Blasting Vibration Effect Research Articles

Numerical Simulation and Field Monitoring of Blasting Vibration for Tunnel In-Situ Expansion by a Non-Cut Blast Scheme.

There have been ever more in-situ tunnel extension projects due to the growing demand for transportation. The traditional blast scheme requires a large quantity of explosive and the vibration effect is hard to control. In order to reduce explosive consumption and the vibration effect, an optimized non-cut blast scheme was proposed and applied to the in-situ expansion of the Gushan Tunnel. Refined numerical simulation was adopted to compare the traditional and optimized blast schemes. The vibration attenuation within the interlaid rock mass and the vibration effect on the adjacent tunnel were studied and compared. The simulation results were validated by the field monitoring of the vibration effect on the adjacent tunnel. Both the simulation and the monitoring results showed that the vibration velocity on the adjacent tunnel's back side was much smaller than its counterpart on the blast side, i.e., the presence of cavity reduced the blasting vibration effect significantly. The optimized non-cut blast scheme, which effectively utilized the existing free surface, could reduce the explosive consumption and vibration effect significantly, and might be preferred for in-situ tunnel expansion projects.

Analysis of blasting vibration duration considering frequency and energy and its application

Blasting vibration's effect on ground vibration is essentially an energy transfer and transformation process (Hongtao et al., 2010) [1]. In engineering, the blasting vibration duration is often used as an objective index to evaluate the blasting vibration hazard. Thus, this study on the factors influencing blasting vibration duration is essential. In this study, the blasting vibration duration prediction formula uses frequency and energy as independent parameters, which are analysed using a statistical t probability distribution. With the blasting vibration duration prediction formula, the delay time taken for the structure to reach the resonance frequency is obtained by calculating the dominant frequency of the structure. The results indicate that the frequency and energy of the blasting vibration signal are highly correlated with the duration of blasting vibration, and their introduction as independent parameters in the prediction formula can better improve the prediction accuracy. The dominant frequency should not be neglected in blasting vibration safety evaluations, and the use of blasting vibration duration prediction to calculate the dominant frequency can better avoid the resonance phenomenon in the structure.

Blasting damage mechanism and excavation stability of surrounding rock of shallow-buried metro station

Given the significant impact of damage on the deformation and stability of surrounding rock in shallowly buried metro stations, understanding the behaviors of rocks, with the blasting vibration effect considered, is crucial. This study examines the blasting damage mechanism, including an analysis of damage factors and radii. The results revealed a nonlinear decreasing relationship between the damage factor and the distance from the blasting source. Hence, equations for the radii of the surrounding rock's crushing and crack zones are established under the influence of blasting shock and stress waves. On-site acoustic testing indicated that the surrounding rock suffers severe damage within a 0–0.6 m range from the blasting source. A damage disturbance zone exists within a 0.7–1.7 m range while the rock remains intact within a 1.7–4.7 m range. The on-site measured radius of the crushing zone differs by 9.59% from the theoretical value, and the crack zone's radius deviates by 16.47%. In addition, a simulation model is developed to investigate the stability of surrounding rock under different rock span ratio (RSR). For shallowly buried, large-span hard rock stations, the findings suggested that with RSR between 0.15 and 0.25, a smaller ratio correlates with increased settlement of the surrounding rock, higher horizontal stress values, and larger plastic zone areas post-excavation, confirming the evaluation index's rationality and scientific validity.

Mathematical simulation modeling analysis of sub-sea tunnel blasting based on grey correlation

Blasting in the ocean tunnel has a great impact on Marine life and seabed vegetation, so it is necessary to control the impact of blasting vibration on the surrounding Marine environment. In this paper, taking Xiamen Tunnel as an example, the blasting vibration response characteristics of undersea tunnel are studied, and the velocity attenuation rules of tunnel structure in different directions are obtained. The grey correlation theory is innovatively applied to analyze the correlation degree of factors affecting the blasting vibration effect of the undersea tunnel, and the key factors and secondary factors affecting the blasting vibration effect of the tunnel are determined. The grey correlation theory is used to analyze the correlation degree between the blasting vibration effect of the cross-tunnel, which is conducive to improving the safety and stability of tunnel construction. It provides a new idea and method for vibration control of similar projects.

