Effect of salt grain additions on fibrous peat consolidation

Abstract

Peat has been considered a problematic geotechnical material, with extremely high water content, low shear strength and high compressibility. Although initially high, fibrous peat undergoes dramatic reductions in permeability under compression, with secondary compression (creep) accounting for a large proportion of the settlement under loading. The key to accelerating the whole consolidation process for fibrous/hemic peats is to create a means of accelerating water flow from micropores (within the cellular structure) or humus contained in the peat. This paper presents the results of preliminary laboratory trials performed using the hydraulic consolidation (Rowe) cell apparatus to investigate a novel approach involving the addition of salt grains to fibrous peat towards accelerating its rate of primary consolidation and reducing its creep rate. Under similar loading conditions, salt-treated specimens were found to have reduced rate and magnitude of creep settlement, explained by larger volumes of micropore water expelled during primary consolidation.