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软弱破碎围岩地层预应力管-索结构的提出及应用

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针对高地应力软弱破碎围岩隧道变形控制难题,分析不同类型锚杆优点和不足并结合模型试验,研发一种隧道新型预应力管-索结构,详细阐述其结构形式及受力机制,通过理论分析,建立深-浅预应力体耦合力学承载模型,并对其承载效应进行系统分析,最终,通过现场试验验证新型结构的可靠性.研究结果表明:预应力管-索支护结构能够实现"注浆加固、承载结构形成及应力扩散"的协同作用,进而实现对支护强度的2次放大.对管-锚支护而言,注浆提高预应力体力学参数是围岩控制的关键手段,但调整管-索间排距提升围岩承载能力的方式在施工中更为直接高效;进一步分析表明,浅层预应力体合理厚度b1为隧道半径r0的0.8倍,深层预应力体合理厚度b2为隧道半径的1.44倍,可为管-索的参数设计提供一定依据.工程实践表明预应力管-索支护能够有效提高软弱破碎围岩的稳定性,为类似工程提供参考.
Prestressed pipe-cable support structure in weak broken surrounding rock stratum and its application
In order to reduce the deformation of tunnels located in broken surrounding rock with high ground stresses,the advantages and disadvantages of different types of bolts(cables)are analyzed.Combined with model test,a new type of prestressed pipe-cable(PPC)structure for tunnels is developed.This study introduces the bearing mechanism of the new developed PPC structure and sets up a coupling mechanical bearing model based on the PPC structure by theoretical analysis.Furthermore,the bearing effect of PPC structure is systematically analyzed.Finally,the reliability of the new structure is verified by field test.The research results indicate that the PPC structure can reinforcement the rockmass by grouting and forming a bearing structure.More importantly,the PPC structure can amplify support capacity.The PPC structure,it is important to adopt grout to improve the mechanical parameters of surrounding rockmass,but adjusting the row spacing between adjacent PPC to improve the bearing capacity of surrounding rock is more direct and efficient.Further analysis indicate that the reasonable thickness b 1 of the shallow prestressed body is about 0.8 times of the tunnel radius r0,and the reasonable thickness b2 of the deep prestressed body is 1.44 times of tunnel radius,which can provide theoretical basis for the parameter design of the PPC.The field test shows that the prestressed pipe-cable support can effectively improve the stability of soft and broken surrounding rock,and can provide reference for similar projects.

tunnel engineeringweak and broken surrounding rockpipe-cable structuredeep-shallow prestressed bodybearing enhancement factorengineering application

余涛、罗虎、姜逸帆、姚志刚、李梦可、方勇

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西南交通大学土木工程学院,四川成都 610031

隧道工程 软弱破碎围岩 管-索结构 深-浅预应力体 承载增强系数 工程应用

国家自然科学基金资助项目云南省科技计划项目

52078428202303AA080005

2024

10.13722/j.cnki.jrme.2023.1079

岩石力学与工程学报
中国岩石力学与工程学会

岩石力学与工程学报

CSTPCD北大核心
影响因子：2.589
ISSN：1000-6915
年,卷(期)：2024.43(6)