Issue 7

Abdoullah Namdar et alii, Frattura ed Integrità Strutturale, 7 (2009) 73-79; DOI: 10.3221/IGF-ESIS.07.06 74 M ETHODOLOGY AND EXPERIMENT he experiments are conducted by the direct shear test method, in the Geo-technical Engineering Laboratory of S. J. College of Engineering- Mysore, to evaluate mixed soil characteristics. Using the current experiments, several models have been developed to improve red soil (plastic soil) by mixing with sand, gravels and non-plastic soils. In this investigation liquid limit, plastic limit, wet sieve analysis, standard compaction test and direct shear test have been employed to characterize accurate behavior of models in the laboratory. Calculation of the safe bearing capacity of any mixed soil is done using the Terzaghi calculation method. The necessary factors to characterize soil foundation include, C, Φ, moisture and unit weight of the soil, which are used to find the best safe bearing capacity of soil. Materials have been used for creation of the model illustrated in Table. 1. All models have an assumed depth of 1.5 m and widths of 2.5 x 2.5 ft 2 , that are used in calculation of safe bearing capacity. Sl. No % Of Red Soil % Of Sand % Of Gravel 4.75 mm % Of Gravel 2 mm % Of Black Soil % Of Green Soil % Of Dark Brown Soil % Of Yellow Soil % Of Light Brown Soil 1 100 0 0 0 0 0 0 0 0 2 55 45 0 0 0 0 0 0 0 3 55 0 45 0 0 0 0 0 0 4 55 0 0 45 0 0 0 0 0 5 55 15 15 15 0 0 0 0 0 6 55 0 0 0 45 0 0 0 0 7 55 0 0 0 0 45 0 0 0 8 55 0 0 0 0 0 45 0 0 9 55 0 0 0 0 0 0 45 0 10 90 0 0 0 2 2 2 2 2 11 80 0 0 0 4 4 4 4 4 12 70 0 0 0 6 6 6 6 6 13 60 0 0 0 8 8 8 8 8 14 50 0 0 0 10 10 10 10 10 15 70 0 0 0 10 10 10 0 0 16 70 0 0 0 10 10 0 10 0 17 70 0 0 0 10 10 0 0 10 18 70 0 0 0 10 0 10 10 0 19 70 0 0 0 10 0 10 0 10 20 70 0 0 0 10 0 0 10 10 21 70 0 0 0 15 15 0 0 0 22 70 0 0 0 15 0 15 0 0 23 70 0 0 0 0 0 0 15 15 24 70 0 0 0 15 0 0 15 0 25 70 0 0 0 15 0 0 0 15 26 70 0 0 0 0 15 15 0 0 27 70 0 0 0 0 15 0 15 0 28 70 0 0 0 0 15 0 0 15 29 70 0 0 0 0 0 15 15 0 30 70 0 0 0 0 0 15 0 15 31 55 0 0 0 0 0 0 0 45 Table 1 : Mixed soil models. For all models, real soil characteristics were considered in order to assess soil foundation improvement. It has been done by performing laboratory tests thorough the interpreting of the test results. Formulas for calculation of safe bearing capacity, are the following: T