The Study Of The Engineering Geological Chatacters Of The Black Stratum Of Yanguanian Stage In Guilin Region

Due to containing the special minerals such as pyrite, marcasite, etc. black stratum prone to occur hydrolysis, oxidation and a series of geochemical processes, in the environment rich with oxygen and surface water, to cause the alteration of it's mineral composition and structural damage. Finally the processes not only result in decreasing it's strength, but more importantly forming weathering product-acidic water which can further exacerbate the physical and mechanical properties of the black stratum weaken. Therefore, it is necessary to study and remediate the black stratum of research area in order to prevent the disaster which is caused by the black stratum.By collecting the topography, lithology, geological structure data of study area and conducting field investigation and sampling action, it is obtained chemical characteristics and weathering alteration properties of the black stratum of investigation area, based on rock mineral identification, chemical composition identification and mineral composition identification, etc of the representative rock samples.The changing rule of the inner mineral composition of the black stratum can be obtained through the immersion test in laboratory which can simulate the field weathering process. Because the black stratum's weathering damage is mainly caused by acid corrosion and alteration under water-rock interaction, so getting the change trend of the inner mineral of the black stratum and the acidity of the acid water has important meanings for studying the process of the weathering damage of the black stratum.Finally, through the analysis of the chemical composition, the mineral composition, the weathering alteration components and the geochemical process of the black stratum, the engineering geological characteristics of the black stratum of the study area are preliminary summarized, which are disintegration after weathering destroy and water erosion and injury to the black stratum. Moreover, the distribution data of the black stratum is collecting in the study area, and that where distributes and the geological disasters triggered by it include: acidic water erosion of slope's crack, spallation with weathering, the landslide of the shallow weathering zone and collapse of road cutting slope. At last, the prevention measures for the engineering secure have been made up in order to prevent the disasters caused by the black stratum.