摘要
为实现地下工程支护体系的定量化分析与设计,以典型的均匀应力条件下深部圆形隧道为依托,将围岩视为地下支护体系中的独立承载构件,采用稳定系数作为定量表征围岩构件稳定程度的量化指标,提出基于围岩稳定系数的隧道稳定性量化分析方法。首先,结合统一强度理论和RABCEWICZ提出的围岩剪切滑移模型,同时考虑中间主应力效应、脆性软化及剪胀特性的影响,推导围岩极限径向收敛和稳定隧道所需的最小虚拟支护压力的解答。在此基础上,基于收敛约束原理(Convergence-confinement method,CCM),求解被视为独立承载构件的围岩的极限承载能力,推导表征围岩稳定程度的稳定系数指标。通过解析解和室内物理模型试验验证了该方法的有效性。此外,探讨了围岩力学参数和应力条件等因素对围岩稳定极限状态的影响特性。最后,通过工程实例分析,开展基于围岩稳定系数的隧道稳定性评估,阐明了该方法的实用性。研究结果表明:围岩最小支护压力和极限径向应变均与中间主应力系数呈非线性负相关,忽略中间主应力效应会低估围岩力学潜能;极限径向应变随剪胀参数β的增大呈线性增大;最小支护压力和极限径向应变均随初始地应力的增大而增大;围岩抗剪强度参数显著影响围岩稳定极限状态,应考虑其变异性。本研究可为地下支护体系的定量化分析及设计提供新思路。
To achieve the quantitative analysis and design of underground support systems,the surrounding rock of deep circular tunnel under uniform stress conditions is regarded as an independent load-bearing component.The stability factor index was used to quantitatively describe the degree of stability of surrounding rock components.A quantitative analysis method for tunnel stability was proposed based on the stability factor of surrounding rock.First,combining the uniform strength theory and shear-slip model proposed by RABCEWICZ,the solutions to the ultimate radial convergence and minimum support pressure required for tunnel stabilities were derived with the consideration of the effects of intermediate principal stress,brittle softening and dilation characteristics.On this basis,based on the convergence-confinement method(CCM),the ultimate carrying capacity of surrounding rock as an independent bearing component was solved,and the stability factor index was derived to characterize the stability degree of surrounding rock.The effectiveness of the proposed method was verified through analytical solutions and physical model experiments.In addition,influences of rock mechanical parameters and stress conditions on the ultimate state of surrounding rock were discussed.The results indicate that the minimum support pressure and ultimate radial strain are both negatively correlated with the intermediate principal stress coefficient,and ignoring the effect of intermediate principal stress would underestimate the mechanical potential of surrounding rock;the ultimate radial strain increases linearly with the increasing dilatancy parameterβ;the minimum support pressure and ultimate radial strain both increase with increasing initial stress;the shear strength parameters of surrounding rock significantly affect the ultimate state of surrounding rock and should be considered for their variability.Finally,through the analysis of a project case,the tunnel stability assessment based on the stability factor of surrounding rock was carried out,and the practicality of this method was clarified.This study can provide a new insight for the quantitative analysis and design of underground support systems.
作者
刘阳阳
苏永华
罗彪
杨忠武
陈斌
LIU Yangyang;SU Yonghua;LUO Biao;YANG Zhongwu;CHEN Bin(College of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第10期4175-4186,共12页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(52178330)。
关键词
定量分析
收敛约束
剪切滑移模型
中间主应力
脆性软化
剪胀特性
quantitative analysis
convergence-confinement
shear slide model
intermediate principal stress
brittle softening
dilation characteristic
