Upper bound seismic limit analysis of geosynthetic-reinforced unsaturated soil walls

• Published in: Geotextiles and geomembranes Vol. 48; no. 4; pp. 419 - 430
• Main Authors: Alhajj Chehade, H., Dias, D., Sadek, M., Jenck, O., Hage Chehade, F.
• Format: Journal Article
• Language: English
• Published: Essex Elsevier Ltd 01-08-2020; Elsevier BV; Elsevier
• Subjects: Backfill; Civil Engineering; Discretization; Dynamic stability; Earth reinforcement; Earth retaining wall; Earthquake loads; Engineering Sciences; Failure mechanisms; Geosynthetics; Geotechnology; Groundwater levels; Géotechnique; Limit analysis; Matric suction; Nonlinear equations; Pseudo-dynamic; Retaining walls; Seismic analysis; Seismic engineering; Seismic stability; Shear strength; Soil stability; Soil strength; Soil suction; Soils; Stability analysis; Systems stability; Unsaturated soil; Unsaturated soils; Upper bounds; Water table; Geosynthetics; Limit analysis; Discretization; Unsaturated soil; Earth retaining wall; Pseudo-dynamic
• ISSN: 0266-1144; 1879-3584
• DOI: 10.1016/j.geotexmem.2020.02.001

The assessment of the internal stability of geosynthetic-reinforced earth retaining walls has historically been investigated in previous studies assuming dry backfills. However, the majority of the failures of these structures are caused by the water presence. The studies including the water presence in the backfill are scarce and often consider saturated backfills. In reality, most soils are unsaturated in nature and the matric suction plays an important role in the wall's stability. This paper investigates the internal seismic stability of geosynthetic-reinforced unsaturated earth retaining walls. The groundwater level can be located at any reinforced backfill depth. Several nonlinear equations relating the unsaturated soil shear strength to the matric suction and different backfill type of soils are considered in this study. The log-spiral failure mechanism generated by the point-to-point method is considered. The upper-bound theorem of the limit analysis is used to evaluate the strength required to maintain the reinforced soil walls stability and the seismic loading are represented by the pseudo-dynamic approach. A parametric study showed that the required reinforcement strength is influenced by several parameters such as the soil friction angle, the horizontal seismic coefficient, the water table level, the matric suction distribution as well as the soil types and the unsaturated soils shear strength.