Field Study on Undrained Shear Strength of Soft Soil around Micropiles

Abstract

Micropile (Cerucuk) is widely used to increase the bearing capacity of soft soil in South Kalimantan. Some researchers have reported that the use of micropile can increase the bearing capacity of soft soil. However, most studies were conducted in the laboratory. This paper discusses the influence of micropile on undrained shear strength in the soft soil around the piles. The study was performed in the field. In this study, cerucuk used was Galam (Melaleuca Leucadendron) that have a nature-lined leather-wrapped stick, hard and dense. Galam has a diameter (D) of 0.10 m and a length of two meters. The piles were penetrated with different spacing (i.e., 2D, 3D, and 4D). Shear strength was measured directly in the field using the field vane shear. Considering time effect, measurements were made before installation, and 1, 7, 14, and 28 days after installation. The results show that the closer pile, the greater the soil shear strength. The piles affect the soil shear strength at a distance up to 0.20 m. Soil shear strength increases by time up to 14 days.