Abstract: Adopting palm as a reinforcement material for Shanghai clay, the direct shear tests are carried out to study the effect of palm on Shanghai clay strength characteristics by changing the reinforcement ratio and palm size of reinforcing material. The results show that: (1) Compared with the pure soil, the reinforced soil shear strength and cohesion have improved significantly, but small changes in the angle of internal friction. (2) The optimal rate of reinforcement is 0.6%. (3) The shear strength of shanghai clay with palm size of 6 mm×12 mm is higher than that with palm size of 6 mm×6 mm and 6 mm×18 mm. (4) When the vertical load is 100 kPa, the stress-strain curve is of strain softening type; with the vertical load increasing, the stress-strain curve is of strain hardening type. (5) Compared with pure soil, the reduction of residual strength of reinforced soil is reduced; and its resistance deformation enhance. At the same time, the reinforcement mechanism of the clay shearing strength and the effect of the palm in the clay are expounded. Therefore, the palm can be used as an effective method for reinforcing Shanghai clay.

Key words: palm, Shanghai clay, direct shear test, strength characteristics