Using the overall variation trend and fitting of Na-feldspar crystal plane spacing after chemical corrosion to prevent rock disasters

Abstract

Sulfuric acid pollution, caused by acid rain, acidic wastewater, and natural acidic wastewater from mines, poses a significant risk to the stability of natural stone slopes and human stone structures. This study aims to develop a non-mechanical testing method for assessing the degree of acid corrosion in rocks, facilitating early intervention by safety engineers. The proposed method involves using XRD to measure the crystal plane spacing of Na-feldspar corroded by different concentrations of sulfuric acid, followed by mathematical analysis to determine the overall deviation degree of the crystal plane spacing. Four Deviation indices were defined to characterize the degree of acid corrosion, and all four indices increased with increasing acidity. By comparing trend charts, an optimized number of crystal planes for analysis was identified. Selecting the 100 sets of data with the largest spacing yielded similar trend results as selecting all the data. In addition, five different fitting methods were compared, and the power function fitting of Weighted Sum of squares of cumulative errors (WSSCE) was found to provide the optimal empirical formula, with a correlation coefficient exceeding 0.98.