The spoiling is a key factor influencing the advancespeed for the shaft excavation, especially for the excavation of large cross section and deep shaft.
对于竖井开挖 ，尤其是大断面 深竖井开挖 ，出碴这一环节 ，往往是决定掘进速度快慢的关键因素。
3
The speed and force of the huge waves there make it impossible to know in advance when they are coming.