Effect of wetting and drying cycles on microstructure of rock based on SEM

To study the effect of periodic water circulation on rock mass, chlorite–amphibolite rocks from the slope of Nanfen open-pit iron mine in Liaoning province were chosen as the engineering samples and were investigated using uniaxial compressive experiment and scanning electron microscopy. The effect of different wetting and drying cycles on the mechanical properties and microstructure of the rocks was investigated. The characteristics of pore parameters from the SEM images were obtained by Image Pro Plus image processing software. The results show that with the increase in number of wetting and drying cycles, the uniaxial compressive strength of the rock decreases and the porosity increases significantly. The weakening of macroscopic mechanical properties of rocks is closely related to the changes in microstructures of rocks. The water–rock interaction changes the size, shape and porosity of the rock pores and then affects its mechanical properties. Based on the combination of macro and micro, quantitative analysis of the weakening process of rocks subjected to wet and dry cycles can provide a better reference index for evaluating the stability of geotechnical engineering.