A Study of Correlation Between California Bearing Ratio (CBR) Value With Other Properties of Soil Dr. Dilip Kumar Talukdar

Abstract-- California Bearing Ratio (CBR) value is an important soil parameter for design of flexible pavements and runway of air fields. It can also be used for determination of sub grade reaction of soil by using correlation. It is one of the most important engineering properties of soil for design of sub grade of rural roads. CBR value of soil may depends on many factors like maximum dry density (MDD), optimum moisture content (OMC), liquid limit (LL), plastic limit (PL), plasticity index (PI), type of soil, permeability of soil etc. Besides, soaked or unsoaked condition of soil also affects the value. Determination of CBR is a very lengthy and time consuming process. An attempt has been made here to correlate soaked CBR value with MDD, OMC, LL, PL and PI of some soil sample collected from different locations of Nogaon District of Assam, India. These tests can easily be performed in the laboratory. Soaked CBR is considered as Assam is a flood prone state and some rural roads remain under water for two or three days. Correlation coefficient (r) of each of these properties with CBR is determined and their significance is tested by using statistical t- test. Finally a linear multiple regression model was developed by using linex statistics of Microsoft Excel (version 13.0) for determination of CBR value involving the above mentioned soil parameters