• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 가을 학술발표회 논문집
• /
• pp.463-470
• /
• 2000

In tunnel excavation by blast beneath the surface structures in urban area, the characteristics of ground vibration induced by blast and its influence on surface structures are analyzed by the field test and the numerical analysis on dynamic behaviors of the structure. According to the field test on the propagating characteristics of blast vibration through the rock mass and the concrete foundation pile. the attenuation index of peak particle velocity with distance shows the range of 1.7∼2.0 for the rock mass and the range of 2.0∼2.3 for the concrete pile. This shows that the blast vibration reduces more rapidly in the concrete pile. It is known from the numerical analysis on dynamic behavior of the structure that the coefficient of response, velocity ratio of structure response to input wave, is different according to the story of the structure. It can be said from this research that the characteristics of the ground vibration and the dynamic behavior of the structure should be well evaluated and be considered as important factors for safe blasting design especially in underground excavation at shallow depth in urban area.

• 한국공작기계학회논문집
• /
• 제16권3호
• /
• pp.88-95
• /
• 2007

Generally, the integrated system using ion beam consists of 4 major parts, which are SEM, FIB, nano stage, and chamber. Among them, the nano stage and the chamber are designed and manufactured. The whole systems are integrated. Also, FE models are built to perform modal analyses of each part and the whole integrated system with a commercial program. Through these analyses, it is found that each part and the integrated system are very safe against vibrations including external excitations from ground and any others, because their natural frequencies are much larger than frequencies of external excitations. Also, isolation of ground induced vibration is considered.

• 소음진동
• /
• 제7권4호
• /
• pp.597-604
• /
• 1997

Ground vibrations induced from railroad were measured to get the basic data that can be usde to prepare countermeasures for solving environmental vibration problems. Vibration levels were measured simultaneously at three points in double distances from railroad. These data were analuzed with the kinds of trains, media to understand the magnitudes and characteristics of distance attenuation of railroad vibrations.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2002년도 춘계학술대회 논문집
• /
• pp.597-602
• /
• 2002

This study reviews several of the procedures that have been used to predict ground-born vibration. The vibration responses are measured at three sites that have different soil qualities. The measured vibration levels are compared with the predicted results by previously used vibration level prediction models. In this study a numerical method, which is based on explicit differential method, is used to compensate tot existing prediction models. Although numerically computed results are not quantitatively in good agreement with the measured results, the trends are comparable in the sense that vibration level does not decrease monotonically with distance. Also, The site with the deepest tunnel gives the highest vibration level.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 추계학술대회 논문집
• /
• pp.119-125
• /
• 2000

In this study, field measurements and analysis of vibration before and after the installation of continuously welded rail were performed. The vibration data obtained at the same locations before and after were analyzed to find out the characteristics of vibration level. The component of train-induced impulsive vibration at the rail joints varies depending upon the distance from the source, however mostly low frequency vibration which propagates long distance causes the problems of vibration. Even though it is expected that there may be certain degree of discrepancy in the amount of reduction in vibration depending upon site ground conditions, it was found that installation of continuously welded rail shows reduction in train-induced vibration.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.1631-1636
• /
• 2003

The purpose of this study is to analyze the phenomena of the thermally-induced vibration for the flexible space structure due to abrupt change of radiation heating circumstance using the numerical analyze and experiment test. In order to verify this structure, numerical approaches on the simplified flexible tube were compared with experimental test results at the ground experimental facility In this analyze, it was found that the thermal deformation occurs firstly due to fast radiation heating of flexible structure and then the thermally-induced vibration would be induced due to small periodic change of temperature. According to comparison of numerical and experimental result, in case of no tip mass, the first mode vibration by the numerical analyze was O.78Hz same as that of the experimental result However in case of increase tip-masses of 8g l6g, 50g and 100g, the first modes vibration theoretical analyze were 1.75Hz, 1.3Hz, 0.87Hz and O.73Hz, in decrease trend respectively and those by experimental test were 234Hz, 1.5Hz, O.78Hz and O.78Hz in decrease trend respectively Although using the simpled equation for the estimation, the estimation results were similar to experimental results.

• 화약ㆍ발파
• /
• 제34권1호
• /
• pp.11-18
• /
• 2016

도심지나 보안건물과 근접한 곳에서 폭약을 사용하는 발파작업이 수행되는 경우 지반진동 및 소음의 영향을 최소화 시킬 필요가 있다. 이러한 지반진동과 소음은 암반의 천공내에 장전된 폭약이 기폭되며 주변 암반을 파괴하고 남은 일부 충격에너지에 의하여 발생된다. 최근 천공 내 U형 철재장약홀더를 삽입하여 충격파의 전파방향을 제어하여 자유면방향으로 파쇄효과를 유지하며 암반 내로 전파하는 충격진동을 감쇄시키는 발파 공법이 제안되었다. 본 연구에서는 U형 철재장약홀더를 적용한 암반발파에서 충격파의 전파특성을 파악하기 위하여, AUTODYN 소프트웨어를 이용하여 장약홀더 내 장전된 폭약의 폭굉을 모사하고 주변암반에 전달된 충격파를 측정하였다. 또한 장약홀더 발파의 암파쇄 효과를 파악하기 위하여 동적파괴과정해석코드인 DFPA(Dynamic Fracture Process Analysis)를 적용하여 장약홀더를 이용한 장약조건을 고려한 2자유면 발파를 모사하였다. 일반발파의 장약조건을 고려한 충격파 발생 및 파괴과정해석을 추가적으로 수행하여 장약홀더의 암파쇄효과를 비교하였다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1993년도 학술발표집 지반진동 영향평가
• /
• pp.117-146
• /
• 1993

• 소음진동
• /
• 제7권3호
• /
• pp.419-426
• /
• 1997

The psychological, physiological, and material effects of ground vibrations induced from railroad were surveyed with the magnitudes of vibration sensing using questionnaire on residents living near railroad. These magnitude of vibration sensing and effects were compared as rate or percent total based on double distances from railraod. Also overall effects of railraod vibrations were compared with vibration levels measured or predicted. The about 70% of residents living within 40m from railroad sense railroad vibration, 15% of residents are influenced phychologically. But physilogical and material effects disappeared beyond 40m.

• 한국지반공학회지:지반
• /
• 제11권3호
• /
• pp.55-68
• /
• 1995

본 연구는 수직구의 바닥굴착을 위한 바닥발파시 삼승근환산식과 자승근환산식의 발파진동상수 및 감쇠지수와 암질지수(RQD)와의 관계를 시험발파계측을 통하여 정리분석한 것이다. 각종 발파시 발파진동의 크기는 장약량, 발파원과 발파진동 측정지점과의 거리, 지반의 특성에 따라 크게 좌우되며 본 논문에서는 지반의 특성이 발파진동에 미치는 영향을 규명하기 위하여 암반의 절리특성을 대표하는 RQD와 발파진동 크기와의 관계를 연구한 것이다. 시험결과 RQD의 증가에 따라 발파진동상수 K와 감치지수 n의 절대치는 상대적으로 증가하는 것으로 나타났으며 본 연구결과에 의하여 향후 암질지수에 따른 바닥발파의 발파진동속도를 예측할 수 있다.