Experimental study on the disintegration of granite residual soil under the combined influence of wetting–drying cycles and acid rain

Abstract

Granite residual soil has obvious disintegration characteristics, resulting in serious water and soil losses in South China. There is a lack of studies on the disintegration of granite residual soil. Therefore, it is important to determine the disintegration characteristics of granite residual soil, especially under combined influence of wetting–drying cycles and acid rain. Granite residual soil from Jinqiao Village, Yudou County of South China, was used as experimental material. The disintegration velocity was evaluated to investigate the effects of wetting–drying cycles and acid rain on soil disintegration characteristics. Under the pH conditions of acid rain, disintegration velocity increases as the number of wetting–drying cycles increases (from 0 to 4), reaches a maximum after four wetting–drying cycles; then remains relatively constant as the wetting–drying cycle number increases from 4 to 7. Meanwhile, under conditions of a given wetting–drying cycle number, disintegration velocity increases with the decrease in pH from 7 to 4, reaches a maximum at a pH of 4, and then remains relatively constant when the pH decreases from 4 to 1. Moreover, the disintegration velocity under the combined influence of wetting–drying cycles and acid rain is considerably higher than that under individual factor.