Production Thematic Map for Predicated CBR and MR Values for Subgrade Soil of Baghdad City Using GIS Tools

الملخص

The aim of this research is to produce thematic maps for California Bearing Ratio (CBR) and Resilient Modulus (MR), for Baghdad city depending on traditional soil properties obtained from soil investigation reports of the case study taking advantage of the ability of GIS tools , these maps are used in varies pavement design layers. In this research the available data are collected from soil investigation reports such as Atterberg limits or parameters and sieve analysis these values are used in correlation equations to predict CBR and MR values, then thematic maps are drawn for several municipalities used in design and evaluate the pavement. Due to the thematic maps that produced depending on the collected data of the study area this research conclude that subgrade for Baghdad soil is classified as fair to poor according to AASHTO Classification. Some regions in study area shows high percentages of sulphate content (SO3) therefore these areas should be either treated or avoided to reduce the effect of erosion of subgrade or lower layer of pavement system. The pH value of subgrade soil explains alkaline action (greater than 7) and T.S.S (Total Soluble Salts) value is rather low so it can be used as a filling material or embankment for roads.