경남 창원시 진해 지역의 발파진동 예측에 관한 연구

이충원(Lee, Chung-Won) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.4

국가기반시설의 확충을 위한 발파 등 각종 건설공사에 기인한 진동 문제는 민원에 의해 그 중요성이 점증하고 있는 실정이다. 진동은 대표적인 환경피해 요인으로, 건설방재적 관점에서도 대단히 큰 의미를 갖는다. 본 연구에서는 경남 창원시 진해 지역에서 실규모 시험발파를 수행하여 심발발파 종류에 따른 파쇄암의 입경을 분석하고, 이에 대한 진동 계측 결과를 통해 신뢰수준 95%의 자승근식을 발파진동 추정식으로 제안하였다. 실규모 시험발파 결과와 비교시, 거리에 따른 발파진동 추정치는 미 광무국 식이 실규모 시험발파 결과보다 보수적인 것으로 확인되었다. 따라서, 현장 여건을 고려한 최적의 발파설계를 위해서는 실규모 시험발파를 통한 진동의 계측 및 이에 근거한 발파진동 추정식을 도출할 필요가 있다. 그러나, 터널 굴착 등의 실제 발파시에는 진동을 함께 계측함으로써 주변의 보안물건에 피해가 발생하지 않도록 유념하여야 할 것이다. Vibration problems due to a number of construction works including blasting for infrastructure development are getting important because of a civil appeal. Vibration is representative factor of environmental damage, hence, this has great meaning to prevent potential disasters. In this study, through the real-scale test blasting performed at Jinhae area, Changwon, Gyeongnam, the diameter of blasted rock was analyzed with blasting method, and square root equation(SRE) with 95% confidence level was proposed for prediction of blasting-induced vibration. From the comparison between tendencies of blasting-induced vibration with distance, it was confirmed that the predicted blasting-induced vibration by USBM(U.S. Department of Interior, Bureau of Mines) equation was more conservative than that by proposed equation based on the real-scale test blasting. Therefore, measuring vibration and determining equation for prediction of blasting-induced vibration through the real-scale test blasting are needed for optimal blast design considering field condition. However, in the case of real blasting including tunnel excavation, measuring vibration is required for damage prevention to surrounding facilities.

Improvement of fluid penetration in soil by plasma blasting

장현식,백인준,송재용,이근춘,장보안 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.6

Plasma blasting by high-voltage arc discharge was performed in laboratory-scale soil samples to investigate fluid penetration. A plasma blasting device with a large-capacity capacitor and columnar soil samples with a diameter of 80 cm and a height of 60 cm were prepared. The columnar soil samples were made of sand and silt mixed in a 7:3 ratio (the A samples) or a 9:1 ratio (the B samples). When fluid was injected by pressure without plasma blasting, fluid penetrated into the soil only near the borehole, and the penetration area ratio was less than 10%. In further tests, fluid was injected by plasma blasting with different discharge energies of 1–27 kJ. When plasma blasting was performed once in the A samples, the penetration area ratios of the fluid were 16–25%; after five consecutive blasts, the penetration area ratios were 30–48%. When five consecutive plasma blasts were carried out on the B samples, the fluid penetration area ratios were 33–72%. This difference indicates that the fluid penetration area increases with higher discharge energy of plasma blasting and with a greater number of blasts. The fluid penetration radius was calculated to assess the fluid penetration volume. When the fluid was injected by hydraulic pressure only, the penetration radius was 9–12.4 cm, whereas the penetration radius was 27–33.2 cm when blasting was performed five times. The radius was increased by up to 200% by plasma blasting. In the field tests, the fluid injection in the test hole subjected to plasma blasting was greater by about 170% compared with the control test hole, in which the fluid was injected only by hydraulic pressure. In addition, the electrical resistivity around the test hole subjected to plasma blasting was markedly lower, and fluid diffused from this test hole to a minimum radius of 2 m. These results indicate that a cleaning agent will penetrate further and the remediation efficiency of contaminated soil will be improved if plasma blasting is applied for in situ cleaning of low-permeability contaminated soil.

