The accurate and reliable classification of rock mass is the basis of a reasonable engineering design. In the Xishan mining region of Sanshandao Gold Mine, three conventional rock mass classification methods of Tunneling Quality Index (Q), Rock Mass Rating (RMR) and China National Standard-basic quality (BQ), were compared in the burial depth area above 780 m, and it was discovered that the classification results of different rock mass classification methods had a low coincidence rate in the deep area; Therefore, this paper adopted entropy weight method, TOPSIS method and grey correlation analysis method to calculate the entropy weight and relative closeness of different methods in different middle sections. The study’s findings revealed that in the deep area, the relative closeness between each classification mass was: RMR > Q > BQ; Based on the above results, the IRMR method with modified RMR was selected for comprehensive analysis, and the concept of importance degree of evaluation index was defined; it was found that the importance degree of evaluation index of in-situ stress loss was the highest, while the importance degree of joint direction was the lowest; The “ETG” rock mass classification method based on “site-specific” is established, which provides a reference for the establishment of deep rock mass classification method.

Sporosarcina Pasteurii was chosen for the experiment to study the effect and mechanism of fine‐grained uranium tailings reinforced by MICP. The biochemical characteristics of strains and microbial immobilization in uranium tailings were analyzed. The results showed that the CaCO₃ production rate is positively correlated with the physiological activity of Sporosarcina Pasteurii and the concentration of calcium sources, and the higher the solution concentration of CaCl₂, the lower the discharge rate of bacterial liquid from the sand column, but high concentration of CaCl₂ solution will affect the uniform distribution and migration of bacteria in the uranium tailings. After 16 days, the direct shear was used to test the reinforcement effects of fine‐grained uranium tailings by MICP. The cohesive force and the internal friction angle of fine‐grained uranium tailings were increased by 140.1% and 46.7%. The production amount of CaCO₃ is 138.89 kg/m³. The results showed that the MICP‐reinforced technology can effectively improve the shear strength of the uranium tailings, and the experiment provides a new method for the reinforcement of the fine‐grained uranium tailings dam.

Deep surrounding rocks are highly statically stressed before mining (excavating) and will inevitably experience disturbances from unloading, mining, stress adjustment or their combinations during mechanical or blasting excavation, which actually suffer from a typical coupled static-dynamic stress. A split Hopkinson pressure bar was used to carry out dynamic-static loading test on rock specimens with different fracture angles. The results show that the change law of energy utilization efficiency is similar to the energy absorption rate that they increase first and then decrease with the increasing of axial pressure. The elastic energy of specimens would also increase first and then decrease with the increasing of axial pressure, while the plastic energy generally decrease overall. Both the energy utilization efficiency and energy absorption rate increase with the growth of dynamic compressive strength under impact loading, which indicate that the energy dissipation exhibits a positive with the dynamic strength. The energy absorption density and energy utilization efficiency gradually increase linearly with the increasing of the average strain rate, while the relationship between energy utilization efficiency and incident energy basically follows the exponential function increasing law. The rock burst of pre-flawed rock is related to the static load level under dynamic-static loading, it occurs obviously under the action of medium energy when the axial pressure is high. Based on the energy dissipation theory, the damage variable model was further established, the damage variable can reasonably describe the damage evolution of crack granite under dynamic-static loading.

Different fractures exist widely in rock mass and play a significant role in their deformation and strength properties. Crack rocks are often subjected to dynamic disturbances, which exist in many fields of geotechnical engineering practices. In this study, dynamic compression tests were carried out on rock specimens with parallel cracks using a split hopkinson pressure bar apparatus. Tests determined the effects of strain rate and crack intensity on dynamic responses, including progressive failure behavior, rock fragmentation characteristics, and energy dissipation. Based on the crack classification method, tensile–shear mixed cracking dominates the failure of rock specimens under the action of impact loading. Increasing the flaw inclination angle from 0°–90° changes the predominant cracking mechanism from tensile cracking to mixed tensile–shear cracking. The larger the loading rate, the more obvious the cracking mechanism, which indicates that the loading rate can promote the cracking failure of rock specimens. The fragmentation analysis shows that rock samples are significantly broken at higher loading rates, and higher loading rates lead to smaller average fragment sizes; therefore, the larger the fractal dimension is, the more uniform the broken fragments of smaller sizes are. Energy utilization efficiency decreases while energy dissipation density increases with increasing strain rate. For a given loading rate, the energy absorption density and energy utilization efficiency first decrease and then increase with increasing flaw inclination, while the rockburst tendency of rock decreases initially and then increases. We also find that the elastic–plastic strain energy density increases linearly with the total input energy density, confirming that the linear energy property of granite has not been altered by the loading rate. According to this inherent property, the peak elastic strain energy of the crack specimen can be calculated accurately. On this basis, the rockburst proneness of granite can be determined quantitatively using the residual elastic energy index, and the result is consistent with the intensity of actual rockburst for the specimens.

Microbial-induced calcium carbonate precipitation (MICP) technology is a new green reinforcing technology in soil stabilization. Targeting on the problem that seepage is the main factor of causing the instability of a tailings dam, a comparative experiment is conducted, which includes the MICP technology on reinforcing tailings with or without the effect of a seepage field. The results of the comparative experiment are as follow: the mercury penetration test indicates that, under the function of a seepage field, the total pore in the tailing is relatively decreased; SEM shows that under the function of a seepage field, the intergranular pore increases; the direct shear test shows that under the function of a seepage field, the tailings’ shear strength decreases; the determination of calcium ion content shows that the distribution of calcium carbonate in the tailings under the action of a seepage field is more uneven.