Abstract:
Currently, there are many methods of soil reinforcement have been used on soft soil to increase the shear strength of the soil. Detail informations, interaction between soft soil and vertical piles in laboratory works were needed to complete it. This research was conducted by physical model of laboratory scale using practise behaviour approach. The approach is modifying direct shear test with large box. The large box is used to avoid friction effect between vertical piles and vertical plane of the
box. The shear strength test was applied by several variations, namely; ratio of pile insertion, spacing of piles group, piles number, and piles diameter. The results showed that shear resistance of soil is increase by increasing of length piles below the sliding surfaces and spasing piles of 3D to 5D. Shear resistance of soil decreases for piles spacing of 5D to 8D. The use of more piles as resistance against sliding would decrease the lateral capacity of each individual pile, similar to that of efficiency factor used in group of piles under axial loading. Maximum shear resistance was reached by pile spacing of 5D. Piles diameter
also affect the shear resistance of soil, larger diameter increase it than lower diameter
