圆形小断面引水隧洞渗涌水特征分析与控制措施

Characteristic Analysis and Construction Measures of Seepage and Water Gushing Disaster in Circular Small Cross-Section Diversion Tunnel

渗涌水防治是隧洞工程必须面对的难点和挑战。针对圆形小断面引水隧洞渗涌水问题,依托贵州省夹岩水利枢纽工程水打桥隧洞,对引水隧洞渗涌水破坏形态、渗涌水量及渗涌水特征进行分析,发现渗涌水与围岩裂隙密切相关,围岩裂隙越密集、张开度越大、延伸能力越好,其透水能力越强;提出楔型凹槽排水管引排法、线槽预埋管引排法、防水卷材配合环纵向排水法、超前圆环预加固间隔分段灌浆法等防排水措施并创新施工工艺,有效减少了隧洞渗涌水,加快了工程施工速度,保证了施工安全,具有一定的工程借鉴意义。

Prevention and control of seepage and water gushing is a difficult point and challenge that must be faced by tunnel engineering.In view of the seepage and water gushing problems in circular small cross-section diversion tunnel,this paper is based on the construction of Shuidaqiao Tunnel in Jiayan Hydro-complex Project in Guizhou to analyze the damage pattern,amount of water inflow and characteristics of seepage water in the diversion tunnel,and find that the seepage water is closely related to the fracture of surrounding rock.The denser the surrounding rock fissure is,the larger the opening degree is,the better the extension ability is,and the stronger the water permeability is.Then,some drainage prevention measures,such as drainage method by wedge-shaped groove drainage pipe,drainage method by embedded pipe in the trunking,longitudinal drainage method of rolled waterproofing materials matching rings,interval segmental grouting method of advanced ring pre-reinforcement,are put forward,and many innovations are achieved accordingly in the construction technology,which effectively reduce the seepage and water gushing in tunnel,accelerate the construction speed,ensure the construction safety,and have a certain engineering significance.