Strength of Vegetated Coal-Bearing Soil under Dry-Wet Cycles: An Experimental Study

Abstract

Strength of vegetated coal-bearing soil is of great significance to evaluate the shallow stability of vegetated slopes in coal-bearing soil regions. This paper takes D-W cycles, dry density, water content, and vegetation root (VR) content as four factors and carries out the triaxial test for the orthogonal design of vegetated coal-bearing soil in southern China. The strength curves of vegetated coal-bearing soil under four factors were obtained. The Taguchi method was used to quantitatively analyse the effects of four factors. The microstructure of coal-bearing soil under D-W cycles and the theory of soil reinforcement by VR were discussed. The results indicated that D-W cycles had a significant effect on the cohesion and internal friction angle ( P < 0.05 ). The internal friction angle was little affected by the water content and VR content, which had considerable influence on the cohesion. The cohesion could be improved with less than 2% VR content. The cohesion was the largest for no D-W cycles, 10% water content, and 2% VR content. The links between mineral particles go from a stable layered structure to unsteadiness chain structure with the increase in the number of D-W cycles.

A study on the shear strength characteristics and microscopic mechanism of coal-bearing soil under dry-wet cycles

“…However, most studies have focused on the micro-structure of the red clay, expansive soil, loess, and silty sand (ALDAOOD et al, 2014;Jiang et al, 2014;AHMED, 2015;Lin and Amy, 2015;Sun and Cui, 2018;Xiao et al, 2020;Wang et al, 2021), for instance. Some studies had also investigated the slope protection and the reinforcement of the CBS, the physical and the mechanical properties of the soil, and the micro-structure parameters (Hang et al, 2019;Huang and Zheng, 2021;Zhang et al, 2021). There are few studies, however, on the relationship between the microstructure and the macroscopic strength of the unsaturated CBS under the wetting and drying cycles.…”