Effect of Perforated Plates on the Relative Density of Uniformly Graded Reconstituted Sands Using Air Pluviation Method

This paper presents the details of an air pluviation system suitable for preparing large-scale uniform sand specimens for conducting various types of laboratory test models namely static or dynamic tests on footings, piles, and liquefaction. A series of laboratory tests on three types of uniformly graded sands with average particle size (D50) of 0.27 to 0.90 mm were performed to study the effect of perforated plate (PP) porosity on the relative density (RD) and deposition intensity (DI). To this aim, two practical graphs were elicited which show the variation of RD and DI versus normalized values of PP holes’ diameter with average particle size (PP/D50). Accordingly, for PP/D50 < 30, RD and DI significantly increases and decreases, respectively. Also, a locus between two separate height of falls (HF) can be described which reveals the attainable RDs for a constant PP/D50. Moreover, an optimum range of diffuser mesh size (ms) can be identified which leads to higher RDs. While, for smaller ms than its optimum range, the arching phenomenon is expected to appear. Also, results show that critical HF (HFcr) can be varied for a specific type of sand for different conditions, i.e., pluviating with or without diffuser mesh. Eventually, small cylindrical molds were placed at five different locations in the plan, and four different elevations of the model tank to evaluate the uniformity of the specimen. The mean values of RD coefficient of variation (COVRD) are reported by approximately 3.25% and 4.5% for the horizontal and vertical direction, respectively.