Steady state performance of construction dewatering systems in fine soils

Preene, M. and Powrie, W. (1993) Steady state performance of construction dewatering systems in fine soils. Géotechnique, 43 (2), 191-205. (doi:10.1680/geot.1993.43.2.191).

Record type: Article

Abstract

The applicability of conventional theory to construction dewatering systems in fine soils is uncertain for a number of reasons. This Paper uses case records from 30 dewatering systems in fine soils to assess the suitability of various methods of analysis of conditions at the steady state. Guidelines are proposed for the selection of soil permeability from such data as are likely to be available at the design stage. The use of these guidelines, together with analytical techniques appropriate to the field boundary conditions, gives calculated flow rates which are generally within a factor of 3 of the recorded values. The field data suggest that dewatering systems in fine soils should not be designed to operate with average hydraulic gradients at entry into the wells in excess of 4 for well-points, or 10 for ejectors. It is shown that whereas the effectiveness of a dewatering system in a fine soil should not normally be affected significantly by a variation of a factor of 3 in the average soil permeability, an unexpected close source of recharge will seriously impair the performance.

This record has no associated files available for download.