引水隧洞塌拱影响因素及其防治措施研究

为了弄清隧洞塌拱的原因和寻找合理有效处理塌拱的工程措施,以曾达电站引水隧洞1、2号支洞施工中发生的不同程度的塌拱行为为实例,分析了地下水、岩体结构、施工因素等对塌拱的影响;进一步研究了处理和防治塌拱的施工措施和原理。研究结果表明:地下水的影响是塌拱发生的重要原因之一,岩体结构及施工因素特别是支护的时机对保护围岩的稳定性非常重要;现场采用超前小管棚预注浆与锚喷支护综合技术处理隧洞塌拱取得了良好效果。

Study on Influencing Factors and Protection Method of Collapse in the Arch of Hydraulic Tunnel

In order to find the reason of collapse in arch and reasonable construction method to deal with collapse in arch, the influence of underground water, rock structure, construction factors on collapse in arch were analyzed, the tunnel collapse of different degree in arch during construction of the NO.1 and NO.2 sub-tunnel of the hydraulic tunnel in ZENGDA power station are taken as example. The theory and construction method to deal with and protect the tunnel collapse in arch are studied. The results show that underground water is one of the main reasons of collapse in arch and the rock structure and construction factors (especially supporting time) are very important to protect the stability of surrounding rock. On the spot, using small pile-shed forepoling with bolting and shotcreting support to deal with the tunnel collapse in arch is successful.