The open pit mine is excavation soil from the Earth's surface, leading to presence of cut steep slopes with stability-concerned manners. Mae Moh open pit mine has the main component of claystone with ambiguous properties under stress condition changes from mine operations. Therefore, the strength of the claystone must be studied to be used for the slope stability analysis. Shear strength parameters for slope stability analysis were derived from the Triaxial Compression tests. Claystone is a type of sedimentary rock. Therefore, it is necessary to improve the equipment of the triaxial compression strength test to fit with intrinsic soft rock characteristics of the Mae Moh Claystone. Determination of parameters was based on Mohr Coulomb model, because it is the basis for slope stability analysis and can be resulted from the triaxial compression test. In addition, many computer-based programs for slope stability analysis also were relied onthe Mohr Coulomb model, including PLAXIS used in this study. Before the analysis, the model were validated by the function of “Simulation of Lab Test” in PLAXIS. Comparison on triaxial compression test results between the Mohr-Coulomb Model from PLAXIS and triaxial compression tests were made. This article reported the strength characteristics of Mae Moh claystone.
The slope stability problem at Mae Moh Lignite Mine, Lampang Province, Northern Thailand
