三峡库区丰都段泥质岩的工程地质特性及其水稳性分析

Engineering geological properties of argillaceous rock and stability of the reservoir slope in Fengdu County of Three Gorges Reservoir Area

三峡库区丰都段基岩岸坡主要由J2～3泥质岩与砂岩互层组成。其中泥质岩(包括泥岩、粉砂质泥岩、泥质粉砂岩)所占比例较大。根据野外调查和室内试验测试结果,三峡库区丰都段泥质岩普遍具有较高的成岩胶结程度,大部分泥质岩膨胀性弱或不具有膨胀性,因而具有良好的水稳性和崩解耐久性,并且随着粗颗粒含量的增大,泥质岩的水稳性明显提高。可以认为,三峡库区丰都段目前稳定的泥质岩岸坡在水库蓄水后仍将比较稳定。相对而言,粘粒含量较高的泥岩岸坡在水位波动带受干湿交替影响比较明显。

The reservoir slope in Fengdu County of the Three Gorges Reservoir area mainly consists of the alternation of J2-3 argillaceous rocks and sandstones, thereinto, the argillaceous rocks including mud rock, sandy mud rock and muddy silt rock account for a large part of the slope rocks. Field geological investigation and laboratory tests show that the J2-3 argillaceous rocks have better engineering geological properties, such as higher consolidated degree, low or no expansion, as well as strong water endurance, and the stability of argillaceous rocks in water increases obviously as the content of the coarse grains rises up. Thus, it can be considered that most of the reservoir slopes formed by the argillaceous rocks are generally stable in present day and after water storage, in contrast, the stability of those with more clayey component is obviously lowered within the waterwaved zone.