Influence of Lithology on the Characteristics of Wave Propagation and Dynamic Response in Rocky Slope Sites Subject to Blasting Load Via the Discrete Element Method

Abstract To investigate the dynamic response and attenuation law of rock slope sites subjected to blasting, three lithological numerical models, including slate (hard rock), tuff (relatively soft rock), and shale (soft rock), are established by using MatDEM. By analyzing the wave field, velocity, and acceleration response of the models and their Fourier spectrum, combined with stress and energy analysis, their dynamic response characteristics are investigated. The results show that blasting waves propagate from near field to far field in a circular arc, and the attenuation effect of waves in soft rock is less than that in hard rock. The influence of lithology on the dynamic response of the ground surface and bedrock is different. Blasting waves mainly affect the dynamic response in the near-field area of the blasting source. In addition, the dynamic amplification effect of slopes is as follows: hard rock > relatively soft rock > soft rock. The slope surface has an elevation attenuation effect. A dynamic amplification effect appears in the slope interior within the relative elevation (0.75, 1.0). The Fourier spectrum has an obvious predominant frequency, and that of the slope crest and interior is less than that of the slope surface. Moreover, the total energy generated by the rocky sites gradually changes into kinetic energy, gravitational potential energy, elastic potential energy, and heat. Energy-based analysis shows that the attenuation effect of blasting waves in hard rock is larger than that in soft rock overall. This work can provide a reference for revealing the blasting vibration effect of rock sites.

Experimental Study on Stability Analysis of Shallow-Buried Metro Station Hard Rock Excavation under Blasting Vibration Effect

Abstract By considering a certain metro station of Qingdao Metro Line 4 as the research object, a three-dimensional geotechnical testing model has been developed to analyze the stress and deformation characteristics of the surrounding rocks under blasting vibration effect. The simulation of the surrounding rock blasting process is achieved through an electric spark source. We conducted simulation tests on the excavation stability of shallow-buried hard rock metro stations with and without considering blasting damage effects, respectively. The stress, displacement, and primary support stress changing laws of the surrounding rock under different overburden thicknesses using the arch cover method and the primary support arch cover method have been revealed. Finally, we analyzed the applicability of the primary support arch cover method in terms of vault settlement, clearance convergence, and floor heave. Results show that the surrounding rock of the arch has roughly gone through three deformation stages, namely a slow deformation stage, rapid deformation stage, and stable deformation stage. Whether it is blasting excavation or non-blasting excavation, the settlement of the arch is within a safe and controllable range. Because of the refinement of the excavation process by the primary support arch cover method, the stress release is relatively stable throughout the entire excavation process, but the significant impact of blasting vibration on the surrounding rock cannot be ignored. The excavating of the left and right guide holes is the key process for the displacement and stress variation. The deformation and stress generated by the arch cover method have a small difference compared to the deformation and stress generated by the primary support arch cover method, indicating that the latter excavation method can be used under current engineering geological conditions. No large-area collapse and instability occurred in the experimental process, which provides a theoretical basis for similar projects.

Blasting vibration effect and safety evaluation method of railway cross tunnels

The evolution characteristics of the peak particle velocity and frequency of an existing railway cross tunnel are systematically studied. The analysis results show that there is a difference in the blasting vibration response before and after the new tunnel face is built. In this paper, a set of blasting vibration response evaluation methods that can quantitatively consider the influence of frequency by means of dimensional analysis is introduced. In addition, relevant knowledge on topics such as wavelet packet analysis, signal processing, structural dynamics, and explosion mechanics is applied to research the influence of the frequency. The research results show that the influence of the frequency on the blasting vibration response can be quantitatively analyzed by quantifying the dynamic amplification factor. To resolve the insufficiency of field monitoring, the distribution of the blasting vibration response along the entire section of the existing tunnel is studied through numerical simulation. Based on the theory of distortion energy in material mechanics, a new idea for evaluating the blasting vibration response of a cross tunnel is proposed.

