https://gstl.co.uk/site-services/plate-bearing-test

The test shall be carried out in general accordance with BS 1377: Part 9 1990 'in-Situ Tests'.
A circular plate having a maximum diameter of 300 - 600mm shall be used.

Interpretation of the Test Result

Results from the test shall consist of raw data, load-settlement curve, yield pressure, recommended allowable pressure for foundation design, and modulus of subgrade reaction (K) for road design.


Interpreting the VSS test results, carried out using plates with a diameter of 600 and 700 mm shall be taken into account that the results are averaged the result of interactions
layer capacity stabilization and slab layers of the ground.


http://www.cfms-sols.org/sites/default/files/Actes/3005-3008...
Furthermore, the interpretation of plate loading tests is not as straightforward as in soils, due to the heterogeneity of the landfill. It is advisable to use large diameter plates (>600 mm), which is feasible because there is no need to apply large loads in order to produce the needed deformations or even to reach failure due to the soft nature of the MSW.
Several researchers have used this method for deformability and strength characterization of MSW. The UC Geotechnical Group (Palma, 1995; Sánchez et al, 1993) used load plates,
interpreting the results using a multi-layer model for MSW and covering layers. In some occasions the rigid plate has been replaced by a container full of material, achieving larger size but lower pressure.

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