Numerical simulation and sensitivity analyses of full-scale test embankment with reinforced lightweight geomaterials on soft Bangkok clay

作者：Tanchaisawat T; Bergado D T^*; Voottipruex P

来源：Geotextiles and Geomembranes, 2008, 26(6): 498-511.

DOI：10.1016/j.geotexmem.2008.05.005

• Numerical simulation
• Reinforced embankment
• Sensitivity
• Lightweight

A full-scale test embankment was constructed on soft Bangkok clay using rubber tire chip-sand mixture as a lightweight geomaterial reinforced with geogrid under working stress conditions. The facing of the embankment was made of segmental concrete blocks with rock filled gabion boxes as the facing to the sloping sides. This paper attempts to simulate the behavior of the full-scale test embankment using PLAXIS finite element 2D program by means of undrained analysis in the construction stage and thereafter consolidation analysis was performed during the service stage. The settlement predictions of the soft clay foundation mostly depended on the assumed thickness of the weathered crust and the OCR values of the soft clay layer. The predicted excess pore water pressures were sensitive to the OCR values of the soft clay layer. The lateral wall movements were overpredicted by the analysis due to the partially drained consolidation process at the early stage of the construction. The FEM computed geogrid movements were smaller than the observed field data due to the use of lightweight tire chips-sand backfill. The maximum tension line agreed reasonably well with the coherent gravity bilinear failure plane. The sensitivity analyses of settlements, excess pore water pressures, lateral wall movements, geogrid movements and tensions in geogrid were performed by varying the weathered crust thickness, the OCR values of soft clay, the permeability values of the soft clay and the interface coefficient of the geogrid. The settlements and the excess pore water pressures changed significantly when the OCR and the permeability values of soft clay were varied. The interface coefficient of the geogrid reinforcements affected the lateral wall movements, geogrid movements and tensions in the geogrids. The higher interface coefficient yielded less wall/geogrid movement and resulted in higher tensions in geogrids as expected. The results of analyses show that the FEM analysis using 2D plane strain conditions provided satisfactory predictions for the field performance.

• 出版日期2008-12