System interaction in plate loading tests

Plate loading tests involve a loading system, a system for deflection measurement, and the plate. These three components of the total system are all in contact with the soil mass, and a change in the force imposed on the soil by anyone of the three will cause movement of the other two parts of the system. This applies both to flat plate and screw plate tests, and is important because some of these movements influence the measured deflections and hence the value of modulus determined, to an extent which is not always realised.

Elimination of any significant interaction by moving the component parts of the system further apart may prove to be impractical, and hence it may be appropriate to correct the results for interaction effects. This paper discusses methods of calculating interaction effects, and some typical results of such calculations.