Shear strength properties of clay with sand column

Direct shear tests were performed on low plastic residual clay reinforced with different diameter and number of sand columns. The tests were carried out under unconsolidated undrained condition. Sand used in the tests is poorly graded passing No: 5 sieve and retaining on No: 40. Effects of sand column diameter and number of sand columns in sand-clay mixtures on shear strength parameters internal friction angle and cohesion were investigated. The test results showed that shear strength parameters of sand-clay mixtures were affected by diameter of sand column and sand content. Internal friction angle of sand-clay mixtures for the same sand column diameter increases with increasing number of sand columns but cohesion reduces. The test results also showed that internal friction angle with same sand content area of sand-clay mixtures increases with increasing sand column diameter. However, under the same condition, cohesion of the mixtures decreases. In addition, volume of the sand-clay mixtures was affected by number and diameter of sand column during shear of the mixture.