黄河小浪底地区冰碛泥砾之发现及其工程地质意义

Discovery of Glacier Deposition of Clay and Gravels at Xiaolangdi Dam Site and Its Effects on Engineering Geology

经野外工程地质调查和室内扫描电镜观察,均发现在黄河小浪底坝址区的黄土层覆盖下存在有第四纪冰川堆积的红土卵石层。该层的形成和分布与冰川作用及其间冰期的风化作用密切相关,其主要特征是颗粒大小相差悬殊,堆积杂乱,砾石成份单一,砂砾石均遭受了强烈的风化,石英砂岩砾石上形成厚度不等的风化晕圈。由于红土卵石层具有透水性弱,抗渗强度和固结性好等特点,因此它的发现对坝址防渗及坝基稳定性评价都有重要影响。

A red clay layer with gravels of Quaternary deposition under loess in Xiaolangdi area, located on the Yellow River, was discovered through both engineering geologic investigation and observing it on a seanning electron microscope. The formation and distribution of the layer are the results form the Quaternary glacier action and weathering in the glacier period, from main characteristics of gravels in the layer: large variation in demensions, piling, disoderly, uniform mineral component, weathered seriously uneven with weathered halo on gravels in quartz conglomerate. The discovered layer with good antiseepage strength, low premibility and good consolidation, is important for evaluating foundation stability against seepage of Xiaolangdi Dam.