Construction technology of underground river section of Wuzhaoguan tunnel

The underground river section of the Wuzhaoguan Tunnel entirely buried by the deposit of the fertile silt at the bottom of the river intersects the underground river at DK49+274～+345(71 m in length) with a right angle.The compounds contained in the water of the underground river are mostly composed of the dissolved constituents from the carbonate rock.The water discharge is 0.6 m3/s in the dry season and 10 m3/s in the raining season.Additionally,because the underground river is a recharging source for Hanging Spring(Wuzhao Spring) of Wuzhaoguan and it will be expected to be used by the Wuzhao Hydroelectric Power Station to generate electricity,the water may not be pumped from the river for the further construction of the project.Thus,according to the above mentioned and the spacial relationship between the underground river and the tunnel,a series of measures were designed to ensure that the construction of the underground river section of the Wuzhaoguan Tunnel could be completed safely and smoothly.