Comparison between Two Different Pluviation Setups of Sand Specimens

Abstract

Sand pluviation is a method used to prepare a model sand specimen to carry out some particular laboratory tests such as static and dynamic tests on footings, retaining walls, piles, as well as calibration of static and dynamic penetrometers. Preparation of uniform reconstituted sand specimens of required density is a prerequisite for obtaining reliable results. In this paper, two rainer systems, which are capable to prepare homogeneous sand specimens, are introduced. The first is a rainer system with a perforated plate and the second is a portable curtain rainer system. The portable curtain rainer system essentially consisting of a sand storage, flexible hose, a hopper, rigid tubes, and curtain with different opening widths. This study aims to reach a better understanding of the effects of deposition intensity (DI) and height of fall (HF) on the relative density (RD) of reconstituted sand specimens. The uniformity of the sand bed is verified by measuring the relative densities of 20 samples at different locations of the tank. By using a portable curtain rainer system, large uniform sand specimens with a wide range of RD=23–96% can be achieved. The results demonstrate that at a lower value of HF, the variation of RD is significant, while it has an insignificant effect on RD for values of HF≥600 mm. Furthermore, in order to achieve a dense to very dense sand bed, the DI should be controlled. It was also observed that both systems significantly improve the horizontal and vertical homogeneities of the sand specimens. With an increase in the RD of reconstituted sand specimens, higher repeatability of uniform pluviation was achieved.