scholarly journals Vibration Characteristic of High-Voltage Tower Influenced by Adjacent Tunnel Blasting Construction

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Limin Duan ◽  
Wenshuai Lin ◽  
Jinxing Lai ◽  
Peng Zhang ◽  
Yanbin Luo
Keyword(s):  
High Voltage ◽  
Peak Velocity ◽  
Maximum Velocity ◽  
Field Tests ◽  
Control Measures ◽  
Vibration Velocity ◽  
Measuring Point ◽  
Main Frequency ◽  
Tunnel Blasting ◽  
Tower Foundation

The effects of tunnel blast excavation on the adjacent existing high-voltage tower are comprehensively studied for the Chashan highway tunnel project as a case study. To investigate the effect of blast-induced vibration from the tunnel on the adjacent existing tower, field tests and numerical simulations method were adopted to study the vibration velocity and vibration frequency of the existing tower. Moreover, the relationship between the transverse distance from the detonation center and the peak velocity is discussed in detail. The results showed that the peak velocity of the measuring point in tower foundation increases with the distance between the detonation center and tower foundation approaches, and the maximum velocity is appearing when detonation center is 0 m. Furthermore, the corresponding energy spectrum distributions of the existing tower under the effect of blast induced by vibration is also analyzed, and the main frequency of vertical vibration is generally higher than that of transverse vibration. On combining the peak velocity with the main frequency and the natural frequency of the tower, the safety evaluation of the blasting area is proposed, and the corresponding control measures of blasting vibration are put forward. A guideline for the blast safety zone is proposed based on vibration velocity, main frequency, and the quantity of explosive.

Small Spacing Tunnels the Blasting Excavation Dynamic Effect

2013 ◽  
Vol 353-356 ◽  
pp. 1484-1489
Author(s):  
You Mo ◽  
Bin Teng ◽  
Zu Yin Zou ◽  
Lin Li ◽  
Mei Zhong
Keyword(s):  
Peak Velocity ◽  
Dynamic Effect ◽  
Element Model ◽  
Euler Method ◽  
Vibration Velocity ◽  
Back Side ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Clear Distance ◽  
Small Spacing

Kinetic research of Small spacing tunnel blasting excavation is always the hot issue both at home and abroad. In this paper, the entrance section of a small spacing tunnel is chose as an example, the Explicit dynamic finite element model and the Euler method is adopted to accurately simulate the process of blasting vibration, and the peak vibration velocity response of the tunnel is gotten. Studies has shown that, the peak velocity is more sensitive to space change when clear distance is less than 1.5 times of the hole diameter; various depth of tunnel causes different clamping action of surrounding rock, thus has different effects on peak velocity; vibration velocity at head-burst side is 5-8 times more than that at back side, vibration velocity at tunnel waist is 1.98-2.23 times more than that at up side, vibration velocity at tunnel shoulder is 1.68-1.85 times more than that at up side, so the waist position at head-burst side should be given exclusive attention.

scholarly journals Propagation Laws of Blasting Seismic Waves in Weak Rock Mass: A Case Study of Muzhailing Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Lijun Chen ◽  
Jianxun Chen ◽  
Yanbin Luo ◽  
Yalong Guo ◽  
Yongjun Mu ◽  
...  
Keyword(s):  
Vibration Frequency ◽  
Energy Input ◽  
Low Frequency ◽  
Vibration Velocity ◽  
Weak Rock ◽  
Blasting Vibration ◽  
Main Frequency ◽  
Tunnel Blasting ◽  
The Right ◽  
Rock Tunnels

