• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1796-1802
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• 2000

The purpose of this work is to analyze the vibration characteristic of boring bar with dynamic vibration absorber and find out the effective design parameters. Using the finite element method and modified optimum design concept, conventional optimum design based on approximate lumped parameter model is checked and practical design to be measured with modal analysis is compared with optimum design from numerical analysis. Also, the performance of reducing vibration is investigated with variation of shape of boring bar. The considered model of boring bar with dynamic vibration absorber is selected among manufactured boring bars with the best performance.

• 화약ㆍ발파
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• 제20권3호
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• pp.59-71
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• 2002

The points of this design case are the planning and excavation method of a new double-tracked railroad tunnel which is approx. 11∼22 meters apart from existing single-tracked railroad tunnel. For the optimum excavation method some needs are required in design stage, such as the reduction of noise and vibration, public resentment, damage of buildings and construction costs. Hence the estimation and application of allowable noise and vibration criterion is important. The ground coefficient (K, n) of this site is determined by field trial blasting. The excavation method is chosen to satisfy the allowable noise and vibration criterion. In addition, in order to ensure the stability of existing single-tracked railroad tunnel, the instrumentation of maintenance level is accompanied during the construction stage. As a result of this design condition, central diaphragm excavation with line drilling and pre-large hole boring blasting is applied to the area within 15 meters apart from existing tunnel. And above 15 meters apart, pre-large hole boring blasting is designed.

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.928-934
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• 2009

Underwater impulsive sound such as underwater blasting noise, piling noise and stone breaking hammer affects marine animal hearing response and organs. This study describes the characteristics of various impulsive noise from waterfront construction site and their effect on fish. Time constant, peak pressure, energy and SEL(sound exposure level) of four different underwater impulsive sounds are quantified. Auditory and non-auditory tissue damage ranges are derived by comparing their quantities to the exposure criteria for fish. Damage ranges of auditory tissue and non-auditory tissue of underwater boring blast of 150 kg of charge, are about 100 m and 300 m, respectively. Other three impulsive sounds also gives damage effects but less than that of underwater boring blast.

• 설비공학논문집
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• 제26권3호
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• pp.103-107
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• 2014

To assess a various of workplace noise environment in the tunnel construction site, the measurement is performed while tunnel constructing work. This study focuses on the sound attenuation according to the sound frequency characteristics and the distance from various works in the tunnel. Also, the noise distribution while blasting work is measured according to distance in this study. In addition, the boring processing, muck treatment, and tunnel lining by distance are measured for the noise distributions.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.583-588
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• 2002

As environmental problem in course of construction has been a matter of interest, noise and vibration in the process of piling are considered as a serious problem. For this reason, the use of SIP method inserting pile as soon as boring and cement grouting is rapidly increasing for preventing vibration and noise. But a resonable bearing capacity formula for SIP method does not exit and even the standard specification for domestic condition isn't formed, though the lateral friction between cement paste and the ground does an important role and boring depth largely influences to the design bearing capacity, applying the SIP method . Therefore, the lateral friction was analyzed after the direct shear test worked with the lateral face of SIP and the soil.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.199-202
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• 2014

In recent years the downtown, Top-down method has been applied in a major method to solve the complaints due to noise, vibration, dust and safety issues such as cracking due to settlement when the excavation close to the building. Until it is installed underground permanent foundation, the Pre-founded Column is a pile foundation as well as a column to bear the upper construction load. The Pre-founded Column is constructed by PRD method generally. The EnP(Enlarging Pile) method can be expanded locally boring diameter of the embedment zone as compared to the PRD method existing general. Since the bearing capacity is increased by the boring diameter is expanded, the embedment length is reduced, the construction cost is reduced.

