Yorkshire Geotechnical Group – January 2022 Event

Synopsis

Ground improvement using rigid inclusion methods falls between the high vertical stiffness and low settlement behaviour of pile groups and piled rafts on the one side, and the lower stiffness and higher settlement of vibro stone columns on the other. The presentation will introduce and describe this method of ground improvement. It will show how rigid inclusion methods are part of a family of techniques; some have been in use since the early part of the 20th Century. Ground improvement using rigid inclusions has been used intermittently for a similar period of time, but the concept has really only been widely available in the UK over the last 20 years. The presentation will describe the more common construction methods, the main uses, and the types of ground model that are ideal for this ground improvement technique.

The presentation will show that current design based on black box FEA methods are opaque with regards to how rigid inclusions work. The FEA approach hides key mechanisms that control behaviour and performance. However, it is possible to use simplified spreadsheet methods together with ‘off-the-shelf’ design software which can provide a much better understanding of the mechanisms and identify risk areas.

Some examples of projects and designs will be given. If time allows, the presentation will describe how this form of ground improvement is likely to be covered by the Second-Generation BS EN 1997 British Standards currently under development.