Evolution characteristics and development height prediction method of water-conducting crack zone in thick weak cemented overlying strata

The development height of water-conducting fracture zone in thick weakly cemented strata is of great significance to coal production safety and groundwater resource protection in Shaanxi-Inner Mongolia weakly cemented mining area. The study found that the overlying Cretaceous rock layer in the thick weakly cemented mining area has the characteristics of large thickness, low strength, poor cementation and undeveloped joints. However, during coal mining in this area, the overburden is severely damaged and the water-conducting fracture zone is highly developed, with a fracture-to-mining ratio of about 30, seriously threatening the production safety of the mine. How to accurately predict the development height of water-conducting fracture zone in thick weakly cemented overburden has become one of the keys to safe and efficient coal mining in thick weakly cemented mining area. Based on this, this paper takes a working face in Shilawusu mining area as the research background, and uses UDEC numerical simulation software combined with measured data to explore the evolution characteristics of water-conducting fracture zone in thick weakly cemented overburden. It is concluded that the overall shape of water-conducting fracture zone in thick weakly cemented overburden is ∆, which is significantly different from the saddle characteristics in the east. Moreover, its shape and development height are affected by mining height, thickness and location of weakly cemented rock layer and other factors. The thick weakly cemented overburden has a significant control effect on the development shape and height of water-conducting fracture zone. On this basis, a prediction model for the development height of water-conducting fracture zone in thick weakly cemented overburden is established using the plate theory, and it is applied in the Shilawusu mining area, verifying the effectiveness and accuracy of the established model. © 2025 China Coal Society. All rights reserved.