9.1.1 California Bearing Ratio Test “CBR"
The CBR test expresses an index of the shearing strength of the soil. The resistance of soil to
penetration is expressed as a percentage of the resistance for a standard crushed limestone.
Figure 9- 1 is the CBR test results for the subgrade material near Al-Auja Airport site. As shown in
the figure the CBR value is 47. The report was obtained from Al-Sahwah Contracting Company.
Figure 9 - 1 Ain Al-Auja Subgrade Material Test Results
Note: The attached CBR value is used on the assumption that all the airport area gives the same
CBR value as the location referred to in the subgrade material test results, due to the lack of accurate
data, and the difficulty of visiting the site.