Stress-strain state index of the Imex quarry rock mass, Bioko Island, Equatorial Guinea

Purpose. The purpose of this research is to determine the index of the rock mass stress-strain state in the Imex quarry, Bioko Island, Equatorial Guinea. Methods. To determine the number of required samples by the method of stratified random sampling, the t-Student principle is used. The physical-mechanical properties of rocks have been determined by tests and methods of saturation, pycnometry, hydrostatic weighing, axial loads and clock-type indicators. The classification of the degree of weathering has been carried out to assess its impact on the physical-mechanical properties of rocks and rock mass on the basis of direct observation in different areas of the studied rock mass. To determine the rock mass stress-strain state, the Hoek-Brown failure criterion is used, including laboratory tests to determine the models, dimensions and shapes of ruptures. Findings. Significant changes in rocks, high values of stress and weathering, which generate distributions of new forces in the rock mass and originate instability and large deformations, as well as a high porosity index, average values of compressive strength and a high value of elasticity modulus, have been revealed. Significant differences in the degree of weathering in the prevailing zones, from insignificant values of weathering in the northern areas to moderate values of weathering in the south, have been confirmed. Originality. Information is presented on the physical-mechanical properties, the degree of weathering and the stress-strain state index of the rock mass in the Imex quarry, Bioko Island, Equatorial Guinea. Practical implications. Knowledge about the rock quality, management and implementation of technological processes during operation can be used as a useful material for the construction industry.