The occurrence of downhole debris flows in caving mines has burst, concealment, and destruction characteristics. This study aimed to investigate accurate prevention and control measures for downhole debris flows. The research background was a downhole debris flow in the Plan copper mine. The disaster chain theory was applied to study prevention and control methods for downhole debris flows. Using a model of source generation, chain breaking, and disaster reduction, we proposed accurate prevention and control measures for downhole debris flow disasters, which prevent and control the downhole debris flows at the source. The results showed that the disaster chain type of downhole debris flow disasters is the compound periodic cycle chain, which has the characteristics of the branch basin chain and the periodic cycle chain. Based on the chain-effect nature of disasters caused by downhole debris flows, active and passive prevention and control methods for downhole debris flow disasters were proposed. The active prevention and control measures for chain breaking and disaster reduction involve isolating the generation conditions from the source, inducing a downhole debris flow disaster. This prevention and control method is difficult to implement during the actual production process. The idea of disaster reduction through passive defensive chain breaking is based on the fact that if the three essential types of conditions for the downhole debris flow formation are not present at the same time, then a disaster accident of a downhole debris flow can be effectively prevented and controlled. Accordingly, the following measures are proposed for preventing and controlling downhole debris flows: (1) reinforcement measures applied to the slope body of the landslide material source in the collapse pit; (2) adopting comprehensive flood control measures such as locking, intercepting, dispersing, draining, and blocking under hydraulic conditions; (3) blocking the formation of the channel by adjusting the ore drawing conditions; (4) addressing the inducing factors by blasting with a small amount of explosive. According to the disaster chain theory, prevention, and control methods for downhole debris flow in caving mines were investigated in this study, which not only broadens the research of the debris flows but also fills the gap in the systematic research on downhole debris flows.

In slopes where a mixture of coarse and fine particles is present, the infiltration of rainfall can cause the migration of fine particles. This migration alters the hydraulic properties of the soil and has implications for slope stability. In this study, the slope under investigation is a tailings dam composed of loosely consolidated soil with a wide particle size distribution. Due to rainfall infiltration, fine particles tend to migrate within the voids of the coarse particle framework, leading to changes in hydraulic properties and inducing slope instability. The classical internal erosion constitutive model, known as the Cividini and Gioda erosion criterion, is commonly used to predict the behavior and effects of fine particle erosion in geotechnical engineering. However, certain parameters in this erosion criterion equation, such as long-term density, are challenging to obtain through experiments. To investigate the coupled evolution of seepage and erosion within landfill slopes under the influence of rainfall infiltration and to understand the mechanisms of slope instability, this research assumes the erosion of fine particle suspension and adopts the Worman and Olafsdottir erosion criterion to establish a coupled model of unsaturated seepage and internal erosion. The developed model simulates the coupled response of seepage and erosion in unsaturated landfill slopes under three different rainfall intensities. It is then combined with the infinite slope model to quantitatively analyze the impact of fine particle migration on soil permeability and slope stability. The numerical simulations provide the following findings: The Worman and Olafsdottir erosion criterion, unlike the Cividini and Gioda erosion criterion, only requires the determination of the soil’s gradation curve to estimate the erosion rate. Internal erosion primarily occurs within the leading edge of moisture penetration, accelerating the advancement of the wetting front and reducing slope stability. When the rainfall intensity is lower than the saturated permeability coefficient, the influence of internal erosion can be disregarded. However, under rainfall intensities equal to or greater than the saturated permeability coefficient, considering internal erosion results in a difference in the depth of the wetting front of up to 34.2 cm after 6 h in the R₂ scenario. The safety factor without considering internal erosion is 1.12, whereas considering internal erosion yields safety factors between 1.08 and 1.09. In the R₃ scenario, the difference in the depth of the wetting front reaches 53.8 cm after 6 h, with a safety factor of 1.12 without considering internal erosion and safety factors between 1.06 and 1.07 when considering internal erosion.

