Modeling of Gravel Loss for Unsealed Roads

Mekonnen, Getahun

Modeling of Gravel Loss for Unsealed Roads

Date

2015-02

Authors

Mekonnen, Getahun

Publisher

Addis Ababa University

Abstract

Gravel loss is the reduction in thickness of the surfacing course of gravel road. It can be caused by many factors. Traffic as average daily traffic (ADT), climate in terms of mean monthly precipitation (MMP), geometric design parameters of the roads represented by absolute gradient (G), surface material of the road in terms of plasticity index (PI) and the duration of observation (D) was used as the model independent variable. The dependent variable of the model, gravel loss, was collected by observing the selected gravel roads in three month interval. The selected roads were D/Birhan-Kasima, D/Birhan- Ankober and Chacha-Tsgerada –Ginager. The samples were prepared in to a grid of 15m of which divided into 5m interval. Elevation, across the width of the road, was observed using total station. Independent variables included in the model were gathered using standard procedure and methods. Two models were developed using SPSS 15.0.The first model used multiple linear regression (MLR) model and it had a prediction power of 87.9% (R2 of 0.879). The second model used general linear modeling (GLM) and it had a prediction power of 99.4% (R2 of 0.994). The model helps the parties involved in managing gravel roads. It can be used in gravel roads management system; in determination of maintenance and rehabilitation requirement and in predicting the residual life of gravel roads.