Investigation into the cause of road failure has been carried out along a 60 km long Sagamu –Papalanto highway southwestern Nigeria. Geochemical, mineralogical, geotechnical and geophysical analyses were conducted to evaluate the cause of failure along the study area. The results of the laboratory tests showed that the percentage amount of fines ranges from 12 to 61.3%, natural moisture content from 6.8 to 19.7%, liquid limit in the range of 25.1–52.2%, linear shrinkage between 3.96 to 12.71%, plastic limit ranges from 18.2–35%, plasticity index ranges from 5.2 to 24.6%, free swell in the range from 5.17–43.9%, maximum dry density ranges from 1.51–1.74 g /cm3, specific gravity ranges from 2.52–2.64 and CBR between 3 and 12%. The Cone Penetrometer Test (CPT) shows a resistance value of 20–138 kgf/cm2. The major clay mineral that is predominant in the studied soil is kaolinite. The major oxides present are SiO2, Al2O3, Fe2O3, K2O, Na2O, MgO and CaO. The result of the 2D Electrical Resistivity Imaging revealed a low resistivity values for profile 2 and 3 ranging from 100 Ωm – 300 Ωm, between a distance of 20 m – 240 m along the profile to a depth of 7.60 m and a low resistivity value ranging from 50 Ωm – 111Ωm, between a distance of 80 m − 120 m along the profile to a depth of 15 m. It was concluded that the low CBR, low MDD and the class of subsoils namely A-26, A-7, A-2-7 (clayey soils) which were identified are responsible for the cause of failure experienced in the study area. These makes the soils unsuitable as road construction materials and hence, there is need for stabilization during the reconstruction and rehabilitation of the road.

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尼日利亚西南部Sagamu-Papalanto公路沿线道路故障的原因调查

已对尼日利亚西南部60公里长的Sagamu –Papalanto公路进行了道路故障原因调查。进行了地球化学，矿物学，岩土工程和地球物理分析，以评估研究区域的破坏原因。实验室测试的结果表明，细粉的百分比范围为12％至61.3％，自然水分含量为6.8％至19.7％，液体极限范围为25.1–52.2％，线性收缩率介于3.96％至12.71％，塑性极限范围从18.2％至35％，可塑性指数范围从5.2至24.6％，自由膨胀范围从5.17至43.9％，最大干密度范围从1.51至1.74 g / cm3，比重范围从2.52至2.64，CBR为3和12％。锥形渗透计测试（CPT）显示电阻值为20–138 kgf / cm2。在研究的土壤中主要的主要粘土矿物是高岭石。存在的主要氧化物是SiO2，Al2O3，Fe2O3，K2O，Na2O，MgO和CaO。二维电阻率成像的结果显示，剖面2和3的低电阻率值介于100Ωm– 300Ωm之间，沿着剖面的距离为20 m – 240 m，深度为7.60 m，而电阻率值范围很低从50Ωm–111Ωm，沿着轮廓的80 m − 120 m的距离到15 m的深度之间。得出的结论是，确定的低CBR，低MDD和地下土壤类别（即A-26，A-7，A-2-7（粘土））是造成研究区域出现故障的原因。这些使得土壤不适合用作道路建筑材料，因此，在道路的重建和修复过程中需要稳定化。