Permeability Behavior of Tropical Sapric Peat under Isotropic Compression

Abstract

Abstract Tropical sapric peat has a distinctive origin, which originates from highly decomposed woods. It consists of organic particles with colloidal microstructure and jelly-like texture. Such feature influences the permeability and the rate of pore water dissipation. This paper discusses the tropical sapric peat permeability behaviour from a series of flexible wall permeameter tests. A special peat specimen preparation method is presented. Each specimen was isotopically compressed under different effective stresses in a modified triaxial apparatus and digitally monitored for 2 days-long permeability tests. The results showed that the permeability decreases with time following a negative power function, which indicated that the flow of liquid progresses gradually from the transient to the steady states. A graphical method is proposed to distinguish the transient state and the steady state flow at which a representative coefficient of permeability can be determined. The time taken to achieve the steady state was found to be correlated with the level of compression. A good linear relationship between the coefficient of permeability and the log of effective stress was found. The tropical sapric peat in this study has lower permeability-to-effective stress ratio when compared to the amorphous sapric peat data from the literature. The present finding provides references for academic and engineers to better understand the permeability behavior of tropical sapric peat.