Abstract: This study aims to address the challenge of rapid tunnel excavation without the use of explosive. A new oxygen expansion rock breaking technology suitable for general tunnel excavation such as cutting, expanding, auxiliary and peripheral holes is explored, researched, and summarized. The drilling and blasting parameters optimized for tunnel excavation are also provided in detail. The experimental study section consists of granite with a compressive strength ranging from 90 to 100 MPa, developed cleavage cracks, and average blastability. Through field tests and continuous improvement, an average cycle footage of 2.5 m per two-day cycle is achieved for a tunnel area of approximately 65 m², meeting the requirements for rapid excavation when explosives cannot be used. The research demonstrates that the new gas expansion rock-breaking technology can effectively excavate tunnels in hard rock masses. It offers advantages such as safe operation, high efficiency in rock breaking, no involvement with civil explosives or dangerous chemicals used in explosive production, absence of explosion shock waves and low vibration amplitude. This technology provides a solution to situations where civil explosives are prohibited due to complex environmental conditions or slow progress using mechanical methods.

Feed and its additive dusts have a high combustion heat, which poses significant risks of dust explosions during production, thereby threatening life and property safety. Currently, premix inhibitors are widely used as explosion suppression measures. However, traditional inhibitors are inedible and cannot be added to feed dust to achieve explosion suppression. Therefore, this study focuses on the dust of DL-methionine (DLM), a primary additive in feed, and investigates the effect of self-synthesized phytic acid-cytosine (PA-CY), an edible biomass-based compound with nutritional value and environmental friendliness, on the flame propagation characteristics of DLM dust explosions. The flame propagation process was recorded through high-speed photography and visualized in a vertical pipe while calculating the flame velocity. Additionally, thermocouples were used to monitor changes in flame temperature. The results indicate that as the mass fraction of PA-CY increases, the luminosity of DLM dust explosion flames consistently decreases, severely disrupting the flame structure. After adding 20% PA-CY, there is a reduction of 50.0%, 52.2%, and 46.7% in peak velocity (from 27.66 m/s to 13.83 m/s), average velocity (from 14.39 m/s to 6.88 m/s), and peak temperature (from 1014℃ to 540℃) respectively. Moreover, when the mass fraction of PA-CY reaches 30%, ignition of the dust cannot occur indicating significant inhibitory effects provided by PA-CY.

To study the explosion equivalent of DT-3 and its influencing factors caused by fire stimulus during storage, transportation and use, the propagate detonation ability of that was studied by the extremely insensitive to detonating substances (EIDS) gap test. High-speed cameras and a shock wave pressure acquisition system were utilized to obtain information on the deflagration processes and shock wave hazards of DT-3 under external flame effect. Additionally, an infrared thermal imager was employed to determine the highest temperature of the surface fireball. Further calculations were conducted to determine the explosive TNT equivalent of 18 kg and 120 kg DT-3 samples. The experimental results indicate that direct exposure to a strong shockwave does not cause DT-3 propagation detonation. However, different packing strengths can lead to deflagration events under external fire conditions, potentially resulting in an overall detonation reaction. The average TNT equivalents for standard packaged 18 kg and 120 kg DT-3 samples were found to be 0.629 and 0.0293 respectively. Furthermore, there is no positive correlation between the scale effect and shock wave impact. Under fire stimulus conditions, package design strength significantly influences the explosive characteristics of DT-3. To enhance safety measures, it is recommended that package design strength be reduced within acceptable limits for actual usage in order to effectively mitigate the risk of detonation hazard.

Aiming at the problem of reasonable spacing-burden ratio in wide hole spacing blasting technology, laboratory blasting experiments of PMMA plates with the spacing-burden ratios of 1.7, 2.5, 3.5 and 4.5 were carried out based on related rock fragmentation mechanism at home and abroad. Meanwhile, a blasting calculation module was developed to study the crack propagation process and the response law of displacement based on the principle of near-field dynamics of conventional modes. The results show that the radial cracks present the character of branching to the corner of the free face and finally form the main cracks of a funnel shape, affected by the reflected tensile stress wave. Under the condition of fixed minimum resistance line, the stress reduction area gradually increases with the increase of the spacing-burden ratio, and the radial cutthrough cracks between the blastholes in the same row disappeared. An excessive spacing-burden ratio will further cause the disappearance of the cutthrough cracks between two rows of holes, and finally lead to the occurrence of individual hole blasting. The displacement results further confirm the above rule, and the rock ridge left by the front row of holes is just broken by the rear row of holes when the spacing-burden ratio is small. This breaking effect gradually decreases with the increase of the spacing-burden ratio. It is suggested that the spacing-burden ratio should be appropriately adjusted according to the mechanical properties of rock mass, geological conditions and blasting purposes to reduce explosive consumption and boulder yield in practical projects.

