To study the influence of rock fracture characteristics with different inclination angles, the notched semi-disk bending (NSCB) specimens were prepared based on the 3D printing technology for experiments on typeI static fracture characteristics of rock mass. Specifically, the straight-cut groove half-disc bending specimens (NSCB) with crack angles were prepared by 3D printing technology to investigate the influence of different pre-fabricated crack angles on rock fracture characteristics. Furthermore, the printed specimens were placed in dry ice and subjected to quasi-static three-point bending tests when their surface temperature reached-30℃ after the solidification and baking treatments. The experiment revealed the influence of pre-fabricated crack angles on fracture toughness, initiation angle, and fracture energy. The results show that the average fracture toughness of NSCB specimens containing fissures is smaller than that of standard NSCB specimens. The fracture toughness of specimens is positively correlated with the fissure inclination angle. For NSCB specimens containing fissures, the initiation angle increases with the increase of the fissure inclination angle when β is between 0° and 90°, and the crack propagation path shows a distinct ‘deflection’ phenomenon. The fissure inclination angle significantly impacts the complexity of the NSCB specimen propagation path. The crack propagation path becomes more complex when the fissure inclination angle and fractal dimension increase. From the perspective of fracture energy, the fracture energy increases with the increase of the fissure inclination angle.

To address the instability problem of shallow-buried tunnel with unsymmetrical pressure under blasting, the potential energy equation of surrounding rock was derived by considering both blasting damage and water weakening effect. Using the cusp catastrophe theory and its calculation method, a catastrophe instability criterion of surrounding rock mass in a shallow-buried tunnel with unsymmetrical pressure under blasting was established. Then, the effects of water weakening, blasting damage and unsymmetrical pressure on the instability of the surrounding rock mass were discussed. Taking Dayangan tunnel in the national high-speed G5615 (Tianbao-Malipo section) as an example, a catastrophe criterion k of surrounding rock mass under different working conditions was calculated according to the physical and mechanical parameters of surrounding rock and the results of the field acoustic wave test. Meanwhile, a shallow-buried tunnel's surrounding rock stability state with unsymmetrical pressure was determined. The results show that the necessary condition for abrupt instability in shallow-buried tunnels with biased pressure under blasting is the abrupt failure criterion k<1, indicating a potential state of abrupt instability. The degree of bias pressure is the critical internal factor affecting tunnel instability surrounding rock mass. Additionally, the greater the degree of bias pressure, the more prone the tunnel is to sudden instability. The practical evaluation results are consistent with the field observations, verifying the practicability and validity of the criterion.

Since the problems of significant rock clamping effect and ore depletion were caused by deep hole blasting in steeply inclined thin veins, a combination of on-site investigation, PMMA (organic glass) blasting model experiment and numerical simulation was used to explore the mechanism and a quantitative characterization method of rock clamping effect by taking a gold mine in Gansu Province as the engineering background. Firstly, to analyze the distribution pattern of blasting cracks under different mining conditions of thin ore veins, a PMMA blasting model experiment was conducted. The results show that reducing the mining width of the thin ore veins reduces the radius of blasting crushing and fracture areas around the blast hole and suppresses the development of blasting cracks. Furthermore, different blasting conditions of thin ore vein mining were simulated. The results show that as the mining width of thin ore veins decreases, the blasting energy reflected and superimposed at the blasting-free surface decreases, and the volume of blasting rock decreases accordingly. Meanwhile, more blasting energy is dissipated as kinetic energy, which could not be effectively used to break the rock. Finally, a quantitative characterization method for the clamping coefficient of thin ore vein blasting was proposed based on the analysis of blasting energy. A clamping coefficient was defined by the ratio of the total energy peak at the center point of the blasting free surface under semi-infinite and narrow amplitude working conditions, and this index characterized the size of the clamping effect. As a result, a prediction model for the blasting clamping coefficient was established through the mining width and rock mechanics parameters. The study of this paper can provide a theoretical basis and technical support for the optimization design of deep hole blasting parameters in steeply inclined thin ore veins.

