By R M Telling, North East London Polytechnic, B K Menzies, University of Surrey, and J M Coulthard, Teeside Polytechnic
This paper was first published in GE’s November 1978 issue. This is the final article in a series of three papers on the effectiveness of cut-offs. The first on cut-off efficiency, performance and design appeared in the January 1978 issue, The second on the effectiveness of jointed cut-off walls beneath dams on pervious soil foundations was published in May 1978
This paper examines the problem of assessing the effectiveness of partially penetrating cut-off walls beneath water retaining structures. Previous work undertaken in this area is reviewed. An approximate method of analysis is developed which together with presented numerical data enables the effectiveness of cut-off walls of uniform permeability to be assessed both in terms of flow efffciency and head efliciency. The resulting design method is broadly applicable to slurry trench walls, grout membranes and grout curtains. On the basis of the work carried out some general points are made regarding cut-off wall design.