Structural plane is one of the key factors controlling the local stability of rock mass engineering. It is a prerequisite for rock mass stability analysis to find out the occurrence and combination of structural planes. Geological survey is often used at present. However, a high-cost supplementary survey is often needed when there are omissions due to the limitation of this survey means. Therefore, the surface vibration response law of the structural plane model was studied by laboratory tests. The study shows that the amplitude of the particle in front of the structural plane increases for the single structural plane model. For a block model cut by two structural planes, the amplitude-amplification effect exists only in front of the structural plane far from the power input side. Furthermore, the rock mass models with different structural plane dip angles were simulated respectively. The results show that, when the angle θ between the structural plane and the ground in the direction of the explosion source is less than 90°, the particle amplitude in the incident area of the vibration wave in front of the structural plane has an obvious amplification effect, and the particle amplitude behind the structural plane significantly attenuates. With the decrease of the angle θ between the structural plane and the boundary plane, the increase rate of the peak vibration velocity of the particle in front of the structural plane gradually increases, and the amplitude of the wave amplifies 2.8 times when θ=20°.

The seismic wave signal acquisition will result in the mixed noise in the measured signal due to the monitoring environment, test system and other factors, and the existence of noise will lead to the distortion of the time-frequency analysis results of the signal Hilbert-Huang Transform. There are two reasons. One is that the empirical mode decomposition (EMD) algorithm will obtain the intrinsic mode function (IMF) component with modal confusion phenomenon when processing the blasting seismic wave signal containing noise; The other reason is that because the Hilbert transform is constrained by the Bedrosian theorem, which will produce negative instantaneous frequencies when dealing with modal confusion components. These lead to huge analytical errors. In order to obtain real blasting vibration properties, HHT should be improved. Complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) can be obtained by adding adaptive noise signal to EMD. Then normalized Hilbert transform is performed on the IMF obtained by CEEMDAN, and an improved normalized Hilbert transform (INHT) is obtained. Through the above two steps, the CEEMDAN-INHT time-frequency analysis algorithm can be established. In order to verify that the algorithm can effectively improve the time-frequency analysis accuracy of the noise-containing blasting seismic wave vibration signal, a comparative study on the time-frequency analysis of the HHT and CEEMDAN-INHT noise-containing simulated vibration signals is carried out. Finally, CEEMDAN-INHT is used in the time-frequency analysis of blasting seismic wave signals in an underground cavern, and it is found that the algorithm can effectively overcome the inherent mode confusion of EMD, and at the same time obtain the time-frequency-energy characteristic parameters reflecting the real blasting vibration attributes. It is of practical significance to carry out resonance analysis of blasting excavation in caverns from the perspective of frequency and energy, and to realize blasting seismic wave hazard control.

In order to explore the blast-induced crack propagation behavior in rock mass with two vertical prefabricated defects, a series of blasting experiments of models with double vertical cracks were carried out based on digital laser caustics. The evolution process of blast-induced crack is shown and the effect of single-hole charge on the crack propagation behavior (crack propagation length, stress intensity factor, propagation velocity, and initiation time, et al) in rock mass with defects was explored. The results show that the crack propagation length, propagation velocity, crack initiation toughness and stress intensity factor at the end of the double vertical cracks increase with the increase of single-hole charge. For crack J_u, the effect of single-hole charge on crack propagation velocity is small, and the limit velocity of crack propagation is about 0.38 times of the shear wave velocity. For cracks D_l and D_r, the initiation time decreases, but the peak stress intensity factor increases with the increase of single hole charge. Besides, the stress intensity factor and propagation length of crack D_r increases significantly compared with crack D_l. The crack D_l starts to crack earlier than the crack D_r when the energy of the blasting stress wave acting on both ends of defect B is enough to cause the crack to propagate on both sides. The increase of charge in a single hole can increase the propagation velocity of crack D_r, but has little effect on the propagation velocity of crack D_l.

