Abstract: In order to improve the strengthdeformation characteristics of Shanghai soft cohesive soils, the palm and wheat straws are added in the target soil samples, respectively. The unconfined compressive strength of the soils reinforced with palm or with wheat straw is analyzed by selecting different reinforcement lengths and reinforcement ratios as influence factors. The results show that: 1) Unconfined compressive strength of the palm reinforced soils is higher than that of the wheat straw reinforced soils. Both of the reinforced soils have the higher strength than the original soil samples. 2) The optimum reinforcement length of the palm straw is approximately 15 mm and the optimum reinforcement ratio is about 1.0 % in weight; The optimum reinforcement length of tubercular wheat straw is approximately 15 mm and the optimum reinforcement ratio is about 0.3%~0.4% in weight. 3) The stressstrain curves of the palm reinforced soils tend to be strainhardening type. The stressstrain curve of the wheat straw reinforced soils appear to be strainsoftening type. The preliminary results show that the palm and wheat straws are both suitable for being used as reinforcement materials. The reinforcement effect of palm straws has a better result comparing with soils reinforced by the wheat straws.

Key words: Reinforced Soils；Unconfined Compressive Strength, Palm Straws； Wheat Straws