水工隧洞进、出口靠近地表,一般均处于风化严重、断裂发育的不良地质区域内.所以,在不良地质条件下,隧洞进、出口开挖中的进洞方法和洞脸加固是隧洞施工中很普遍而且是很重要的问题之一.衡量进洞方法是否合理,洞脸加固措施是否得当,应满足以下基本条件:(1)在保证安全的条件下尽快进洞;(2)明挖工程量小. Generally, the hydraulic tunnel entrances and exits are close to the earth’s surface and are generally in the bad geological area with serious weathering and fault rupture. Therefore, under unfavorable geological conditions, the tunneling methods and the reinforcement of the tunnel face during the excavation of the tunnel entrance and exit are as follows It is very common and very important to measure the hole approach is reasonable, hole face reinforcement measures are appropriate, should meet the following basic conditions: (1) to ensure safe conditions as soon as possible into the hole; (2) digging works Small amount.