An investigation has been carried out into a new technique for upheaving soil bodies. An example of where this technique can be applied is a road embankment that has settled at a different rate from a bridge because of the weight and properties of the subsoil. The conventional technique for remedying the situation involves closing the road, removing the asphalt and supplementing the underlying material. All this is expensive, time consuming and causes additional traffic jams. The new method under investigation involves up-heaving the road embankment by means of expanding tubes. In this technique, tubes of woven material are thrust horizontally into the road embankment, starting at the slope, by means of steel tubes. The steel tubes are then withdrawn while injecting a filling material to expand the woven tubes to a diameter of approximately 800 mm.

In the interests of gaining a better understanding of the upheave mechanism, small scale tests were carried out in the geotechnical centrifuge of the University of Delft. The investigation looked into the magnitude of the upheave relative to the expansion volume and any differences in effect between applying the tubes singly or in groups.

It was found that expanding tubes can be applied successfully in upheaving soil bodies. At least 5 tubes were required to eliminate boundary effects at the centre. Where a single tube is applied, more pressure is required than for a group.