Wellpoint systems
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Wellpoint systems are used to lower groundwater levels to provide stable working conditions in excavations. Wellpoint systems are particularly suited to dewatering for shallow foundations and trench works.
A wellpoint system consists of a closely spaced series of small-diameter shallow wells. The wellpoints are connected to a common headermain and are pumped with a high-efficiency vacuum dewatering pump. For drawdowns in excess of 6 m further stages of wellpoints are required, installed at successively lower levels as excavation proceeds.
Rapid and cost-effective wellpoint installation may be achieved in sandy soils by jetting using high-pressure water; drilling installation may be necessary in coarse or cohesive soils.