NDC 및 Wide Space 혼합공법을 통한 발파효율 개선 사례연구

노상림(Sang-Lim No),노승환(Seung-Hwan Noh),이상필(Sang-Pil Lee),이훈연(Hoon-Yeon Lee),이태노(Tai-Ro Lee) 한국암반공학회 2006 터널과지하공간 Vol.16 No.5

본 연구는 발파 시 발생하는 진동을 저감시키고 발파효율을 증진시키기 위하여 NDC(New Deck Charge) 공법 및 Wide space 공법을 혼합하여 발파를 실시한 사례연구이다. NDC 공법은 종이분리봉을 이용하여 분산장약을 실시하는 공법으로 발파 시 진동은 저감시키나 공저부에서 발파효과가 저감되는 경향을 보인다. Wide Space 공법은 기존의 일반적인 발파공법에 비해 파쇄입도를 조절하고 발파효율을 높이는데 유리한 공법이다. 본 사례 연구에서는 두 가지 공법을 혼합하여 현장 적용성을 검토한 결과, 진동속도가 감소되고 발파효율이 증가하는 결과를 확인하였으며, 향후 다양한 조건에서 발파를 실시하여 자료를 축적한다면 민원저감 및 공기단축에 기여할 수 있는 유용한 발파패턴을 정립할 수 있을 것으로 사료된다. This paper introduces the combination of two blasting methods applied to reduce blast-vibration and increase blast efficiency. NDC (New Deck Charge) blasting method using air deck effect with separation tube made of paper was effective to reduce blast-vibration, while blast efficiency was decreased a little in the bottom of a blasthole. Wide Space blasting method has an advantage to control the fragmentation and to increase blast efficiency over conventional blasting methods. In this study new blasting method combining NDC blasting method and Wide Space blasting method was applied to the field, it was confirmed to reduce blast-vibration and increase blast efficiency. It is expected to make useful blasting method to cover the public complaints and to shorten construction time by accumulating blasting data using new method with various conditions.

건공화 공법의 발파 성능 평가를 위한 현장 시험에 관한 연구

이승훈(Lee, Seung Hun),정성훈(Chong, Song-Hun),최형빈(Choi, Hyung Bin) 대한토목학회 2022 대한토목학회논문집 Vol.42 No.2

암반층이 얕은 깊이에서 출현하는 국내 지층 조건과 지하 공간의 활용도 증가로 인해서, 발파에 의한 굴착은 여전히 이용되고 있다. 발파 천공 이후에 존재하는 물이 있는 조건에서 실시되는 표준 발파는 폭굉압력 감소, 일정 장약량 사용, 디커플링과 같은 기술적인 어려움이 있다. 하지만, 기존의 표준 발파 공법을 대체할 만한 공법이 없는 실정이다. 본 논문에서는 건공화 펌프 시스템을 이용하여, 천공 내부에 존재하는 물을 제거하는 건공화 ANFO (Ammonium Nitrate Fuel Oil) 발파와 발파 성능의 비교를 위해서 추가적으로 표준 발파를 수행하였다. 각각의 발파 공법에서 계측된 진동 속도 데이터들과 환산거리의 함수로 이루어진 경험적인 발파진동 추정식을 이용하여, 최소제곱법에 의한 선형회귀분석을 실시하고, 궁극적으로 발파 성능을 정량적으로 분석하였다. 그 결과, 건공화 ANFO 발파에서 진동 감쇠가 더 크게 발생하고, 암반 파쇄에 더 많은 에너지를 소비하여, 더 가까운 거리에서 진동 허용 기준을 만족하는 진동 속도를 보였다. 또한, 표준 발파의 발파 진동 영향권이 건공화 ANFO 발파보다 더 멀리 있고, 발파 패턴의 범위가 더 넓은 것으로 나타났다. 본 연구에서 수행된 현장 발파 실험 결과로부터, 건공화 ANFO 발파 공법의 발파 성능이 효율적임을 확인하였다. The existence of shallow bedrock and the desire to use underground space necessitate the use of blasting methods. The standard blasting method under water after drilling is associated with certain technical difficulties, including reduced detonation power, the use of a fixed charge per delay, and decoupling. However, there is no blasting method to replace the existing blasting method. In this paper, a dry hole charged with ANFO blasting is assessed while employing a dry hole pumping system to remove water from the drill borehole. Additional standard blasting is also utilized to compare the blasting performances of the two methods. The least-squares linear regression method is adopted to analyze the blasting vibration velocity quantitatively using the measured vibration velocity for each blasting method and the vibration velocity model as a function of the scaled distance. The results show that the dry hole charged with ANFO blasting will lead to greater damping of the blasting vibration, more energy dissipation to crush the surrounding rock, and closer distances for the allowable velocity of the blasting vibration. Also, standard blasting shows much longer influencing distances and a wider range of the blasting pattern. The pilot test confirms the blasting efficiency of dry hole charged with ANFO blasting.

