高地应力下深部硐室底鼓破坏围岩稳定性分析

Analysis on the Stability of Surrounding Rock Damaged by the Floor Drum of Deep Underground Chamber under High In⁃situ Stress

为研究西部山区高地应力作用下深部硐室的稳定性问题,根据普氏压力拱理论,综合考虑深部硐室冒顶,片帮以及底鼓破坏,建立了高地应力下深部硐室底鼓破坏模式,基于极限分析上限法和非线性Hoek-Brown破坏准则,推导了该破坏模式下深部硐室的围岩压力理论公式,求解了该破坏模式下深部硐室围岩压力上限解,并将本文结果与数值模拟和已有成果进行对比分析。此外,通过该破坏模式研究了各参数对围岩压力和潜在破坏面的影响。结果表明:(1)随着初始地应力场参数中σ_(V)和λ增大,深部地下硐室围岩压力q逐渐增大,硐室围岩潜在破坏面逐渐增大,其中σ_(V)表现尤为显著;(2) Hoek-Brown破坏准则参数中GSI、σ_(ci)和m_(i)的增大对深部硐室围岩稳定性有明显的提高效应,而D增加则会降低硐室围岩的稳定性;(3)随着底部压力相关系数μ增加,深部地下硐室顶板和两帮的围岩压力表现为减小的趋势。研究成果可为深部硐室的支护设计提拱有效的理论支撑。

In order to study the stability issues of deep underground chambers under high in-situ stress in China′s western mountainous areas,based on the theory of the Proctodyakonov′s pressure arch,considering the roof caving,sidewall instability,and floor drumming of deep underground chambers,a floor drumming damage model of deep underground chambers under high in-situ stress was established.Leveraging limit analysis upper bound method and nonlinear Hoek-Brown failure criterion,the theoretical formula of surrounding rock pressure in the deep underground chambers under this damage mode was deduced.The upper bound solution for surrounding rock pressure was obtained.Comparative analysis was conducted between the results of this study,numerical simulations,and existing literature.Furthermore,the influence of various parameters on surrounding rock pressure and potential failure surface was studied through this damage mode.The results showed that:1)With an increase in the initial stress field parametersσ_(v) and λ,the surrounding rock pressure q of deep underground cham‐bers gradually increased,along with the expansion of potential failure surfaces,among which σ_(v) was particularly significant.2)The increase of GSI,σ_(ci) and mi in the Hoek-Brown failure criterion parame‐ters had a significant improvement effect on the stability of the surrounding rock,while an increase in D reduced the stability of the chamber′s surrounding rock.3)With the increase in the bottom pressure correlation coefficientμ,the surrounding rock pressure of the roof and sidewalls tended to decrease.The findings provide effective theoretical support for the design of support systems for deep under‐ground chambers.