SEISMIC GEOTECHNICAL ROBUST DESIGN OF CANTILEVER RETAINING WALL USING RESPONSE SURFACE APPROACH

Parishad Rahbari ； Nadarajah Ravichandran ； C. Hsein Juang

《Journal of GeoEngineering》 12卷4期 (2017/12) Pp. 147-156

https://doi.org/10.6310/jog.2017.12(4).2

摘要

Seismic geotechnical design of retaining walls should consider the uncertainties not only in soil properties such as friction angle of the backfill but also in earthquake load such as peak ground acceleration (PGA). When the uncertainties are incorporated in the design, the robustness which is a measure of sensitivity of a design to uncertain parameters must be considered and evaluated for obtaining suitable design and corresponding construction cost. This paper presents a response surface-based robust geotechnical design approach for cantilever retaining wall subjected to earthquake load. First, the upper and lower bounds of the design variables were determined through dynamic retaining wall design using Mononobe-Okabe method for possible variations in the uncertain parameters. Then, dynamic finite element analyses were performed on a subset of designs by applying El Centro earthquake motions with varying PGA for computing the maximum wall tip deflection which is considered as the serviceability indicator. A response surface for the wall deflection was developed as a function of uncertain and design variables and validated. Finally, a design optimization was performed considering cost and robustness index as the objectives. Two robustness indices, standard deviation of the response and signal to noise ratio were used in this study and the results were compared. The optimization yielded a set of preferred designs, known as Pareto front, and the knee point concept was used to select the final optimal design.

關鍵字

Uncertainty ； dynamic load ； retaining wall ； response surface ； robust design ； design optimization