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Stabilization of Sandy Soil Against Internal Erosion Using Lime
Banu, Shaziya Ahmed
Banu, Shaziya Ahmed
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Description
A Master of Science thesis in Civil Engineering by Shaziya Ahmed Banu entitled, “Stabilization of Sandy Soil Against Internal Erosion Using Lime”, submitted in May 2021. Thesis advisor is Dr. Mousa Attom. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
Failure of hydraulic structures due to internal erosion is one of the most critical failures faced in civil engineering projects as it can destroy properties and lives. Many materials such as cement, lime, bitumen, and some chemical compounds have been used to stabilize soil. The main aim of this research is to investigate the use of lime to stabilize the sandy soil against internal erosion (or piping). To achieve the objective of this study, poorly graded and well-graded sandy soil were selected and used in this study. The initial properties of both the types of soil such as gradation, silt content, clay content, optimum moisture content (OMC) and maximum dry density were determined in accordance with ASTM standard specifications. The soils were mixed with lime at different percentages based on the dry weight of soil and were tested for different curing times (24 hours, 2 days and 7 days). Hole Erosion Test (HET) was used to evaluate the rate of erosion of lime stabilized sandy soil specimens. Soil parameters such as friction factor, coefficient of soil erosion, critical shear stress and erosion rate index were obtained from the hole erosion test and analysed. Lime was found to be more effective in stabilizing well graded sandy soil compared to poorly graded sandy soil. As application of 3% of lime by dry unit weight of soil with a curing time of 48 hours stabilized well graded soil against internal erosion to very slow type of soil erosion. While poorly graded soil required nearly double (about 5% of lime by dry unit weight of soil) with same (48 hours) curing time to get stabilized to only moderately slow type of soil erosion. Furthermore, the results proved that the increase in percentage of lime, increases the critical shear stress and the erosion rate index and hence, stabilizes the soil against internal erosion. Additionally, it was found that that addition of lime decreases the final diameter of water flow path and therefore proves soil stabilization has occurred. Moreover, the stabilized soil-lime-mixture was found to be unaffected by submersion (for up to two months) upon investigation.