There are hundreds of blast holes in a tunnel blasting. Since the traditional manual drawing of the blasting scheme is laborious and depends on the experience of blasting engineering, a digital method for the planar and three-dimensional spatial distribution of blast holes was proposed based on formula derivation to study an intelligent design method for tunnel blasting blast holes. Subsequently, the programming of blast hole parameters was achieved by utilizing computer programming techniques, which can lead to the development of an intelligent blast hole design system. The results show that the parametric expression method of tunnel contour, cut holes, peripheral holes and auxiliary holes can realize their rapid creation and meet the needs of tunnel blasting. By establishing a correlation between the coordinates of the blast hole opening and bottom, a refined expression of the spatial distribution of the blast hole can be realized, and intuitive guidance for on-site drilling operations can be provided. Furthermore, a computer programming method can realize an intelligent and fine design of a blast hole layout. After tunnel blasting, the residual marks of the blast holes are complete, the contour of the tunnel excavation is smooth, and the overall excavation effect is good. The research results can improve the efficiency and intelligence of tunnel blast hole design.

To explore the attenuation law of blasting stress waves in concrete under different charging structures, the strain values at different positions of the experimental models were tested by a 16-channel dynamic strain gauge based on similarity theory. Meanwhile, the attenuation law of axial and radial blast stress waves in concrete under different charge structures was obtained by calculating the peak stress. The results show that the blasting stress wave exhibits a power exponential decay as the distance between the blasting centers increases. The initial pressure and maximum pressure on the borehole wall of the coupled charge structure are the highest, and the detonation wave acts on the medium for a short time. The uncoupled charge structure reduces the initial pressure on the borehole wall and prolongs the time of detonation pressure action. The coupled charging structure consumes much energy in the crushing zone, and the energy transfer is uneven. The stress wave attenuation of the uncoupled charging structure during blasting is slow, and the energy transfer is uniform.

Numerical simulation is a vital tool for studying the dynamic characteristics of rock, with the accurate determination of models and parameters being the key to ensuring the reliability of simulation results. Among the 34 parameters of the RHT model, 19 parameters can be obtained through experimental and theoretical calculations, but the remaining 15 are challenging to determine. Nineteen basic parameters of anhydrite were obtained through experimental analysis and theoretical calculation to identify the model parameters suitable for anhydrite. Furthermore, the LS-DYNA performed SHPB simulation tests on the 15 challenging parameters. The sensitivity of stress-strain curves to these parameters was compared, and the values were optimized. Parameters with high sensitivity were identified through orthogonal testing. Finally, simulation results were compared with laboratory test results. The findings indicate that RHT parameters B, , n, D₁, n_f, P_comp and N have minimal impact on the stress strain curve, while parameters A, , , Q₀, , ξ, and A_f significantly influence the curve. Furthermore, the parameters with a significant impact on the stress-strain curve were determined by orthogonal tests, and the RHT model parameters fitting the SHPB impact test curve were obtained. Under varying loading strain rates, the dynamic stress-strain curves and failure patterns of anhydrite simulation tests were consistent with laboratory tests, verifying the suitability of the model parameters for anhydrite.

Researching controlled blasting technology for hazardous rock bodies in complex environments holds significant theoretical importance and provides valuable reference points for enhancing highway construction efficiency and mitigating potential risks. This study focuses on the Gulin-Jinsha highway construction project, aiming to eliminate the dangers posed by hazardous rock bodies during construction. Six scanning stations were established using 3D laser scanning technology to create a high-precision 3D Digital Terrain Model (DTM) of the hazardous rock bodies. Additionally, four object detection lines were deployed using a high-density electrical method to achieve 3D visualization of the geological features in the hazardous rock area. A fracturing test was conducted based on the high-precision 3D model. The designed depth of the shell hole was 70% of the height of the hazardous rock body, with fracturing pipes connected in series and each pipe carrying a total charge of 720 g. The results demonstrated that the constructed high-precision 3D model accurately reflects the morphological characteristics of the hazardous rock body, providing reliable information for the blasting design. The fracturing pipes showed effective fracturing performance, facilitating the removal of the hazardous rock body during subsequent stages. This method offers a viable reference for similar projects, showcasing the potential for efficient and safe removal of hazardous rock bodies in complex environments.

