Characteristics of Palangkaraya fibrous peat

¹ Departement of Civil Engineering, Universitas Madura, Jawa Timur, Indonesia
² Departement of Civil Engineering, Universitas Kaltara, Kalimantan Utara, Indonesia
³ Departement of Civil Engineering, Universitas Lambung Mangkurat, Kalimantan Selatan, Indonesia

^* Corresponding author: faisal_ey@yahoo.co.id

Abstract

Palangkaraya fibrous peat soil is a soil with high organic content and was formed due to decomposition of plants in submerged areas for long periods. In the tropics, peat has a high fiber content that affects the physical and engineering characteristic and have different behavior with clay. Laboratory and field tests were conducted to determine the physical and engineering characteristic of fibrous peat and to compare it with clay. The results of the tests on fibrous peat show peat soil parameter very different from clays. The unit weight of peat is 1.04 gr/cm³ with specific gravity is 1.4 and water content reach 650%. This physical parameter shows that peat is a very soft soil that is dominated by water in its structure. Organic content of peat reached 97% with a very low ash content of 3%. This behavior indicates that the decomposition of plants causes physical properties of peat that are very different from clays. The bearing capacity of the peat is also very low. The shear strength was about 26.8 kPa (ov = 50 kPa) and was dependent on the fiber distribution in the sample under test. Vane shear test results also show the same thing that is 5-7 kPa. The very different behavior of fibrous peat with clay is the consolidation. Peat has 4 stages of compression wherein secondary compression is the main compression. This behavior is due to the fibrous peat has two pores, that are micropores and macropores. The results of comparisons can serve as a basis for determining appropriate peat soil improvement methods.