Soil-roots performance of Pennisetum setaceum ‘Rubrum’ on mechanical soil strength

Abdullah, Muhamad Firdaurs (2017) Soil-roots performance of Pennisetum setaceum ‘Rubrum’ on mechanical soil strength. Masters thesis, Universiti Tun Hussein Onn Malaysia.

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Abstract

The potential of Pennisetum setaceum ‘Rubrum’ root in soil reinforcement was investigated. This African native perennial bunchgrass has been introduced in many parts of the world as an ornamental plant and for soil stabilization. The traditional civil engineering techniques such as concreting of welded wire walls for slope stabilization may not be sustainable in the long term due to high initial capital cost. It also looks harsh and unnatural to the road users. Alternatively, vegetation can be used together with inert structure as a way of reducing the visual impact of civil engineering works. Hence, the study is aimed towards the establishment of a flowery plant that able to perform decent soil-root shear strength reinforcement. P. setaceum ‘Rubrum’ has been planted at the field plots at RECESS. A series of laboratory direct shear tests was performed on rooted and non-rooted samples at 100, 200 and 300 mm soil depth, every month throughout the seven months of study period. The roots tensile strength was determined using an Instron Universal Testing Machine (Model 3369). Plant morphological data such as shoot biomass, root density and plant height were also measured. The direct shear test results show that shear strength of rooted sample of P. setaceum ‘Rubrum’ increases with time for all depths, with the highest increment of 441 % over the control sample, that belong to one of rooted soil sample of month 7 at 300 mm soil depth. The increment is due to high root tensile strength (43.68 kPa ± 3 kPa) and root density (9.36 kg/m3). In term of average peak shear stress, month 7 was highest at all depth. Its shear stress values were 307 ± 82 kPa (100 mm), 181 ± 42 kPa (200 mm) and 179 ± 41 kPa (300 mm). Whereas, root tensile strength decreased with increasing diameter of roots following the power function with the highest average tensile strength of 50 ± 2 MPa (month 6). The results of this paper improve the knowledge about biotechnical characteristics of root systems of P. setaceum ‘Rubrum’ and indicate that this species could potentially serve as soil reinforcement.

Item Type:Thesis (Masters)
Subjects:T Technology > TA Engineering (General). Civil engineering (General) > TA703-711 Engineering geology. Rock mechanics. Soil mechanics.
ID Code:9864
Deposited By:Mr. Mohammad Shaifulrip Ithnin
Deposited On:27 Mar 2018 12:31
Last Modified:27 Mar 2018 12:31

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