<p> Micropiles made their debut as a cost effective way to retrofit existing historical structures. Recently, micropiles have increased in popularity all over the world and are being used for bridges, buildings, slope stability, antenna towers, and residential construction. Micropiles excel in difficult drilling conditions where other deep foundation methods are not plausible and consist of any combination of grout, rebar, hollow bar, steel pin, and steel casing. Due to their slender nature, defined less than 300 mm in diameter and lengths up to 100 feet, micropiles offer a distinct challenge in quantifying load transfer behaviors. Research at the University at Buffalo investigated the load transfer behavior of a single micropile and the influence of steel casing in soil using the finite element software ABAQUS. Soil models of sand, clay, and rock were fabricated. Simulated load testing determined micropile axial and lateral capacities for various cased length ratios, the cased length to micropile length, and were compared to field load tests. For both the clay and sand models an increase in cased length ratio resulted in lower axial capacities and higher lateral capacities. For the lateral case, diminishing returns on lateral capacities are observed for cased length ratios over 1:2. An increase in axial capacity was observed when casing to shale rock. The results are compared to various case studies, typical construction practices, and current design methodologies.</p>

<p> As the final line of defense against flood, it is important to protect the levees against erosion. The erodibility potential of levee material has an influence on scour generation in levees. In this investigation, the effect of various soil parameters including compaction ratio, plasticity index and saturation ratio on levee erosion due to overtopping is considered. For this purpose, physical models of a typical levee on the banks of Mississippi river with a scale of 1:20 were constructed in the laboratory using a variety of soil types including Non-Plastic Silt, Low-Plastic Clay, and the combination of these two to achieve various soil characteristics for levee material. A sharp wooden plate, which was embedded vertically in the crest of the levee, represented the floodwall. </p><p> During the lab tests different geometric and hydraulic parameters of the levee were monitored to identify scour development. In addition, the erodibility of the levee materials was determined using an Erosion Function Apparatus (EFA). The results of EFA tests were compared to physical model test results to explore and discuss the vulnerability of levee systems to erosion with change in levee material characteristics. The results were also compared to levees without floodwalls. The effect of wall inclination was also considered and analyzed. The effect of each soil parameter is discussed in detail on erosion characteristics measured by EFA and levee tests. </p><p> These tests and comparisons resulted in the observation that EFA yields lower erosion rates comparing to the simulated levee tests. Increasing the compaction rate and plasticity index improves the erodibility of levee material while increasing in saturation ratio, causes the erodibility of soil to increase. Wall Inclination does not have a significant effect on scour generation while levees without floodwalls show comparatively lower erosion rates.</p>

<p> A transparent soil model of granular fused quartz is developed to study the mechanics of shallow foundations. Soil models, unreinforced and reinforced, prepared at relative densities 0.34 (loose) and 0.64 to 0.69 (medium dense) are tested using a rectangular footing (25 mm wide x 40 mm long) under strain-controlled loading. Digital Image Correlation is used to identify displacements of a seeded central plane parallel to footing width (<i>B</i>) and construct vector fields and contour plots. Fiber-reinforced soil model data analysis is inconclusive. For the unreinforced medium-dense soil, minimum and peak magnitude horizontal displacements occurred directly under the footing at the footing edges; whereas in the loose soil, peak magnitude horizontal displacement occurred directly under the footing. Vector and contour plots revealed that a medium dense soil gradually distributes smaller magnitude displacements over a broad area, in contradistinction to acute, highly localized displacements of larger magnitude in a loose soil.</p>