To study the influence of different geo-stress levels on the propagation of explosive stress waves in natural environment such as mountains and dams, numerical simulation technology was used to simulate the explosion of concrete specimens under different geo-stress conditions. First, by applying different stresses to the boundary of the concrete specimens, the failure of specimens subjected to explosive load were observed. And then, the peak stress and particle velocity of the four preset measuring points on the specimen were obtained by changing the unilateral ground stress value and keeping the same explosion load on different models. Finally, the influence of geo-stress on the propagation of explosion stress wave was analyzed on different characteristic parameters of explosion wave, such as the peak stress and particle velocity. The results show that the influence of geo-stress on explosion stress wave is mainly manifested as “restraining propagation” and “promoting propagation” under high and low stress level, respectively. During the explosion process, the superposition coupling of explosion stress wave and in-situ stress increases the peak stress intensity of the measuring point. On the contrary, the high ground stress inhibits the displacement of the medium particles, thereby reducing the particle velocity. The research starts from the influence of different ground stress levels on the propagation of explosive stress waves, and creatively analyzes the inhibition of ground stress on stress waves.

In order to investigate the dynamic response and stability of a steep slope under blasting vibrations from multiple blasts, the displacement, stress, maximum shear strain, safety factor and sensitivity of the steep slope were analyzed by field monitoring, numerical simulation and mathematical methods based on the an open-pit mine in Inner Mongolia. The data fitting results show that the radial vibration velocity has the highest correlation coefficient, with all the coefficients of three directions greater than 0.8. The relative error of the prediction results is larger in the near-blasting area, while smaller in the far area. After a single blast, the horizontal displacement increases rapidly and reaches the maximum value on the right side of the blast hole at 0.05 s. In the vertical direction, the stress increases gradually from top to bottom and the bottom is prone to stress concentration. The overall stress distribution of the slope gradually increases from the slope surface to the slope interior. After multiple blasts, the displacement and horizontal stress of the slope generally continues to increase with the increase of blasting times. The peak value of vertical stress and acceleration are generally oscillating with the increase of blasting times. For a period after the blasting, the acceleration is still not 0, and it takes a long time for the blasting energy to completely dissipate. Multiple blasting vibration will continue to reduce the safety factor of the slope to a certain extent. With the increase of blasting times, the change rate of the safety factor of the slope will gradually increase. Based on the gray correlation coupling analysis of safety factor and orthogonal tests, the sensitivity of each factor is as follows: charge per delay (X₅) > total explosive charge (X₆) > hole spacing (X₃) > blast distance (X₂) > blasting vibration duration (X₄) > hole number (X₁). It is indicated that in actual construction, it is necessary to control the charge per delay and total charge in order to ensure safe production.

According to continuous blasting vibration monitoring results carried out on three monitoring points (bottom, middle, and top) at different vertical positions at the same horizontal distance from an underwater blasting project in a channel adjacent to high-rise buildings, the three-dimensional spatial patterns of blast vibration velocity, vibration frequency, and vibration energy were analyzed, and the elevation effect mechanism of blasting vibrations on high-rise buildings was explored. The analysis results show that: (1) Blasting vibration velocity is influenced by the combined action of the elliptical motion of Rayleigh wave, energy attenuation, and whiplash effect. It presents a significant three-dimensional spatial effect in the propagation among high-rise buildings, in which the vertical direction is dominated by Rayleigh wave elliptical motion and whiplash effect, showing a significant elevation amplification effect, while the horizontal and tangential directions are dominated by Rayleigh wave elliptical motion and energy attenuation, exhibiting an elevation attenuation effect. (2) The propagation of blasting vibration frequency in high-rise building is mainly affected by the vertical distance from the wall, showing an elevation attenuation effect in all three directions. (3) The distribution of vertical blasting vibration energy presents a significant elevation amplification effect from the bottom, middle to the top of the building. Specifically, the high-frequency energy proportion shows an elevation attenuation effect in the middle and top relative to the bottom, while the low-frequency energy proportion exhibits an elevation amplification effect in the middle and top relative to the bottom.