• 한국해양공학회지
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• 제26권2호
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• pp.14-19
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• 2012

There are insufficient data to consider the effect zone for the marine life of coastal fisheries, because no standard has been defined for the sound level of marine life. In this study, equations for distance attenuation were used to determine the effect zone for oceanic noises. A reference noise level was divided into 4 parts to consider the characteristics of the fishes, and the effect zone of each reference noise level was determined. To increase the reliability of the effect scope, approximately 100 repetitions of blasting work split into several parts by the boring depth, the sound level of the source caused by an increase in weight, and the effect zone were calculated using the prediction equation. According to the prediction, the maximum distance of the effect zone was 4.92 km.

• 한국구조물진단유지관리공학회 논문집
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• 제26권3호
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• pp.39-47
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• 2022

국내의 공동주택 보급률 증가에 따라 층간소음으로 인한 문제가 증가하고 있다. 이를 예방하기 위하여 바닥 충격음 차단 구조에 대한 수요가 높아지고 있으며 해당 구조에 대한 성능 인증이 이뤄지고 있지만 소음 차단 성능이 현장에서는 재현되지 않는다는 문제점이 있다. 해당 구조가 제 성능을 발휘하기 위해서는 일정 두께 이상의 마감 모르타르 타설이 필요하며, 해당 구조의 시공 적정성 판정을 위하여 GPR을 이용한 두께 측정 실험을 진행하였다. 본 연구에서 개발한 두께 측정 알고리즘은 측정된 데이터를 기반으로 상대유전율을 설정할 수 있어 정확한 두께 값을 측정할 수 있다. 네 종류의 바닥 충격음 차단 인증 구조에서 GPR 두께 측정 실험을 진행하였으며, GPR 데이터와 천공 측정 데이터 간 평균 오차는 1.95mm로 나타났다. 또한 마감재 유무가 측정값에 미치는 영향을 조사하기 위하여 총 3가지 종류의 마감재를 배치하고 실험을 진행으며, 평균 오차는 1.70mm로 나타났다. 추가적으로 장비의 샘플링 오차, 개발 알고리즘 변수, 천공 오차등을 종합적으로 고려하였을 때, GPR 계측 및 제안 알고리즘은 매우 높은 정확도로 슬래브 마감 모르타르의 두께 측정에 적용할 수 있음을 확인하였다.

• 한국기계가공학회지
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• 제12권2호
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• pp.121-126
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• 2013

Precision machine tools for high dignity cutting are needed for efforts to improve machining accuracy. However, there are many factors to improve machining accuracy. This study investigated how machining accuracy changes when variation and unbalance amount in rotational speed domain is decreased. Machining accuracy of initial machine tools depends on manufacturing and assembly of parts such as bearing. And then, vibration and noise vary with volume of unbalance amount when it is rotation, so it effects unbalance amount. Also vibration and noise increased by unbalance shorten spindle's life and it especially makes worse boring accuracy. Therefore, this study studied the change of roundness and cylindricity of workpiece when it decreases variation and unbalance in rotational speed domain.

• 디지털융복합연구
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• 제18권10호
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• pp.219-224
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• 2020

본 연구는 연약지반상에 PHC 파일 시공시 발생하는 인장파에 의해 발생하는 인장 균열에 의한 파일 파손 방지를 위하여 일반적으로 시공되는 선굴착 공법을 대체할 장비 개발에 목적이 있다. 연약지반상에 PHC 파일 항타 중 해머타격시 발생하는 인장파에 의해 인장 균열이 발생하며, 이는 결국 부실시공으로 이어진다. 항타시 발생하는 인장파 발생을 방지하기 위하여 연약층에서는 별도의 항타력 증대 장치를 이용하여 인장파 발생을 방지하여 파일 손상을 방지할 수 있다. 또한 장비 개발시 시공 속도 향상, 시공비 절감 및 소형장비를 사용할 수 있어 매연 및 소음을 감소시키는 친환경 공법이다. 본 개발 장비는 대심도 연약지반이 분포하는 새만금 간척지, 동남아시아 건설시장을 개척할 수 있는 효과적인 장비이다.