Aiming at the strength optimization problem of filling body in the newly delineated recoverable area of the security pillar of a gold mine, the determination and verification of the strength parameters of the filling body were systematically carried out. In view of the limitations of the traditional single method, a variety of analytical methods such as empirical formula calculation, elastic-plastic mechanics theory analysis and FLAC3D numerical simulation were innovatively used to focus on the regulation mechanism of different strength filling bodies on stope stability and rock strata movement. Finally, the optimal filling scheme considering both safety and economy was constructed. The results show that the reasonable maximum strength of filling body is in the range of 0.72−1.99 MPa through empirical formula and theoretical calculation. The improvement of the strength of the filling body can effectively control the horizontal deformation of the wellbore and the displacement of the rock strata around the stope. When the filling body strength of the upper upward drift filling mining method and the deep shallow-hole shrinkage subsequent filling mining method is set as 2.0 MPa, it can not only effectively control the rock strata movement in the mining area and ensure the stability of the stope, but also take into account the economic cost and achieve the balance between safety and economy.

Aiming at the slope stability challenges of open-pit of Kisanfu Copper-Cobalt Mine (KFM Copper-Cobalt Mine), the slope instability mechanism was studied by multi-method integration and an optimized evaluation model was established to ensure the safe mining and economic benefits of the mine. Based on the engineering geological characteristics of the mining area such as structural development, rock mass strength characteristics and hydrological conditions, a theoretical correlation model linking rock compressive strength with rock mass strength parameters was constructed. Then the failure mechanisms of open-pit mine slope was analyzed, and the calculation method for the most dangerous composite slip surface was optimized by the limit equilibrium method of slope stability. Finally, two typical geological sections were selected as case studies, the deformation and failure process of stope slopes were analyzed by numerical simulation technology. The results are concluded as follows. Firstly, when the tectonic effect is significant, the slope is prone to sliding failure along the inclined rock layer, while when the influence of tectonic effect is small, the main failure is circular arc failure. Secondly, numerical simulation reveals that the upper part of the slope in the mining area is mainly characterized by settlement deformation (69.9 mm and 36.3 mm), the local free surface appears horizontal deformation, and the slope foot area shows strain concentration. Thirdly, the stability coefficient of the stope slope, obtained through both the limit equilibrium method and numerical simulation analysis is between 1.400 and 2.278, which meets the safety reserve requirement of slope 1.20. The research results can provide a scientific basis for slope design and disaster prevention at the KFM Copper-Cobalt Mine, and ensure the safety production demand of mine.

Aiming at the difficulty of quantitative calculation of qualitative evaluation index of blasting safety in open-pit mine, a blasting safety evaluation model of open-pit mine based on combination weighting and interval approximation method was proposed to improve the accuracy of the evaluation results. Firstly, combined with the actual blasting engineering, 15 influencing factors were selected to construct a safety evaluation indicator system of open-pit mine blasting. Secondly, based on the idea of combination weighting, the subjective and objective weights calculated by the order relation analysis method (G1 method) and the improved indicator correlation weight determination method (improved CRITIC method) were coupled to obtain the comprehensive weight of the indicators. Then, based on the principle of interval approximation, the number of evaluation intervals of the indicators was determined, and the blasting safety level was comprehensively judged by calculating the deviation distance of a single indicator and the comprehensive deviation distance. Finally, taking 5 open-pit mine blasting cases in Hunan Province as the research object, the combination weighting and interval approximation method model was applied for comprehensive analysis. The results indicate that the blasting safety level of all five mines are "relatively safe", and the evaluation results are in line with the actual situation, verifying the applicability of the model in the blasting safety evaluation of open-pit mines.

In order to improve the reliability of rock mass quality evaluation in deep mines and overcome the controversial problem of index weight assignment in traditional evaluation models, five influencing factors were selected, with the help of moment estimation theory, a reasonable descending sequence of index weight was obtained, and the partial order set was introduced into rock mass quality classification. A comprehensive evaluation model of rock mass quality in underground mines based on moment estimation theory-partial order set was proposed. The model was tested with 12 typical rock samples as sample data and compared with the results of traditional evaluation models. The results show that the evaluation results of the model are completely consistent with the evaluation results of the matter-element extension model and the unascertained measure theory, and are completely consistent with the ranking results of the VIKOR model, indicating that it can accurately realize the rock mass quality classification and has good applicability in the rock mass quality evaluation under complex geological conditions. Finally, the model was applied to the evaluation of rock mass quality of a copper mine in Anhui Province. It is determined that marble belong to class Ⅱ rock mass, serpentinite and diorite porphyrite belong to class Ⅲ rock mass, and skarn belongs to class Ⅳ rock mass, which is consistent with the field investigation. Based on the results of rock mass quality classification, the support optimization scheme is proposed, and the optimized support scheme can effectively control the deformation of roadway and ensure the long-term stability of roadway.