플라즈마 발파를 이용한 토양 내 유체의 침투 효율 개선

백인준 ( In-joon Baek ),장현식 ( Hyun-shic Jang ),송재용 ( Jae-yong Song ),이근춘 ( Geun-chun Lee ),장보안 ( Bo-an Jang ) 대한지질공학회 2021 지질공학 Vol.31 No.3

고전압 아크 방전에 의한 플라즈마 발파의 유체 침투 효율을 검증하기 위해 실험실 규모의 토사 시료에 대하여 발파 시험을 실시하였다. 이 연구를 위해 대용량 축전기가 포함된 플라즈마 발파 장치와 직경 80 cm, 높이 60 cm 크기의 컬럼형 토사 시료를 제작하였다. 토사 시료로는 사질토와 실트를 7:3 비율로 섞은 A 시료 7개와 9:1 비율로 섞은 B 시료 3개가 제작되었다. A 시료에 플라즈마 발파 없이 수압만으로 유체를 주입했을 때는 시추공 주변으로 국소적인 침투만 발생되었고 침투면적비는 5% 이하로 분석되었다. 플라즈마 발파에 의한 유체 침투 시험은 1 kJ, 4 kJ 그리고 9 kJ의 방전 에너지로 실시되었다. A 시료에 대한 플라즈마 발파 시험에서 유체의 침투면적비는 1회만 발파하였을 때는 16~25% 이고 5회 연속 발파 시에는 30~48%로 분석되어, 수압만으로 유체를 주입했을 때보다 침투면적이 최대 9.6배까지 넓어졌다. B 시료에 대한 5회 연속 플라즈마 발파 시험에서 유체의 침투면적비는 33~59%로 분석되어 동일 조건의 A 시료 시험에 비해 침투면적이 1.1~1.4배 정도 넓어졌다. 이러한 결과는 플라즈마 발파 시에 방전 에너지가 클수록, 발파 횟수가 증가할 수록 유체의 침투면적이 증가하며, 투수성이 큰 토양에서 플라즈마 발파가 더욱 효과적임을 보여준다. 유체 침투 효과를 삼차원적인 부피로 분석하기 위해 유체 침투반경을 계산하였다. 수압으로만 유체를 주입했을 때의 침투반경은 9 cm인 반면에, 9 kJ의 에너지로 5회 발파 시에는 침투반경이 27~30 cm로 계산되어 유체 침투 효과가 최대 333%까지 증가되었다. 이러한 연구결과는 투수성이 낮은 실제 오염토양에서 원위치 토양 세정을 실시할 때 플라즈마 발파 기술을 적용하면, 세정제의 전달범위가 증가되어 정화효율이 개선될 수 있다는 것을 보여준다. Plasma blasting by high voltage arc discharge were performed in laboratory-scale soil samples to investigate the fluid penetration efficiency. A plasma blasting device with a large-capacity capacitor and columnar soil samples with a diameter of 80 cm and a height of 60 cm were prepared. Columnar soil samples consist of seven A-samples mixed with sand and silt by ratio of 7:3 and three B-samples by ratio of 9:1. When fluid was injected into A-sample by pressure without plasma blasting, fluid penetrated into soil only near around the borehole, and penetration area ratio was less than 5%. Fluid was injected by plasma blasting with three different discharge energies of 1 kJ, 4 kJ and 9 kJ. When plasma blasting was performed once in the A-samples, penetration area ratios of the fluid were 16-25%. Penetration area ratios were 30-48% when blastings were executed five times consecutively. The largest penetration area by plasma blasting was 9.6 times larger than that by fluid injection by pressure. This indicates that the higher discharge energy of plasma blasting and the more numbers of blasting are, the larger are fluid penetration areas. When five consecutive plasma blasting were carried out in B-sample, fluid penetration area ratios were 33-59%. Penetration areas into B-samples were 1.1-1.4 times larger than those in A-samples when test conditions were the same, indicating that the higher permeability of soil is, the larger is fluid penetration area. The fluid penetration radius was calculated to figure out fluid penetration volume. When the fluid was injected by pressure, the penetration radius was 9 cm. Whereas, the penetration radius was 27-30 cm when blasting were performed 5 times with energy of 9 kJ. The radius increased up to 333% by plasma blasting. All these results indicate that cleaning agent penetrates further and remediation efficiency of contaminated soil will be improved if plasma blasting technology is applied to in situ cleaning of contaminated soil with low permeability.

