A critical review on seismic design of earth-retaining structures

Abstract

The dynamic response of earth-retaining structures is a complex issue. The design of these structures under seismic loading conditions is, therefore, quite challenging. Because there are not many case histories on field performance of earth-retaining structures, the theory of dynamic response has been based on the results from both model tests and numerical analyses. The most common approach to the seismic design of retaining walls, especially where the expected ground acceleration is less than or equal to 0.29g, involves estimating the loads imposed on the wall during earthquake shaking and then ensuring that the wall can resist those loads. Because the actual loading on retaining walls during earthquakes is extremely complicated, seismic pressures are usually estimated using the Mononobe-Okabe pseudo-static method. The Mononobe-Okabe equation is an extension of the Coulomb’s classical solution, which accounts for inertial forces. Another approach for designing against seismic loading is to allow for an “acceptable permanent deformation” and determine the dimensions of the structure accordingly. This approach is typically more appropriate for retaining structures to be built in highly seismic regions, where the peak ground acceleration for the design earthquake is larger than 0.29g. Neither the Mononobe-Okabe method nor the displacement method accounts for the characteristics of the ground motion. More realistic dynamic response analysis can be performed using the results from laboratory studies and numerical models. This paper presents the state-of-the-art for the design of earth-retaining structures under dynamic loading conditions. The commonly used simplified design procedures were presented. Relatively recent laboratory studies and numerical solutions were reviewed. Some case histories regarding the seismic performance of retaining walls were also listed