摘要
对双江口水电站三大洞室围岩变形的时空特征及机理进行了分析,并以厂房洞室为研究重点,利用围岩变形、支护荷载监测数据以及钻孔声波检测数据,采用考虑洞周松弛区动态演化的力学参数反演方法,开展施工期监测反馈设计。结果表明:双江口厂房洞群围岩空间变形由应力卸荷效应主导,并叠加洞群效应和高边墙效应,呈现出上下游不对称变形的基本特征,开挖完毕后实测洞周最大位移仅为28 mm;三大洞室变形时间特征表现为在开挖揭露后以及后续2~3个下卧分层开挖期间,变形以卸荷回弹为主,随着进一步的下卧开挖,时效变形开始显现,但时效变形量级较小,且在洞群开挖结束后很快趋稳;在围岩存在时效变形的情况下,采用考虑洞周松弛区动态演化的参数反演与数值计算,能够较为合理地反映围岩的渐进劣化并对后续开挖引起的围岩变形增量做出较为准确的预测;基于变形预测结果对支护强度做减弱调整后,围岩变形未出现异常增长,说明反馈设计是合理的。
The temporal and spatial characteristics and mechanisms of perimeter rock deformation in the three large cavern chambers of Shuangjiangkou Hydropower Station are analyzed,and with the plant cavern as the focus of the study,the monitoring feedback design for monitoring during the construction period was carried out using perimeter rock deformation,support load monitoring data as well as drilling acoustic wave detection data,and by adopting the inversion method of the mechanical parameter that took into account the dynamic evolution of the relaxation zone around the cavern.The results show that:The spatial characteristics of rockmass deformation result from superposition of unloading effect,the cavern group effect and high wall effect with unloading effect as a main factor which result in unsymmetrical deformation of powerhouse;Thanks to the good quality of granite rockmass,the high ratio of rock strength to in-situ stress and scarcity of weak structural plane,the largest peripheral displacement of powerhouse is 28mm;For surrounding rockmass that has been just exposed or merely experienced 2~3 underlying slicing excavation,the only component of total displacement is excavation induced rebounding deformation;For rockmass that has experienced more than three underlying slicing excavation,time related deformation due to progression degradation of rockmass can be found in total displacement but occupy a small proportion and converge very quickly after the excavation of powerhouse has been finished;In case of time effect existed properly modeling of damaged zone around cavern is necessary and numerical calculation based on such model can give a good prediction of deformation increment.There exists no abnormal deformation in surrounding rockmass when the intensity of rock bolt support is decreased at some important construction stages according to prediction of future deformation,which means that feedback design of support is reasonable.
作者
杨云浩
张顺利
袁国庆
Yang Yunhao;Zhang Shunli;Yuan Guoqing(Power China Chengdu Engineering Corporation Limited,Chengdu 610072,P.R.China;Large-scale Underground Engineering Affiliation of National Hydropower Technology Research and Development Center,Chengdu 610072,P.R.China)
出处
《地下空间与工程学报》
北大核心
2025年第6期2167-2179,共13页
Chinese Journal of Underground Space and Engineering
基金
中国电建集团核心攻关项目(DJ-HXGG-2023-04)。
关键词
地下洞群
硬岩
变形破坏
施工期
监测反馈
underground openings
hard rock
deformation and failure
construction period
monitoring and feedback
