Experimental and theoretical investigation of strength of soil reinforced with multi-layer horizontal–vertical orthogonal elements

In conventional reinforced soil structures, the reinforcements are often laid horizontally in the soil. In this paper, a new concept of soil reinforced with horizontal–vertical (H–V) orthogonal reinforcing elements is proposed. In the proposed method of soil reinforcement, H–V orthogonal elements instead of conventional horizontal inclusions are placed in the soil. A fundamental difference between the H–V orthogonal reinforcing elements presented in this paper and other forms of inclusions is that the soil enclosed within the H–V orthogonal reinforcing elements will provide passive resistances against shearing that will increase the strength and stability of the reinforced soil. A comprehensive set of triaxial tests were carried out on sand reinforced with multi-layer H–V orthogonal elements and vertical ones. The behavior of sand reinforced with different H–V orthogonal elements was studied in terms of stress–strain relationship and shear strength. Based on experimental results, a strength model of the soil reinforced with H–V orthogonal elements was developed by means of the theory of limit equilibrium. The results of proposed strength model are compared with those obtained from the triaxial tests. It is shown that the results of prediction are in good agreement with those of the triaxial tests.