Sand Raining System

A custom-built automated sand raining system is under construction for the beam centrifuge facility. The system is used to prepare sand models of controllable relative density Dr, maintaining repeatability. This is achieved by dry pluviation of the sand with controllable mass flow rate and drop height. The flow rate is adjustable by controlling the velocity and the aperture of the sand hopper. Equipped with servo-electric motors, the system allows fully-automated control of lateral and vertical motion, ensuring constant velocity and drop height.

To minimize the time required for model preparation, the system is designed to facilitate completion of the biggest possible model with a single fill-up of the 1.8 m wide hopper, which can carry up to 2 tons of sand. Six independent hopper openings offer the possibility to adjust the raining width, depending on the dimensions of the soil container. The desired drop height is automatically adjustable using laser sensors. The system has a maximum operational capacity of 0.5 m3/h, and can produce specimens with Dr ranging from 30% to 90%.