Laboratory testing and numerical modelling on bearing capacity of geotextile-reinforced granular soils

Abstract

This paper summarises the details of an experimental work and numerical simulation on the bearing capacity of geotextile-reinforced granular soils with different fine grain contents (10 and 15%) which are mostly used in pavement design. The effects of position and number of geotextile layer(s) on the bearing capacity of reinforced specimens were investigated. The standard laboratory California Bearing Ratio (CBR) test was conducted to investigate the load-penetration behaviour of the unreinforced granular soils as well as reinforced ones with nonwoven geotextile layer(s). The reinforcements have been placed in samples in seven different scenarios (one, two and/or three layers of reinforcement in the bottom, middle and/or top compacted soil layers). The results indicated an increase in bearing capacity for most of the scenarios due to placing the geotextile layer(s); however, it was seen that increasing the number of reinforcement layers will not necessarily increase the reinforced soil mass bearing capacity. Also it was found that the efficiency of placing the reinforcement layers in order to increase the bearing capacity is higher for the soil mass with higher fine content in compare to the soil mass with lower fine content; even in some scenarios for the soil with lower fine content, the geotextile would decrease the bearing in compare to the unreinforced sample. Besides this laboratory testing, Finite Element (FE) software was used to simulate the CBR tests. The FE analysis results showed that the ratio of predicted to measured CBR value is varied between the range of 1.06–1.20 for the soil with lower fine content and 0.86–1.086 for the soil with higher fine content. After the FE model was validated, it was tried by changing the properties of the nonwoven geotextile with a woven one in software to make a comparison between two reinforcement types.