Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

In sedimentary rocks (especially soft rocks), swelling and slaking are caused by the change of ground-water level, stress relief by excavation, and repeated drying and wetting cycles. In this study, swelling test (confined swelling pressure test, unconfined swelling strain test), uniaxial compressive strength test, and slake durability test were performed to obtain the physical and mechanical characteristics of mudstone in Pohang area (Buk-kun Hunghae- myon, Cenozoic era - Tertiary period) and black shale in Taegu area (Dalseou-ku, Mesozoic era - Cretaceous period). Uniaxial compressive strength test was taken under three conditions (natural, dry, wet) and the difficulty of strength deterioration of mudstone and black shale caused by drying and wetting was verified. As a result of statistical treatment to uniaxial compressive strength for mudstone and black shale, the difficulty of strength deterioration was shown in the order with dry, natural and wet state. In addition, water condition data (temperature, pH) quoted by the Ministry of Environment (NakdongRiver Environmental Management office : classified by month, 1999) was applied to slake durability test to know the influence factor of slaking. As a result of the slake durability test, black shale was not influenced by temperature and pH but mudstone was not under the influence of pH but temperature.