林，陶志刚. 深埋隧道灾变防控方法[J]. 工程地质学报，2022，30(6)：1 777–1 797.(HE Manchao，REN Shulin，TAO Zhigang. Disaster prevention and control methods for deep buried tunnels[J]. Journal of Engineering Geology，2022，30(6)：1 777–1 797.(in Chinese))
[45] 汪 波，郭新新，王智佼. 软岩隧道变形主动控制[M]. 北京：科学出版社，2022：95–104.(WANG Bo，GUO Xinxin，WANG Zhijiao，et al. Research on deformation of soft rock tunnel controlled by active support[M]. Beijing：Science Press，2022：95–104.(in Chinese))
[46] 谭忠盛. 中老铁路软岩隧道大变形控制技术[M]. 北京：人民交通出版社，2024：238–254.(TAN Zhongsheng. Large deformation control technology of soft rock tunnel in China-Laos railway[M]. Beijing：China Communications Press，2024：238–254.(in Chinese))
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