Modeling of Gravel Loss for Unsealed Roads
No Thumbnail Available
Date
2015-02
Authors
Journal Title
Journal ISSN
Volume Title
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.
Description
Keywords
Environmental Engineering