Effect of Decomposition on the Compressibility of Fibrous Peat

Abstract

This paper reviews the mechanisms of decomposition and, in particular, its effect on the compressibility of fibrous peat. Decomposition refers to the breakdown of fresh plant tissue, with the detritus becoming progressively finer, until eventually all vestiges of the original fibrous structure are lost and the peat has an amorphous, almost granular form. From a geotechnical perspective, the partly decomposed plant matter has a major influence on peat behavior, with the peat properties closely related to the average state of decomposition. The destruction of the plant tissue causes a reduction in the material's water holding capacity and weakens the absorption complex which results in the reduction of both its water content and liquid limit values. The reduction in the organic content and the destruction of the inherent fibrous structure also causes an increase in bulk density. An evaluation of the compressibility characteristics of peats at different states of decomposition has been performed from a review of previous research reported in literature. The C /C c ratio of peat ranges between 0.035 and 0.1, with the lower value corresponding to amorphous peat. Hence, it is expected that the more decomposed the peat material, the lower its compressibility. This paper also presents a preliminary study on the potential for decomposition of peats maintained at a constant temperature of 30 C and under partially-saturated conditions over an extended period.

Acceleration of Decomposition Process by Lignocellulolytic Bacteria and Its Effect on the Physical and Engineering Properties of Kalimantan Fibrous Peat

“…This was caused by the decrease in the water content in peat as a result of chemical reaction of water absorption by lime for the process of forming CaSiO3 jelly. The decrease in water content in the sample caused acceleration of the peat decomposition process which resulted in the increase in compression of the relevant peat [7].…”

Deformation behaviour of geotechnical materials with gas bubbles and time dependent compressible organic matter

“…Biogas has been found in these materials because of the decomposition of organic matter. Pichan and O'Kelly (2012) discussed that organic matter in peat can be converted into gases including carbon dioxide and methane. The total gas voids content for peats and other organic soils is generally in the range of 5% to 10% (Hobbs, 1986).…”

Water Content Determinations for Peat and Other Organic Soils Using the Oven-Drying Method

“…According to the modified von Post peat classification system, [25] the Ballydermot peat deposit was classified as SCWPh-H 4-7 -B 3-4 -F 2 -R 2 -W 1 , the Clara peat material as SCN-H 4 -B 3 -F 3 (S)-R 1 (N)-W 1 (N), and the Derrybrien peat material as CErPh-H 3-4 -B 4 -F(Er) 2 -R(CPh) 3 -W 1. Full descriptions of these peat deposits and their geotechnical properties have been reported for the Ballydermot site by Pichan and O'Kelly [26,27] and O'Kelly and Pichan, [23] for the Clara site by O'Kelly and Zhang [28] and Zhang and O'Kelly, [29,30] and for the Derrybrien site by AGEC. [31] Refined Clara peat material (denoted by Cr) was also prepared for oven-drying tests by blending some of the remolded peat material using an electric handheld blender.…”