Model test on mechanical behavior of composite retaining wall with counterfort and relief shelves

ObjectiveThis study investigates the mechanical behavior of composite retaining wall with counterfort and relief shelves, aiming to optimize structural design and reduce construction cost for high fill slopes by the unloading effect.MethodThree-models, i.e., counterfort, short relief shelve and long relief shelve, test was conducted to investigate the retaining wall horizontal soil pressure distribution rule, counterfort stress and structural deformation rule.ResultThe lateral earth pressure on each relief shelf of composite structure increased from zero with depth, and the lateral earth pressure distributions were different from that of the counterfort structure. The curve of lateral earth pressure distribution on composite structure was similar to that calculated with Klein method. The lateral earth pressure, buttress stress, and displacement of composite structure was smaller than those of counterfort structure. The longer the relief shelve, the lower the lateral earth pressure, and the lower the lateral earth pressure joint effort, but the higher the point of action of lateral earth pressure, therefore, the less the corresponding bending moment.The counterfort stress with long relief shelf combined structure was not much different from that with short relief shelf combined structure.The counterfort stress and lateral earth pressure were respectively used to calculate the sectional bending moments of composite structure. The sectional bending moment calculated with stress was larger than that calculated with earth pressure.This study hypothesizes that force is exerted in the lower part of the unloading zone, which should be further researched, due to the differences among bending moment derived from the test, the theoretical lateral earth pressure, and that calculated from test counterfort stress. The displacement of composite structure is similar to the bending deformation of cantilever beam.ConclusionThese conclusions lay a foundation for the application of composite retaining wall in engineering.