摘要
采用导流洞泄流的水利水电工程,蓄水期需将临时导流洞依次下闸封堵,蓄水后转换成永久泄水建筑物泄流,导流洞下闸封堵期上游水库水位不断提高,导流洞在高水头条件下能否安全下闸封堵,决定着工程能否按期蓄水,发挥工程效益。以金沙江乌东德水电站为例,针对导流洞下闸封堵期^(#)5导流洞围岩稳定与安全,采用三维数值分析方法对Ⅳ_(2)类围岩条件和F_(3)断层条件两种不同地质洞段进行对比分析,系统研究了两种地质洞段下,岩体渗流场、围岩增量变形、围岩应力、围岩塑性区、支护结构受力和衬砌应力;同时,考虑衬砌失效后,该洞段封堵施工期围岩稳定性,评价隧洞支护系统安全状态。结果表明,洞身排水孔排水效果明显,大幅降低了洞周孔隙水压力;洞周围岩整体呈向洞内变形趋势,围岩增量变形较小;围岩应力分布有一定调整,但总体变化不大,塑性区范围基本无扩展;支护系统均处于正常受力状态,断层附近的部分锚杆受力较大;衬砌受力较小,衬砌配筋满足衬砌受力要求,^(#)5导流洞下闸封堵期围岩稳定安全性较好。
For the water conservancy and hydropower projects that adopt diversion tunnels for flood discharge,the temporary diversion tunnels need to be closed and blocked successively during the water storage period,and the flood discharge will be shifted to the permanent flood discharge structures after water storage.During the closing and blocking period of the diversion tunnels,the water level of the upstream reservoir continues to rise.Whether the diversion tunnels can be safely closed and blocked under high water head conditions determines whether the project can store water on schedule and exert its benefits.Taking the Wudongde Hydropower Station on the Jinshajiang River as an example,this paper focuses on the stability and safety of the surrounding rock during the sluicing sealing period of the^(#)5 diversion tunnel.Three-dimensional numerical analysis methods was used to compare and analyze the geological tunnel sections under ClassⅣ_(2) rock conditions and near the F_(3) fault.It systematically studied the rock mass seepage field,incremental deformation of the surrounding rock,stress in the surrounding rock,plastic zones in the rock,stress on anchorage support,and lining stress.Additionally,considering the failure of the lining,the stability of the surrounding rock during the sealing construction period of this tunnel segment was analyze to assess the safety of the tunnel support system.The results indicate that the drainage holes in the tunnel body effectively reduced the pore water pressure around the tunnel;The surrounding rock generally showed a trend of deformation towards the inside of the tunnel,with minor incremental deformation;The stress distribution in the surrounding rock was adjusted slightly,but overall changes were minimal,with no significant expansion of the plastic zone;The support system was in a normal working condition,with some anchors near the fault experiencing greater stress;The lining was under minor stress,and the reinforcement of the lining met the requirements for bearing the stress,suggesting good stability and safety of the surrounding rock during the sluicing sealing period of the^(#)5 diversion tunnel.
作者
王科
李娇娜
王洁
林紫婕
WANG Ke;LI Jiao-na;WANG Jie;LIN Zi-jie(Changjiang Survey,Planning,Design and Research Co.,Ltd.,Wuhan 430010,China)
出处
《水电能源科学》
北大核心
2024年第10期135-139,共5页
Water Resources and Power
关键词
导流洞
下闸封堵期
围岩稳定
支护安全
三维数值计算
排水孔子模型
diversion tunnel
sluicing sealing period
stability of surrounding rock
support safety
three-dimensional numerical calculation
drainage hole model