플라즈마 블라스팅을 이용한 유류오염토양의 투수성과 정화효율 개선을 위한 실험적 연구

장현식 ( Hyun-shic Jang ),김기준 ( Ki-joon Kim ),송재용 ( Jae-yong Song ),안상곤 ( Sang-gon An ),장보안 ( Bo-an Jang ) 대한지질공학회 2020 지질공학 Vol.30 No.4

유류오염 토양의 투수성 및 정화효율을 개선하기 위하여 고전압 아크 방전에 의한 플라즈마 블라스팅을 토양에 적용하였다. 이 연구를 위하여 고전압 발생장치를 새로 제작하였고, 실트질 모래인 토양시료, 토양시료에 소석회를 혼합한 시료와 토양시료에 시멘트를 혼합한 세 종류의 토양시료를 다져서 소형 토조와 대형 토조를 제작한 후 각각의 토조내에서 플라즈마 블라스팅을 시행하여 유체확산의 범위와 투수성의 변화를 측정하였다. 플라즈마 블라스팅이 시행된 토양시료에서는 플라즈마 블라스팅이 시행되지 않은 대조군에 비해 유체의 확산 부피가 약 11~71% 증가하였다. 낮은 전압하에서 플라즈마 블라스팅이 시행되면 토양 내에서는 구조적 취약면(다짐면)을 따라 수평적 확산이 우세하게 나타났으나 높은 전압에 의한 플라즈마 블라스팅은 토양 내에 구형의 입체적인 확산을 발생시켰다. 플라즈마 블라스팅은 투수성 또한 증가시켰으며, 소석회 및 시멘트가 혼합된 토양에서 더욱 뚜렷하게 관찰되어, 플라즈마 블라스팅이 시행된 시료들은 대조군 시료에 비해 투수계수가 450~1,052% 범위로 증가하였다. 플라즈마 블라스팅이 1회만 실시된 토양시료의 투수계수는 방전 전압이 높아질수록 증가하였으나 동일한 전압으로 여러 번의 블라스팅이 시행된 토양시료의 투수계수는 증가하거나 감소하였다. 토양시료에 경유를 이용하여 인위적으로 오염시킨 토양시료에 플라즈마 블라스팅을 실시하여 정화효율을 측정하였다. 플라즈마 블라스팅이 시행되면, 방전지점 근처의 토양에서는 평균 393%, 방전지점으로부터 20 cm 이상 이격된 하부 토양에서는 평균 239% 정도의 정화효율이 개선되었으나 방전 전압과 정화효율은 상관성을 보이지 않았다. 위의 결과는 플라즈마 블라스팅이 토양의 투수성과 정화효율을 상당히 개선하므로, 유류오염 토양의 원위치 정화에 효율적으로 이용될 가능성을 보여주었다. Plasma blasting which is generated by high voltage arc discharge of electricity is applied to soil mass to improve permeability of soil and cleaning efficiency of oil contamination. A new high voltage generator was manufactured and three types of soil including silty sand, silty sand mixed with lime and silty sand mixed with cement were prepared. Small and large soil columns were produced using these types of soil and plasma blasting was performed within soil columns to investigate the variation of soil volume penetrated by fluid and permeability. Soil volume penetrated by fluid increased by 11~71% when plasma blasting was applied in soil. Although plasma blasting with low electricity voltage induced horizontal fracture and fluid penetrated along this weak plane, plasma blasting with high voltage induced spherical penetration of fluid. Plasma blasting increased the permeability of soil. Permeabilty of soils mixed with lime and cement increased by 450~1,052% with plasma blasting. Permeability of soil increased as discharge voltage increased when plasma blasing was applied once. However, several blastings with the same discharge voltage increase or decrease permeability of soil. Oil contaminated soil was prepared by adding diesel into soil artificially and plasma blasting was performed in these oil contaminated soil. Cleaning efficiency increased by average of 393% for soil located nearby the blasting and by average of 239% for soil located far from the blasting. Cleaning efficiency did not show any correlation with discharge voltage. All these results indicated that plasma blasting might be used for in-situ cleaning of oil contaminated soil because plasma blasting increased permeability of soil and cleaning efficiency.

