大腸疾患의 漢方療法

河益守 藥業新聞社 1981 (月刊) 醫藥情報 Vol.1981 No.6

지진파괴확률 영곡선 활용 국내 식수전용 흙댐의 지진위험도 분류 사례 연구

하익수 한국지진공학회 2022 한국지진공학회논문집 Vol.26 No.4

Most of the drinking water dams managed by the local governments in Korea are earthfill dams, and these dams have almost no geotechnical property information necessary for seismic performance evaluation. Nevertheless, in the rough planning stage for improving seismic safety for these dams, it is necessary to classify their relative seismic hazard against earthquakes and conduct an additional ground investigation. The zero seismic failure probability curve is a curve suggested in this study in which the probability of failure due to an earthquake becomes ‘0’ regardless of the geotechnical properties of the earthfill dam. By examining the method and procedure for calculating failure probability due to an earthquake suggested in previous researches, the zero seismic failure probability curves for an earthquake in 1,000-year and 2,400-year return periods in Korea were presented in the form of a hyperbola on the plane of the dam height versus freeboard ratio (ratio of freeboard to dam height), respectively. The distribution characteristics of the dam height and the freeboard ratio of 81 Korean earthfill dams were presented. The two proposed zero seismic failure probability curves are shown on the plane of the dam height versus freeboard ratio, and the relative seismic hazard of 81 dams can be classified into three groups using these curves as boundaries. This study presented the method of classifying the relative seismic hazard and the classification result.

3차원 수치해석을 이용한 기계진동을 받는 단말뚝의 허용 연직지지력 산정방법 검토

하익수,한진태,Ha. Ik Soo,Han. Jin-Tae 한국방재학회 2013 한국방재학회논문집 Vol.13 No.5

본 연구에서는 국내에서 통상적으로 적용하고 있는 플랜트 진동기기초의 연직지지력 산정 방법의 타당성을 검토하고자 하였다. 이를 위하여 현재 작동중인 진동기계를 지지하고 있는 군말뚝 기초 중 단일 말뚝을 대상으로, 경험적 지지력 산정식을 이용하여 말뚝-지반의 상호작용을 고려할 수 있는 3차원 단말뚝 하중-변위 거동 수치모형을 구성하였다. 구성된 수치모형에 대하여 허용하중까지 축방향 정하중을 재하한 후, 추가로 단말뚝 두부에 기계 진동을 가하는 3차원 동적해석을 수행하여, 기계진동에 의해 추가적으로 말뚝 두부에 발생할 수 있는 연직하중을 산정하였다. 해석결과, 기계진동에 의해 발생하는 추가적인 동적하중은 정적 허용하중의 약 13% 정도로 나타나, 모든 진동 및 지반조건에 대하여 동적하중이 정적 사용하중의 100%로 증가된다고 간주하고 설계하는 국내 설계 관행은 지극히 보수적이며 과다설계로 이어질 수 있음을 보여주었다. In this study, the applicability of the method for evaluating the axial bearing capacity of a single pile subjected to machine vibration, which is generally applied in Korea, is examined. Firstly, the 3D model for the load-displacement behavior of a single pile, which is one of the group pile supporting a rotating machine, was constituted. In the constituted numerical model, the soil-pile interaction was considered by using the empirical formulae for evaluating axial bearing capacity and conducting the repeated numerical analyses. After the model was statically loaded to the allowable bearing load in static numerical analysis, the axial vibration due to machine vibration was added to the pile top in dynamic numerical analysis. From these procedures, the additional axial dynamic load caused by machine vibration was computed. From the analysis results, it was found that the additional dynamic load caused by machine vibration was about 13% of the allowable static load and it was thought that the domestic design concept, assuming that the additional dynamic load due to machine vibration equals to the allowable static load, is excessively conservative.

