본 연구에서는 콘크리트 블록발파 실험과 AUTODYN수치해석을 통해 몇 가지 전색제 및 충전재가 폭발결과에 미치는 효과를 분석하였다. 전색제와 충전재는 공기, 모래, 폴리머 겔을 이용하였다. 이들 재료들의 전색효과 및 충전효과는 밀장전 조건의 경우와 비교하였다. 매립된 콘크리트 블록을 사용하여 현장 누두공 시험을 실시하였다. 콘크리트 블록 실험 및 수치해석 결과 폴리머 겔을 사용한 경우가 모래 및 디커플링의 경우에 비해 누두공의 크기와 발파공 주위의 최대압력이 더 크게 나타나는 것을 확인하였다. 또한, 수치해석 결과는 현장시험 결과와 잘 일치하는 경향을 보여주었다. 주변암반 중에서 계산된 최대압력은 폴리머 겔, 모래, 무전색 및 디커플링 조건일 때 각각 37, 30, 16 MPa로 나타났다. 수치해석 모델 내 밀장전 시 최대 압력은 52 MPa로 가장 높게 나타났다. 그러나 손상영역의 크기는 폴리머 겔을 사용한 경우보다 작게 나타났다. 또한, 밀장전은 기준 실험으로 사용되었다.
본 연구에서는 콘크리트 블록발파 실험과 AUTODYN 수치해석을 통해 몇 가지 전색제 및 충전재가 폭발결과에 미치는 효과를 분석하였다. 전색제와 충전재는 공기, 모래, 폴리머 겔을 이용하였다. 이들 재료들의 전색효과 및 충전효과는 밀장전 조건의 경우와 비교하였다. 매립된 콘크리트 블록을 사용하여 현장 누두공 시험을 실시하였다. 콘크리트 블록 실험 및 수치해석 결과 폴리머 겔을 사용한 경우가 모래 및 디커플링의 경우에 비해 누두공의 크기와 발파공 주위의 최대압력이 더 크게 나타나는 것을 확인하였다. 또한, 수치해석 결과는 현장시험 결과와 잘 일치하는 경향을 보여주었다. 주변암반 중에서 계산된 최대압력은 폴리머 겔, 모래, 무전색 및 디커플링 조건일 때 각각 37, 30, 16 MPa로 나타났다. 수치해석 모델 내 밀장전 시 최대 압력은 52 MPa로 가장 높게 나타났다. 그러나 손상영역의 크기는 폴리머 겔을 사용한 경우보다 작게 나타났다. 또한, 밀장전은 기준 실험으로 사용되었다.
In this study, several concrete-block blast tests and AUTODYN numerical analyses were conducted to analyze the effects of different stemming and coupling materials on explosion results. Air, sand, and polymer gel were used as both the stemming and coupling materials. The stemming and coupling effect...
In this study, several concrete-block blast tests and AUTODYN numerical analyses were conducted to analyze the effects of different stemming and coupling materials on explosion results. Air, sand, and polymer gel were used as both the stemming and coupling materials. The stemming and coupling effects of these materials were compared with those of the full-charge condition. Soil-covered or buried concrete blocks were used for field crater tests. It was found from the concrete block tests and numerical analyses that both the crater size and the peak pressure around the blast hole were higher when the polymer gel was used than when the sand and the decoupling condition were used. The numerical analyses revealed the same trend as those of the field tests. Pressure peaks in concrete block models were calculated to be 37, 30, and 16 MPa, respectively, for the cases of the polymer gel, sand, and no stemming and decoupling condition. The pressure peak was 52 MPa in the case of full-charge condition, which was the highest pressure. But the damage area for the case was smaller than that obtained from the use of polymer gel. Full-charge was also used as a reference test.
In this study, several concrete-block blast tests and AUTODYN numerical analyses were conducted to analyze the effects of different stemming and coupling materials on explosion results. Air, sand, and polymer gel were used as both the stemming and coupling materials. The stemming and coupling effects of these materials were compared with those of the full-charge condition. Soil-covered or buried concrete blocks were used for field crater tests. It was found from the concrete block tests and numerical analyses that both the crater size and the peak pressure around the blast hole were higher when the polymer gel was used than when the sand and the decoupling condition were used. The numerical analyses revealed the same trend as those of the field tests. Pressure peaks in concrete block models were calculated to be 37, 30, and 16 MPa, respectively, for the cases of the polymer gel, sand, and no stemming and decoupling condition. The pressure peak was 52 MPa in the case of full-charge condition, which was the highest pressure. But the damage area for the case was smaller than that obtained from the use of polymer gel. Full-charge was also used as a reference test.
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가설 설정
2) The pressure peak obtained from the use of the polymer gel was most similar to that from the full charge.
4) In the crater tests using buried concrete blocks, the polymer gel exhibited a superior performance compared to the other coupling materials.
5) Cost-effectiveness is an another advantage of the polymer gel. It is cheaper than sand.
제안 방법
Even if water is an excellent coupling material, it is difficult to stem the blast hole with water especially in the case of horizontal blast holes in tunnel rounds. In this study, a polymer gel was selected as the stemming and coupling material instead of water because it not only can maintain its shape but also is an excellent medium for transferring shock waves to the surrounding media. The polymer gel is an environment-friendly and non-toxic material and absorbs water quickly as soon as it gets dry (Dai et al.
In this study, the effects of different stemming and coupling materials in a blast hole were investigated by conducting both the soil-covered or buried concrete-block blasting tests and numerical analyses on AUTODYN (Fig. 1).
In this study, it was demonstrated that a polymer gel can be substituted for water as an excellent stemming and coupling material that can transfer shock waves efficiently to surrounding rock mass and thus overcome the aforementioned shortcomings of water. To test the feasibility of the selected matters, both crater tests using concrete blocks and associated numerical analyses were conducted for different stemming and coupling conditions. The important conclusions are summarized as follows:
대상 데이터
The explosive material used in the test was an ordinary emulsion explosive with the weight of 100 g and the diameter of 32 mm. In the case of the full-charge test, the charge weight was 200 g, which played the part of the reference weight.
The parameters alpha and beta are compression-state exponential interpolation parameters, “A” is bulk modulus (kbar), “es” is sublimation energy, “eo” is energy of incipient, and “esd” is the energy of complete vaporization. The material properties of the concrete having a compressive strength of 35 MPa was selected from the AUTODYN library. The coupling material and explosives inside the blast hole were modeled as Eulerian parts, and the Euler–Lagrange coupling scheme (fluid-structure interaction technique) supported by AUTODYN was used for the simulations.
이론/모형
The coupling material and explosives inside the blast hole were modeled as Eulerian parts, and the Euler–Lagrange coupling scheme (fluid-structure interaction technique) supported by AUTODYN was used for the simulations.
성능/효과
3) It is thought that the polymer gel can exhibit a positive effect on explosion magnitude owing to the pulsating motion of fluid, provide a higher workability, and eliminate the requirement for sealing.
However, water is a material which is difficult to seal and maintain its shape so that there are some difficulties in using it as a stemming and coupling material in a blasthole. In this study, it was demonstrated that a polymer gel can be substituted for water as an excellent stemming and coupling material that can transfer shock waves efficiently to surrounding rock mass and thus overcome the aforementioned shortcomings of water. To test the feasibility of the selected matters, both crater tests using concrete blocks and associated numerical analyses were conducted for different stemming and coupling conditions.
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