Meitan xuebao (Apr 2024)
Disaster-causing mechanism and prevention and control path of different types of coal seam roof water disasters in China
Abstract
China is the country with the most complicated coal-forming and occurrence conditions in the world. The roof water disaster, caused by the diversity and complexity of the hydrogeological conditions of the coal seam roof, the mutuality and time-varying coupling of the mining overburden fracture field and the seepage field, and the uniqueness and harmfulness of the coal mine roof water inrush, is one of the main mine disasters in China, especially in the western coal mining area. In order to better understand the roof water disaster, promote the existing technology and explore new technologies to prevent and control such mine disasters, based on the comprehensive analysis of the law of roof water disaster accidents in China’s coal mines in recent years and the occurrence conditions, water inrush mode, dynamic characteristics and mechanical behavior of roof water-filled aquifers, the types and characteristics of roof water disasters are systematically divided. The disaster mechanism of the main categories and the existing prevention and control technologies of roof water disasters are reviewed, and the future development direction of roof water disaster prevention and control is prospected. The study found that: ① The main structure of roof water disaster includes five types: gushing (leaching) water in thick bedrock aquifer, water-sand coupling inrush in weak cementation layer of thin bedrock, water storage and energy storage water inrush in abscission layer space, skylight recharge water inrush, and surrounding rock burning and permeability enhancement. They are concentrated in the north of the Qinling Mountains-Huaihe River. Shaanxi, Inner Mongolia and Ningxia are the main gathering places of roof water disasters. ② Mining-induced “Z” -type separation space is developed in the primary fractures of overlying strata under the super-thick bedrock aquifer, resulting in a large area of water gushing (leaching) in the stope. The fracture conditions of composite key strata are established, and the power source of water-sand coupling inrush disaster in weak cemented layer of thin bedrock is clarified. The critical criterion for assessing the instability of water inrush from bed separation is constructed, and the water inrush from bed separation is divided into three modes: static load disturbance, “dynamic+static” load composite disturbance and repeated disturbance of composite coal seam mining. The lack of laterite aquiclude and the mining-induced deterioration damage in the weak area of laterite are the main causes of skylight leakage recharge. The surrounding rock is burnt to increase permeability and porosity, and a new water-bearing structure is formed after receiving water supplement from adjacent water sources. Under the induction of mining, burnt rock water pours into stope and causes water disaster accidents. ③ The current prevention and control technology system of coal mine roof water disaster “exploration-discharge-treatment” is evaluated, and the future development direction is put forward, such as the conjugate linkage of upper and lower wells, the drilling-mining (excavation) high-level collaborative geological exploration system, the geological guarantee work guided by the “three zones” division of water prevention and control, the green mining and water prevention concept of “coal-water-ecology” multi-objective co-management, and the digital intelligence and transparent mine hydrogeological disaster information maintenance system.
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