Influence of mining-induced ground fissures on soil infiltration characteristics and its erosion effect in coal mining area of northern Shaanxi in the middle reaches of the Yellow River

SONG Shijie; CHENG Xing; WANG Shuangming; LIU Lu; LI Yuanhong; ZHANG Jiajie; CHEN Baodeng

doi:10.13225/j.cnki.jccs.XH24.1484

Abstract：Cracking the soil and water loss effects of mining-induced surface fissures in the coal mining area of the middle reaches of the Yellow River is of great significance for ecological environment protection and high-quality development in the coal mining region of northern Shaanxi.Taking the soil around the mining-induced ground fissures with widths of 0-10,10-20,20-30 cm(within 80 cm in horizontal distance and shallower than 20 cm in vertical depth)in the typical mining-induced ground fissure development area in the north wing of Ningtiaota mine field in northern Shaanxi as the re-search object,the soil infiltration rate,cumulative infiltration,saturated hydraulic conductivity(Ks),organic matter,mech-anical composition and＞0.25 mm water-stable aggregates were measured by constant head method and instrument ana-lysis method,respectively.The influence of mining-induced ground fissures on soil infiltration characteristics was re-vealed.Based on the RUSLE2 model calculation,the soil erosion effect on the small spatial scale of mining-induced ground fissures considering infiltration characteristics is clarified.The results showed that:① The infiltration rate of soil around the mining-induced fissures exhibits a dynamic variation process over time,characterized by three stages:transient(0-3 min),gradual(3-60 min),and stable(60-110 min).② The effect of mining-induced ground fissure development on soil Ks is the most significant,with an average increase of 60.63％.This effect increases with the increase of mining-in-duced ground fissure width and the decrease of horizontal distance from ground fissure.③ Soil cumulative infiltration and Ks were significantly positively correlated with very fine sand(p＜0.01),but significantly negatively correlated with clay and organic matter(p＜0.01),and significantly negatively correlated with＞0.25 mm water-stable aggregates(p＜0.05).④ The variation range of erodibility K-value calculated by considering infiltration characteristics is 1.12-2.13 times lar-ger than that without considering infiltration characteristics.Based on the exponential function,the prediction model of the influence range of mining-induced ground fissures with different widths on the infiltration rate and erodibility K-value of the surrounding soil was constructed.It was found that when the horizontal distance from the mining-induced ground fis-sures exceeded 226 cm and 157 cm,respectively,the effect of mining-induced ground fissures on increasing the infiltra-tion rate and erodibility of the surrounding soil basically disappeared.It can be used as a precise prevention and control target area for soil erosion in the loess mining-induced ground fissure development area in the middle reaches of the Yel-low River.