Analysis of Accumulated Damage Effects on the Roof of Mined-Out Areas under Blasting Vibration

2011 ◽  
Vol 250-253 ◽  
pp. 2346-2351 ◽  
Author(s):  
Shu Ren Wang ◽  
Hui Hui Jia ◽  
Meng Shi Chang
Keyword(s):  
Normal Incidence ◽  
Damage Effect ◽  
Vibration Velocity ◽  
Time Interval ◽  
Blasting Vibration ◽  
Three Dimension ◽  
Response Characteristics ◽  
Accumulated Damage ◽  
Equal Time Interval ◽  
Technical Basis

Under the repeated blasting vibrations, the roof of the mined-out areas will suddenly collapse and fall because of its accumulated damage, which is a hidden danger for the miners and equipment on the surface. Based on the mined-out areas in Antaibao Surface Mine, the three-dimension engineering geological model and computational model were built using FLAC3D technique. According to the effect of the load of the mechanical construction equipment, and the blasting vibration velocity recorded by field monitoring, the equal-time-interval blasting vibration as normal incidence was exerted on the surface of the mined-out areas three times. Consequently the accumulated damage effect of the roof and surrounding rocks of mined-out areas were analyzed, the stress concentration extent and the range of principal stress were discussed as well. The dynamic response characteristics of deformation and the accumulated progressive displacement were revealed via the monitoring displacement curves. The above mentioned results can provide theoretical and technical basis for similar projects on reducing the hidden danger and ensuring safe mining.

scholarly journals Influence of Blasting Vibration of MLEMC Shaft Foundation Pit on Adjacent High-Rise Frame Structure: A Case Study

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5140
Author(s):  
Nan Jiang ◽  
Yuqi Zhang ◽  
Chuanbo Zhou ◽  
Tingyao Wu ◽  
Bin Zhu
Keyword(s):  
Numerical Model ◽  
Frame Structure ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Reinforced Concrete Structure ◽  
Foundation Pit ◽  
Line Energy ◽  
Response Characteristics ◽  
High Rise ◽  
Maximum Charge

The construction of metro line energy management center (MLEMC) is one of the important parts of metro line, which is the key organization to realize the energy consumption management of the metro operation. To protect the safety of adjacent high-rise buildings during the blasting of subway foundation pit engineering, it is crucial to study the response characteristics of building structures. This paper takes the MLEMC vertical pit blasting project of Wuhan Metro Line 8 as an example. The law of blasting vibration attenuation along the earth’s surface and the vibration velocity response characteristics of the building structure were analyzed by small explosive test. LSDYNA numerical model was established, and the reliability of the model and parameters was verified by experimental data. Combined with the relevant specifications, the maximum charge in single delay was calculated and analyzed. The numerical model of the maximum charge in single was established, and the prediction model of the vibration velocity related to the floors of high-rise buildings was further proposed. Combined with the failure principle of reinforced concrete structure, the safety of high-rise buildings under blasting vibration was analyzed and evaluated.

scholarly journals Vibration Response Characteristics of Adjacent Tunnels under Different Blasting Schemes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jianxin Yu ◽  
Zhibin Zhou ◽  
Xin Zhang ◽  
Xiaolin Yang ◽  
Jinxing Wang ◽  
...  
Keyword(s):  
Free Surface ◽  
Vibration Velocity ◽  
Three Dimension ◽  
Tunnel Face ◽  
Response Characteristics ◽  
Unit Charge ◽  
Site Monitoring ◽  
Tunnel Blasting ◽  
Lining Structure ◽  
The Impact

The vibration caused by the tunnel blasting and excavation will harm the surrounding rock and lining structure of the adjacent existing tunnels. This paper takes a two-lane large-span highway tunnel as the research object, conducts on-site monitoring tests on the impact of vibration caused by the blasting and excavation of new tunnels on the existing tunnels under different blasting schemes, and analyses in detail the three-dimension vibration velocity by different excavation footages. From the vibration speed, it is concluded that the influence of the existing tunnel of the newly built tunnel blasting team is affected by various factors, such as distance, free surface, charge, and blasthole distribution. With different blasting schemes, the greater the amount of charge, the greater the vibration caused by blasting. Existing tunnels correspond to the front of the tunnel, and the axial and radial vibration peaks are greater than the vertical. Although the cut segment uses a less amount of explosive and has a less blasthole layout, there is only one free surface. Because of the clamping of the rock, it is compared with the other two segments. The vibration caused is the largest. Although the peripheral holes are filled with a large amount of explosive, the arrangement of the blast holes is relatively scattered and there are many free surfaces. Hence, the vibration caused is the smallest. Corresponding to the back of the tunnel face, since there is no rock clamp, the vibration caused by the cut segment is the smallest, and the vibration caused by the peripheral segment and the floor segment is relatively large. The vibration caused by the front explosion side is significantly greater than the vibration caused by the back explosion side. The vibration velocity caused by the unit charge of 1.5 m footage is greater than that of the 3.0 m footage. The vibration velocity caused by the unit charge of the cut segment is the largest, and the vibration velocity caused by the peripheral segment and the floor segment is smaller. The research results provide a reference for the blasting control of similar engineering construction.

