红层堆积体软弱夹层形成中的水-岩(土)化学作用

Water-rock (soil) chemical reaction during formation process of weak interlayers in red bedded accumulation

红层堆积体内软弱夹层的形成过程是一复杂且长期的过程,分析红层堆积体内部水-岩(土)化学作用是了解软弱夹层形成过程的有效手段。以大型红层堆积体滑坡——关平古滑坡为例,在地质调查及取样、ESR地质测年、X射线衍射分析、地下水水质分析及物理力学试验的基础上,对红层堆积体内部水-岩(土)化学作用特征、软弱夹层成因及物理力学性质进行了研究。结果表明:古滑坡及其软弱夹层基本是同一时期产物,软弱夹层主要矿物为黏土矿物,在矿物成分上二者具有同源性;软弱夹层是红层堆积体发生水-岩(土)化学反应后的产物向过水断面富集形成的,软弱夹层的厚度与水-岩(土)化学反应时间成正比;物理力学试验表明软弱夹层属于红层堆积体中的易滑地层。

The formation process of weak interlayers within red bed accumulation is a complex and long-term process,and analyzing the water-rock(soil)chemical action inside the red bed accumulation is an effective means to understand the formation process of weak interlayers.Taking a large red bedded landslide,Guanping ancient landslide,as an example,based on geological investigation and sampling,ESR geological dating,X-ray diffraction analysis,groundwater quality analysis and physical and mechanical tests,the characteristics of water-rock(soil)chemistry,the causes of weak interlayer formation and physical and mechanical properties of the red bedded landslide have been investigated.The results showed that the ancient landslide and its weak interlayer were basically the products of the same period,the main minerals of the weak interlayer were clay minerals,and the landslide and its weak interlayer were homologous in term of mineral composition;the weak interlayer was formed by the enrichment of the products of the water-rock(soil)chemical reaction of the red layer accumulator transporting to the water flowing cross-section,and the thickness of the weak interlayer was directly proportional to the time of the water-rock(soil)chemical reaction;physical and mechanical tests showed that the weak interlayer was a slippery stratum in the red layer of the accumulation body.