Safety Criterion for Hollow Pipe Piles Under Blasting Vibration Based on Wave Function Expansion Method

When the drilling and blasting method is used to excavate urban subway tunnels, the blasting seismic waves will inevitably produce vibration effects on the pile foundations under the surface buildings, which will seriously threaten the safety of surrounding buildings and the environment. Based on the transmission and reflection laws of stress waves at the interface between soil medium and pile medium and the displacement–stress continuous assumption, the wave function expansion method is used to analyze the whole process mechanism of vibration effect of hollow pipe piles under the action of incident [Formula: see text] waves. In addition, the theoretical model of safety criterion for hollow pipe piles under blasting vibration is proposed and the reliability of the model is verified. Furthermore, the impacts of the elastic modulus, density, and pile section parameters of soil and piles on the safety criterion for the blasting vibration effect of hollow pipe piles are analyzed. The results show that as the elastic modulus and density of the soil increase, the critical peak particle velocity (PPV) curves of hollow pipe piles move to the high-frequency and low-frequency bands, respectively, resulting in a decrease in the overall safety of piles. This indicates that hollow pipe piles should not be buried in soil layers with high elastic modulus and density. It is also shown that the larger the hollow area of hollow pipe piles, the lower their safety. Compared to solid circular piles, hollow pipe piles have a higher overall seismic safety reserve. The study results have guidance and reference value for effectively evaluating and controlling the harm of blasting vibration effects of hollow pipe piles.

The Blasting Vibration Characteristics of Layered Rock Mass under High-Pressure Gas Impact

Firstly, the experimental test of blasting vibration was carried out to study the propagation characteristics of the peak particle velocity (PPV) and dominant frequency (DF) of the blasting vibration of layered rock mass under high-pressure gas impact. The test results show that the PPV and DF of blasting vibration of layered rock mass decrease gradually with the increase in distance from the explosion source. The PPV and DF of layered rock mass under the same impact pressure of high-pressure gas are lower than those of single rock mass at the same measuring points. With the increase in hole spacing, the PPV and DF of blasting vibration become smaller, and the blasting effect first becomes better and then worse. Next, the relationship models between the PPV and DF and their influencing factors were deduced by the dimensional analysis method, which can be simplified as exponential forms that decay with the scaled distance. In addition, through a numerical simulation test, it was found that the optimal hole spacing recommended in an excavation example of an underground pipe gallery is 100 cm. Finally, the blasting vibration effects under the two excavation methods of high-pressure gas impact and explosive blasting were numerically simulated and compared. The results indicate that high-pressure gas impact can significantly reduce the blasting vibration effect of layered rock mass compared with explosive blasting. This study has important theoretical guiding significance and practical value for revealing the propagation law, forecasting and controlling the harm of blasting vibration effect of layered rock mass caused by high-pressure gas impact.

Vibration effect and ocean environmental impact of blasting excavation in a subsea tunnel

Drill-blast method is one of the important methods in the current subsea tunnel excavation construction. Controlling the vibration effect during blasting construction and its impact on the marine environment has been a key topic in the construction of subsea tunnels. This paper takes the Xiamen subsea tunnel excavation and blasting project as the background, combines blast vibration monitoring in the tunnel and underwater sound pressure testing in seawater, analyzes the attenuation law of subsea tunnel blast vibration propagation along the rockmass, studies of the characteristics of shock waves formed in water following the propagation of blast stress waves to seawater. Based on the dynamic finite element numerical calculation, the impact of blasting vibration effect of mainline tunnel on the adjacent built service tunnel structure and the characteristics of shock wave pressure distribution in water excited by blasting vibration are analyzed. Considering the influence of the burial depth of tunnel blasting source, a mathematical prediction model of the attenuation law of underwater sound pressure in water caused by subsea tunnel blasting is established. Based on the pressure control standard of marine organism safety, the control range of marine organism safety under the influence of subsea tunnel blasting is proposed.

