Experimental study of post-peak behavior of bimrocks with high rock block proportions

Design and construction of engineering structures in geomaterials with block-in-matrix texture (referred as bimrock) such as conglomerates, breccias and agglomerates are challenging tasks for engineers. When dealing with these materials in important structures such as open pits with high walls and pillars of deep underground mines, understanding the complete stress-strain behavior, including post-peak region, is a formidable yet crucial engineering practice. To study the post-peak behavior of bimrocks, artificial specimens were fabricated with a mixture of rock blocks and a cementing agent. All the experiments were conducted under uniaxial compression using a servo-control testing machine. The results show that the specimens with the highest block proportion (around 90% by mass) showed a small decrease in stress with strain increment in the post-peak region. The specimens with lower block proportions were characterized by an approximately steep fall in stress and following to residual stress. Based on the study, it is inferred that all the artificial specimens undergo post-failure deformation and the type of post behavior depends on rock block proportions.