Influence of Shape of Footing on Coefficient of Elastic Uniform Compression of Soils

Abstract

Coefficient of elastic uniform compression (Cu) of soil used in design of vibrating bases is generally determined from cyclic plate load test conducted at the site. The value of Cu determined for test plate is correlated to the size of actual footing based on Barkan’s equation. The bases of machines may be square or circular and hence, the values of Cu are required accounting for shape of the footing. The effect of shape of footing on Cu will be different in cohesive and cohesionless soils. So, correlations between Cu values of square and circular footings are required to tackle the different field requirements. In the present study, an attempt is made to correlate the coefficients of elastic uniform compression of square and circular plates of same size in cohesive soils based on cyclic load tests conducted on specimens prepared in CBR moulds. Self straining loading frame is used in the test for application of cyclic loading as it facilitates maintenance of load with settlement, easy loading and unloading of the specimen. Cohesive soils considered in the study are clayey sand and clay of low compressibility. The results of study revealed the ratio of coefficients of elastic uniform compression of circular plate to square plate in cohesive soils under study as 1.2.