Abstract: The lateral earth pressure coefficient is an important parameter in the calculation and analysis of earth pressures and is one of the influence factors on the earth pressure distributions. This paper presents a new earth pressure formula under different failure planes and friction angles of the back of the retaining wall. The results from the new lateral earth pressure formula are compared with the results from the classical formula. The results indicate that, when searching the planar failure plane using Coulomb method, the lateral earth pressure coefficient is a constant, which is consistent with the Coulomb earth pressure coefficient. Under the curved failure plane assumptions, the lateral earth pressure coefficient is not a constant and the active lateral earth pressure coefficient increase with the decrease of the friction angle of the back of the retaining wall. The passive earth pressure coefficient, however, has the reverse trend. The paper also concludes that the nonlinear lateral earth pressure coefficient change with the curved failure plane assumptions is due to the nonlinear behavior of soils.
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Key words: Soil Stress States, Lateral Earth Pressure Coefficients, Angle of Failure Planes, Friction Angle at Back of Retaining Wall