Numerical Analysis of Directional Rock Blasting with Continuous-Discontinuous Element Method

Yunpeng Li,Chun Feng,Yiming Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

When simulating the directional blasting process, many researchers focus on the cutting and splitting effects who might pay more attention on the crushing effects when studying conventionalcut blasting. In this case, a numerical tool capable of capturing the strong discontinuity processes of quasi-brittle materials is highly preferable, where many blasting parameters should be calibrated and inputted. In this work, a hybrid finite-discrete elements method with explicit iterative procedure named Continuous-Discontinuous Elements Method (CDEM) is adopted to study the directional rock blasting processes. Landau model is used to capture the detonation effects, where the parameters are calibrated by comparing to the results provided by published literatures. We found that: i) The crack propagation mode of directional rock blasting is similar to those found in Brazilian splitting tests where the crack initiates from the midpoint of the connecting line of blast holes; ii) Compared with traditional cut blasting, the free surface has no significant influence on the blasting effect of directional cut blasting, while the spacing of the hole has great influence on the cutting effect. The index of fracture degree can be used to evaluate the blasting effect quantitatively. This work partly reveals some cracking patterns and rules of directional rock blasting, which may assist the engineers to develop improved precise blasting technologies.

시추공 시험발파를 이용한 대전 신탄진 지역의 발파진동 예측

이충원 ( Lee Chung-won ),박성용 ( Park Sung-yong ) 한국농공학회 2018 한국농공학회논문집 Vol.60 No.4

Problems on vibration due to blasting for infrastructure development are getting important because of a civil appeal. Blasting-induced vibration is representative construction pollution, hence, it is possible that a number of environmental damages occur. In this study, borehole test blasting was conducted at Sintanjin area, Daejeon and square root equation with 95% confidence level was proposed for prediction of blasting-induced vibration. The vibration value predicted from this equation was more conservatively evaluated than the values predicted from U.S. Department of Interior, Bureau of Mines (USBM) and Nippon Oil & Fats Co., Ltd. (NOF) equations. Therefore, the proposed equation in this study seems to contribute for safety blast design. However, for optimal blast design, inducing equation for prediction of blasting-induced vibration through the identical test blasting with field construction such as rock slope blasting would be required.

단일공 발파파형 중첩모델링 자료를 이용한 지반 진동의 예측

김종인(Jong-In Kim),강추원(Choo-Won Kang) 한국암반공학회 2007 터널과지하공간 Vol.17 No.6

국내에서는 주로 환산거리 진동예측식에 의한 발파진동 예측 방법이 사용되고 있다. 그러나 이러한 환산거리방식은 실규모의 발파가 시행되어져야 할 필요성이 있다. 최근 국내에서는 터널 등의 공사 시행 전 사전 조사단계에서 발파진동의 영향권을 예측하려는 시도로서 지질 조사용 시추공 등에 장약ㆍ발파하여 지반진동을 측정하고 본 발파의 발파 진동을 예측하는 방법이 사용되고 있다. 그러나 이러한 발파진동 예측 방법은 본 발파시의 진동의 전달 특성을 완전하게 반영하지는 못한다. 이러한 발파진동 예측방법의 결점을 보완하기 위하여 본 연구에서는 사전 조사 단계의 단일공 파형 중첩 모델링을 통하여 발파진동을 예측하는 방법을 개발하였다. The blasting vibration prediction in the country is mainly carried out by using the scaled distance method. But, this method needs a real-scale test blasting. The blasting vibration prediction has been performed using the data measured at borehole blasting for the purpose of a geological investigation before beginning a construction of a tunnel. In this prediction method, it is difficult to reflect the propagation characteristics of ground vibration generated from a real-scale blasting. propagation. This paper presents a new method for estimating blasting vibration by using superposed data of single hole blasting waveform with a delay time.

Blasting wave pattern recognition based on Hilbert-Huang transform

Li, Xuelong,Wang, Enyuan,Li, Zhonghui,Bie, Xiaofei,Chen, Liang,Feng, Junjun,Li, Nan Techno-Press 2016 Geomechanics & engineering Vol.11 No.5

Rockburst is becoming more serious in Chinese coal mine. One of the effective methods to control rockburst is blasting. In the paper, we monitored and analyzed the blasting waves at different blast center distances by the Hilbert-Huang transform (HHT) in a coal mine. Results show that with the increase of blast center distance, the main frequency and amplitude of blasting waves show the decreasing trend. The attenuation of blasting waves is slower in the near blast field (10-75 m), compared with the far blast field (75-230 m). Besides, the frequency superposition phenomenon aggravates in the far field. A majority of the blasting waves energy at different blast center distances is concentrated around the IMF components 1-3. The instantaneous energy peak shows attenuation trend with the blast center distance increase, there are two obvious energy peaks in the near blast field (10-75 m), the energy spectrum appears "fat", and the total energy is greater. By contrast, there is only an energy peak in the far blast field, the energy spectrum is "thin", and the total energy is lesser. The HHT three dimensional spectrum shows that the wave energy accumulates in the time and frequency with the increasing of blast center distance.