The behavior of six reduced-scale reinforced soil walls under base excitation is investigated using physical shaking table tests. The models were tested to isolate the influence of facing geometry, facing mass and facing toe condition on response to simulated seismic loading. The walls were instrumented to measure facing lateral displacement, reinforcement strain, toe reaction loads and accelerations. The model walls were constructed with a structural facing and polymeric geogrid reinforcement layers and subjected to a stepped amplitude sinusoidal base input acceleration. The toe boundary condition and facing panel configuration were found to have a significant effect on model response. For example, the magnitude of the accumulated facing lateral displacement at the top of the vertical wall models and at the same base acceleration magnitude was less for vertical walls with a less massive facing panel regardless of toe boundary condition. For the same boundary condition, a wall with an inclined facing displaced less than the nominal identical vertical wall for the same base excitation level. The horizontally restrained toe in reduced-scale models attracted approximately 40% to 60% of the peak total horizontal earth load during base excitation, demonstrating that a stiff facing column plays an important role in resisting dynamic loads under simulated earthquake loading. Measured footing and reinforcement loads are compared with values predicted using current pseudo-static analysis and design methods for geosynthetic-reinforced soil walls, and the implications of differences in predicted to measured values to current North American design practice are identified.

Soft to medium clay soil possesses major sources of damages to the pavement layers overlying them because of their potential failure under moisture changes and external heavy traffic load. In such situations, soil stabilization methods can be used to improve the soil properties and satisfy the desired engineering requirements. This study presents the use of sugarcane bagasse ash (SBA) and lime as chemical stabilizers for a clay soil subbase. Sugarcane bagasse ash and lime are used individually and as mixtures at varying percentages to stabilize a clay soil from Taxila, Pakistan. Various geotechnical laboratory tests such as Atterberg limits, compaction test, and California Bearing Ratio (CBR) are carried out on both pure and stabilized soils. These tests are performed at 2.5%, 5%, and 7.5% of either SBA or lime by weight of dry soil. In addition, mixtures of lime and SBA in ratios of 1:1, 2:1, 3:1, 1:2, and 1:3 are used in 5%, 7.5%, and 10% of dry soil weight, respectively. Results indicate that soil improved with 7.5% SBA showed a 28% increase in the liquid limit, while soil mixed with 2.5% lime in combination with 7.5% SBA showed an increase of 40% in the plastic limit. For the plasticity index, the soil mixed with 7.5% SBA showed an increase of 42%. Moreover, 2.5% lime in combination with 2.5% SBA showed the best improvement in soil consistency as this mixture reduced the soil plasticity from high to low according to the plasticity chart. Furthermore, 2.5% SBA in combination with 5% lime demonstrated the largest improvement on the CBR value, which is about a 69% increase above that of the pure soil. Finally, the cost analysis indicates a promising improvement method that reduces pavement cost, increases design life, and mitigates issues of energy consumption and pollution related to SBA as a solid waste material.