• Korean Journal of Agricultural Science
• /
• v.24 no.2
• /
• pp.145-155
• /
• 1997

The large scaled field test by prefabricated vertical drains was performed to evaluate the superiority of vertical discharge capacity for drain materials through compare and analyze the time-settlement behavior with drain spacing and the compression index and consolidation coefficient obtained by laboratory experiments and field monitoring system. 1. The relation of measurement settlement($S_m$) versus design settlement($S_t$) and measurement consolidation ratio($U_m$) versus design consolidation ratio($U_t$) were shown $S_m=(1.0{\sim}1.1)S_t$, $U_m=(1.13{\sim}1.17)U_t$ at 1.0m drain spacing and $S_m=(0.7{\sim}0.8)S_t$, $U_m=(0.92{\sim}0.99)U_t$ at l.5m drain spacing, respectively. 2. The relation of field compressing index($C_{cfield}$) and virgin compression index($V_{cclab.}$) was shown $C_{cfield}=(1.0{\sim}1.2)V_{cclab.}$, But it was nearly same value when considered the error with determination method of virgin compression index and prediction method of total settlement. 3. Field consolidation coefficient was larger than laboratory consolidation coefficient, and the consolidation coefficient ratio($C_h/C_v$) were $C_h=(2.4{\sim}3.0)C_v$. $C_h=(3.5{\sim}4.3)C_v$ at 1.0m and 1.5m drain spacing and increased with increasing of drain spacing. 4. The evaluation of vertical discharge capacity with drain spacing from the results of the consolidation coefficient ratio showed largely superior in case the Mebra drain and Amer drain than other drain materials at 1.0m and 1.5m drain spacing, while the values showed nearly same value in case same drain spacing.

• The Journal of Engineering Geology
• /
• v.33 no.3
• /
• pp.371-388
• /
• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.3
• /
• pp.53-65
• /
• 2007

Appropriate representation of hydrologic boundaries in groundwater models is critical to the development of a reliable model. This paper examines how the model predictions are affected by the uncertainty in the conceptualization of the hydrologic boundaries including groundwater divides, streams, and the lower boundaries of the flow system. The problem is analyzed for a study area where a number of field data for model inputs were available. First, a groundwater flow model is constructed and calibrated for the area using the Visual Modflow code. Recharge rate is used for the unknown variable determined through the calibration process. Secondly, a series of sensitivity analyses are conducted to evaluate the effects of model uncertainties embedded in specifying boundary conditions for streams and groundwater divides and specifying lower boundary of the bedrock. Finally, this paper provides some guidelines and discussions on how to deal with such hydrologic boundaries in view of developing a reliable conceptual model for the groundwater flow system of Korea.

