The excavation of deep buried karst tunnel will cause special damage and failure forms of the surrounding rock mass, and the damage zone will also affect the seepage field of the surrounding rock mass and the water inflow condition of the tunnel boundary. To understand the impact of blasting excavation on surrounding rock damage and seepage, a numerical model was created using COMSOL Multiphysics software. The model included a stress-seepage-damage coupling equation for calculations. The stress distribution of surrounding rock during tunnel excavation was calculated using both analytical and numerical methods. The results showed that there was consistency between the two methods. Large tensile stress was observed near the shoulder and foot of the tunnel due to the blasting load. Additionally, a tooth-shaped damage zone was formed in the water-resisting rock mass after blasting, leading to increased infiltration velocity in the shoulder and foot area, which can aid in determining the direction of the cave. Furthermore, changes in cave spacing and diameter, as well as water pressure, can influence the “tooth” extension angle, maximum water inflow position, and water inflow at the tunnel boundary. By considering the extension direction of the “teeth”, a reasonable position for detecting the damage zone can be determined. Moreover, adjustments in water inflow prevention measures and key prevention and control areas can be made based on changes in the maximum water inflow position and water inflow on the tunnel boundary.

To solve the problem of the filling bodies failure on both sides of the room caused by differential blasting of large diameter deep holes in underground mine, the stress field generated by differential blasting should be studied to determine a reasonable edge hole spacing and a delay time between the holes. According to the stress wave propagation and attenuation law, the front and rear detonation hole distance, delay time, and edge hole distance generated by complex stress field were determined. Furthermore, the superposition of the stress wave generated by the two-hole differential blasting in the blasted rock mass and the filling body was analyzed according to the wave theory. The stress field function analytical formula of the two-hole differential blasting was obtained. Meanwhile, the collapse range of the blasted rock mass and the failure range of the filled body under different side hole spacing conditions under the same hole spacing and delay time were determined. The LS-DYNA numerical simulation software established six numerical models, and the stress critical points were selected in the blasted rock mass and filling body for analysis after simulating the initiation of explosives under different schemes. The simulation results show that different edge hole distances had almost no effect on the collapse range of the exposed rock mass when the distance between edge holes was more significant than the range of the crack zone. Appropriately increasing the distance between edge holes can effectively reduce the damage caused by stress waves to the filling body. Finally, the field industrial test of four groups of blasting parameters was carried out, and the optimized blasting parameters were determined as the spacing between the two holes on the same side was 2.0 m, the delay time between the front and rear initiation holes was 9 ms, and the side hole spacing was 1.8 m.

To investigate the impact of a radially uncoupled charge structure on energy transfer and blasting effects of explosives, with the goal of improving energy efficiency and enhancing rock crushing, dinitrodiazophenol was placed in a standard shale specimen with a diameter of 50 mm and a height of 100 mm. A blasting model experiment was conducted using four radial uncoupled charge coefficients-1, 1.5, 2 and 2.5. The strain waveforms in the axial direction of the specimen were analyzed using the ultra-dynamic strain testing system and the complementary set empirical mode decomposition method. The strain behavior of different sections of the specimen was studied, along with the damage fractal dimension and crack development in these sections. The analysis of the explosive energy propagation laws, combined with the strain curve, revealed that the tensile strain peak values were generally higher than the compressive strain peak values. The specimen eventually failed after experiencing significant and repeated tensile and compressive stresses. Importantly, when the radial uncoupling coefficient was 1.5, the energy utilization of the explosive was significantly improved, along with the prolonged action time of the detonating gas. Additionally, the damage fractal dimension of the specimen section with an uncoupled charge structure changed from top to bottom in an “n-type” manner, resulting in the most uniform damage distribution across each section, a fully expanded crack area, and the best blasting effect.

