Development of a Mechanized Traveling Pluviator to Prepare Reconstituted Uniform Sand Specimens

Comparison between Two Different Pluviation Setups of Sand Specimens

“…There are three methods for preparation of reconstituted sand specimens, tamping, vibration, and pluviation (Lo Presti et al 1992;ASTM 2006). Among these methods, pluviation has been widely used due to its ability to achieve a wide range of relative densities for sand bed (Rad and Tumay 1987;Fretti et al 1995;Choi et al 2010; Dave and Dasaka 2012;Gade and Dasaka 2015). Additionally, this method is mainly advantageous when it is needed to reconstitute large specimens for model tests or calibration chamber tests within a short time (Fretti et al 1995).…”

“…The relative density (RD) of sand reconstituted by air-pluviation depends on the height of fall (HF), the deposition intensity (DI), uniformity of raining sand, the porosity of the diffuser sieve, the opening width of the curtain in curtain technique, particle characteristics, and other parameters (Kolbuszewski 1948;Kolbuszewski and Jones 1961;Butterfield and Andrawes 1970;Rad and Tumay 1987;Vaid and Negussey 1988;Lo Presti et al 1992, 1993Fretti et al 1995;Lagioia et al 2006;Choi et al 2010;Dave and Dasaka 2012;Gade and Dasaka 2015).…”

“…of Mashhad, 9177948974 Mashhad, Iran (corresponding author). E-mail: s.abrishami@um.ac.ir (Choi et al 2010;Gade and Dasaka 2015). Experimental results of Miura and Toki (1982) showed that the effect of HF on RD of the specimen is insignificant in the pluviation method.…”

“…Deposition intensity (DI) is the mass of soil falling in the container/chamber per unit of area per unit of time and it is controlled by the effective area of the opening provided at the bottom of the sand hopper through which soil flows into the rigid tubes or directly falls into the container being used for the preparation of the specimen (Lo Presti et al 1993;Dave and Dasaka 2012;Gade and Dasaka 2015). The opening area can include single or multiple circular or rectangular holes.…”

“…For a certain HF, an increase in DI augments the porosity of deposition (Kolbuszewski 1948;Walker and Whitaker 1967), an increase in void ratio (Rad and Tumay 1987), and a decrease in RD of the sand specimen (Miura and Toki 1982;Lo Presti et al 1992, 1993Fretti et al 1995). At higher values of DI, the volume of sand that leaves the sand hopper is much higher, increasing the chances that the soil particles collide with each other before falling into the container (Gade and Dasaka 2015). Conversely, at a lower value of DI, individual particles freely fall into the container with minimum interference and could achieve critical velocity and much higher densities (Vaid and Negussey 1988;Cresswell et al 1999).…”