不利地质构造及软弱地层是卡拉水电站地下洞室群围岩稳定控制的关键性因素,鉴于此,采用离散元方法建立了包含不同级别结构面及软弱地层的节理岩体模型。在节理岩体模型的基础上,对处于优化设计阶段的卡拉水电站进行洞室群稳定性分析以及主副厂房洞和主变洞间距优化研究。数值计算结果表明:地下厂房洞室群整体稳定性较好,地下厂房区围岩具备成洞条件;但存在软弱地层T3z2-5区域围岩变形较大,局部区域节理相互切割易造成块体滑落等工程地质问题,需要对其重点关注;结合洞群开挖后围岩内场量的分布情况以及经济指标和力学指标,从定性和定量角度对洞室间距进行了优选,最终确定主副厂房洞和主变洞间距50 m为最优方案。相关研究成果对于卡拉水电站洞室优化、安全施工具有一定指导意义。
Abstract
Unfavorable geological structures and weak strata play a decisive role in regulating the stability of surrounding rock in underground caverns at the Kala hydropower station. In light of this, a 3D fine jointed rock mass model with different levels of discontinuities and weak strata is constructed by using the discrete element method. Utilizing this jointed rock mass model, the stability of the underground caverns and optimal spacing between the main powerhouses and the main transformer room are analyzed. The numerical findings indicate favorable overall stability of the underground caverns, affirming their feasibility for construction. However, some engineering geologic concerns emerge, including significant deformation of the surrounding rock mass in the T3z2-5 weak stratum zone and block sliding triggered by joint cutting. Addressing these issues necessitates tailored support treatments. The spacing between the main powerhouses and the main transformer room is optimized via a qualitative and quantitative assessment accounting for variations in the surrounding rock field following cavern excavation as well as economic and mechanical indicators. The optimum spacing between the main and auxiliary powerhouses and the main transformer room is determined as 50 meters. Comprehensive analysis enables the identification of an optimized spacing that enhances economic efficiency and operational performance. The research findings carry substantial implications for both the optimization of cavern design and the safe construction of Kala hydropower station.
关键词
地下洞室群 /
围岩稳定性 /
结构面 /
3DEC /
洞室间距优化 /
卡拉水电站
Key words
underground caverns /
stability of surrounding rock /
discontinuities /
3DEC /
optimization of cavern spacing /
Kala hydropower station
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基金
国家自然科学基金-雅砻江联合基金重点项目(U1865203);中国科学院科技服务网络计划(STS计划)项目(KFJ-STS-QYZD-174);国家自然科学基金项目(41941018)
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