基于分级颗粒成分分析的软弱夹层泥化机制

Argillation Mechanism of Weak Intercalation Based on Component Analysis of Different Grading Particles

以三峡库区黄土坡库岸斜坡巴东组第三段泥化夹层为例,采用颗粒筛分试验、X射线衍射法、X射线荧光光谱法,从不同颗粒组分的矿物成分、化学成分对比分析其泥化的物理化学机制.结果表明:软弱夹层泥化砾类土的分级颗粒在从粗变细的过程中存在泥化差异,方解石的含量表现为先降低再增加再降低的变化特征,而黏土矿物与方解石的含量变化呈现负相关,其中粒径2~5 mm和<0.075 mm颗粒中的方解石含量较低、黏土矿物含量较高,2~5 mm颗粒表面溶蚀也最强烈;随着颗粒变细,绿泥石含量逐渐减少,绿蒙混层矿物逐渐增多;分级颗粒主量元素氧化物的含量变化特征也反映了泥化夹层的水岩作用过程.

In order to reveal the argillization mechanism of weak intercalation, the mineral component and chemical composition of different grading particles from argillaceous intercalation in Tb~3 rock mass in Huangtupo bank slope of Three Gorges Reservoir area are compared. Differences in argillization mechanism of grading particles are reflected by variation characteristics of mineral content of grading particles of gravelly soil from intercalation argillization. During particles’ thinning process the content of calcite in the particles first decreases, then increases and then decreases, the content changes of clay minerals show negative correlation with calcite content. Calcite content is low, and clay mineral content is high in particles 2~5 mm and less than 0.075 mm, 2~5 mm particles’ surfaces are strongly corroded. Chlorite content decreases gradually and chlorite-montmorillonite mixed minerals increase gradually during particle thinning process of argillaceous intercalation. The variation characteristics of the relative content of major element oxides in graded particles of argillaceous intercalation also reflect the water rock interaction process during particle thinning process.