Testing Microscopic Characteristics of Weathered Rock Formations by Optical Microscopy

  • Yigai Xiao
Keywords: Black Rock Formation, Weathering Failure, Chemical Weathering, Light Microscope


The weathering of rocks has caused a variety of cultural relic diseases and caused severe damage to the value of
stone cultural relics. The main component of the rock is plagioclase reacting with H2O to form kaolinite. Rock
carbonate cement reacts with SO2, CO2, H2O. in the air to generate gypsum, hydrobromite, and nodrite. The
strength of the bonding between the mineral particles was finally caused to loosen the rock structure. Based on the
above background, the purpose of this article is to study the microscopic characteristics of weathered rock
formations using optical microscopy. First of all, the present paper investigates and samples the black rock
formations in the study area, and conducts mineral and chemical composition identification to obtain its
geochemical characteristics, providing a basis for a more thorough study of the damage caused by weathering of
black rock formations. Then this paper uses optical microscope, x-ray diffractometer, scanning electron
microscope and other testing methods to study the micro-characteristics of about 30 weathered rock core samples
in a certain area. Finally, this paper starts from the internal causes of the changes in the material composition of the
black rock formation, and fundamentally looks for the reasons for the poor engineering geological properties of
the black rock formation. It is found that the expansion rate of water in the rock can reach 9%. The pressure
generated by the expansion of water in the rock will cause the rock voids to increase and reduce strength. Kaolin
has good plasticity, and the expansion pressure of water and anhydrite has become an important cause of rock
formation and cracks. The generation of cracks not only reduces the mechanical properties of the rock, but also
provides a good channel for water seepage from the top, which accelerates the weathering of the stone carvings.