Numerical Verification for Seismic Response of Reinforced Soil Embankment on Soft Clay Foundation

Geotechnical Engineering Journal of the SEAGS & AGSSEA ISSN 0046-5828

Vol. 53 No. 2 June 2022

Numerical Verification for Seismic Response of Reinforced Soil Embankment on Soft Clay Foundation

Ripon Hore and Sudipta Chakraborty, Kamruzzaman Kamrul, Ayaz Mahmud Shuvon, and Mehedi A. Ansary

ABSTRACT: The findings of a series of shaking table tests and numerical analysis using PLAXIS 3D software to investigate the seismic influence of wrap-faced geotextile-reinforced embankment lying on soft clayey soil were presented in this paper. The test scheme included a succession of 1D Shake Table Tests (STT) with 0.05g to 0.2g base acceleration on a 0.4 m high model, lying on a 0.3 m thick, soft clay layer. This research aimed to understand the dynamic behavior of the model embankment resting on soft clayey soil. Both experimental and computational numerical studies were conducted to meet this purpose. The experimental study was a model study using a shake table. To assess the seismic behavior, harmonic sinusoidal input motions were subjected towards the model with different frequencies. The base acceleration, frequencies, and surcharge load were varied in several shake table tests with different relative densities of 48% for Sylhet sand. The pore water pressure and strain were also influenced by the base excitation, frequency, and surcharge pressure. The results obtained from PLAXIS 3D were compared with those obtained from model shake table tests. Acceleration response increased an increase of the base acceleration, the change further visible at higher elevations. The pore water pressures and strain values increased with elevation but decreased with the surcharge load. The strains were smallest at the bottom layer, and the strains at the top layer were the highest. The reason behind this is the geotextiles that are placed in the top layers. It enhances the earthquake strength of the embankment with a reinforced wall. The value of the findings from the test result was lower than the numerical result; the deviation was less than 15%. These results help to predict the dynamic behavior of the reinforced embankment wall. It will also help to design this type of retaining wall in the construction sector of Bangladesh.

KEYWORDS: Dynamic responses, soft clay foundation, Model reinforced wall, Variable input motions, PLAXIS 3D.