ABSTRACT
This chapter describes the wellpoint pumping method, including good practices, installation procedures and practical limitations. It considers variations to the wellpoint system to cope with differing soil conditions. A wellpoint system consists essentially of a series of closely spaced small-diameter water abstraction points connected via a manifold to the suction side of a suitable pump. Single line of wellpoints installed immediately adjacent to one side of a narrow trench. Pumping from the wellpoints lowers groundwater levels to allow the trench to be dug in workably dry conditions. The header main has connections for wellpoints at regular intervals, perhaps every metre. Self-jetting wellpoints and placing tubes used with disposable wellpoints are installed using high-pressure water supplied from a high-pressure jetting pump. The wellpoint and its steel riser pipe are assembled to the required length, and a flexible jetting hose is attached to the top of the riser pipe via a jetting adapter.