Numerical simulation of rock mass blasting vibration using particle flow code and particle expansion loading algorithm

In the numerical analysis of rock mass blasting using the particle expansion loading algorithm in the PFC method, the size of the blasting funnel is usually consistent with the experiment, but the blasting seismic wave produced is quite different from the reality. By reasonably determining the micro-parameters that affect the simulation effect of blasting vibration, the particle expansion loading algorithm can better simulate the actual situation of the blasting effect of the rock mass. The studied rock's density, uniaxial compressive strength, and elastic modulus are 2500 kg/m3, 80.1 MPa, and 65 GPa, respectively. Firstly, based on the theory of the PFC method and the law of energy conservation, the attenuation process of the seismic waves was controlled by the critical damping ratio and contact stiffness of the model. Then, the rock blasting numerical simulation is carried out using the particle expansion loading algorithm. The critical damping ratio mainly affects particle vibration's kinetic energy attenuation rate. At the same time, the contact stiffness can control both the peak velocity and the duration of blasting vibration. Finally, the field blasting experiment verifies the rationality of the quantitative relationship between the critical damping ratio and contact stiffness and the specific parameters of blasting seismic waves in the simulation of rock blasting vibration. It is verified that the particle expansion loading algorithm in the PFC method can not only simulate the blasting funnel forming well but also simulate the blasting vibration effect in the outlying area, which provides a more reliable numerical simulation method for the simulation of rock blasting.

Analysis of Blasting Vibration Effect of Railway Tunnel and Determination of Reasonable Burial Depth

Based on specific examples of underpass tunnel blasting, field measurements, and numerical simulation studies are carried out. According to the results of the blasting vibration data measured on-site, a regression model of the blasting vibration velocity is established. Based on the wavelet packet energy spectrum analysis method, the effect of frequency on the vibration response intensity is studied. In addition, the maximum charge per delay allowed for tunnel blasting is obtained by formula inversion. Relying on ANSYS/LS-DYNA to establish a three-dimensional numerical model, the accuracy of numerical simulation can be checked by the measured vibration data. The results show that the numerical simulation has high precision and can meet the subsequent analysis needs. Using numerical simulation, the variation law of the vibration response characteristics of ground blasting under different tunnel burial depths is studied. The analysis results show that with increasing tunnel burial depth, the ground blasting vibration velocity decays exponentially. According to the corresponding specification of blasting vibration, a reasonable value range of the buried depth of the underpass tunnel can be obtained. The research ideas and methods introduced can be used for reference for similar railway tunnel blasting control and railway tunnel route selection.

Coal\u2013rock damage characteristics caused by blasting within a reverse fault and its resultant effects on coal and gas outburst

In view of the coal and gas outburst accidents occur frequently caused by blasting in geological structural belt, in order to study the mechanical characteristics of coal rock in tectonic belt disturbance by blasting and blasting vibration effect influenced on the stability of surrounding rock, coal–rock damage and failure characteristics within a reverse fault caused by a blasting stress wave were investigated using numerical analyses and experiments. According to the experimental results, the causes of coal and gas outburst dynamic disasters within a reverse fault during blasting are analyzed. The outcomes indicated that the crushing circle created by the crack propagation near the blasting hole severely damaged the fault plane and floor rocks adjacent to the footwall of the reverse fault. Fractures also extended to the upper and lower coal seams of the reverse fault; this caused the surface of the coal seam to fall off and severe internal damage. According to theoretical analysis, the reflection of the blasting stress wave propagating to the reverse fault intensified the damage to coal and rock. Elastic strain energy accumulation within the reverse fault structural zone was accompanied by high-stress concentration. The reverse fault tectonic region was destroyed by blasting vibration. It increased gas pressure and caused a weak surface, which provided a channel for gas flow and a dynamic basis for the occurrence of coal and gas outburst. The research results have important theoretical value to reveal the mechanism of coal and gas outburst in tectonic belt induced by blasting.