지진하중을 받는 CFRD 정상부 변위에 영향을 미치는 사력재료 입력물성에 대한 민감도분석

하익수 한국지진공학회 2007 한국지진공학회논문집 Vol.11 No.1

본 연구는 지진하중을 받는 콘크리트 표면차수벽형 석괴댐(CFRD)의 정상부 변위에 대한 사력재료 주요물성의 민감도를 정량적으로 분석하는데 그 목적이 있다. 이를 위해 현재 운영 중인 국내 CFRD 형식의 D댐에 대해 2가지 지진파, 각 지진파에 대해 2가지 설계진도, 사력재료에 대해 수행된 대형삼축압축시험 결과로부터 얻어진 물성값을 조합하여 만든 물성값이 다른 해석단면 27개를 작성, 총 108개 해석단면에 대한 동적 수치해석을 수행, 그 결과를 이용한 대역적 민감도분석을 수행하였다. 민감도분석 결과, 지진하중 작용 시 댐 정상부 침하량은 입력지진의 종류와 설계진도 크기에 상관없이 절대적으로 사력재료 전단탄성계수에만 영향을 받았으며 댐 정상부 횡변위의 경우에는, 사력재료 전단탄성계수의 영향이 크나 그 영향의 정도는 침하량에 미치는 정도에 비해 상대적으로 작으며, 침하량과는 달리 지진파의 종류와 크기에 따라 차이를 보였다. 본 연구결과에 한해 사력재료의 마찰각은 지진하중에 의한 CFRD 정상부 변위에는 전혀 영향을 주지 않는 것으로 나타났다. The purpose of this study is to carry out the quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of CFRD(Concrete-Faced Rockfill Dam) subjected to earthquake loading. The total 105 dynamic numerical analyses (2 input earthquake, 2 magnitudes for each earthquake. 27 rockfill material property combinations obtained from large triaxial tests) on CFR type "D" dam in operation were conducted. The global sensitivity analysis was carried out using the results of numerical analysis. From the results of sensitivity analysis, It was found that the crest settlement of the CFR type dam subjected to earthquake was absolutely affected by the shear modulus of rockfill material irrespective of the input earthquakes and the maximum acceleration of each earthquake. Also, it was found that the horizontal displacement of the dam crest was highly affected by the shear modulus of rockfill material though the extent of effect on that was smaller than the settlement and the extent of effect depended on the input earthquakes and the maximum acceleration of each earthquake. On the contrary, it was found that the effect of friction angle was negligible.

[특집Ⅰ: 포항지진과 방재대책] 포항지진 시 발생된 액상화 현상에 대한 이해

하익수 한국방재학회 2018 한국방재학회지 Vol.18 No.1

필댐 3차원 내진 해석요소망 작성 기법

하익수,Ha, Ik-Su 한국전산구조공학회 2009 전산구조공학 Vol.22 No.4

간기능계에 관한 문헌적 연구 - 간과 (肝) 목의 (目) 기능을 중심으로 -

하익수,김완희 대구한의대학교 제한동의학술원 1982 東西醫學 Vol.7 No.2

N/A

인공발파진동실험을 이용한 흙댐 축조재료의 전단파속도 산정

하익수,김남룡,임정열,Ha, Ik-Soo,Kim, Nam-Ryong,Lim, Jeong-Yeul 대한토목학회 2013 대한토목학회논문집 Vol.33 No.2

본 연구의 목적은 인공 발파진동실험을 이용하여 흙댐 축조재료의 전단파속도를 추정하고 산정 방법의 실효성을 확인하는 것이다. 이를 위하여 운영 중인 성덕댐에 대하여 국내 최초로 실대규모 근접 발파진동 실험을 수행하였다. 장약량과 발파 시추공심도를 4가지 유형으로 달리한 발파진동을 유발시키고, 각 유형별 발파 시에 폭원에 인접한 기반암노두와 댐 정상부에서 가속도를 각각 계측하였다. 발파진동실험으로부터 댐 정상부에서 얻어진 계측기록을 주파수 분석하여 대상댐의 고유진동수를 산정하고, 계측된 가속도기록으로 산정한 고유진동수와 기반암에서 계측한 발파파 가속도를 입력하중으로 한 반복적인 동적수치해석을 수행하여 계산한 고유진동수를 일치시키는 방법으로, 흙댐 성토재료의 심도별 전단파속도를 추정하였다. 산정된 대상댐 성토재료의 전단파속도는 발파유형에 영향을 받지 않고 일관성 있는 결과를 산정함을 확인하였고, 기존의 경험적 연구결과와 비교하여 그 실효성도 확인하였다. 이로부터 지진계가 설치되지 않아 실지진 계측기록을 이용할 수 없는 중소규모 댐의 경우, 인접발파에 따른 발파진동계측기록에 대한 분석으로도 댐 축조재료의 전단파속도를 실효성 있게 추정할 수 있음을 확인하였다. The objective of this study is to estimate shear wave velocity of earth dam materials using artificially generated vibration from blasting events and to verify its applicability. In this study, the artificial blasting and vibration monitoring were carried out at the site adjacent to Seongdeok dam, which is the first blasting test for an existing dam in Korea. The vibrations were induced by 4 different types of blasting with various depths of blasting boreholes and explosive charge weights. During the tests, the acceleration time histories were recorded at the bedrock adjacent to the explosion and the crest of the dam. From frequency analyses of acceleration histories measured at the crest, the fundamental frequency of the target dam could be evaluated. Numerical analyses varying shear moduli of earth fill zone were carried out using the acceleration histories measured at the bedrock as input ground motions. From the comparison between the fundamental frequencies calculated by numerical analyses and measured records, the shear wave velocities with depth, which are closely related to shear moduli, could be determined. It is found that the effect of different blasting types on shear wave velocity estimation for the target dam materials is negligible and the shear wave velocity can be consistently evaluated. Furthermore, comparing the shear wave velocity with the previous researchers' empirical relationships, the applicability of suggested method is verified. Therefore, in case that the earthquake record is not available, the shear wave velocity of earth dam materials can be reasonably evaluated if blasting vibration test is allowed at the site adjacent to the dam.