• Proceedings of the KOR-KST Conference
• /
• 1996.02a
• /
• pp.29-58
• /
• 1996

현재 서울은 교통사고문제, 교통혼잡문제와 자동차로부터 배출되는 유해가스에 의한 대기환경오염문제를 갖고 있다. 본 논문의 목적은 대기환경오염을 악화시키는 자동차의 주된 배출오염가스인 일산화탄소, 탄화수소 및 질소화합물량을 교차로 교통량을 중심으로 어떻게 계산하는가에 있다. 연구의 대상지역은 서울시의 송파구 교차로들과 도심지역의 링크들을 선택하였다. 그리고 교통량, 지체시간, 링크길이, 정지회수, 운행속도, 주행속도 등을 고려하여, 제작차 배출가스 허용기준, 총량기준, 불량차 기준, 속도기준 등에 의한 계수산정 및 TRAF-NETSIM에 의한 시뮬레이션을 통하여 일정 도로상의 제한된 범위내의 배출량 산출을 시도하였다. 본 연구의 결과에 의하면 첫째, 어느 방법이든 실제배출량의 정확한 값을 표현 할 수는 없는 것이고, 단지 상대적인 비교에 의하면 배출가스량의 수준을 추정 할 수 있었다. 또한, 시뮬레이션 배출율표를 우리 현실에 맞는 자료에 의해 수정할 수 있다면, 그 결과는 실제량에 보다 근접할 수 있을 것이다. 둘째, 서울도로의 현재 혼잡상태에서 속도의 저감에 배출량이 민감한 반응을 보이고 있다는 사실이다. 셋째, 교통량변화에 따른 배출량의 변화가 일산화탄소에서 가장 심하게 나타남을 알 수 있었고, 신호운영상의 옵셋값이 잘못 설정되면 탄화수소는 35%, 일산화탄소는 40%, 질소산화물은 75%까지 초과발생할 수 있으며, 유해배출가스량을 최소화시키는 측면에서의 신호최적화를 위해서는 현재의 Stop Penalty는 상향 조정되어야 함이 밝혀졌다. 앞으로는 자동차로 인한 대기환경오염 농도의 저감을 위해서는 도로별 자동차 유해가스 배출 총량규제 방안도 고려해 볼 가치가 있으며, 이를 위해 환경공학과 교통공학의 다학제적 공동연구가 지속적으로 필요하며 교통정책에 반영되어야 할 것이다.분석, 리용수 학모형대이십일세기상해항공운량진행예측, 제출발전상해항공운수적전 략목표급발전중점. 예측2020년 상해항공항총객운탄토량4300만인/년, 화운량달120만돈; 2050년객운량장달18150만인차/년, 화운량518만돈. 사, 발전상해민항기출경제정책, 제출위료$\ll$진흥상해, 개발포동, 복무전국, 면향세계$\gg$ 화도이십일세기중기국민경제달도중등발달국가수 평굉관전략목표적실현, 제료필수재지도사상상파교통운수진정방도전략 산업지위, 환응재관리체제상채취과단유효적개혁조시, 재기출경제정책 상급여대력부지. 오, 전략목표, 위파상해건설성위태평양서안최대적경제, 김융, 무역적중심, 요구상해항공항성위화동지구통향세계각지항선망출발참, 구성대외개방선면축심, 실현국제항선적함접화국내항반적전항, 형성다축심복사식항선망; 가강기장건설, 개피포동제이국제기장건설, 괄응포동개발경제발전적수요. 부화개시일은 각 5월 26일과 5월 22일이었다. 11. 6월 중순에 애벌레를 대상으로 처리한 Phenthoate EC가 96.38%의 방제가로 약효가 가장 우수하였고 3월중순 및 4월중순 월동후 암컷을 대상으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase i

• Journal of Astronomy and Space Sciences
• /
• v.25 no.1
• /
• pp.43-52
• /
• 2008

As the next generation of global satellite navigation system, the Galileo project is about to witness an initial orbit validation stage as the successful test of navigation message transmission from Giove-A in 2007. The Space Geodesy division ana the Radio Astronomy division of the Korea Astronomy & Space Science Institute had collaborated on the field survey for the Galileo Sensor Station (GSS) RF environment of the proposed site near Jeju Tamla University from August 3rd to August 5th, 2006. The power spectrums were measured in full-band $(800{\sim}2000MHz)$ and in-band (E5, E6 and L1 band) in frequency domain for 24 hours respectively. Finally, we performed a time domain analysis to characterize strong in-band interference source based on the result of the previous step.

• Journal of the Korea Concrete Institute
• /
• v.18 no.3 s.93
• /
• pp.415-423
• /
• 2006

As the shortage of natural & good quality aggregate for concrete, it is needed development of alternative aggregate. At the present time, the crushed sand is widely used among the alternation aggregate, and the usage of crushed sand will be increased more and more. Generally, crushed sud is produced with wet process in domestic, but some manufacturing companies which are handicapped with local restrict are produced by dry process. In this study, analyzing the facilities of dry crushed sand, the quality properties of dry crushed sand was done by Korean Industrial Standards. Based on the quality results of dry crushed sand, the experiment of concrete with the dry crushed sand which is substitute for sea sand was done. As the results of basic qualities, the amount of 0.08 mm sieve passing ratio was over KS criteria, and the fineness modulus was higher than sea sand, and the other physical properties of dry crushed sand was similar to sea sand. The results of concrete experiment, according to the substitutive ratio of dry crushed sand is increased, the slump and air content of concrete was decreased by increase of fine particles of dry crushed sand, and the unit weight content, compressive & tensile strength of concrete were increased on the contrary. The physical properties of concrete used dry crushed sand were showed same tendency without relation to W/B. Consequently, if the fine particle contents of dry crushed sand was lower, it is judged that dry crushed sand is no problem to use for concrete aggregate and the amount of usage will be increased.