In order to study the propagation laws of blasting vibration waves in weak rock tunnels, the longitudinal and circumferential blasting vibration tests in Muzhailing Tunnel were carried out, and the measured data were analyzed and studied using the methods of Sadov’s nonlinear regression, Fourier transform, and Hilbert–Huang transform (HHT) to provide a reference for the optimization of blasting design of Muzhailing Tunnel or similar weak rock tunnels. The results showed that the tangential main frequency decreases rapidly and the radial main frequency decreases slowly with the increase of proportionate charge quantity. Under a certain charge quantity, as the distance from the explosion source increases, the spectrum width of the blasting vibration frequency becomes narrower, the overall energy is more concentrated, and the vibration frequency tends to be closer to the low frequency. At a certain distance from the explosive source, the frequency of blasting vibration decreases gradually, and the amplitude of low-frequency region increases with the increase of charge quantity. The vibration velocity on the left side of the tunnel is larger than that on the right side, and the vibration velocity at the vault and the arch foot of lower bench decreases rapidly, while the vibration velocity at the arch feet of upper bench and middle bench decreases slowly. The vibration frequencies of the left arch foot of the middle bench and the right arch foot of the upper bench are higher than those of other positions, while the frequencies of the left arch foot of the upper bench are the lowest. During tunnel blasting, the energy input to the strata media is mainly concentrated in the stage of the blasting of the cut hole. The blasting has more energy input to the left arch foot of the upper bench and the tunnel vault, which is consistent with the conclusion of frequency analysis.

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.

scholarly journals Field Tests and research of Large Deformation Control Measures for Soft Rock Tunnel with High Geostress

2020 ◽  
Vol 570 ◽  
pp. 042006
Author(s):  
Xiaoming Sun ◽  
Bo Zhang ◽  
Yong Zhang ◽  
Xiaobing Qiao ◽  
Zhijiao Wang ◽  
...  
Keyword(s):  
Large Deformation ◽  
Field Tests ◽  
Soft Rock ◽  
Control Measures ◽  
Deformation Control ◽  
High Geostress ◽  
Rock Tunnel

Haemodynamic changes with the use of neuromuscular electrical stimulation compared to intermittent pneumatic compression

2014 ◽  
Vol 30 (5) ◽  
pp. 365-372 ◽  
Author(s):  
KJ Williams ◽  
HM Moore ◽  
AH Davies
Keyword(s):  
Electrical Stimulation ◽  
Healthy Subjects ◽  
Peak Velocity ◽  
Neuromuscular Electrical Stimulation ◽  
Haemodynamic Effect ◽  
Maximum Velocity ◽  
Intermittent Pneumatic Compression ◽  
Laser Doppler ◽  
Thrombosis Prophylaxis ◽  
Electrical Stimulator

Introduction Enhancement of peripheral circulation has been shown to be of benefit in many vascular disorders, and the clinical effectiveness of intermittent pneumatic compression is well established in peripheral vascular disease. This study compares the haemodynamic efficacy of a novel neuromuscular electrical stimulation device with intermittent pneumatic compression in healthy subjects. Methods Ten healthy volunteers (mean age 27.1 ± 3.8 years, body mass index 24.8 ± 3.6 kg/m2) were randomised into two groups, in an interventional crossover trial. Devices used were the SCD Express™ Compression System, (Covidien, Ireland) and the geko™, (Firstkind Ltd, UK). Devices were applied bilaterally, and haemodynamic measurements taken from the left leg. Changes to haemodynamic parameters (superficial femory artery and femoral vein) and laser Doppler measurements from the hand and foot were compared. Results Intermittent pneumatic compression caused 51% ( p = 0.002), 5% (ns) and 3% (ns) median increases in venous peak velocity, time-averaged maximum velocity and volume flow, respectively; neuromuscular electrical stimulator stimulation caused a 103%, 101% and 101% median increases in the same parameters (all p = 0.002). The benefit was lost upon deactivation. Intermittent pneumatic compression did not improve arterial haemodynamics. Neuromuscular electrical stimulator caused 11%, 84% and 75% increase in arterial parameters ( p < 0.01). Laser Doppler readings taken from the leg were increased by neuromuscular electrical stimulator ( p < 0.001), dropping after deactivation. For intermittent pneumatic compression, the readings decreased during use but increased after cessation. Hand flux signal dropped during activation of both devices, rising after cessation. Discussion The neuromuscular electrical stimulator device used in this study enhances venous flow and peak velocity in the legs of healthy subjects and is equal or superior to intermittent pneumatic compression. This warrants further clinical and economic evaluation for deep venous thrombosis prophylaxis and exploration of the haemodynamic effect in venous pathology. It also enhances arterial time-averaged maximum velocity and flow rate, which may prove to be of clinical use in the management of peripheral arterial disease. The effect on the microcirculation as evidenced by laser Doppler fluximetry may reflect a clinically beneficial target in microvascular disease, such as in the diabetic foot.