여유고만으로 추정된 국내 재해위험 저수지의 지진시 파괴확률

하익수,이수권,임정열,정영훈 대한토목학회 2016 대한토목학회논문집 Vol.36 No.3

The objective of this study is to illustrate the methods and procedures for estimating the failure probability of small fill dams subjected to earthquake events and to estimate the seismic failure probability of the Korean disaster risk fill dams where geotechnical information is not available. In this study, first of all, seismic failure probabilities of 7 disaster risk small fill dams, where geotechnical information is available, were evaluated using event tree analysis. Also, the methods and procedures for evaluating probabilities are illustrated. The relationship between dam height and freeboard for 84 disaster risk small dams, for which the safety diagnosis reports are available, was examined. This relationship was associated with the failure computation equation contained in the toolbox of US Army corps of engineers. From this association, the dam height-freeborard critical curve, which represents ‘zero’ failure probability, was derived. The seismic failure probability of the Korean disaster risk fill dams was estimated using the critical curve and the failure probabilities computed for 7 small dams. 본 연구의 목적은 소규모 필댐의 지진시 파괴확률을 산정하는 방법과 절차를 예시하고, 지반공학적 정보가 부족한 국내 재해위험 저수지의 지진시 파괴확률을 추정하는 것이다. 이를 위하여, 국내 재해위험 저수지로 지정된 저수지 중 지반공학적인 정보를 얻을 수 있는 7개 저수지에 대해사건수 분석 기법을 적용하여 지진에 대한 파괴확률을 평가하였으며, 그 방법 및 절차를 예시하였다. 안전진단보고서를 확보한 84개 재해위험저수지의 댐높이와 여유고와의 관계를 검토하였고, 미공병단 평가도구로 이용되는 파괴확률 산정식을 이러한 댐높이와 여유고와의 관계에 연관시켰다. 이러한 연관관계로부터, 지진시 파괴확률이 ‘0’이 되는 댐높이-여유고 임계곡선을 도출하였고, 이러한 임계곡선과 7개 저수지에 대해 산정한 지진시 파괴확률로부터 물성확보가 어려운 국내 재해위험 저수지의 개략적인 지진에 대한 파괴확률을 추정하였다.

1-g 진동대시험을 이용한 포화된 모래지반의재액상화 강도 특성 평가

하익수,김명모 한국지반공학회 2005 한국지반공학회논문집 Vol.21 No.4

Many case histories of re-liquefaction phenomena seem to support the idea that sand deposits, if they once have been liquefied, could be reliquefied again by a subsequent earthquake even though the earthquake is smaller than the previous one. The magnitude of the strains induced in the initial liquefaction has a significant influence on the resistance of the sample to re-liquefaction. The deposits undergoing liquefaction experience large shear strain during liquefaction. And this previous strain changes the microstructure into highly anisotropic structure such as columnlike structure and connected voids. This type of anisotropy is so unstable that it can reduce re-liquefaction resistance. It is known that the extent of anisotropic structural change depends on the gradation characteristics of ground. The purpose of this study is to estimate the correlation between the gradation characteristics of the sand and the ratio of re-liquefaction resistance to liquefaction resistance. In this study, 1-g shaking table tests were carried out on five different kinds of sands. During the tests the values of excess pore pressure at various depths and surface settlements were measured. Re-liquefaction resistances were not affected by the initial void ratio and the effective confining pressures, and the deposits of all test sands which had once been liquefied were reliquefied in the cyclic loading number below 1 to 1.5. The ratio of re-liquefaction resistance to liquefaction resistance linearly decreased as D10/Cu increased, and was constant as about 0.2 above the value of D10/Cu, 0.15 mm.