Engineering geological characteristics of the working face weathering zone and its impacts on mining effect: a case study of Zhangji coal mine
Year: 2026
Type: article
Abstract: In concealed coalfields, weathering zones within the roof overburden stratum play a critical role in the excavation of shallow working faces. The weathering process affects the engineering geological properties of the rocks, complicating roof support management and increasing the risk of hydrogeological hazards. To elucidate these effects, the 1410 (3) working face of the Zhangji Coal Mine in the Huainan mining area, Anhui Province, was selected for detailed investigation. Through underground drilling, a comprehensive exploration and coring of the rock stratum within a 30 m interval from the roof of the working face were conducted. Employing X-ray diffraction (XRD), an analysis of the mineral composition of rocks in the weathering zone was conducted. Rock cores obtained from various locations underwent physical and mechanical testing to determine the depth and degree of weathering zones. Two geological models were established: weathering stratum and normal stratum. Numerical simulation was employed to study the mining impact on surrounding rocks under these two different conditions. The results were as follows: (1) Weathering stratum were found to be distributed across the roof area of the working face, with depths ranging from 18 to 32 m and an average depth of 25 m. The weathering rocks exhibited darker coloration and poorer structural integrity compared to normal rocks. (2) The mineral composition of the bedrock weathering zone was predominantly clay minerals, such as kaolinite, montmorillonite, and illite, which were highly susceptible to expansion upon contact with water. This characteristic was beneficial in inhibiting the development of water-conducting fracture zones. (3) The average porosity of normal and weathering rock was 14.23% and 19.92%, respectively, reflecting a 40.02% increase. The average uniaxial compressive strength for normal and weathering stratum was 40.44 MPa and 17.78 MPa, respectively, indicating a 56.03% decrease. The average tensile strength of normal and weathering stratum was 3.69 MPa and 1.21 MPa, respectively, showing a 67.23% decrease. (4) Numerical simulation revealed that the height of the plastic failure zone and vertical displacement on the roof of the working face were significantly elevated due to rock weathering. The weathering effect induced substantial fluctuations in the stress field of the surrounding rocks within the roof range of the goaf, demonstrating a strong disturbance mechanism.
Source: Frontiers in Physics
Language: English
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,077
OpenAlex ID: W7204450333