Rockburst intensity prediction is a critical task in mine safety management. To improve prediction accuracy and practical applicability, a rockburst intensity prediction model named NRBO-BPNN that combined the Newton-Raphson Based Optimizer (NRBO) with a BP Neural Network (BPNN) was proposed. By integrating a gradient-guided search mechanism based on the Newton-Raphson method, the model effectively overcomes the problem that the traditional BPNN is easy to fall into the local optimal solution during the training process, and significantly improves the global search ability and convergence efficiency. Experimental comparisons demonstrated that the NRBO-BPNN model achieved an accuracy of 100% on the training set and 86.67% on the testing set. The total accuracy rate is 96%, and only four misjudgments occur. It is superior to common models such as traditional BPNN, Support Vector Machine (SVM), Random Forest (RF) and Extreme Learning Machine (ELM). Finally, a comprehensive system for predicting rockburst intensity was developed based on the proposed model and successfully applied to on-site data analysis of Maluping Mine and Dongguashan Copper Mine, verifying its engineering applicability and practical value. The research results indicate that NRBO-BPNN can provide more efficient and accurate decision support for mining engineering safety design, and has significant potential for engineering promotion.

In order to study the meso-mechanical properties and instability mechanism of concrete-granite composite under uniaxial compression, based on the particle flow, the uniaxial compression numerical tests under the coupling of different joint shapes and joint dip angles were carried out. The evolution characteristics of strength, deformation parameters and micro-crack propagation law of the composite were compared and analyzed. The energy evolution damage characteristics were revealed, and the instability index of the composite considering the energy form was proposed. The results show that the elastic modulus of the composite specimen gradually decreases first and then increases sharply, showing a “U” shape change characteristic, and the peak stress shows a “V” shape change characteristic that decreases first and then increases. With the increase of joint dip angle, the failure modes of the composite are divided into three types: tensile shear failure, oblique tensile failure and splitting shear failure. When the joint dip angle of the composite is 90°, the damage parameter D changes fastest, the damage characteristics of the composite are the most obvious, and the stability is the worst. Under different joint shapes, when the joint dip angles are 0°, 30°and 45°, the damage characteristics of the triangular joint shape sample are the most obvious. The average instability values of concrete-granite composite specimen under different working conditions have the same variation law, which gradually decreases with the increase of joint dip angle. Only when the trapezoidal joint dip angle is 60°−90°, the average instability value of the composite specimen increases slightly. The larger the joint dip angle is, the more likely the composite specimen is to instability. With the increase of the joint dip angle, the average instability value S of the trapezoidal joint composite specimen increases significantly, which can be used as a sensitive index to determine its stability. The research results can provide reference for the safe construction of tunnel (roadway) engineering.

The structural plane of rock mass plays a key role in geological engineering, and its shear behavior has an important influence on the stability of rock mass and engineering safety. In order to deeply understand the shear behavior characteristics of rock mass structural plane, PFC2D was used to analyze the mechanical behavior of regular structural plane, asymmetric structural plane and irregular structural plane with different roughness under different normal stress conditions. The results show that the shear failure modes of the specimens can be divided into four types: the structural plane sliding along the sawtooth surface, the structural plane slides along the sawtooth surface and the sawtooth tip is cut off, the failure surface penetrates from the sawtooth bottom to the other side of the sawtooth, and the sawtooth bottom is completely cut off. With the increase of normal stress and undulating angle, the failure mode gradually changes from the structural plane sliding along the edge of the sawtooth force side to the sliding along the whole serrated surface, and finally evolves into the complete shear of the sawtooth bottom. The shear strength of the structural plane increases approximately linearly with the increase of normal stress and undulating angle. In the initial stage, the shear stress of the irregular structural plane increases approximately linearly with the increase of the shear displacement, and the normal stress has almost no correlation with the joint roughness.

