• Explosives and Blasting
• /
• v.34 no.3
• /
• pp.17-20
• /
• 2016

This paper introduce a multistage parallel non-vibration electronic tunnel blasting cases which adapts Electronic Blasting System(EBS) and the center-cut blasting method to excavating a single line railway tunnel close to residential area. As a result, it was revealed that the vibration and noise showed a reduction of 23.5% and 75% of compared with the allowable standard. We successfully completed the tunnel excavation with decreasing construction time and construction cost and without civil compliant.

• Explosives and Blasting
• /
• v.26 no.2
• /
• pp.1-10
• /
• 2008

The safe level for residential structures has usually been prescribed as just 'particle velocity' in various specifications in Korea. It implies that there is a possibility of interpreting the 'particle velocity' as the PPV (Peak Particle Velocity), PVS (Peak Vector Sum), or something else, depending on the interpreter. As a result, there have always been some difficulties in both designing a controlled blasting and controling the blast-induced ground vibrations. This paper is intended to show what the role of the safe level criteria such as PPV or PVS is, and also how we should use the concept of the scaled distance equation in a controlled blast design. The paper also emphasizes the importance of the allowable level for various residential structures and its uses in each stage of the controlled blast design.

• Journal of the Korean GEO-environmental Society
• /
• v.24 no.10
• /
• pp.5-13
• /
• 2023

With the recent increase in development projects centered on urban areas, the construction of building structures is increasing in areas adjacent to the urban railway operation section. In this case, since ground vibration is generated by the train in operation and affects the adjacent structure, the building structure needs appropriate vibration reduction against train vibration generated at the adjacent location from the desing phase. However, the vibration levels calculated vary depending on the train vibration evaluation method, which means that the implementation of vibration reduction may vary depending on the train vibration evaluation method. Therefore, this study calculated the vibration level according to ground conditions, tunnel depth and separation distance between vibration sources and adjacent structures using numerical analysis and train vibration evaluation methods, and compared them to designning phase. And the appropriate separation distance between the tunnel and the adjacent structure was evaluated by comparing the vibration level with the allowable standards. As a result of the study, the Ungar and Bender evaluation method is evaluated as the most appropriate among the train vibration evaluation methods, and the appropriate separation distance between the tunnel and the adjacent structure is evaluated to be more than 4.5D.

• Explosives and Blasting
• /
• v.31 no.1
• /
• pp.64-75
• /
• 2013

This case study deals with an excavation blasting carried out at "Sooseo-Pyeongtek ${\bigcirc}$-${\bigcirc}$ section construction site" in the vicinity of residential area. Originally, the sequential blasting (multi-stage blasting) using electric detonators was planed in this area. However, there was a concern that the sequential blasting method could increase the construction cost by delaying the construction period due to possible complaints from local residents. As an alternative, electronic deck blasting technique was taken in order to meet the ground vibration regulation (0.2cm/s, in apartment area) and to keep the construction schedule. The performance of the electronic deck charge blasting was two times better than the sequential blasting with electric detonators and the level of ground vibration was also within the regulatory value (0.2cm/s). In particular, it was shown that the use of electronic detonater eDevII, which was developed for tunnel, could provide more convenient and electrically safer working condition.

• Journal of the Korea Concrete Institute
• /
• v.18 no.6 s.96
• /
• pp.721-728
• /
• 2006

Earthquakes are reported thai building structures have been colossal damaged, but before 1988 designed structures which were not applicate seismic design code have no seismic performance. Especially, for the apartment structures were indicated that it have no resist wall element of earthquake before 1988 designed structures. We have to evaluate for seismic performance this structures, therefore it will be retrofitted for seismic index sufficient structures. We performed seismic performance evaluation for model structures by MIDAS which is general structure analysis software. In this study, it was performed shaking table test to evaluate model structure which is reinforcement concrete and 5 floors for seismic performance index. We made specimens by similar's law and tested shaking table test. In the shaking table test it is not performed prototype model test because of space and equipment condition. So we had made scale-down model for 1/5 by similar's law. That's why it needs for the evaluation of performance. However, it is not possible to do an experiment of prototype owing to the shortage of space and the limit of an experimental instrument in the shaking table test. Then, modeling and reducing the part of prototype do the experiment. In this experiment a shaking table test is done and seismic performance of model structures is evaluated by using similitude laws for scale down specimen. As a result it is proved that non-seismic design structures need to retrofit since seismic performance shows life safe grade in 0.12g of an earthquake.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.473-485
• /
• 1994