With the continuous development of blasting equipment, the popularization of high-precision detonator detonators and electronic detonators have been widely used in open-pit bench blasting. However, the definition is vague in the selection of the maximum amount of initiating charge and the distance from the detonation source to the vibration measurement point for the linear regression analysis of the Sadovsky formula when the vibration measurement point is close to the blasting area, and the dispersion position of the blast hole cannot be ignored. A proportional distance was used to measure close-range blasting vibrations by hole blasting. The total charge with a delay interval smaller than 8 ms or the charge quantity nearest to the vibration measurement point was selected as the maximum blasting charge in a section. The distance between the detonation source and the vibration measurement point was selected as the three-dimensional distance between the center of the hole range of the maximum blasting charge and the vibration measurement point or the three-dimensional distance between the hole and the nearest vibration measurement point. The one with a smaller proportional distance was selected for linear regression by comparing the group proportional and single proportional distances. The results show that it has relatively accurate linear regression using this method for the same direction or near the direction of the vibration point value after the noise reduction process.

For large cross-section tunnel blasting, the rock mass in the middle of the tunnel face often experiences the phenomenon of “bulging” due to the unreasonable arrangement of the cutting holes. In order to eliminate the “bulge belly” phenomenon in large cross-section tunnel blasting, a new method of “wedge cut+high-energy hole” blast hole layout was proposed. Taking the Gonghe Village Tunnel of the Luqiao Expressway in Yunnan Province as the engineering background, a numerical model of “wedge-shaped cut+high-energy hole” was established using finite element software LS-DYNA. The effective stress at the bottom of the blast hole and dynamic damage of the rock mass were studied and compared with the on-site tunnel cut blasting plan. At the same time, the proposed new method was verified through on-site blasting experiments. The research results indicate that the “wedge cut+high-energy hole” blasting hole layout method can effectively eliminate the “bulge” phenomenon, reduce the number of cut holes and digital electronic detonators, and determine the rationality and applicability of this method. Besides, the stress values generated by measuring points 1, 2, and 3 at the bottom of the main cutting hole are relatively small. As the stress sharply rises to 454.9 MPa, the middle-retained rock mass can be effectively broken after the main cutting hole blasted with the high-energy hole explodes. Using the improved blasting method, the excavation efficiency increased by 16.9%, the average utilization rate of blast holes reached 91.5%, and the explosive consumption reduced by 19.7%. The proposed layout method of “wedge-shaped cutting+high-energy holes” for large cross-section tunnels can not only ensure construction safety, but also achieve the effect of reducing costs and improving construction efficiency.

Rock's mechanical parameters and fragmentation characteristics significantly change under the freezing and thawing environment in high-altitude cold regions, and it is difficult to directly apply traditional blasting parameters for excavation. Therefore, researching blasting design parameters in freeze-thaw environments is of great importance. This study analyzed the impact of freeze-thaw cycles on rock mechanical properties and conducted the crater experiments of single-hole and double-hole simultaneous blasts in ore rocks under freeze-thaw conditions based on Jurong Copper mine. Futhermore, the geometric parameters and block size distribution of the crater were measured after blasting, and the reasonable parameters for blasting design were determined using the mathematical fitting methods. Additionally, the changes in the blasting crater parameters of the mine were also compared and analyzed under four different rock conditions. The results show that the mechanical properties of rock mass significantly deteriorate with a decrease in uniaxial compressive strength and elastic modulus of up to 40.6% and 54.0% under freeze-thaw cycles, respectively. The optimal burial depth ratio for single-hole blasting of freeze-thaw ore rocks is 0.678~0.789 under different lithological conditions, and the ratio of the optimal charge burial depth to crater radius is distributed in the range of 0.875~1.076. For Chibula mining area, the hole diameter is 152 mm, the diorite hole net parameter is 4.5 m×3 m, the corresponding explosives consumption is 0.56 kg/m³, and the tuff hole net parameter is 5 m×4 m with a 0.63 kg/m³ explosives consumption. For Jurong mining area, the hole diameter is 310 mm, the tuff blasting hole net parameter and explosive consumption is respectively 7 m×5 m and 0.61 kg/m³, and the granite porphyry hole net parameter and explosive consumption is respectively 8 m×5 m and 0.64 kg/m³.