There are many tunnels that air interlinked, so when we remove mud from one part of the tunnel because of the pressure differences, more mud comes in from other tunnels, so the speed of work is not as fast as we would like.
有很多隧道是相互連通的空氣,所以當我們從隧道的某一個部分清除泥漿時,因為壓力差,從其他隧道進入的泥漿更多,所以工作的速度沒有我們想象的那麼快。