Well points are to be used to dewater a large trench excavation that
extends 10 m below the surface of the water table. Assume that the
bottom width of the trench excavation is 20 m.
(1) Develop a simple sketch of the necessary two-stage well point sys-
tem. Use separate diagrams to show the progress of the necessary
stages of installation.
(2) Assume that half of the necessary lowering of the water table eleva-
tion is achieved using the outer row of well points. If the soil being
dewatered is a fine-to-medium sand, approximately at what dis-
tance beyond the well point location is the original groundwater
table that is not affected by well point dewatering?