The distribution characteristics of blasting pile is an important index indicator to evaluate blasting effect. In view of the inadequacy of the current direct and indirect methods of measuring fragment size of the blast pile, a spatial distribution measurement method for adaptive stratification of the blast pile is proposed. It uses the GA-LSSVM model to predict the shape parameters α and β of the Weibull function and sets multiple prediction points to predict the three-dimensional blasting pile morphology. By converting and fusing the parameters of the Kuz-Ram fragment prediction model, a distance prediction model of blast pile stratification is established and applied to the Weibull-GA-LSSVM model to achieve an automatic stratification of the blast pile. Through field application, the stratification design is continuously optimized for the best stratification position to realize the adaptive stratification. The results show that: (1) the Weibull-GA-LSSVM model can accurately predict the morphology of the blast pile with a good stability that the average relative error of the prediction results of the maximum forward distance of the blast pile is only 5.6% and the relative error of the prediction results of the looseness coefficient is mostly around 9%. (2) The Kuz-Ram-based blast pile stratification model can reasonably output the layer distance and number before blast, which ensures the shoveling efficiency after blast. (3) The optimal layer distance formula is derived to achieve the adaptive stratification of the blast pile, and the measurement accuracy of the fragment size distribution of the blast pile is significantly improved, which is closer to the overall fragment size distribution.

The primary support is the main load-bearing structure in the tunnel construction stage, the response rule and safety control of the primary support under dynamic disturbance are of great significance to ensure the safe and rapid construction. Figuring out the dynamic response characteristics and the safety control of the primary support is an important issue for the blasting excavation of a soft rock tunnel with reserved core soil. A three-dimensional finite-element numerical model was established by ANSYS/LSDYNA for the Linchang tunnel blasting excavation, and the reliability of the numerical model was verified by the field vibration monitoring data. The stress distribution characteristics of the primary tunnel support under the simultaneous action of two blast sources was studied combined with the construction characters of the reserved core soil method. The attenuation law of blasting vibration was obtained by using Sadovsky empirical formula. The safety criterion of blasting vibration velocity for the primary tunnel support under the simultaneous blasting excavation of both sides of the lower bench was proposed by taking stress as the control standard. The results show that the maximum vibration velocity appears at the arch foot of the primary support rather than at the tunnel floor or vault, which is different from the full section method and bench blasting method. Meanwhile, the propagation path of the blasting stress wave is dramatically affected at the un-backfilled area of the tunnel invert. The vibration velocity of the primary tunnel support is larger and attenuates faster on the left arch foot versus right arch foot. The maximum tensile stress and shear stress appear on the left arch foot of the tunnel under simultaneous blasting with 7.544 MPa and 2.78 MPa, respectively, which exceed the allowable value of the specification. According to the established linear stress-vibration velocity relationship, a blasting vibration safety criterion of primary tunnel support is proposed based on the ultimate strength. In addition, the safety vibration velocity threshold of the primary support in Linchang tunnel is 10 cm/s.

In open-pit bench blasting, blasting TBlasting toe rocks is an important indicator to measure the blasting effect in open-pit bench blasting, and it is most directly influenced by the blasting parameters have the most direct influence on the formation of blasting toes. In order to find outresearch the influence of ultra-deepsubdrilling on the smoothness flatness of bench in deep-hole bench blasting, statistical analysis of the relationship between damage variables and wave velocity in rock mass was conducted based on the basic theories of rock damage mechanics. based on the basic theories of rock damage mechanics and through statistical analysis of the relationship between damage variables in engineering and wave velocity in rocks, Tthe threshold values of damage variable, D_d for critical damage variable damage state of of rock mass is determined as Dd that is was 0.2, and the damage threshold D_t of for rock breaking mass in critical broken state is was were defined as 0.2 and 0.8, respectively. based on the basic theories of rock damage mechanics and through statistical analysis of the relationship between damage variables in engineering and wave velocity in rocks. Furthermore, Based on the dynamic damage model of rock with comprehensive consideration of the damage effect of tension and compression, the damage range of bench blasting under different conditions of with different subdrilling conditionsultra-deep was simulated by using the dynamic finite element analysis program LS-DYNA based on the dynamic damage model of rock mass with a comprehensive consideration of tension and compression effect. Meanwhile; based on the threshold of critical damage variable, the fluctuations distribution image of the bench surface after blasting was drawn to determine the optimal ultra-deep of subdrilling hole based on D_t the threshold of critical damage variable, and the image is was used for the quantitative analysis, so as to ensure that the rock mass of upper bench was fully damaged without affecting the construction of the lower bench surface. Finally, combined with the actual situation of deep-hole bench blasting in Ezhou Airport, the influence mechanism of ultra-deepsubdrilling on blasting toes is was verified in the deep-hole bench blasting of Ezhou Airport, and an optimal method for determining the optimal ultra-deepsubdrilling value for deep-hole bench blasting is was concluded.