考虑岩石剪胀及应变软化特性的隧道围岩力学模型  

Tunnel surrounding rock mechanical model considering rock dilatancy and strain softening characteristics

作　　者：周书东 张彤炜 刘文学 张光雄 刘红岩[4] ZHOU Shudong;ZHANG Tongwei;LIU Wenxue;ZHANG Guangxiong;LIU Hongyan(Dongguan Institute of Building Research Co.,Ltd.,Dongguan,Guangdong 523809,China;Algeria Branch of China State Construction Engineering Co.,Ltd.,Beijing 100125,China;Poly Explosive Hami Co.,Ltd.,Hami,Xinjiang 839000,China;School of Engineering and Technology,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]东莞市建筑科学研究院有限公司,广东东莞523809 [2]中国建筑股份有限公司阿尔及利亚公司,北京100125 [3]保利民爆哈密有限公司,新疆哈密839000 [4]中国地质大学(北京)工程技术学院,北京100083

出　　处：《公路交通科技》2025年第3期204-214,共11页Journal of Highway and Transportation Research and Development

基　　金：国家重点研发计划项目(2019YFC1509701);新疆维吾尔自治区“天池英才”领军人才计划项目(XJTCYC2023-BLMB1);北京市自然科学基金项目(8222031)。

摘　　要：【目标】为描述中、低强度岩石力学行为对隧道围岩应力、位移及塑性区等力学特性的影响,克服目前常用的岩石剪胀或软化模型存在的参数多、适用性差且多适用于硬岩等不足,建立考虑岩石剪胀及应变软化特性的隧道围岩力学模型。【方法】首先基于前人提出的围岩应力释放法及摩尔库伦屈服准则,建立了同时考虑岩石强度峰后阶段剪胀角非线性衰减和强度软化特性的隧道围岩力学模型,并给出了该模型半数值半解析解的求解方法与流程;而后通过隧道内壁位移、塑性区峰值和残余半径等指标计算结果对该软化模型及其两个特例即理想弹塑性和弹脆性模型的合理性进行了验证;然后,对比分析了目前常用的5种剪胀模型对隧道围岩变形及塑性区的影响;最后,研究了弹脆性模型、理想弹塑性模型和应变软化模型等3种本构模型对隧道围岩应力、位移和塑性区半径等计算结果的影响。【结果】发现随着剪胀角的增加,洞壁处的围岩位移、塑性区峰值半径及残余半径均呈增长趋势;理想弹塑性模型低估了围岩塑性区范围及变形,易造成安全隐患。而弹脆性模型则会高估围岩塑性区范围及变形,导致支护结构工程量增加,造成不要的浪费。而应变软化模型由于能够很好地反映围岩的软化特性,因而可以精确地预测围岩应力、位移及塑性区范围。【结论】相较于常用的理想弹塑性模型,所提出的考虑岩石剪胀及应变软化特性的隧道围岩力学模型能更准确地刻画中、低强度隧道围岩的力学特性。[Objective]To describe the influence of medium and low strength rock mechanical behavior on tunnel surrounding rock stress,displacement and plastic zone,and to overcome the deficiencies(e.g.,too much parameters,poor applicability,and mostly applicable to hard rock)existing in the often used rock dilatancy or softening models,the tunnel surrounding rock mechanical model was established considering the rock dilatancy and strain softening characteristics.[Method]First,based on the proposed surrounding rock stress release method and Mohr-Coulomb yield criterion,a tunnel surrounding rock mechanical model was established.The model can take into account the nonlinear attenuation of dilatancy angle and the strength softening in post-peak stage at the same time.The method and process for solving semi-numerical and semi-analytical solution of model were given.Second,the calculation results of indicators(i.e.,tunnel inner wall displacement,plastic zone peak radius and residual radius)were adopted to verify the rationalities of softening model and its two special cases(i.e.,ideal elastoplastic and elastic-brittle models).Third,the influences of 5 kinds of dilatancy models on tunnel surrounding rock deformation and plastic zone were compared and analyzed.Finally,the influences of elasto-brittle model,ideal elasto-plastic model and strain softening model on calculation results(i.e.,tunnel surrounding rock stress,displacement,and plastic zone radius)were studied.[Result]The tunnel inner wall displacement,plastic zone peak radius and residual radius all increase with the increase of dilatancy angle.The ideal elasto-plastic model underestimates the surrounding rock plastic zone range and deformation,which is prone to cause safety risk.Meanwhile the elastic-brittle model will overestimate the surrounding rock plastic zone range and deformation,resulting in an increase in engineering quantity of supporting structure and unnecessary waste.While the strain softening model can perfectly reflect the softening behavior of surrounding ro

关 键 词：隧道工程 应变软化模型 应力释放法 隧道围岩 剪胀角 围岩塑性区 

分 类 号：U452[建筑科学—桥梁与隧道工程]