Passive earth pressure against retaining wall using log-spiral arc

Abstract

Passive earth pressure against retaining wall depends on a number of factors such as, soil friction angle φ, soil wall friction angle δ, backfill angle (ground surface inclination behind wall β), inclination of wall face on horizontal α, and surface of rupture. Several theories have been developed to overcome this problem, i. e., determination of the coefficient of passive earth pressure using the plane surface of rupture. One of the important parameter which affect the coefficient of the passive earth pressure is the surface of rupture. In the present paper, formulation is proposed for calculating coefficient of passive earth pressure on a rigid retaining wall undergoing horizontal translation based on surface of rupture consisting of log-spiral and linear segments assisted by computer program (MATLAB program). The present study is compared with coulomb’s results. The comparisons of that the present study predicted values of earth pressure are much less than those of coulomb’s values specially if δ≥ 0.3 φ. These results agree well with another research. In order to facilitate the calculation of coefficient of passive earth pressure, using the proposed equations, a modified coefficient of passive earth pressure is provided. It is a function of (φ, δ, β, α).