• Journal of Energy Engineering
• /
• v.19 no.1
• /
• pp.8-15
• /
• 2010

As environmental friendly energy system, distributed micro gasturbine is focused on new energy source for overcoming brand new construction area of power generation. This distributed micro gasturbine system has the powerful characteristics as belows; 1) environmental friendly features NOx < 9 ppm, noise < 65 db 2) various fuel flexbility which is used such as natural gas, diesel, low calory new & renewable fuel, kerosene. 3) high specific output power based on small area and is avilable for very easy and compact installation. There are many new installation sites in USA and Japan from 1998. On the other hand the exhisting large power system was constructued by the sea side, this compact power system is now installed by enduser in downtown area and supplying combined heat & power, has the various apllication on-site power generation. In recently, there is the very important issue for new & reliablbe energy development and spreading out. This paper represent as belows for important system characteristics; 1) grid connection modeling 2) system operation characteristics 3) on-site operation result and evaluation output of power quality analysis.

• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.77-86
• /
• 1999

Partitioning of two hydrophobic organic compounds (HOCs), phenanthrene and naphthalene, to kaolinite and sorbed surfactants was studied to evaluate the feasibility of surfactant-enhanced remediation (SER) of contaminated subsurface systems. Sorbed surfactant partition coefficients. $K_ss$, showed a strong dependence on the surfactant sorption isotherms at low sorbed surfactant levels $K_ss$ values were at their highest and then decreased with increasing surfactant sorption densities. $K_ss$ values for SDS were always larger than corresponding $K_mic$values. For Tween 80, however. $K_ss$ values $K_mic$ were higher than $K_mic$ values only at the lower sorbed surfactant densities. HOC distribution between immobile and mobile phases varied with surfactant dose distribution coefficients increased initially with increasing surfactant concentrations and then decreased at higher doses. This observation shows directly the competition between sorbed and micellar surfactants for HOC partitioning. Overall results of this study demonstrate that surfactant sorption to the solid phase can lead to increases in HOC retardation in some SER applications. Therefore, before an SER process is selected, appropriate consideration of surfactant sorption and HOC partitioning to immobile versus mobile phases pertinent to a specific subsurface system must be contemplated.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.6 no.4
• /
• pp.347-356
• /
• 2008

The purpose of Radioactive Waste Acceptance Criteria(WAC) is to verify a radioactive waste compliance with radioactive disposal facility requirements in order to maintain a disposal facility's performance objectives and to ensure its safety. To develop WAC which is conformable with domestic disposal site conditions, we furthermore analysed the WAC of foreign disposal sites similar to the Kyung-Ju disposal site and the characteristics of various wastes which are being generated from Korea nuclear facilities. Radioactive WAC was developed in the technical cooperation with the Korea Atomic Energy Research Institute in consideration of characteristics of the wastes which are being generated from various facilities, waste generators' opinions and other conditions. The established criteria was also discussed and verified at an advisory committee which was comprised of some experts from universities, institutes and the industry. So radioactive WAC was developed to accept all wastes which are being generated from various nuclear facilities as much as possible, ensuring the safety of a disposal facility. But this developed waste acceptance criteria is not a criteria to accept all the present wastes generated from various nuclear facilities, so waste generators must seek an alternative treatment method for wastes which were not worth disposing of, and then they must treat the wastes more to be acceptable at a disposal site. The radioactive disposal facility WAC will continuously complement certain criteria related to a disposal concentration limit for individual radionuclide in order to ensure a long-term safety.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.3
• /
• pp.65-74
• /
• 2014

Borehole investigation which is mainly used to figure out geotechnical characterizations at construction work has the benefit that it provides a clear and convincing geotechnical information. But it has limitations to get the overall information of the construction site because it is performed at point location. In contrast, geophysical measurements like seismic survey has the advantage that the geological stratum information of a large area can be characterized in a continuous cross-section but the result from geophysics survey has wide range of values and is not suitable to determine the geotechnical design values directly. Therefore it is essential to combine borehole data and geophysics data complementally. Accordingly, in this study, a three-dimensional spatial interpolation of the cross-sectional distribution of seismic refraction was performed using digitizing and geostatistical method (krigring). In the process, digital map were used to increase the trustworthiness of method. Using this map, errors of ground height which are broken out in measurement from boring investigation and geophysical measurements can be revised. After that, average seismic velocity are derived by comparing borehole data with geophysical speed distribution data of each soil layer. During this process, outlier analysis is adapted. On the basis of the average seismic velocity, integrated analysis techniques to determine the three-dimensional geological stratum information is established. Finally, this analysis system is applied to dam construction field.