摘要
为研究富水岩溶垂直分带渗透特征对深埋长输水隧洞外水压力的影响,选取环北部湾广东水资源配置工程云开山隧洞分界河谷洞段为研究对象,采用研制的一种新型钻孔压水试验装置,开展分层水力联系的钻孔压水测量试验,查明隧洞上覆岩体上、下层之间的渗透特性,对隧洞上覆岩体进行垂直分带划分。研究结果表明:分界河谷洞段上覆岩体自上而下可分为现代岩溶层、中层强化岩溶层和深层孤立洞隙层,其中现代岩溶层的下限埋深约为100 m,中层强化岩溶层的下限埋深约为160 m,隧洞位于深层孤立洞隙层,距中层强化岩溶层底板约30 m。基于此,通过数值模拟对比分析垂直分带渗透特征与均质渗透特征对隧洞外水压力的影响,发现相较于均质渗流模型,考虑岩溶垂直分带的渗流模型中,岩层内渗透系数的变化导致漏斗状孔压等值线分布特征逐渐消失,且外水压力在拱顶处最大(为7.13×10^(5)Pa),在拱底处最小(为7.07×10^(5)Pa);考虑垂直分带的隧洞最大外水压力为均质渗流模型计算结果的231.5%。
To investigate the influence of vertical zonation permeability characteristics of water-rich karst on external water pressure in deep-buried long-distance water conveyance tunnels,the Fenjie river valley section of the Yunkai Mountain Tunnel in the Beibu Gulf Guangdong Water Resources Allocation Project was selected as the study site.A novel borehole water pressure testing device was developed to conduct stratified hydraulic connection measurements,revealing the permeability characteristics between upper and lower rock layers above the tunnel and enabling vertical zoning of the overlying rock mass.Results indicate that the overlying rock mass of the valley section can be vertically divided into a modern karst layer,a middle enhanced karst layer,and a deep isolated karst void layer.The lower boundary of the modern karst layer is approximately 100 m,the middle enhanced karst layer extends down to about 160 m,and the tunnel is located within the deep isolated karst void layer,approximately 30 m away from the bottom of the middle enhanced karst layer.Based on this,numerical simulations were conducted to compare the effects of vertical zonation permeability and homogeneous permeability on external water pressure.Compared with the homogeneous seepage model,the seepage modele considering karst vertical zonging eliminates the funnel-shaped pore pressure contour distribution due to variations in permeability within rock layers.The maximum and minimum external water pressures occur at the tunnel crown(7.13×10^(5)Pa)and invert arch(7.07×10^(5)Pa),respectively.The maximum external water pressure in the vertically zoned seepage model reaches 231.5%of that predicted by the homogeneous seepage model.
作者
李振嵩
郭清华
张宁
何荣坚
张小平
张浩然
LI Zhensong;GUO Qinghua;ZHANG Ning;HE rongjian;ZHANG Xiaoping;ZHANG Haoran(China Water Resources Pearl River Planning,Surveying&Designing Co.,Ltd.,Guangzhou 510610;Guangdong Yuehai Yuexi Water Supply Co.,Ltd.,Zhanjiang 524000)
出处
《现代隧道技术》
北大核心
2025年第4期37-49,共13页
Modern Tunnelling Technology
基金
国家自然科学基金项目(41927806).
关键词
富水岩溶
垂直分带
渗透特征
外水压力
引水隧洞
分层水力联系
Water-rich karst
Vertical zonation
Permeability characteristics
External water pressure
Water conveyance tunnel
Stratified hydraulic connection
