鸿图特长隧道高压涌水成因分析

Cause Analysis of High Pressure Water Gushing in Hongtu Extra-Long Tunnel

鸿图特长隧道是广东大丰华高速穿越莲花山脉的关键控制性工程,隧道最大埋深达740 m,隧道开挖过程中遭遇到压力4.8 MPa下大流量涌水,最大水量达14万m^(3)/d。通过分析隧道地质构造影响,阐述开挖过程中高压涌水水量状况及其主要导水构造,同时对涌水过程水量进行跟踪,比较不同洞段位置涌水水质,提出了鸿图特长隧道受莲花山断裂影响下形成的桐子洋向斜蓄水构造、岩体侵入接触蓄水构造和断裂裂隙蓄水构造等3种蓄水构造模式。综合隧道全线涌水量特征与地质构造关系,提出隧道高压涌水机制主要为受莲花山断裂影响形成的地垒式水文地质模型作用,使得隧道在开挖时遭遇到高压大流量涌水,在贯通后受深部储水循环控制,重新构建稳定的地下水系统后,隧道每天涌水达6万m^(3),与实际吻合。

The Hongtu extra-long tunnel is the key control project of the Dafenghua Expressway crossing Lianhua Mountain in Guangdong Province.The maximum buried depth of the tunnel is 740 m.In the process of tunnel excavation,a large flow of water was encountered under the pressure of 4.8 MPa,and the maximum water volume is 1.4×105 m^(3)/d.By analyzing the influence of tunnel geological structure,the situation of high-pressure water inflow and its main water-conducting structure were expounded during the excavation process.At the same time,the water volume during the water inflow process was tracked,and the water quality of water inflow at different tunnel sections was compared.Three water storage structure modes,such as Tongziyang syncline water storage structure,rock mass intrusion contact water storage structure,and fracture fissure water storage structure,were proposed under the influence of the Lianhuashan fault in the Hongtu extra-long tunnel.Based on the relationship between the water inflow characteristics of the whole tunnel and the geological structure,it was proposed that the high-pressure water inflow mechanism of the tunnel was mainly affected by the horst-type hydrogeological model formed by the influence of the Lianhuashan fault,which makes the tunnel encounter high-pressure and large-flow water inflow during excavation.After penetration,it was controlled by the deep water storage cycle.After the stability of the groundwater system was rebuilt,nearly 60000 m^(3)large-flow water inflow per day is consistent with the actual situation.