Study of sandy slopes through small-scale physical modeling

This research study integrates experimental studies on small-scale physical model tests with finite element analysis to investigate the behavior of locally loaded sandy slopes and locally loaded sandy slopes stabilized with piles. The primary objective of this study was to develop an experimental setup for small-scale physical models, replicating the behavior of full-scale locally loaded sandy slopes. Initially, a series of tests was conducted on the sand selected for the model test to assess its index and strength parameters. Then, density calibration tests were performed on the pluviation setup to examine the effects of valve opening and drop height on the relative density of the sand. The sand was placed in the model tank at the desired density, and a series of tests were carried out on the small-scale (1/40) physical slope model. Local loads were exerted on the sandy slope models using a displacement-controlled loading system. The slope failure shapes were observed by taking continuous images of the slope from the top and one side of the model tank. Tests were conducted on slopes with sand prepared at 40% (medium dense) and 70% (dense) relative density values. The piles were modeled using hollow polyvinyl chloride pipes. The mechanics of a stabilized sandy slope were investigated, with a particular focus on the role of pile stabilization in enhancing the arching mechanism, improving load distribution and slope stability, and reducing displacements. For validation purposes, the experimental results from the physical model tests were compared with the numerical analysis results of the physical model, obtained using the three-dimensional finite element method. The results of this study showed that the behavior of the newly developed small-scale physical slope model was similar to that obtained from the numerical analysis. The dense sandy slope model exhibited a stiffer (steeper) initial curve for the vertical displacement versus vertical stress response compared to the medium-dense sandy slope model. For the same vertical displacement, pile stabilization significantly improved the vertical stress response of the of the locally loaded slope constructed with medium dense sand. The results of the numerical analysis showed a load response behavior similar to that observed in the experimental results. The differences observed between the experimental and numerical results were primarily attributed to the limitations of small-scale tests.