Vibration control of concrete slab mounting precision instrument is needed to make the working vibration environments in frequency domain as well as time domain. In order to take the vibration control countermeasures, signal and system analyses of the concrete slab are processed. Through them the dynamic responses of concrete slab are obtained in frequency domain, and frequency response functions are acquired by exciting the concrete slab and measuring dynamic responses at various points across its surface. The dynamic characteristics of concrete slab are determined by experimental modal analysis. Based on modal parameters from a set of frequency response function measured, it is possible to investigate the effects of potential design modifications and reduce the dynamic response of concerned point by moving or suppressing an objectionable modal resonance conditions through structural dynamics modification.

• Explosives and Blasting
• /
• v.21 no.1
• /
• pp.69-76
• /
• 2003

Test blasting has been performed with V-cut to investigate the characteristics. Blasting vibrations were measured at two directions, the proceed direction and side direction. Propagation characteristics were determined by regression analysis; square root scaled distance and cube root scaled distance with maximum charge per delay of the blast. Testing result, The cross point was 62m in the allowable vibration velocity of 3mm/sec and 46m In 5mm/sec. Also, vibration level with measuring point was highest and decayed fastest, adapting to cube root scaled distance, for the proceed direction on ground.

• Explosives and Blasting
• /
• v.28 no.1
• /
• pp.63-70
• /
• 2010

This study is investigated the extent of the noise and ground vibration in an adjacent zone of a cattle pen and an antiquated housing structures for judgement of the spot applicability on the extents of the noise and ground vibration of the rock-splitting method by an oil pressure. It is studied by measuring and analysing in an adjacent position the extents of the noise and ground vibration according to the work process of the rock-splitting method, such as drilling, rock-splitting, arranging rock, loading and by being compared with the permitted level on the noise and ground vibration fixed at the spot. To the results, it is identified that the influence to the noise has to be considered, even if the rock-splitting method is applied as an excavation method to lower a ground vibration by the classification on blasting method of the ministry of land, transport and marine affairs.

• Explosives and Blasting
• /
• v.33 no.4
• /
• pp.14-24
• /
• 2015

We conducted test blasting in 3 sites to identify the effect on safety of the earth retaining wall by near blasting vibration. As a test result, we confirm that underground structures(earth anchor et al.) are relatively safer than surface structures as the underground vibration is 10~52% of surface vibration at a same distance. We derived surface and underground vibration prediction equations by regression analysis of measured 3 sites' surface and underground vibration PPV. Also we calculated minimum separation distance by blasting pattern about underground and surface curing concrete. Unless any discontinuity which are unsafe on the earth retaining wall appear, blasting work using under 2.4kg per delay is not meaningful to the earth retaining wall's safety as the result of measuring near blasting vibration, confirming change the earth retaining wall's instrument, and observation of structural deformation.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.5 no.3
• /
• pp.251-260
• /
• 2003

Tunnel blasting has been performed with V-cut to investigate the characteristics. Blasting vibrations were measured at two directions, the proceed direction and side direction. Propagation characteristics were determined by regression analysis; square root scaled distance and cube root scaled distance with maximum charge per delay of the blast. Testing result, The cross point was 62m in the allowable vibration velocity of 3mm/sec and 46m in 5mm/sec. Also, vibration level with measuring point was highest and decayed fastest, adapting to cube root scaled distance, for the proceed direction on ground.