The matching relationship between explosives and rocks is crucial for improving the energy utilization efficiency of explosives, enhancing blasting effectiveness, and reducing costs. Firstly, this study analyzed the energy distribution during drilling and blasting operations. Then, the damage zone calculation model was revised considering the non-ideal detonation characteristics of explosives and the strain rate effect on rocks. And an on-site mixed explosives and rock matching model was then developed based on the control of energy transmission efficiency. Finally, field experiments were conducted to verify the rationality of the new explosive-rock matching method. The results show that the new method is more scientific and reasonable than traditional methods, and can intuitively reflect the blasting fragmentation effect and energy utilization efficiency, by taking account of the non-ideal detonation behavior of mixed explosives and the strain rate effects on rock damage partition. Blasting fragmentation tests under various explosive-rock matching conditions revealed discrepancies with the traditional wave impedance theory. By applying the new explosive-rock matching method, the percentage of fines was significantly reduced, and the boulder yield decreased from 6.7% to below 1%, further validating the method's effectiveness.

To study the continuous collapse resistance and dynamic response characteristics of the structure after the blasting failure of the local columns of the RC frame building, the deformation and stress adjustment process of the beam-column substructures adjacent to the columns were observed in real-time through an on-site blasting test of the central column of a blasting and demolition project of an 8-storey frame building. The PKPM was used to establish the corresponding building model. Meanwhile, the dynamic response characteristics of the remaining structure under the failure of the central column and the resistance to continuous collapse was calculated by the demolition component method and the demolition component method in SAP 2000. The results show that the theoretical value of strain after the blast failure of the center column is about 260 με using the strain-moment theoretical formula. The dynamic strain measured in the field is about 377 με, and the value calculated by the numerical simulation is about 238 με. The results of the dynamic strain by the three methods are relatively close. The computed value of the vertical displacement at the failure point is 3.2 mm, close to the field displacement of 2.67 mm, and the calculated value of the plastic angle is 0.051°, close to the field angle of 0.05°. The remaining structure experienced a significant dynamic impact at the instant of the central column failure, and the acceleration values along the positive and negative directions are roughly the same, with a maximum value of 3.5 m/s. After the failure of the central column, the load redistribution occurs in the remaining structure, and the vertical load originally borne by the central column is shared by the surrounding columns, resulting in a significant catenary effect on the upper beam body.

The high-pressure equation of state is the basis of studying the failure mechanism of materials and the propagation law of shock waves under explosion or impact loading. The state of rock has a wide range of applications in the numerical calculation of mining, meteorite impact cratering, rock impact protection, etc. Using a two-stage light gas gun and Photon Doppler Velocimeter (PDV), the Hugoniot relationship, high-pressure equation of state and volume strain equation of red sandstone were studied. The lowest and the highest impact pressure generated by the collision were 7.2 GPa and 19.4 GPa, respectively, and the lowest and the highest planar impact velocity were 0.88 km/s and 1.97 km/s, respectively. At the same time, optic probes were used to measure the shock wave velocity of rock samples. However, The Hugoniot-Elastic-Limit (HEL) point of the red sandstone was not found in the free surface velocity profile recorded by the PDV, indicating that the red sandstone was in a near-fluid state within this impact pressure range. Furthermore, the shock wave velocity D and particle velocity u were linearly fit by the least square method, and the Hugoniot parameters of the red sandstone were C₀=3.04 and λ=1.14, respectively. In addition, the relationship between the volumetric strain η and the impact pressure P were obtained by polynomial fitting, which was P=116η-745η²+1845η³, and the nonlinear fitting coefficient was 0.993. The Hugoniot equation of state and bulk strain equation of red sandstone obtained in this work can provide reference data for numerical calculation and engineering application in red sandstone rock blasting, shock protection engineering, and so on.

Field tests in a region of the plateau were carried out to study the “poly device+emulsion explosives” in tunnel surface blasting and to achieve the feasibility of peripheral hole air spacing charge and poly device on the explosives detonation distance. A seamless steel tube was used to simulate the tunnel peripheral hole for two or more sections of “emulsion explosives+poly device” detonation. A martyrdom test was implemented with#2 rock emulsion explosives. The maximum stable detonation and martyrdom distance were obtained through several groups of experiments. The test results show that the maximum stable detonation and martyrdom distance 15 cm length of polymerized explosives and#2 rock emulsion explosives are respectively 230 cm and 115 cm in the seamless steel tube. The maximum stable detonation distance of multi-section polymerized explosives can reach 80 cm. Due to the radial constraints on the detonation wave of the polymerization device, the front end of the conical metal drug mask explosion formed by the polymerization of energy jets significantly increases the axial and upward shockwave energy, which makes it possible to increase the energy of the shockwave. The emulsion explosives in seamless steel pipe detonation distance increased significantly upward shock wave energy, which can be applied to the tunnel perimeter hole, replacing the detonating cord to achieve air spacing charge and enhance the effect of surface blasting, cost savings, and time savings.