Dynamic disturbance scattering such as blasting generates dynamic stress concentration which is an important factor resulting in instability and damage in underground structures. In this paper, a theoretical model of a deeply buried pipeline under plane P-wave incidence is developed based on the wave function expansion method. Fourier transforms and Duhamel integrals were introduced to solve the transient response around a deeply buried circular aqueduct, and the effect of wavelength on the transient response was analyzed. Considering that the ground stress is a non-negligible factor for the destabilization of deep structures, a numerical model was established with the help of LS-DYNA finite element software to analyze the dynamic response mechanism of deeply buried pipelines under the action of the initial stress. The results of the study show that the compressive stress concentration generated by short-wave incidence is greater, and the tensile stress concentration due to long-wave incidence is greater, and the tensile stress concentration is very easy to occur along the direction of incidence. The larger the lateral pressure coefficient, the more pronounced is the suppression of the dynamic response in the presence of initial stresses. In addition, the pipeline and the surrounding rock mass under the initial stress state will experience more drastic fluctuations in the stress state when subjected to dynamic loading. These research phenomena reveal that the dynamic response mechanism of underground pipelines and the impact of the in-situ stress environment, which can be used for the seismic optimization design of deep underground structures.

In view of the problem of noise and information loss in the CEEMDAN method in the denoising process of actual measurement blasting vibration signals, the clustering analysis method is considered to have good data processing ability. Based on the idea of decomposition-clustering-reconstruction, CEEMDAN-K-means algorithm for denoising of blasting vibration signals is proposed. Firstly, this method decomposes the blasting vibration signal by CEEMDAN method to obtain IMF components of different quantity levels. Then, the K-means clustering analysis algorithm is used to classify the IMF components into five different categories, and variance contribution rate verification is used. Finally, the IMF components of high frequency noise category are removed and the reconstructed pure blasting vibration signal is obtained. Taking the blasting vibration signals from an open-pit mine as example, the signal denoising performance of the CEEMDAN-K-means algorithm was evaluated by signal-to-noise ratio and root mean square error indexes. The research results show that compared with the CEEMDAN method and the EMD-wavelet threshold method, the CEEMDAN-K-means signal denoising method has the largest signal-to-noise ratio (20.06 dB), which is increased by 1.26 dB and 7.7 dB, respectively, and the smallest root mean square error (0.22 10^-3), indicating that the method not only has good denoising effect, but also has good fidelity. Through the comparison and analysis of the denoising effect of different methods, it is known that on the basis of effectively retaining the real signal component, the CEEMDAN-K-means method can effectively remove the high-frequency components contained in the measured blasting vibration signal, and has practicality and effectiveness in the field of blasting vibration signal denoising.

The experimental signals collected in explosion experiments are always mixed with different degrees of noise interference. In order to accurately analyze the variation laws conveyed by these signals, four sets of explosion experiments were designed with different charge amounts and vacuum environments in the vacuum explosion vessel. Then, the collected impact load data were analyzed by applying both Fourier filtering algorithm and median-averaged filtering algorithm. By comparing the P-t curves processed by the two filtering algorithms with the original ones, it is found that the Fourier filtering algorithm is a global analysis of the signal, which can extract the frequency information of the function in the whole frequency domain, while the characteristics of the signal cannot be revealed in a local time range. Although the processing speed is faster, the error for the characteristic parameters is larger, and the effect of the filtering process directly applied to test signals of the blast impact is less satisfactory. The fit degree between the signals of explosion impact processed by the median-averaged filtering algorithm and the original ones is higher, and the varying details of the impact load with time in the blast container can be clearly reflected with a smaller error and a higher reliability.

The peak particle velocity (PPV) of blasting vibration is an important index to measure the impact of blasting vibration on surrounding environment and structures. In order to improve the reliability of PPV prediction, a model based on extreme gradient boosting optimized by the sparrow search algorithm was proposed, and a corresponding blasting vibration prediction system was built using the App Designer of MATLAB. The maximum charge per delay, distance from blast center to measuring point, and elevation difference between measuring point and blast center were selected as the input parameters of 36 sets of training data and 5 sets of test data for the model to predict PPV. The results show that the proposed SSA-XGBoost model has a smaller average relative error compared with the GA-BPNN model and BPNN model, and it has a higher prediction accuracy and better stability proved by the Taylor graph.

