The Effect of Geotechnical Factors in Road of Basrah, Southern Iraq
Most Basrah roads are conducted to a major failure in their layers and bases, which appears in the form of cracking, crushing, landing, as well as massive holes. The influence of geotechnical factors on the performance of Basrah roads has been studied. Sixteen sites were selected for sampling, which are Al-Medaina, West Qurna, Al-Hartha, Al-Dir, Shatt Al-Arab, Al-Tuwaisa, Hayy-Al-Hussein, Al-Shuaiba, Al-Maqal, Al-Gazara, Abu-Al-Khaseeb, Al-Ashar, Umm Qasser, Al-Zubair Petrochemical factory, and Al-Faw. The soil properties were studied up to 3 meters of depth at each location to find out the effect of geotechnical properties on roads. Laboratory tests were carried out on the samples, which included grain size analysis, Atterberg limits, gypsum content, total soluble salts, swelling potential, organic content, and standard penetration test. The results presented that the percentage of gypsum exceeded the allowable limit in the standard specifications at the sites (S7, S8, S13, S14, S16). Also, the percentage of total soluble salts exceeded the allowable limit in the standard specifications at the sites (S5, S8, S16). The results showed that the soils in S1, S2, S3, S4, S7, S11 have medium swelling potential, which requires treating before building roads on them. The results also showed that the percentage of organic materials exceeded the permissible limit in the standards specifications at the sites S1, S2, S3, S4, S5, S9, S10, S11, S12, S15. The results also showed that the cohesive soils in the first meter of the sites (S2, S5, S11), the second meter of the sites (S2, S7, S12) and the third meter of the sites (S5, S9, S10, S11, S12) are medium stiff soils, which requires treating before building roads on them. While the non-cohesive soils at the two sites (S8, S13) are medium dense soils, in two sites (S14, S16) are loose sandy soils in the first meter, while the second meter in sites (S8, S13, S14, S16) are medium dense soils, and the third meter at the site (S14) is medium dense soils.