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Dynamic disasters seriously threaten the safety and effectiveness in deep mining. The mechanism of stick-slip instability occurrence on the deep coal-rock structure was studied in this paper through analyzing the occurrence condition of stick-slip in the weak surface and discussing the friction constitutive of the coal-rock structure. The result indicated that the grinding slip and the soft interlayer formation occurred in weak plane in the coal-rock structure in the process of diagenesis and strata movement, which is more likely to satisfy the stick-slip condition and then trigger dynamic disaster. Based on the mechanism study of coal-rock structure failure caused by stick-slip, it is proposed that the horizontal compression pulse caused by local stick-slip in coal seam could lead the layer-crack and fly out with the broken fragments. At the same time, it is pointed out that the scattering effect of the plane compression pulse in the propagation process induces the serial sliding instability of the coal-rock structure in many places, forming a large range of dynamic disasters. By means of numerical simulation of coal bump accident in a roadway in Yima Coal Mines, the dynamic process of sliding-slip instability of coal and rock mass is inverted, and the mechanism of sliding-slip instability of coal and rock structure is verified. [ABSTRACT FROM AUTHOR]

The shale gas well station plays a critical role in the extraction of shale gas, and its safety status exerts significant influence not only on shale gas production but also on the ecological balance of the surrounding environment. To investigate the response characteristics of the shale gas well station under the impact of tailings dam failure debris flow, a comprehensive analysis was conducted using a combination of physical modeling and numerical simulation. The analysis focused on the dynamic inundation process and the impact siltation law caused by the downstream flow of tailings dam failure debris at the shale gas well station. The depth of inundation and the extent of siltation damage were employed as key parameters for characterization. Experimental findings revealed that the downstream mudflow inundation process could be divided into three distinct stages: rapid increase (0-60 s), steady increase (60-106 s), and slow advance (106-250 s). The pattern of mudflow siltation height variation at the well station exhibited an initial rise, followed by a subsequent decline and eventual stabilization. The highest siltation volumes recorded at measurement points Ato D were 4.4, 4, 5.2, and 6 m, respectively. Additionally, by employing computational fluid dynamics, numerical calculations were performed under unprotected conditions, with the error between the calculated conclusions and the test results not exceeding 15%. Furthermore, the blocking effect of 8 and 16 m debris flow blocking dam on the debris flow was thoroughly investigated. The study demonstrated that the check dam with a height of 16 m yielded the most effective blockage, resulting in the highest sediment siltation height of 0.4 m. The research results provide some reference for the prevention and control of debris flow disasters. [ABSTRACT FROM AUTHOR]

Urban water supply pipelines serve as vital lifelines for urban operations. However, the occurrence of underground pipeline leakage, caused by various factors, results in significant water loss and gives rise to safety hazards such as pavement collapse due to the erosive action of leaking water on the overlying soil. To conduct a more comprehensive investigation into the erosion characteristics of the leaking jet on the soil, this study employed a custom-built soil-test system to investigate the erosive effects of leakage from the water supply pipe network on the clay roadbed above. The study considered water flow rate, leakage port size, and leakage angle as influential factors. The experimental results demonstrated that reducing the water flow rate significantly enhances the soil's erosion resistance. There is a positive correlation between the caliber of pipe leakage, pipe diameter, and the erosion rate of the soil cavity. Under identical conditions, the erosion rate of the specimen increased consistently with an increase in the leakage port angle. The study also investigated and summarized the curve depicting the formation of soil cavities. The aforementioned findings offer valuable insights for the implementation of reinforcement measures using fine-grained cohesive soil backfill in urban water supply pipelines. [ABSTRACT FROM AUTHOR]

Tailings storage facilities (TSFs) are being built globally for containing the chief solid waste stream from mining industry. Catastrophic TSF breach accidents have occurred frequently since the beginning of the 21st century, causing severe impacts on the environment, economy and community safety. The recent example is the 2019 Brumadinho accident in Brazil that released 12 million m3 of tailings and killed more than 249 people. The foreknowledge of the TSF breach run out overland flow can be crucial to prevent or minimize possible losses. Using the Digital Surface Model (DSM) terrain data and the smoothed particle hydrodynamics (SPH) numerical method, this study proposed a procedure to predict the routings of hypothetical TSF breach run out flow over downstream complex terrain. A case study of a planning TSF site in Guizhou Province of China was carried out to evaluate its applicability. The results suggested that the maximum routing distance of the TSF breach run out flow was 1.45 km. At 240 s, the run out flow began to impact the downstream viaduct piers with the maximum submerged depth of 3.3 m and the maximum impact force of 21.8 kPa. Essential protective measures were recommended before the TSF site construction. The proposed procedure is then recommended for the safety management of the TSFs globally.

A portion of the accumulated tailings in a tailings pond exhibits an unsaturated state. The mechanical properties of unsaturated tailings affect the safety and stability of tailings dams. To investigate the effect of moisture content on the deformation characteristics of unsaturated tailings in the mesoscale, a special testing apparatus is applied to experimentally study the settlement deformation and mesostructure evolution of unsaturated tailings under continuous load. The results show that the mesostructure deformation of unsaturated tailings with different moisture contents under load is the same and can be divided into four stages: pore compression, elastic deformation, structure change, and further compaction. However, the critical pressures of the four stages are significantly different; there is an optimal moisture content corresponding to the maximum deformation resistance. Moreover, the influence of the liquid bridge regime on the mesostructure deformation of unsaturated tailings is discussed in this paper. [ABSTRACT FROM AUTHOR]