软弱地层隧道围岩承载环抗力计算  

Calculation Approach of Bearing Ring Resistance of Tunnel Surrounding Rock in Soft Strata

作　　者：苏雅 苏永华[2,3] 刘阳阳 李明 罗彪[2] SU Ya;SU Yonghua;LIU Yangyang;LI Ming;LUO Biao(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China;College of Civil Engineering,Hunan University,Changsha 410082,China;Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education,Hunan University,Changsha 410082,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058 [2]湖南大学土木工程学院,湖南长沙410082 [3]湖南大学建筑安全与节能教育部重点实验室,湖南长沙410082

出　　处：《湖南大学学报(自然科学版)》2025年第3期141-150,共10页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(52408449,52478396)。

摘　　要：软弱地层中隧道锚喷支护的力学效果主要是形成基于空间边界附近围岩的承载环.利用岩体评级(RMR)系统中的相关因素与岩体地质强度指标(GSI)所涉及要素之间的对应关系,建立了GSI各项要素指标及其总值确定的简明途径.利用岩体内摩擦角、黏聚力与霍克-布朗(Hoek-Brown,H-B)准则常数ms、s及a的等效换算关系,结合拉布西维兹剪切楔体滑移失稳模式,导出了基于H-B非线性屈服准则的承载环抗力及其稳定安全系数计算表达式.实例分析计算结果显示,基于H-B准则计算获得的承载环安全系数与实际情况更为接近,而基于Mohr-Coulomb(M-C)准则的安全系数则过于保守.承载环力学机制及其总体特征由岩体自身力学属性及锚喷拱架支护结构协同决定.锚杆长度控制承载环厚度,其与承载环抗力首先正相关,超过一定值后,转变为负相关.拱架的主要效能在于避免围岩早期出现过大变形松散,喷射混凝土是承载环紧固力(围压)的主要贡献者.岩体力学属性是承载环抗力大小的控制性要素.In weak strata,the mechanical effect of tunnel anchoring and shotcrete support primarily results in the formation of a bearing ring based on the surrounding rock near the spatial boundary.Based on the corresponding relationship between the relevant factors in rock mass rating(RMR)system and the factors involved in geological strength index(GSI)of rock mass,concise ways to quantify sub-items of GSI and determine its total value were obtained.Based on the equivalent conversion relationship between the internal friction angle,cohesion force and Hoek-Brown(H-B)constants of rock mass as well as the sliding failure mode of Rabcewicz’s shear wedge,calculation approaches of the bearing ring resistance and its safety factor equivalent to H-B yield criterion were established.The case study results indicate that the safety factor of the bearing ring analyzed based on the H-B criterion is consistent with its actual state,while the safety factor based on the Mohr Coulomb(M-C)criterion is too conservative.The mechanical mechanism and overall characteristics of the bearing ring are determined by the mechanical properties of its rock mass itself and the support structure constituted by rock bolts and shotcrete and steel ribs.The thickness of the bearing ring is determined by the length of rock bolts.The resistance of the bearing ring is first positively correlated with the length of rock bolts,and after exceeding a certain value,it becomes negatively correlated.The main effectiveness of steel ribs is to avoid excessive deformation and loosening of surrounding rocks in the early stages.Shotcrete is the main source of bearing ring tightening force(confining pressure).The mechanical properties of rock mass are the dominant factor for the magnitude of bearing ring resistance.

关 键 词：岩体力学 隧道工程 锚喷支护 霍克-布朗准则 承载环 安全系数 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]