Regression analysis of the blasting vibration effect in cross tunnels

Regression analysis of the blasting vibration effect in cross tunnels

Research on blasting vibration effect and time-frequency characteristics of vibration signals in a road corridor at xianning nuclear power station

Drill and blast is a major method for foundation excavation in nuclear power plant engineering. For transporting heavy components to engineering construction, the blast-induced vibration of foundation excavation in a road corridor may has a great influence on new pouring mass concrete and surrounding bedrock in Xianning Nuclear Power Station, which will affect the safety of the engineering construction. So it is necessary to monitor the process of blasting excavation and put forward effective control measures on blasting vibration effect, in which the peak particle velocity (PPV) attenuation law are investigated through regression analysis of practical field data by Duvall empirical formula and the time-frequency characteristics was analyzed by wavelet transform and wavelet package decomposition. By analyzing the velocity amplitude and power spectrum density amplitude of wavelet components, it shows the blast energy of original vibration signal is mainly within the frequency below 250 Hz and has three sub-band which varies from 10 Hz to 30 Hz, from 40 Hz to70 Hz and from 75 Hz to 125 Hz, respectively. Wavelet packet analysis indicates the energy of the signal in 0-125 Hz accounts for 94.25 % of the total signal. At the same time, for the sake of ensuring the safety of road corridor, Chinese admissibility standards (GB6722-2014) of blasting-induced vibration and the constants obtained from the regression were used to establish the maximum explosive charge per delay for an acceptable ground vibration level that would not cause damage for new pouring mass concrete and bedrock in road corridor. The safety criteria of particle vibration velocity for new pouring mass concrete and bedrock in road corridor could be both set as 5 cm/s, which show the remarkable effect on blasting damage control of the new pouring mass concrete and surrounding bedrock, the results demonstrate that controlling maximum explosive charge per delay methodology can be commendably applied to road corridor to control blasting-induced vibration effects.

Scale model test study of influence of joints on blasting vibration attenuation

Ground vibrations are an integral part of the process of rock blasting. The analysis of blasting vibration attenuation is the basis for a blasting risk assessment. To study the influence of rock joints on the blasting vibration attenuation, an autoclaved aerated concrete block was used as a similar material of rock in model tests of blasting vibration propagation. The attenuation process of the blasting vibration was physically simulated. The attenuation behaviors of the blasting vibrations in different directions to joint strike were fitted. Additionally, a positive correlation between the attenuation parameters and the directions was obtained. Furthermore, the Hilbert–Huang transform (HHT) based on the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) was used to analyze the vibration velocity signals. The characteristics and variation of the energy distribution were studied in the time–frequency domain. The results showed that the energy amplitude decreased as the propagation distance increased. The energy distribution gradually evolved from concentrated to discrete in the frequency domain. The low-frequency components were always present in the velocity signals at each measurement point, but the high-frequency components constantly changed due to the reflection and transmission of the waves after encountering the joint surfaces. The results of this study provide a reference for the prediction and control of the blasting vibration effect in jointed rock masses.

Studying on the characteristics of vibration effect of the blasting of excavating anchorage tunnels of Chishui River Super Bridge

The section of anchorage tunnels, is large, there are variable contour and variable areas and small distance among anchorage tunnels and main tunnels, and easy to form unloading cracks or boulder to bias arch, so blasting excavation maybe easily damage the middle pillars and surrounding rock and to collapses the entrance of holes, which will affect the operation of bridge in the future. For the structure, spatial distribution state of anchorage tunnel and the highway tunnels, and spatial relationship among its, based on the topographic feature, geological structure, rock and lithology of the Sichuan bank of Chishui Rive Super Bridge, according to the correlation between blasting source factors and the energy density distribution characteristic of blasting seismic wave, combined with monitoring, the blasting vibration effect characteristics of tunnel anchorage excavation are studied on, the blasting technology is optimized, and the support are strengthen to ensure the stability of the surrounding rock, middle pillar and mouth, so that the construction will be done successfully.

