DISCO DAVE'S TUNNEL GUIDE
Chapter 5 Phase 4 Shoring the tunnel
Ideally use either 2" by 2" or 3" by 3" timbers for uprights and crossbeams. At the bottom of each upright place a quarter inch thick piece of wood. This will act as a foot to prevent the upright sinking into the ground.
The length and breadth of the foot should ideally be at least 3 inches wider on each side of the upright and around 5 inches longer. Weak soil may dictate the need for wider and thicker feet.
At what intervals you place each piece of shoring depends on the consistency of the soil. IE sand may require shoring every foot to two feet clay on the other hand may only require shoring at four feet intervals. The wider the gap between the shoring the thicker the boarding above the the cross beams will need to be. In most cases half inch boarding will generally suffice.
Phase 2 Shoring the down shaft
Phase 5 Constructing and erecting Shoring
e-mail the author with your comments