The benefits of Rapid Impact Compaction - HENGDA RIC

Rapid Impact Compaction is a technique allied to Dynamic Compaction that can be used to increase the bearing capacity of soils through controlled Impact. The treatment is effective in the top layers of soil, typically up to 6m depth, though improvements up to a depth of 9m have been seen in some conditions.

Drop weights of 10 tonnes are used on our HC150 machines respectively and are dropped from heights of 1.2m – 1.5m onto a special foot assembly at 30 – 80 times per minute. The foot remains in contact with the ground at all times.

The Rapid Impact Compaction for the soil improvement uses a hydraulic hammer mounted on an excavator. The hammer with a weight ranging from 5 up to 12 tons is dropped freely from a height of 1.2 m on a large circular foot. Impacts repeated at a rate ranging from 40 up to 60 blows per minute plunge the steel foot creating a crater.

The control system installed in the operator's cab allows for controlling the compaction process and recording the parameters such as impact energy or foot penetration. It can also be used to change the height from which the hammer is dropped.

The compaction in the Rapid Impact Compaction technology is usually preceded by creating a test plot where the compaction is performed for various spacing and rates of blows. Then, the local compaction of the improved soil is tested and the optimal grid spacing and the number of blows per one point is determined. Depending on the soils, the number of blows varies between 10 and 40 per one point.

Rapid Impact Compaction is a shallow ground improvement and densification technique. This method densifies shallow, granular soils, which repeatedly strike an impact plate on the ground surface using a hydraulic hammer. The energy is transferred to the underlying loose soils and regroups the particles into a denser formation. The impact locations are located on a grid pattern and the spacing of those locations is calculated by the subsurface conditions and foundation loading and geometry.

Rapid Impact Compaction technique is performed at the surface of a terrain and it comprises of a heavy excavator which is equipped with a specially designed arm onto which the hammer is attached. Within the hammer, a 5 to 10 drop weight is hydraulically lifted till a required height after which the weight is dropped using a hydraulic acceleration. This whole process of lifting and dropping of the weight takes place with a frequency of 30 to 80 times a minute.