Compensation Grouting in Sand

Experiments, Field Experiences and Mechanisms

Doctoral Degree of Mr Adam Bezuijen on 9 March 2010

Compensation grouting was developed to compensate for settlement during underground construction. Tubes with a diameter of 0.07 m and a length of up to 60 m are installed prior to the underground construction work together with a monitoring system. The tubes have openings at regular distances covered with rubber sleeves (TAMs) through which grout can be injected.  Injection of grout into the soil at various locations between the underground construction work and the foundations of the building leads locally to heave that compensates the settlement.

This thesis reports on experimental research on compensation grouting in sand. It is investigated in model tests, how the shape of the grout bodies made during injection depends on the grout properties, the density of the sand and the way the tubes are installed. The shape of the grout body affects the necessary injection pressure and whether heave is localised to one injection point or distributed over a wider area.  An analytical model is developed that shows the influence of various parameters.

The evaluation of field measurements shows the influence of soil disturbance. Soil disturbance in a layer of sand may lead to a decrease in density of the sand and compensation grouting in such a layer will have a lower efficiency (a lot of grout has to be injected to create some heave) and long term settlements are possible.

For more information you can contact Mr adam.bezuijen@deltares.nl.