The Study of Soil-Roots Strength Performance by Using Pennisetum Setaceum Grass

Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia

^a Corresponding author : gf130019@siswa.uthm.edu.my

Abstract

Vegetation is regarded as a new engineering material contributes to slope stability and reduces superficial soil erosion, both by soil shear reinforcement and influencing soil water content. Yet, it is aware that roots growth occurred below the soil surface and it is considered as dynamic organs that respond to physical, chemical and hydrological induced by surrounding substrate. This study was carried out to investigate the soil shear strength performance by using Pennisetum Setaceum grass at the different planting period up to three months. The grass was planted in a 150 mm × 200 mm × 700 mm test plot with a suitable soil medium. Pull-out strength test was conducted for each plot to determine the soil pull-out strength according to different planting period. The results show that there is an increment in the pullout strength of rooted-soil sample over different planting period with average results of 6.7 kPa, 11.4 kPa and 25.8 kPa for month 1, 2 and 3 respectively. Based on this study, the soil pull-out strength developments for vegetated soil were observed. The higher pull-out strength was recorded for different growth period. Moreover, root weight was increased for different growth period. Based on the tensile test, the diameter of the root affects the rate of resistance against the tensile forces. This indicated that the roots structure growth affects the soil shear strength.