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.

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.

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.

With the gradual increase of mining depth, the engineering geological conditions of deep broken surrounding rock mass become complex and changeable, greatly affecting underground projects' construction process and subsequent use period's safety. In order to ensure the safety and quality of deep broken soft rock roadway during the construction process, advanced roof control reinforcement and controlled blasting technology for soft rock roadway were put forward. In view of the characteristics of highly developed fissures and poor stability of rock mass at the No. 6 intersection of-550 m level in Zhongjiu iron mine, it was proposed to adopt advanced roof control measures to strengthen the surrounding rock mass of the roof and improve the bearing capacity of deep-buried broken soft rock roadway. In order to facilitate the excavation construction, 17 excavation areas were divided along the northeast side of the No. 6 intersection, and a four-step method was used for segmented construction. To realize the hole-by-hole shot and reduce the influence of blasting vibration, the detonation interval between two adjacent digital electronic detonators was randomly set to 3~5 ms. According to the overall lithology of different excavation areas, the support methods (pipe shed support, W-shaped steel belt, anchor cable support, etc.) were optimized to ensure the safety of the subsequent use of the No. 6 intersection. The test results show that the advanced roof control reinforcement and controlled partition blasting technology can reduce the roof deflection and subsidence of broken soft rock roadway, which ensures the forming effect of the No. 6 intersection section and reduces the cost of support and shotcrete by 8.7%.

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.

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.

To reduce the loss and dilution of ore in Husab Mine, a blasting movement monitoring (BMM) system was introduced and tested in three production blocks with 177 mm diameter drilling holes and a 7.5 m step height. During the field test, 6, 8, and 5 monitoring holes were arranged in each test block. Two displacement monitoring balls were placed in each monitoring hole at a 3.5 m and 9m depth to record the rock body's vertical and horizontal movement after blasting. The results show that the movement of the ore body due to blasting can be detected by BMM, and the average horizontal displacement of the upper ore body of the three test blocks is 6.55 m, 6.97 m, and 9.24 m, respectively. The average horizontal displacement of the lower ore body is 3.2 m, 3.9 m, and 4.0 m, respectively. The average vertical displacement of the upper ore body is 4.1 m, 2.0 m, and 3.2 m, respectively. The average vertical displacement of the bottom ore body is 0.72 m, 0.98 m, and 0.84 m, respectively. The ore body always moves in the direction with the least resistance during blasting. Whether horizontal or vertical displacement, the displacement of the upper ore body is always more significant than that of the lower ore body. In addition to changes in the boundaries between the ore and rock due to horizontal displacement, vertical displacement also has a significant influence on the loss and dilution of ore, and the bottom ore body may also move to the middle or the upper part of the ore body, and vice versa. The blast zone of open pit mines often consists of a variety of rocks, and both horizontal and vertical displacements of the ore body after completing the blast design based on geological information are the leading causes of ore grade reduction. Using the post-blast rock boundaries obtained from the BMM system monitoring to guide the excavation and transportation operations, the average ore dilution rate has been reduced by 1.2%. The average loss rate has been reduced by 1.5%, which can create more than 10 million RMB of economic benefits cumulatively over the entire life of the Husab Uranium Mine. This technology can accurately define the ore-rock boundary after blasts, which is an important technical means to reduce the ore dilution rate, ore loss rate and ore grade classification errors in open pit mines.

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.

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.

To control the height and recoil distance of a frame-shear wall structure after demolition by blasting, a frame-shear wall residential building demolition project in Qingdao was chosen as the subject. The simulation analysis used ANSYS/LS-DYNA software and the orthogonal combination of collapse angle and crotch extension time difference. Firstly, a finite element model of the original scheme was built, and the model's validity was checked by comparing the variance between the model prediction and actual outcomes. Then, the trends of the structure recoil distance and burst pile height with the change were analyzed by changing simply the model's inter-span extension time difference and cut height. Furthermore, the semi-quantitative formulas for the relationships between recoil distance and burst height with notch height and inter-span delay time difference were proposed based on the outcomes of multi-scenario numerical simulation, which were allowed for the determination of the inter-span delay time difference and notch height for the cases of minimum structural recoil distance and burst height, respectively. Finally, the analysis was carried out on the acceptable span-to-span extension time difference and the range of blasting notch heights for demolition blasting of frame-shear wall structures. The results show four fundamental steps to the collapse of frameshear wall structures: blast notch creation, destabilized overturning, notch closure, and landing collapse. The study's findings indicate that the recoil distance of each model primarily increases at first and then decreases as the interspan extension of the blast section is prolonged at the same cut height. Meanwhile, there is a more significant disparity in the structure's recoil distance as the deferred time difference is extended, and the recoil distance increases with the height of the blast cut at the same inter-span extension. Additionally, the height of the detonation pile roughly decreases as the time lag increases. The shear walls simultaneously improve the structural integrity and prevent the building from collapsing during the collapse, resulting in better structural integrity after collapse. The structure reduces recoil distance when employing a short incision height and a 200 ms extension time difference. The most minor burst heights of the structures are those with considerable notch heights and a 300 ms delay time difference. A crotch delay time difference of between 270 and 420 milliseconds is adequate. More importantly, a large blast cut can lower the pile's height, while a tiny blast cut can effectively regulate the recoil. It can be reasonably chosen based on the demands of the area around the structure that will be torn down. The study can provide a guide for determining the incision height and delay time difference for demolishing frame-shear wall structures by blasting.