Author : H.P. Singh

Randomly distributed fiber reinforced soil is among the latest ground improvement techniques in which fiber of desired types and quantity are added in the soil, mixed randomly and laid in position after compaction. Inclusion of randomly distributed fiber makes the soil mass homogeneous and maintains the isotropy in strength. The natural fiber reinforcement causes significant improvement in tensile strength, shear strength, and other engineering properties of the soil. Over the last decade the use of randomly distributed natural and synthetic fiber has recorded a tremendous increase. Keeping this an experimental study was conducted on locally available (Doimukh, Itanagar, Arunachal Pradesh, India) soil reinforced with coir fiber. In this study a number of experiments were conducted on soil reinforced with coir fiber. Soil samples for CBR value tests were prepared at its maximum dry density corresponding to its optimum moisture content in the CBR mould without and with reinforcement. The percentage of coir fiber by dry weight of soil was taken as 0.25%, 0.5%, 0.75% and 1% and corresponding to each fiber content unsoaked and soaked CBR tests were conducted in the laboratory. Tests result indicates that both unsoaked and soaked CBR value of soil increases with the increase in fiber content. It was also observed that increase in CBR value of reinforced soil is substantial at fiber content of 1 %. Thus the significant increase in CBR value of soil due to coir fiber will substantially reduce the thickness of pavement subgrade.

Keywords: CBR value, Soil, Coir fiber, Random Length, Random Diameter