welding in tunnel tube

air blast bore boring city civil concept concrete construction cross dark design drainage drill drink drinking drive driven ducting engineer engineering equipment excavation expert flashlight future futuristic gallery gunite heading inaugural installation installed invert joint large layout light lining machine men method municipal person pipeline plan planning potable quality segment segments sewer shaft shotcrete site steel structural supervision supply surface sustainable system tbm tightness transport tube tunnel tunnelling underground urban walking waste water weld welded welding work