Layered Construction of Novel Reconstituted Soils in Coal Mining Sites

Abstract

This study, which considers coal mining sites, aims to solve problems pertaining to the immense permeability, poor stability, and the environmental pollution of soil. In regard to reconstituted soil, the novel "2+1" layered construction technology entails designing a water-resisting layer, a modified layer, and an evaporation inhibition layer on the surface of the gangue hill. This technology, which entails constructing a novel type of reconstituted soil, considered four mechanical and physical soil properties, namely soil particle size, humidity, unit weight, and soil structure grade. The construction of novel reconstituted soils should consider the influence of biological factors and that of an arid environment, as well as the influence of the soil permeability coefficient, water content, density, temperature, and water-soil interaction; simultaneously, it should consider the chemical composition. With respect to the water-resisting layer, we selected loess and feldspathic sandstone that exhibited high clay content, and we utilized a 20 cm design thickness. The modified layer was composed of sandy loess, weathered coal, and feldspathic sandstone. This layer was exhibited a 60 cm design thickness, and it considered the characteristics pertaining to vegetation, soil compactness, and soil chemical composition. The evaporation inhibition layer was designed using materials such as gravel and straw checkerboard. Regional tests indicated that verified the rational robustness of the novel "2+1" reconstituted soil layered construction. The results provide a reference for ensuring the ecological sustainability of coal mining sites that characterize the arid, desert areas of Northwest China.