黄河西霞院工程坝基黏土岩的工程地质特性研究

黄河西霞院工程电站厂房地基为上第三系洛阳组黏土岩类地层。现场勘察揭示该黏土岩具有特殊的工程地质性质，在开挖或遇水时风化分解较快，由岩石的性质转变为土的性质。为了更好地了解洛阳组黏土岩的工程特性，进行了一系列室内试验和现场大型剪切试验。该黏土岩的黏土含量最高达53.7 %，黏土矿物成分以蒙脱石为主，含量在28 %～38 %，岩体的膨胀率为0.6 %～4.9 %，单轴抗压强度为0.11～1.04 MPa，凝聚力为132.2 kPa，内摩擦角为22.29°。研究表明洛阳组黏土岩具有典型的软岩硬土特征。

Engineering geological properties of claystone in Xixiayuan dam project on Yellow River

The claystones of the upper Tertiary Luoyang Formation has widespread distribution at the foundation of the Xixiayuan Project hydroelectric power station on the Yellow River. The field surveys reveal that the claystones have specific engineering geological characteristics, mainly found to exhibit weather and disintegration within a short period of time when exposed to the atmosphere or moistened, and the rock properties often change to properties with more characteristics of soil during excavation. In order to gain better understanding about the claystone of Luoyang Formation, a series of experimental laboratory studies were carried out involving in-situ large scale shear test. For some samples tested in this study, the clay mineral component of the claystone is high with maximum 53.7 % which have a mount of smectite with a range of 28 %－38 %, the swelling ratio 0.6 %－4.9%, the axial compressive strength 0.11－1.04 MPa, the shear strength (kPa). The claystone of the Luoyang Formation has properties of hard soil-soft rock.