A parametric investigation on the shear strength and bearing capacity of Cenozoic Berea Red Sand with geosynthetic reinforcements

Abstract

The use of Berea Red sands can be seen extensively among civil infrastructure particularly along the eastern coast of South Africa. These cohesive soils vary in colour, composition, and strength. Despite the understanding of limited works being published on the geotechnical properties on Berea Red sands as well as the implementation of reinforcing agents to improve it, this study was undertaken to investigate the bearing capacity and shear strength of Berea Red sands with and without reinforcing agents. In addition, the concept of reinforcing materials was investigated with the probability of improving the Berea Red sands regarding the abovementioned properties, thereby displaying the novelty of this study. Deformation behaviour under an increasing compressive load of 100kPa, 200kPa and 300kPa was implemented through a suite of consolidated undrained triaxial tests. The triaxial tests provided an appropriate technique to study the effects of stress and strain correlation as well as in obtaining the parameters needed to calculate bearing capacity and shear strength. The triaxial tests compared the behaviour of Berea Red sands under reinforced and unreinforced conditions. The implementation of two different reinforcing parameters were investigated and compared with each other as well as with the original unreinforced test results. The two reinforcing agents used resembled that of a diamond mesh and a mosquito net. Different configurations and layers of reinforcement were implemented in the triaxial tests to better study its contribution and influence on the bearing capacity and shear strength of Berea Red sands. The Berea Red sand properties of bearing capacity, shear strength and strength ratio increased by the implementation of reinforcing agents as well as the increase in reinforcing layers with the 4 layer diamond mesh exhibited the best strength properties when compared to unreinforced samples and 2 layer reinforced samples, across all confining pressures (100kPa, 200kPa and 300kPa).