This study aimed to investigate the formation mechanism of the mud-inclusion-type underground debris flows of natural caving underground mines. The characteristics of fine moraine particles flowing through the coarse-grained ore bed were used to analyze the formation process of mud inclusions in the caving ore bed through a physical model test. Based on the movement behavior of the mud inclusions of moraine in the caving ore bed, a formation-mechanism generalized model of underground debris flows with mud inclusions was established. The model was used to examine the formation mechanism of mud-inclusion-type underground debris flows in natural caving. The results showed that the fine moraine particles had good cross-flow characteristics in the process of drawing coarse-grained ore. The accumulation of fine moraine in the ore bed was a prerequisite for the formation of mud inclusions, and the fluid inclusions were formed by a mixture of the particles with the infiltrated water. When mud inclusions in moraine are affected by many factors, such as ore-drawing vibrations, blasting vibrations, and groundwater, the inclusions undergo multiple migration–stop–migration cycles, resulting in separation or fusion. However, the inclusions are released along the optimal random pore path to the outlet, forming a certain scale of underground debris flows accidents. The accuracy and reliability of the formation mechanism were verified through geophysical explorations based on the equivalent inverse flux transient electromagnetic method. This study not only broadens the research on debris flow, but also provides theoretical guidance for the prevention and control of underground debris flows.

The shear factor of ore drawing is an important factor affecting the formation of underground debris flows. The aim of this study was to investigate the effect of the mining shear factor on underground debris flows in natural caving. The research background was the underground debris flow in the Plan copper mine, and we analyzed the characteristics of the slurry material structure of the underground debris flow, as well as the influence of the ore-drawing shear factor on the formation mechanism of the underground debris flow. The results showed that the slurry of the underground debris flow in the Plan mine is both a pseudoplastic and thixotropic fluid. Shearing force induced in drawing deforms the slurry and decreases its viscosity with the increase in shear rate and time. The shear force produced by the flow of ore particles first produces shear action on the paste in the shear boundary region of the ore drawing, reducing the paste viscosity while increasing its fluidity. Consequently, the “activation” makes the paste flowable, which flows along with the bulk ore flowing through the drawing mouth. The continuous ore-drawing process continuously shears the new moraine slurry in the ore-drawing channel and continuously “activates” the moraine slurry in the ore-drawing channel. Finally, destructive underground debris flow accident of a certain scale occurs. To our knowledge, this study thoroughly investigated the effect of the ore-drawing shear factor on the formation mechanism of underground debris flows, which not only broadens the research field of debris flow but also covers the deficiency of systematic research on underground debris flows, providing theoretical guidance for the prevention and control of underground debris flows.

Underground mining in Karst Plateau landform area may cause the loss of support for the upper rock stratum, resulting in rock collapse and large-scale subsidence of the ground surface. Also, the formation of a large-scale goafs may further lead to geo-hazards such as collapse, water gushing, slope instability and so on in the area. To reduce the impact of goaf settlement on local strata stability, this paper established a standardized safe mining detection model for goafs based on the geological safety characteristics of mining goafs. With reference to the statistical analysis of the geological conditions in the mining area, a numerical model with 358 goafs and the proposed mining area was established using FLAC^3D numerical software. The surface subsidence and variations of plastic zone in the mining area were comprehensively analyzed. The results indicated that there was a correlation between the stability of the mining area and the geological occurrence conditions of the goafs. By quantitatively taking the values from standardized safety mining detection models, the standardized safety mining detection and warning technique was finally established. The findings can provide technical guidance for safety detection and early warning in the whole process of underground goaf mining in Karst Plateau karst development zone.

Rock-like damage and fracture are a common geological phenomenon. It not only affects the construction quality and safety of the project but also affects the economic benefits. This study uses the finite element method to calculate the numerical simulation of rock. Therefore, we must study and explore it to improve the success rate and efficiency of drilling under such problems. This study conducts systematic analysis through experimental research on the theoretical knowledge of internal failure and stability of rock-like masses and other related finite element methods. On the basis of predecessors, combined with the professional knowledge I have learned, a set of relatively complete solutions is proposed. This study mainly uses the experimental analysis method and data collection method to study cloud computing related technology and finite element method, rock tensile fracture, and numerical model. According to the experiment, it can be concluded that the degree of rock crack development gradually increases with age. In the early and late stages of stretching, the rock mass will be significantly enhanced by the stress concentration.