Comparing Eurocode 8-5 and AASHTO methods for earth pressure analysis against centrifuge tests, finite elements, and the Generalized Coefficients of Earth Pressure

Abstract

This paper presents an exhaustive comparison of the earth pressure methods included in EN1998-5:2004 (use of Mononobe-Okabe method, M-O), prEN1998-5:2021 and AASHTO (M-O with half peak ground acceleration) standards, against contemporary centrifuge tests, finite elements, and the method proposed by the first author in 2019. The latter is a continuum mechanics approach for deriving earth pressure coefficients for any soil state between the “at-rest” state and the active or passive state, applicable to cohesive-frictional soils and both horizontal and vertical pseudo-static conditions. The same method also provides analytical expressions for the calculation of the required wall movement for the mobilization of the active (or passive) failure state, as well as for the mobilized shear strength values of soil. The comparison includes among others, centrifuge test results from two different studies, and results from 157 finite element models from two different programs. All experimental, numerical, and analytical results show that the EN19985-5:2004 method gives conservative to excessively conservative active earth pressure values, AASHTO’s approach fairly good behavior, while prEN1998-5:2021 excessively conservative values. For the passive state, all methods included in the above-mentioned standards, return unreliable and unconservative results. In contrast, the results obtained by the proposed method show a remarkable agreement with the respective ones obtained both by the finite element method and the various centrifuge tests. Also, it is shown that a pseudo-static earth retention analysis, can be replaced by a respective static analysis, just substituting the (c', φ') values of soil of the original problem with the mobilized ones.

Seismic Behavior of Retaining Walls: A Critical Review of Analytical and Field Performance Studies

“…The groundbreaking contribution of Okabe [2] and Mononobe and Matsuo [3], commonly referred to as the Mononobe-Okabe (M-O) method [2,3], based on a pseudostatic approach, is the prevailing and widely adopted approach for calculating earthquake-induced lateral earth pressures on retaining walls. Subsequently, several alternative analytical approaches were suggested to assess active and passive earth thrust, including pseudo-dynamic methods [4][5][6][7][8][9][10][11][12][13][14], closed-form stress plasticity solutions [15,16], upper -bound [17][18][19] and lower-bound [20,21] limit analysis approaches, the continuum mechanics approach [22,23], and the method of slices [24][25][26]. However, a common limitation in most of these analytical studies is the assumption of a rigid (nonyielding) retaining wall, harmonic motion, or linear amplification of backfill acceleration.…”