Bearing Capacity of Surface Footings on Sand Layer Resting on A Rigid Rough Base

Abstract

Laboratory model tests for ultimate bearing capacity of rough rectangular surface footings in dense sand are presented. These tests were conducted to study the variation of the ultimate soil bearing capacity when a rigid rough base is located at a shallow depth from the bottom of the footings. The length-to-width ratios of the footings used for the model tests varied from one to six. The deducted experimental values of the modified bearing factor, N r ′, and shape factor, λ′ s , have been compared with theoretical values proposed by Mandel and Salencon (1972) and Meyerhof (1974), respectively. The experimental modified shape factor, λ′ s , compared reasonably well with the approximate relation given by Meyerhof. When the rough rigid base is located at a very small depth, i. e., H/B less than about 0. 6, grain crushing takes place at around the ultimate load and also the deduced N r ′ is lower than that predicted by the theory based on the internal angle of friction of soil determined from standard triaxial tests.