Bulletin of the Geological Society of Malaysia, Volume 80, November 2025, pp. 21 – 43

The properties and behaviours of unsaturated peat soil in Malaysia: A review

Maryam Moh’d Subhi Al Jaber, Nurmunira Muhammad^*

Faculty of Civil Engineering Technology, Universiti Malaysia Pahang Al-Sultan Abdullah, Lebuh Persiaran Tun Khalil Yaakob, Kampung Melayu Gambang, 26300 Kuantan, Pahang, Malaysia

*Corresponding author email address: muniramuhammad@umpsa.edu.my

Abstract: A detailed assessment of the properties and behaviour of unsaturated peat soils in Malaysia is presented, with a focus on their noteworthy attributes, including organic matter content of more than 75%, high moisture levels, low structural integrity, and high compressibility, ultimately resulting in substantial construction difficulties. The review assesses key characteristics of Malaysian peat soils, such as shear strength, unconfined compressive strength, specific gravity, moisture content, and compressibility, from the index properties perspective. The characteristics of Malaysia’s peat soils are comparable to those found in typical peat soils globally. A significant discovery is the strong correlation between high moisture levels and organic content, which is associated with low shear strength and specific gravity, and increased compressibility of the soil. This paper fills a substantial omission in the existing research on the behaviour of Malaysian peat in unsaturated environments. Studies revealed that peat soil is significantly impacted by seasonal fluctuations, particularly during periods of heavy rainfall, which lead to a substantial decrease in shear strength and an increase in water infiltration, resulting in settlement, deformation, and slope instability. As depth increases, hydraulic conductivity is reduced due to the growing complexity of the pore structure, thereby hindering water flow. The review significantly improves comprehension of peat soil behaviour under unsaturated conditions, yielding valuable information for the construction industry and policymakers.

Keywords: Peat soil, unsaturated conditions, moisture content, water table, bearing capacity

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Manuscript received 20 August 2024;
Received in revised form 17 October 2024;
Accepted 14 January 2025
Available online 28 November 2025

https://doi.org/10.7186/bgsm80202503

0126-6187; 2637-109X / Published by the Geological Society of Malaysia.
© 2025 by the Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC-BY) License 4.0.