Plate tests for the measurement of modulus and bearing capacity of gravels

Because they are difficult to sample and test in the laboratory, gravels are best tested in situ. Plate bearing tests are widely used to measure the modulus of soils and weak rocks and are also suitable for gravels. Equipment and test procedures have been developed to allow the rapid testing of gravels. The widespread use of trialholes and test pits for foundation investigations in Southern Africa provides the opportunity to perform these tests on a routine basis. The results of 175 plate bearing tests in gravels are analysed in this paper. The soil modulus has been determined from each test using both a simplified elastic analysis and a rectangular hyperbola method. Relationships are presented between modulus and observed consistency and also plate bearing capacity and consistency. As gevolg van hulle aard is dit die beste om die ingenieurseienskappe van gruis deur middel van in situ toetse te bepaal. Plaatdruktoetse word algemeen gebruik om die modulus van grond en rots te bepaal en is ook geskik vir gebruik in gruis. Apparaat en toetsmetodes is ontwikkel vir die vinnige toets van gruise. Die algemene gebruik van toetsgate en putte vir fondamentondersoeke in Suid-Afrika maak dit moontlik om hierdie toetse op 'n roetine basis uit te voer. Resultate van 175 plaatdruktoetse is geanaliseer. Moduluswaardes vir elke toets is bepaal deur gebruik te maak van 'n vereenvoudigde elastiese metode en van die reghoekige hiperbool metode. Die verband tussen modulus en plaatdravermoë teenoor die digtheid van die gruis word aangetoon.