Modeling of California Bearing Ratio with Basic Engineering Properties along East-West Road – Section II (Port Harcourt to Kaiama)

Abstract

In Highway design, California Bearing Ratio (CBR) is one of the most important methods to determine the strength of the subgrade material. To carry out CBR tests requires considerable time and effort, therefore it is vital to develop models for the prediction of CBR value.  This research work aims to develop a statistical model to predict the CBR values of soil using their basic engineering properties which was achieved by collecting results from 46 disturb samples of trial pits and then developing a statistical regression model to predict the CBR. A prediction is a vital tool in Engineering that aid quick decision making. This study is an attempt to develop valid models to determine the CBR value from index properties of soil (such as LL, PL, PI, MDD and OMC) which are quicker to estimate from their standard method of testing. Various laboratory test results were collected from the ongoing Construction of East-West road, Section II (spanning from Port Harcourt to Kaiama). Various relationships between index properties and CBR of the collected samples were investigated using simple and multiple regression analysis and also predictive equations estimating CBR from the experimental index values were developed.