Peat Improvement Under Vacuum Preloading: A Novel Approach for Bog Roads in Ireland

Abstract

This paper presents the preliminary findings of a TCD/NRA vacuum preloading field trial which is part of a research project into construction options for improving rampart roads. Vacuum preloading is a construction method utilized to accelerate settlement and increase shear strength by applying a vacuum pressure to the ground by means of prefabricated vertical drains, impervious tight sheet and a vacuum pump. Consolidating the ground by applying a vacuum load has several advantages over other techniques, for example, no fill material is required, construction periods are generally shorter and there is no need for chemical ad-mixtures. The paper presents a review of current literature on the subject and describes the setup and initial stage of the TCD/NRA vacuum preloading field trial, which is currently being carried out at Ballydermot bog. The test consists in a 10x10m heavily instrumented area in which the settlement, reduction in pore water pressure and increase in shear strength are being investigated to evaluate the improvement achieved in the peat foundation with the vacuum preloading technique.