Monitoring and Analysis of Blasting Vibration of Diversion Tunnel Excavation in Layered Rock Mass

2012 ◽  
Vol 249-250 ◽  
pp. 1047-1052 ◽  
Author(s):  
Hua Feng Deng ◽  
Min Zhu ◽  
Le Hua Wang ◽  
Ji Fang Zhou
Keyword(s):  
Rock Mass ◽  
Vibration Monitoring ◽  
Damage Effect ◽  
Good Effect ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Diversion Tunnel ◽  
Tunnel Excavation ◽  
Layered Rock ◽  
Layered Rock Mass

In order to insure the safety and stability of the existed dam body and dam curtain during the diversion tunnel excavation, the vibration velocities were analyzed based on in-site blasting vibration monitoring. Result shows that the elevation difference between explosion point and monitoring points has a great impact on the vibration velocity in addition to single fire dynamite and blast center distance. During data analysis, the traditional empirical formula of attenuation of blasting earthquake must be amended. Through contrasting and analyzing, the amended formula of attenuation of blasting earthquake wave is precise relatively. At the same time, two collapses during the diversion tunnel excavation were analyzed based on the characteristics of layered rock mass and fault distribution, and the explosion parameters were optimized, so that the damage effect of blasting vibration was controlled effectively. This research also takes a good effect in other similar works.

The Blasting Test with Precise Delayed Time Interval and Wavelet Pocket Analysis for Vibration Signals’ Energy

2014 ◽  
Vol 1023 ◽  
pp. 198-204
Author(s):  
Li He ◽  
Dong Wang Zhong
Keyword(s):  
Total Energy ◽  
Vibration Signal ◽  
Propagation Distance ◽  
Vibration Velocity ◽  
Time Interval ◽  
Blasting Vibration ◽  
Vibration Signals ◽  
Slope Test ◽  
The Impact ◽  
Delayed Time

As a physical carrier, blasting vibration signal includes much information about blasting method, explosive charge structure and propagation medium. Based on the indoor concrete slope test with millisecond blasting and wavelet pocket analysis technology, the blasting seismic signal was analyzed in the features of energy distribution in order to control the blasting vibration hazard better. The attenuation law of the energy and the peak vibration velocity (PPV) with distance decreased were researched. The effects of delayed time interval on PPV and energy are investigated, and the paper have analyzed the weakening degree of energy and PPV of vibration signals when damping ditch exists, so was its effect on the distribution of energy. The conclusions show that: the impact is great about delayed time interval on the total energy of signals in millisecond blasting; the damping ditch made the predominant frequency for energy concentrate on the low frequency band, damping effect of the damping ditch reduced with the delay time interval increasing. When the propagation distance increased, the attenuation trend of the PPV and total energy slowed down gradually near blasting area. The PPV and energy are not necessarily meanwhile the maximum; the energy of the vibration signal is not only determined by the PPV.

scholarly journals Experiment and Analysis of Wedge Cutting Angle on Cutting Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Deqiang Yang ◽  
Xuguang Wang ◽  
Yinjun Wang ◽  
Huaming An ◽  
Zhen Lei
Keyword(s):  
Construction Cost ◽  
Economic Benefits ◽  
Tunneling Rate ◽  
Vibration Velocity ◽  
Utilization Rate ◽  
Engineering Practice ◽  
Blasting Vibration ◽  
Cutting Depth ◽  
Vertical Side ◽  
Cutting Angle

In the process of tunnel excavation, large charge wedge cutting blasting is widely used to improve the effect of cut blasting and speed up the excavation rate, which is tantamount to increasing the construction cost. In order to save economic cost and improve cutting blasting effect, wedge cutting models with five different cutting angles were experimented and studied by using concrete materials on the basis of similarity theory analysis. The relationships among cutting depth, blasting volume, blasting fragment, and cutting angle are studied and deduced by the dimensional analysis method. The polynomial fitting of cutting depth, blasting volume, blasting fragment, and cutting angle is carried out according to the experimental data, and the corresponding fitting formula is obtained. The optimum cutting depth, hole utilization rate, blasting volume, and blasting fragment were obtained when the wedge cutting angle was 67° under the same charge. The values were 1.665 × 10−1 m, 92.5%, 8.390 × 10−3 m3, and 49.07 mm, respectively. With the use of TC4850N type blasting vibration meter, the blasting vibrations on the wedge in four directions are tested and analyzed. The results show that when wedge cutting inclination is 65 degrees, the peak vibration velocity is the minimum and the vibration intensity of the wedge cutting inclined side is generally smaller than that of the vertical side. Considering the cutting depth, blasting volume, blasting fragment, blasting vibration hazard, drilling error, tunneling construction cost, and other factors, the 65°∼69° wedge cutting blasting in engineering practice can improve the blasting tunneling rate and increase economic benefits. The experimental results show that the blasting tunneling rate is increased and the economic benefit is increased with the minimum construction tunneling cost, which has certain engineering significance.