In order to study the blasting vibration prediction and control measures of excavation in urban area under complex environment, the response law of peak particle vibration velocity and main vibration frequency is analyzed based on field blasting tests, and the blasting vibration prediction method is proposed based on the above two factors. The vibration reduction effect of hole by hole initiation and vibration reduction ditch is discussed, so that to obtain the optimal vibration reduction range of the ditch. And the control measures of blasting vibration are also formulated. The results show that the prediction formula of the peak particle vibration velocity and main vibration frequency is realized by considering the actual maximum single-hole charge and the actual total charge. The predicted value is smaller than that solely based on the maximum single-hole charge, and the prediction accuracy is increased by 3.2%. In the aspect of blasting vibration control, the blasting vibration is characterized by low vibration velocity, high frequency and short duration. Among all the measures, the effect of the vibration reduction ditch is remarkable. Considering the peak particle velocity, signal frequency band energy distribution and instantaneous input energy response law, the vibration reduction effect is the best within 1~6 m radius on the side of the ditch opposite to the blast source, and the maximum vibration reduction ratio can reach 77.5% within 1 m radius. For similar projects, the proposed blasting vibration prediction formula can be used for pre-assessment. When the distance of the building from the explosion zone is less than 10 m, it is recommended to implement vibration reduction ditch.

To solve the problem of impact danger to the coal pillars in the bearing section of the coal mine caused by rock burst, the stability analysis of the coal pillars was carried out using a theoretical analysis method during the excavation and backfilling periods of the B4328 working face of the Xinglongzhuang coal mine. The reasonable width of the coal pillars was calculated. A numerical calculation model was established using Phase2 to determine the stress distribution of the coal pillars in different mining states. Based on the degree of stress concentration on both sides of the roadway and the floor, a large-diameter borehole pre-pressure relief plan was implemented, and reinforcement measures for the transportation roadway before backfilling were also developed. The research results show that the plastic zone width of the coal pillar on the excavation side after transportation is 4.71 m and 14.45 m on the goaf. It is believed that the coal pillars are only affected by the impact of single-sided mining and the redistribution of drilling stresses, and the 25 m coal pillars are in a relatively stable state. At the same time, the simulation calculation shows that the transportation excavation area is located in the position where the supporting pressure peak drops in the goaf but the value is still relatively high, and the impact danger of the outer side of the coal pillar is greater than the inner side. Therefore, it is necessary to strengthen the support and take pre-pressure relief measures for the elastic area of the coal pillar. Because the coal pillar is less disturbed during the excavation period, and the two sides are basically in a plastic state after pressure relief, the elastic zone starts to produce plastic deformation, the elastic energy is released slowly, and the impact risk is reduced.

The estimation of equivalent and depth of underwater explosions is an important task of the hydroacoustic monitoring in the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In order to effectively estimate the equivalent and depth of underwater explosion in near and far-fields, the relationship between the ratio of the first and second periods of the bubble pulsation and the bubble radius and depth was fully used based on the semi empirical formula of bubble pulsation period. The analysis results of near-field underwater explosion show that the average estimated equivalent and depth are about 118 g and 7.96 m, 76 g and 21.4 m, 1.23 kg and 44 m for different actual TNT equivalent values and blasting depths of 100 g and 7 m, 100 g and 25 m, 1 kg and 50 m, respectively. These results show that the depth estimation is more accurate than the equivalent estimation. Furthermore, the proposed method failed for a small explosion equivalent of 100 g and a depth of 50 m, which indicates that the method is limited in explosion depth. Finally, this method was used to analyze the far-field underwater explosions recorded by IMS hydroacoustic stations, and the equivalent and depth estimation results were consistent with the references, which indicated that this method is also suitable for the far-field explosion estimation.