Study of physico-mechanical properties of Emeishan basalt saprolites in Yunnan, China

摘要

Saprolites are the weathered products that differ greatly from their parent rock in terms of the physico-mechanical properties because their chemical components are leached, yet differ from a typical soil because they still maintain their inherited structure. Here, typical Emeishan basalt saprolites that are widely distributed in the Guizhou and Yunnan Provinces were examined in terms of their basic physical indexes, compression properties, shear properties and microstructure to identify the differences between the parent rock and weathered product. The Emeishan basalt saprolites are characterized by a low density, high void ratio and medium-low compressibility. Also, these saprolites exhibit inelastic nonlinear response and relatively high cohesion during pressure tests. There is a brittle failure in low confining stresses and plastic deformation in high values, indicating the preservation of structural and textural characteristics from the parent rock; however, with highly developed secondary porosity, its strength is much lower than the parent rock. All the results indicate that Emeishan basalt saprolites are a kind of unique geological material, requiring consideration during construction and engineering within the region.