Deep soil mixing stabilisation of peat: a review of small-scale and 1 g physical modelling test results

Abstract

The deep soil mixing method (DSM) is known as a reliable and cost-efficient method of ground improvement which has been studied in great detail for peat stabilisation. The method has gained popularity for peat soil because of its improvement and broad applicability. The study aims to review the published literature focusing on small-scale and 1 g physical modelling testing of peat stabilised using the DSM method. In the review, attention was given to the effects of different binders with varying dosages on the treated peat’s compressibility and shear strength properties. There is a general agreement among various researchers that problematic peat is found to have upper thresholds for the binder content, which are not numerical-specific but rather site-dependent. In most cases, a range of 100 to 200 kg/m3 was the initial activation content, depending upon the peat type to successfully stabilise it with cement. Overall, the improvement of unconfined compressive strength (UCS), California bearing ratio (CBR), and reduction in compression index (Cc) was achieved using different cement contents ranging from 200 to 400 kg/m3. Previous studies, including both field and 1 g physical modelling tests, have confirmed the effectiveness of end-bearing and floating DSM columns in enhancing the ultimate bearing capacity (UBC) of peats.