ABSTRACT
This chapter addresses the temporary works deep well groundwater lowering system and describes good practices to be used during installation and operation. The design of a well will generally be done after the design of the overall groundwater lowering system has estimated the total flow that must be pumped to obtain the required drawdown for the excavation. The wall thickness of the base pipe forming the well screen and well casing must be adequate to withstand collapse pressures from soil and groundwater loadings. A temporary works groundwater lowering well typically consists of a well screen and casing installed centrally inside a borehole formed by a drilling rig. The annulus between the screen and the borehole wall is filled with granular filter media to form a ‘filter pack’. The methods used to construct wells for temporary works groundwater lowering purposes have much in common with those used to form water supply wells, but there are some differences in techniques and equipment.
