Compaction Effort for Uniform Laboratory-Prepared Cohesionless Soil Bed

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Abstract Laboratory testing in geotechnical engineering plays a paramount role in developing theories and empirical formulas. Soil preparation is an integral part of any experiment, which is often required to prepare uniform cohesionless soils in the testing tank. One of the oldest methods to obtain the desired unit weight throughout the testing tank is by dropping the sand from a predetermined height. This method often suffers from particle segregation, which reflects on the test results. Applying compaction effort on the surface of the soil is another method for soil preparation that is widely used because of its simplicity and the repeatability of its results. The procedure is followed by trial and error by adjusting the thickness of the layer and the appropriate energy level until the desired relative density is achieved. However, this technique often produces overconsolidated sand in the testing tank, which is usually ignored. Using compaction effort, uniform sand in the testing tank is achieved by placing the sand in layers; each receives a predetermined compaction effort. In this procedure, the majority of the energy applied is used to compact the immediate top layer, while the rest seeps through to the lower layers, increasing their compaction level. Accordingly, by adjusting the level of the energy applied to each layer, it is possible to produce uniform homogeneous sand in the testing tank. This article presents a laboratory procedure to produce a uniform sand bed and to measure the level of the overconsolidation in the testing tanks, namely, by controlling the thickness of the sublayer and the level of energy applied on each layer.