Efficient coordination between different processes is crucial in optimizing resource allocation and minimizing energy consumption during blasting operations in open-pit mines. To address these challenges, the theory of blasting sharing control is proposed, which integrates macroscopic ore fragmentation with mesoscopic damage analysis and introduces a novel ore damage model for the shoveling process. By optimizing inter-process connections and considering factors such as wear and depreciation, a comprehensive energy distribution model is developed across drilling, crushing, blasting, shoveling, and transportation processes. Evaluation and control indices are proposed for each process, leading to the establishment of a blasting sharing control model. The results demonstrate that the ore damage model reveals the multi-phase characteristics of rock blasting failure and effectively predicts the crushing energy consumption by regulating fragmentation levels. With a fitting accuracy exceeding 0.8, this model optimizes the crusher operations while reducing energy consumption. Using the blasting sharing control model enables calculation of the optimal solutions for blast parameter design while establishing an optimal comprehensive energy consumption formula under the constraint conditions, thus enabling the accurate adjustment of energy at each link and providing strong support for efficient, safe, and sustainable mine operations.

As tunnels are integral to railways and other transport infrastructures, studying the vibration response and attenuation rule of tunnel blasting for tunnel construction projects is significant. The blasting solutions proposed in this paper are to minimize clear distance in the blasting excavation of a high-speed railway tunnel for the Chongqing-Kunming high-speed railway construction project. A new excavation method was developed to divide the excavation section into alternating blasting on both the left and right sides. Besides, the blasting vibration velocity of the double-line tunnel was monitored. The vibration velocity analysis of the advance tunnel shows that the maximum vibration velocity in the tunnel is mainly caused by cutting hole and vault auxiliary hole blasting, and the radial vibration velocity is the maximum. The vibration velocity of the arch waist of the explosion side wall is 1.3 to 2 times bigger than that of the arch foot on the cross-section, and the ratio caused by the initiation of the cutting hole is relatively small. Meanwhile, the vibration velocity of each point in front of the tunnel face is more significant than that at the relative position behind the vertical section. In contrast, the attenuation rate of the vibration velocity behind is relatively more significant. The research findings have been successfully applied to the engineering practice, and a relevant small clear distance tunnel has been safely connected.

Porous sandwich structures are widely used in anti-explosion due to their excellent specific strength and stiffness. However, current explosion research mainly focuses on the failure mechanism of sandwich structures under small equivalent explosion loading. In contrast, the research on energy absorption characteristics of porous sandwich structures under actual large equivalent loading is rarely reported. To better guide the engineering application, ten kinds of sandwich structures with three kinds of sandwich materials (foam aluminum and honeycomb aluminum with 3 mm×10 mm side length) under different sandwich configurations (single-layer and two-layer sandwiches) and different thicknesses of face sheet/middle sheet/rear sheet were designed. The explosion tests with 0.5 kg TNT and 1 kg TNT equivalent explosion loading were respectively carried out on the above sandwich structures, and the overall deformation characteristics of the sandwich structures were analyzed. The effects of sandwich materials, sandwich configurations and other factors on energy absorption were discussed. Results show that both the foam sandwich structure and honeycomb sandwich structure could absorb energy through the large compression deformation of core material under explosion loading, while the deformation uniformity of the honeycomb structures is better. Furthermore, the energy absorption efficiency of the core is both related to its specific compressive strength and strength/stiffness of the face sheet/rear sheet. It is quite necessary to optimize those parameters to ensure that the core material can obtain a maximum compression and give full play to its energy absorption advantage. It is also found that the double-layer sandwich structure is superior to the single-layer sandwich structure on energy absorption and protection performance, which is an effective way to improve the overall energy absorption of the structure.