Dynamic characteristics and safety criterion of deep rock mine opening under blast loading

The blasting vibration in deep mining affects the safety of the adjacent roadways. To estimate the stability of a deep rock mass opening during blasting excavation, the dynamic responses of the deep rock mass subjected to blast loading are investigated in this study. The relationships between the blasting vibration velocity and the frequency over time, horizontal distance, and depth are analyzed, and the stress distribution of the surrounding rock mass is depicted through field tests and numerical simulation. The failure mechanism of deep rock mass is thus revealed, and a new safety criterion regarding the blasting vibration of the deep rock mass is put forward. The results indicate that the vertical vibration velocity is higher than the horizontal vibration velocity and that the vertical tension of the seismic wave of the blast is larger than that of the shearing action in the near-blasting field, which contrasts that of the far field. Both the vibration velocity and frequency decrease with an increase in time, distance, and depth, and the range of influence of the blasting vibration in terms of depth is larger than that for the horizontal direction. Therefore, the deep rock mass is more vulnerable to damage than the shallow rock mass under blast loading. In addition, the surrounding rock stress tends to transfer from the arc foot on the blasting side to the straight wall on the rear side, and the shear stress is ahead of the tensile stress. It was verified through a case calculation that the new criterion has practical value and can be used as a guide for evaluating the blasting vibration effects of the deep rock mass.

Field measurement and numerical simulation of the influence of blasting excavation on adjacent buried pipelines

The blasting seismic waves generated by tunnel blasting will have an adverse effect on adjacent buried pipelines, which increasing the difficulty of subway construction. In this paper, taking the section of blasting excavation in Dalian Metro Line 1 as the engineering background, the attenuation law of blasting seismic wave in the soil and the vibration response of the buried pipeline are systematically studied by means of field measurement and numerical simulation. The deformation monitoring of the pipeline shows that the time curve of the pipeline and the surface settlement are distributed exponentially, and the trend of them is the same. The attenuation law of seismic wave obtained by numerical simulation is basically consistent with the measured results, which indicates that it is feasible to study the blasting vibration effect by numerical simulation. The Sa Rodolfo J Ki prediction formula is established according to the measured data, which can reflect the propagation law of the blasting seismic wave. It can provide some basis for the construction of subway tunnels at the subsequent stage.

Influence of Small, Clear Distance Cross‐Tunnel Blasting Excavation on Existing Tunnel below

The vibration effect generated during tunnel excavation can influence or damage adjacent tunnels. Studying and controlling the blasting vibration effect has important theoretical and practical significance, especially for new tunnels. This paper takes the tunnel project of Gao Jiu Lu‐Jia Hua Cross Tunnel in Chongqing as the research background and assesses the blasting vibration influence in the up‐down cross‐tunnel. Onsite monitoring and numerical simulation were used to analyze peak particle velocity (PPV) changes, stress distribution, and crown settlement during the excavation process of Gao Jiu Lu I Tunnel at Jia Hua Tunnel Left Line in the cross‐section. Influence laws of blasting excavation in a small, clear distance cross‐tunnel on an existing tunnel below were obtained. Results show that new tunnel blasting vibrations exerted the largest influence on the crown of the existing tunnel below in the cross‐section. The maximum tensile stress of the secondary lining of the existing tunnel below was mainly concentrated in the crown area. The maximum compressive stress during excavation was concentrated in the crown foot, and the stress value was less than the tensile and compressive strength of the concrete. The loosening of the surrounding rock from blasting excavation of the new tunnel caused secondary settlement of the existing tunnel crown below. The cumulative settlement value at the cross‐section of the two tunnels was the largest. With an increase in axial distance from the cross‐section of the existing tunnel crown, the settlement value gradually declined and became stable. These research results have reference value for the construction of a small, clear distance cross‐tunnel and provide theoretical guidance for similar tunnel excavation projects in the future.