Safety Control of Blasting Construction in New Austrian Metro Tunnel

2012 ◽  
Vol 446-449 ◽  
pp. 2462-2465 ◽  
Author(s):  
Hong De Wang ◽  
Xiu Feng Shen
Keyword(s):  
Regression Analysis ◽  
Vibration Monitoring ◽  
Actual Condition ◽  
Vibration Velocity ◽  
Charge Weight ◽  
Blasting Vibration ◽  
Safety Control ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Metro Tunnel

Abstract. Through the analysis and research on the vibration effect caused by the urban New Austrian (shallow embedded) metro tunnel blasting construction, the main harming effect of the blasting vibration on the surface buildings is summarized. According to the actual condition on the site of blasting construction in No.2 line of Dalian metro tunnel, the reasonable vibration monitoring plan for blasting vibration wave is established. At the same time, by means of the regression analysis about the monitoring results of blasting vibration, the vibration wave’s regression formula are set up, which can expression the correlation among the vibration velocity, the charge weight, the distance between the blasting fountains and the buildings. The results show that the Sadaovsk formula can be use to describe the effect of the metro tunnel blasting construction on the surface buildings accurately and reasonably in this construction segment. This kind of regression analysis method can be use to direct subsequent blasting excavation.

Analysis of the Influence of Tunnel Blasting to the Neighbor Tunnel

2011 ◽  
Vol 199-200 ◽  
pp. 870-873
Author(s):  
Hai Liang Wang ◽  
Shu Cui Cong ◽  
Bi Jun Wang ◽  
Lin Sheng Liu
Keyword(s):  
Vibration Velocity ◽  
Vibration Test ◽  
Blasting Vibration ◽  
Guide Line ◽  
Analytical Results ◽  
Tunnel Blasting ◽  
The Relationship ◽  
Peak Value

According to the tunnel blasting vibration test at Kiaochow bay Cross-harbor Tunnel Guide Line Project, the regulation of the tunnel vibration velocity has been studied. Based on the analytical results, this paper finds that the change regulation of vertical, horizontal radial and tangential vibration velocity as the different distances from the work face. The tunnel vibration velocity of the rear work face is greater than the unexcavated area. The peak value of the rear work face is 2-2.5 times as large as that of the front work face, vibration velocity of the front work face attenuates gently. The paper figures out the relationship between vibration velocity and distance from sensor to the work face, which can offer a reference to similar studies.

Isolation Performance Evaluation of Compressor Vibration Isolating Systems Based on LMS Test. Lab Signature

2011 ◽  
Vol 130-134 ◽  
pp. 1220-1225 ◽  
Author(s):  
Li Zhang ◽  
Hao Chen ◽  
Yan Jue Gong ◽  
Hong Wu ◽  
Shuo Zhang
Keyword(s):  
Performance Evaluation ◽  
Evaluation Criteria ◽  
Maximum Velocity ◽  
Single Layer ◽  
National Standard ◽  
Vibration Velocity ◽  
Upward Trend ◽  
Refrigeration Unit ◽  
Comparison Results ◽  
Isolation Performance

In order to reduce vibration and noise of the compressor used in small and medium-sized refrigeration unit, this paper designs different vibration isolating systems and carries out experiment of isolation performance evaluation based on LMS Test. Lab Signature software. The comparison results of four different vibration isolating systems show that the peak values of vibration velocity response in each system mainly appear at 25Hz, 50Hz, 75Hz and 100Hz, and the maximum velocity does not exceed 22mm/s which is less than the maximum allowed by the national standard[1]. And the Vibration Level Difference (VLD) is taken as evaluation criteria for isolating vibration, that of single-layer vibration isolating system is within 10-20dB, and that of double-layer vibration isolating system is within 20-35dB. Furthermore with the increase of middle-mass, the VLD has a clear upward trend.

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