肯尼亚内罗毕南环线黑棉土的矿物学特征分析

以肯尼亚内罗毕南环线公路工程为依托，对黑棉土的矿物组成、化学成分、电子探针及微观结构进行了分析。结果表明:黑棉土Fe2O3含量是广西宁明黑色膨胀土的3倍，Na2O和CaO含量是宁明黑色膨胀土的5~8倍，而K2O含量只是宁明黑色膨胀土的1/3；黑棉土中皂石含量达41.37%，伊蒙混层矿物10.64%，造岩矿物以石英、长石为主，约24.30%，含水矿物（沸石）含量8.33%；高含量的黏土矿物及沸石相是黑棉土水化膨胀性强的重要原因。

Analysis on Mineralogical Characteristics of Black Cotton Soil in Nairobi South Ring of Kenya

Relying on highway project in Nairobi South Ring of Kenya, the mineral composition, chemical component, electronic probe and microstructure of black cotton soil were analyzed. The results show that Fe2O3 in black cotton soil is 3 times as much as that of black expansive oil in Ningming, Guangxi Province; Na2O and CaO are 5~8 times as much as that of black expansive oil in Ningming, while K2O is only 1/3 of black expansive soil in Ningming. The soapstone in black cotton soil reaches 41.37% and mixed-layer minerals of illite and smectite reaches 10.64%. The rock-forming minerals mainly include quartz and feldspar, about 24.30%; and the enhydrite (zeolite) is 8.33%. High content clay minerals and zeolite facies are important reasons for strong hydration expansion of black cotton soil.