To Develop Correlation between California Bearing Ratio (CBR) and Dynamic Cone Penetrometer (DCP) value for subgrade soil of selected stretches of Suredranagar District

Abstract

There is lack of correlation between dynamic cone penetrometer (DCP) and California bearing ratio (CBR) for subgrade materials. This reasearch aims at determining a correlation equation between California bearing ratio (CBR) and dynamic cone penetrometer (DCP) for subgrade soils of surendranagar city in Gujarat allowing to economically and approprietly determine bearing capacity of subgrade soils in pavements design. The relationship developed in this reasearch considers subgrade materials behavior and largely saves time and cost of preliminary and detailed engineering works of road projects. Total 52 pits locations of surendranagar region of Gujarat state, where tests were conducted on in-service flexible pavement and also samples were collected for laboratory test. A series of DCP tests in field and CBR, proctor, Atterberg’s limit and grain size analysis tests in the laboratory has been conducted. Based on the field and laboratory test results relationship between DCP and CBR has been established. Power regression models were found to the best fit, which connecting soaked CBR with DPI shows strong correlation of a coefficient of determination (R2) of 0.876.