Abstract: Bamboo slats (thickness of 5mm, width of 10mm, and length of 20, 40, 60mm respectively) were added into soil in different mass percentage contents (0.2%, 0.4%, 0.6%, 0.8%, 1.0%, and 1.2%). Then large-scale direct shear test was carried out on the soils reinforced with the bamboo slats to investigate the reinforcement mechanism. Results reveal that compared with pure sand, the shear strength of reinforced soil is obviously improved, the peak strength and residual strength are increased; and also cohesion and friction angle have increased, among which cohesion increased greatly; the peak shear strength of reinforced soil increased firstly and then decreased with the increasing size and percentage of bamboo slats; the optimal size of bamboo slat is 10mm×40mm and the optimal ratio of reinforcement is 0.8%.

Key words: soil reinforced with bamboo slats, large-scale direct shear test, strength performance, cohesion, reinforcement ratio