一、概述在葛洲坝工程基础地质勘探中,发现岩体中分布有数量较多变化较大的软弱夹层,并且部分还有泥化现象。由于软弱夹层受构造影响,本身岩性软弱且有破碎现象,特别是泥化现象,应用小口径钻探取芯的效果不好。主要是取芯不易,即使取出了岩芯亦不完整,也看不到原始性状。为了查清基础软弱夹层的分布及性质,为工程设计提供依据,曾经采用大口径钻探及钻孔黑白电视观 I. Overview Geological exploration in Gezhouba project found that there are a large number of rock mass in the distribution of changes in the larger the weak interlayer, and some mud phenomenon. Due to the structure of the weak interlayer, its own weak and fragile lithology, especially mud phenomenon, the application of small-bore drilling coring effect is not good. The main coring is not easy, even if the core is removed is not complete, can not see the original traits. In order to find out the distribution and nature of the basic weak interlayer, provide the basis for engineering design, once used the large-diameter drilling and drilling black and white television view