东津水电站引水隧洞进口不良地质段施工

东津水电站引水隧洞进口段工程地质条件恶劣，施工干扰大，渡汛工期紧。采用喷锚支护洞脸边坡，洞口明挖３ｍ浇筑钢筋混凝土明拱和Ｌ形护坡墙；洞身段采用新奥法施工，先打通上导洞；进口４０ｍ分段开挖，分段衬砌；进水塔压板混凝土模板采用门字框架钢支撑；排除了施工干扰，防止了洞口滑塌，进口段塌方的恶性事故发生，保证了引水隧洞工程的顺利施工。

Construction of poor geologic section at tunnel portal in Dongjin project

The poor geologic section at tunnel poreal in Dongjin project was treated by rockbolt-and -shotcrete suport for tunnel face and side slope,and a reinforced concrete arch and L-type retaining walls were placed.For excavation of the tunnel body NATM was used. The top heading was driven first. For construction of40m long entrance section excavation and concrete lining were done part by part. For the concrete form ofthe floor of the intake tower then type steel frame support was used. As a result no tunnel collapse or rockfall occurred,and the tunnel construction proceeded smoothly.