عنوان مقاله [English]
The effect of sand on the liquid limit of the mixed soil, the relationship between the liquid limit and the percentage of sand and the relationship between the liquid limit of the cone penetration methods and the Casagrande cup have been evaluated. Also, the relationship obtained in this study has been compared with previous researches. The liquid limit of the mixed soil was determined using the Casagrande Cup method with a hard base and cone penetration. The experiments were performed on mixed soils of sand and bentonite clay with a liquid limit between 21 to 78. As the percentage of sand increased, the liquid limit decreased, while the liquid limit was linear in terms of sand percentage and the coefficient of determination for Casagrande and cone penetration experiments was 0.997 and 0.999, respectively. The liquid limit values obtained from the cone penetration device are about 10 units higher than the Casagrande device. In bentonite clay, the psychological limit obtained from the cone penetration device is about 12% higher than the psychological limit obtained from the Casagrande device. As the liquid limit of the mixed soil decreased, the difference between the results of the two experimental devices increased. The higher the plasticity properties of the mixed soil, the smaller the difference between the liquid limits obtained from the two methods.