Recognizing the geometric characteristics of pores and fractures distribution in coal rocks is essential for controlling the directional expansion of these features and improving the permeability of coal composite reservoirs. The evolution of pores and fractures geometry in coal rocks under cyclic temperature impacts was investigated. Cyclic temperature experiments were conducted at high temperature(200 ℃)and low temperature(－196 ℃)for 0, 1, 5, 10 and 15 times of temperature cycles. Anthracite and sandstone specimens were subjected to these cycles, and ultrasonic velocity measurements alongside industrial CT scanning were used to analyze changes in ultrasonic longitudinal wave velocity and the equivalent diameters, openings, and tilting angles of pores and fractures. The influence of temperature impact on the geometric distribution characteristics of pores and fractures was explained. The results are concluded as follows. (1) The largest decrease in longitudinal wave speed for anthracite occurs after the first temperature cycle, with a relative attenuation rate of 31.26%, while the largest decrease for sandstone occurs after the fifth cycle with a relative attenuation rate of 20.86%. The wave speed for both materials continued to decline with increasing cycles. (2) There is a linear correlation between the openness of coal rock pores and their equivalent diameters. Overall porosity increases logarithmically with the number of temperature cycles. Anthracite is more sensitive to temperature changes compared to sandstone during the cyclic impacts. (3) Porosity increases logarithmically with the number of temperature cycles, reaching a maximum of 93.31% for anthracite and 20.97% for sandstone after the 1st and 5th cycles, respectively. (4) The inclination range of primary fractures in anthracite is wide, whereas in sandstone, it is narrowly concentrated around 0°. With increasing cycles, the fracture inclination angle in anthracite decreases logarithmically, while in sandstone, it increases following an exponential decay pattern.

In order to reveal the hydrochemical characteristics and genesis of groundwater under different buried depths in Huibaoling Iron Mine area, and analyze the recharge source of deep fault water, a total of 37 groundwater samples were collected from the fissure water of the Liguan Formation-Tongjiazhuang Formation, the karst fissure water of the Erqingshan Formation, the metamorphic rock fissure water and the fault water. The characteristics and genesises of groundwater hydrochemical components and the recharge source of fault water in this area were discussed by statistical analysis, Piper three-line diagram, Gibbs diagram and ion combination ratio method. The results show that the TDS of groundwater in each layer increases significantly with the increase of buried depth, and the dominant anions and cations gradually evolves from and Ca²⁺ to , Cl^－ and Na⁺. Because the hydrochemical components of each groundwater show obvious zoning in Piper three-line diagram and Gissb diagram, it can be seen that the hydraulic connection between each aquifer is poor. The formation of hydrochemical components of Liguan water and Erqingshan water is mainly controlled by rock weathering, and the ion components are mainly derived from the dissolution of carbonate, sulfate minerals and salt rocks. Metamorphic rock water is controlled by evaporation and concentration. Na⁺ and K⁺ are derived from the dissolution of silicate minerals and the alternating adsorption of cations. Ca²⁺, Mg²⁺, and are mainly derived from the dissolution of carbonate and sulfate and the oxidation of pyrite. The fault water is affected by both rock weathering and evaporation and concentration, and its main recharge sources are Liguan water and Erqingshan water, the prevention and control measures of water disaster should be put forward with emphasis on this source. The research results can provide reference for mine water disaster prevention and control.

In order to accelerate the consolidation of tailings slurry, the influence mechanism of vacuum preloading method based on different drainage channels (sand drains and drainage boards) on the consolidation of bauxite slime was explored. The macroscopic characteristics were analyzed by vane shear tests and consolidation tests. Combined with nuclear magnetic resonance tests, the evolution law of microscopic pore characteristics was revealed. The results show that the moisture content of the slime decreases from 1 80% to 47.88%, the shear strength increases to 26.8 kPa, and the compression modulus reaches 15.5 MPa. The consolidation effect of sand drain is better than that of drainage board, which is mainly due to the fact that sand drain can continuously ensure the transmission of vacuum degree in the process of slime reinforcement. In addition, the pore water in the slime formed after consolidation of different drainage channels has the same distribution laws. The research results can provide theoretical support for accelerating the rapid settlement of tailings slurry.