Influences of Tunnel Excavation Blasting Vibration on Surface High-Rise Building

2010 ◽  
Vol 163-167 ◽  
pp. 2613-2617
Author(s):  
Hai Liang Wang ◽  
Tong Wei Gao
Keyword(s):  
Vibration Frequency ◽  
Vertical Vibration ◽  
Frame Structure ◽  
Vibration Monitoring ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Road Tunnel ◽  
Concrete Frame ◽  
High Rise ◽  
Order Of Magnitude

According to the 33 floors high building, blasting vibration monitoring had been carried on. The building, along Yunnan road tunnel of Qingdao Cross-harbor Tunnel Guide Line Project, has concrete frame structure. Monitoring data had been analyzed. Results showed that rules of vertical vibration velocity and main vibration frequency have similar relevance. Amplification effect of them was existed on the middle and top of the building. From the 2nd floor of downward ground to ground, the value of them suddenly decreased. Main vibration frequency is in the range of 101~102 order of magnitude.

scholarly journals Experimental Investigation of the Propagation and Attenuation Rule of Blasting Vibration Wave Parameters Based on the Damage Accumulation Effect

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Huaibao Chu ◽  
Xiaolin Yang ◽  
Shuanjie Li ◽  
Weimin Liang
Keyword(s):  
Frequency Band ◽  
Damage Accumulation ◽  
Low Frequency ◽  
Experimental Results ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Main Frequency ◽  
Wave Parameters ◽  
Accumulation Effect ◽  
Vibration Wave

The propagation and attenuation rule of blasting vibration wave parameters is the most important foundation of blasting vibration prediction and control. In this work, we pay more attention to the influence of the damage accumulation effect on the propagation and attenuation rule of vibration wave parameters. A blasting damage accumulation experiment was carried out, the ultrasonic wave velocity of the specimens was measured, and the damage value was calculated during the experiment. The blasting vibration wave was monitored on the surface of the specimens, and its energy was calculated by using the sym8 wavelet basis function. The experimental results showed that with the increase in the number of blasts, the damage continues to increase; however, the vibration velocity and the main frequency decrease continuously, the unfocused vibration wave energy in the zone near to the blasting source is rapidly concentrated in the low-frequency band (frequency bands 1 to 3), and the energy is further concentrated in the low-frequency band in the intermediate zone and zone far from the blasting source. There is a distortion process in which the vibration velocity and the main frequency increase slightly and the energy of the blasting vibration wave converges to the high-frequency band (the 5th band) before the sudden unstable fracture failure of the specimens. The experimental results indicate that the prediction and evaluation of blasting vibration should consider the variation rule of blasting vibration wave parameters synthetically based on the cumulative damage effect, and it is not safe to use only one fixed vibration control standard for the whole blasting operation.

Safety threshold of blasting vibration velocity in foundation excavation of Baihetan super-high arch dam

2020 ◽  
Vol 79 (9) ◽  
pp. 4999-5012
Author(s):  
Wenjun Xia ◽  
Wenbo Lu ◽  
Gaohui Wang ◽  
Peng Yan ◽  
Da Liu ◽  
...  
Keyword(s):  
Arch Dam ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
High Arch Dam

Numerical Simulation of Penetration Effect of Spherical Fragment on Square Honeycomb Sandwich Plate

2011 ◽  
Vol 474-476 ◽  
pp. 1869-1873 ◽  
Author(s):  
Tao Wang ◽  
Wen Li Yu ◽  
San Qiang Dong ◽  
Yun Liang Gao
Keyword(s):  
Oblique Incidence ◽  
Sandwich Plate ◽  
Normal Incidence ◽  
Impact Angle ◽  
Damage Effect ◽  
Penetration Effect ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Plate ◽  
Solid Plate ◽  
Active Fragment

In this paper, a spherical fragment penetrating to square honeycomb sandwich plate and solid plate which has the same mass as sandwich plate are simulated by LS-DYNA code. The fragment impacts plates at normal incidence and oblique incidence with 30º impact angle at the velocity of 300m/s, 350m/s, 380m/s, 400m/s, 450m/s and 500m/s separately. And the damage pattern of sandwich plate, the acceleration of fragment and the energy absorption of sandwich plate are acquired. For sandwich plate, the acceleration of fragment is less than that of solid plate and the internal energy absorbed is larger that that of solid plate. The result can be used to design new active fragment to improve the damage effect to sandwich plate.

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