Triaxial tests of sand reinforced with 3D inclusions

In conventional reinforced soils, the reinforcements are often laid horizontally in the soil. In this paper, a new concept of soil reinforced with three-dimensional (3D) reinforcing elements is proposed. In the proposed 3D reinforced soil, besides conventional horizontal reinforcements, some vertical and 3D reinforcing elements are also placed in the soil. A comprehensive set of triaxial tests was carried out on sand reinforced with 3D reinforcements (made of galvanized iron sheet and hard plastic sheet). The behavior of sand reinforced with different 3D reinforcing configurations is studied in terms of stress–strain relationship and shear strength of the soil. Comparison is made between stress–strain relationship and shear strength of the soil reinforced with horizontal reinforcement and with 3D reinforcing elements. The influences of the height of vertical reinforcing elements, the Young's modulus of reinforcement materials and confining pressure on strength of reinforced sand are discussed. The experimental results show that 3D reinforcement not only gives an apparent cohesion to the soil (sand), but it also increases the angle of internal friction significantly, especially with double-sided 3D reinforcing elements. Different configurations of 3D reinforcing elements are discussed and compared.