BEARING CAPACITY OF COMPACTED SOILS

Abstract

In the present study model. tests have been conducted by performing the strain controlled tests on model footings kept in the C.B.R.mould by placing the mould on the triaxial frame. Tests were conducted on 3 x 3 cm, 5 x 5 cm, 3 .cm dia, 5 cm dia and 1.5 x 10 cms,square, circular and strip footings. Study was made on four soils, viz. Ranipur sand, Dhanauri clay, Kaolin clay and Bentonite clay. In case of clays tests were conducted at optimum moisture content, while in case of sand, footings were tested at optimum moisture content also on dry sand by varying density from maximum to minimum. On the basis of investigation it has been found that in sands, local shear failure controlb the bearing capacity upto 0 = 28.5°, while the general shear failure controla the bearing capacity after 38o and in between 28.5°- 38° intermediate condition controld_the bearing capacity of sands. i new approach has been proposed' to calculate the bearing capacity factor N1 for 0 between 28.5o - 380. For calculating A a semi-empirical relationship has been proposed. Reduction factor has been determined to know the value of allowable soil pressure w.r.t. permissible settlement from the ultimate bearing capacity. In case of local shear failure, 0.7 reduction factor of cohesion is more suitable for non-expansive types of clays while 0.67 reduction factor of cohesion in case of expansive types of c lays