高地应力洞室围岩变形破坏规律研究

锦屏一级水电站右岸地下厂房地质条件复杂,地应力高,对围岩稳定造成较大不利影响。统计分析了厂区地下洞室群施工期的围岩变形破坏现象,归纳出高地应力条件下地应力方向、洞室轴线方向对围岩变形破坏的影响规律。研究表明,高应力条件下洞室群围岩破坏程度除了受最大主应力控制,还与洞室规模密切相关;而且高地应力引起的围岩破坏在时间上有滞后性,需研究实施支护的合适时机。上述结论为地下洞室后续合理施工及支护提供了理论依据,也可为高地应力区洞室轴线布置和围岩变形破坏预防提供参考。

Deformation and failure laws of underground cavern rock mass in high ground stress

The right bank underground powerhouse area of Jinping-I Hydropower Station is characterized by complex geolog-ical conditions and high ground stress, causing a great adverse impact on the stability of surrounding rock. We analyzed the de-formation and failure of surrounding rock of underground cavern in the construction stage systematically, and the influence of stress direction and axial direction of underground cavern on the deformation and failure of surrounding rock was summarized. The results show that the failure degree of surrounding rock has a close relation with cavern′s scale besides the principal stress, also the failure of surrounding rock caused by high ground stress has a feature of time-lag, so the time of conducting supporting con-struction is needed to study. The research results provided theoretical basis for the reasonable construction and support of the un-derground cavern, and could provide reference for axial layout of underground cavern and prevention of the deformation and fail-ure of surrounding rock under high ground stress.