Bearing Capacity of Soft Soil Reinforced with Chevron Pattern Bamboo-Geotextile Composite

Abstract

The problem of soft soil is associated with low shear strength and high compressibility, hence low bearing capacity and high settlement. This paper presents the results of the laboratory-model tests on the bearing capacity of a strip footing laid on different thickness (u) of sand layer underlain by soft soil reinforced with bamboo-geotextile composite mattress at the interface. The width (b) of the footing was 50 mm. Bamboo poles of about 5 mm inner diameter (d) were arranged in chevron grid pattern, at various distance (s) between the poles. The embankment ratio (u/b) was limited to 0.25, 0.50, 0.75 and 1, while the bamboo distance ratio (s/d) was set to 5, 10, 20 and 30. The soft soil was prepared in a soil container, from kaolin powder mixed with water of twice its liquid limit, and consolidated in three layers to achieve an undrained shear strength of about 12 to 14 kPa. The loading test was carried out by applying the vertical load slowly to the strip loading plate, placed centrally on top of the sand surface of the soil model assembly. Results show that the chevron grid pattern bamboo-geotextile composite system has the potential to become an alternative cost-saving method for soil stabilisation or improvement, especially in highway construction. The charts developed in this study allows the engineer to use them in the design of embankment over soft soil.