Abstract: The mechanical properties of structural planes with different heights of regular second-order asperities are examined by the monotonic shear tests under constant normal stress.The experimental results show that the structural planes with second-order asperities have multi-peak shear stress and wavy deformation curves,and the failure modes may appear many-times or one-time shearing of asperities,which are different from the structural planes with the only first-order asperities.Peak shear strengt...