中国膨胀土粘土矿物组成的定量研究

    QUANTITATIVE STUDY ON THE CLAY 1VIINERAL COIVIPOSITION OF EX-PANSIVE SOILS IN CHINA

    • 摘要: 由于膨胀土的不良工程特性主要受粘土矿物所控制,因此膨胀土的粘土矿物的定性定量研究一直受到高度的重视。但由于粘土矿物的复杂性和工程地质研究者对棍层粘土矿物的认识及研究的缺乏以及技术条件的限制,其膨胀土粘土矿物的研究结果一直不够理想。自从20世纪90年代后期以来作者运用当代粘土矿物组成XRD测试的先进技术,即通过对<2um天然样、乙二醇处理样和550℃加热处理样定向片的XRD联合测定及计算机信息处理技术,对中国不同地区不同类型的19个膨胀土样品进行了定量测试。研究结果表明,中国膨胀土粘土矿物中的80%以上为膨胀性粘土矿物(S、I/S、K/S、C/S),其膨胀性粘土矿物的绝对含量在30%以上。中国膨胀土的粘土矿物的主要类型为中等混层比(40%~60%)的膨胀性混层矿物,而不是伊利石。

       

      Abstract: Because of clay mineral has important effect on engineering behaviour of expansive soils,for this rea-son, the analysis of clay mineral composition has consistently ply great attention to expansive soils in home and abroad. On the basis of detailed discuss on the advance and present problems in the identification of clay mineral composition of expansive soils before end of last century, this paper presents the results of the 19 Samples quan-titative analysis on the clay mineral composition of expansive soils by new technique of quantitative analysis of XRD at the present. The samples of expensive soils collected from different region and formation type in China.The three prepared slides (normal, Heated and glycolated) of each Somple of the 19 treated Samples were X-rayed. Glycolation method can helps in the identification of the mixed layer type of clays with expandable layers,heating of the oriented clay samples to 550℃for two hours can helps in the identification of the kaolinite and smectite. The study result showed that major clay mineral in expansive clay mineral(S、I/S、K/S、C/S),especial I/S mixed-layer mineral than 80%in full clay mineral,id est expansive clay mineral content than 30%forwhole dry soil weight. Therefor,expansive clay mineral is control engineering properties of expansive soils.

       

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