• 제목/요약/키워드: Ground stress distribution

검색결과 133건 처리시간 0.027초

연약점토층위 이층지반 지표면 재하시 지중응력 특성연구 (A Study on the Stress Distribution beneath Loaded Ground Surface Area of Double Strata Ground on Soft Clay Layers)

  • 임종석;이인형
    • 한국농공학회:학술대회논문집
    • /
    • 한국농공학회 2005년도 학술발표논문집
    • /
    • pp.423-428
    • /
    • 2005
  • If the load of constructing vehicles during the construction work acts on the road or the ground surface on the soft ground, due to the excess stresses in soils the trafficability of the vehicles influences the constructing efficiency, constructing period and so on. Stress distribution in soils is the very important element to design and to solve the problems of settlement, safety of foundations and trafficability of constructing vehicle in civil engineering. This research represents the comparative estimation of the actual and theoretical measurement on the underground stress of outer layer for each soil after the observation of each top soil layer for its vertical and horizontal stress in (1)homogeneous sand ground (2) weak stratum with the sand soil (3) weak stratum with gravel of the soil model, and it also investigates the effect of subsidence of ground by the repeated load. The underground stress turn out to be different in the value of theoretical and actual measurement after the trial examination of model.

  • PDF

지반보강용 그라우팅 말뚝의 응력분담비에 대한 수치해석적 연구 (Numerical Study on the Stress-distribution Ratio of Grouting Pile for Reinforced Ground)

  • 이경주;이준규;張維維;송기일
    • 한국지반공학회논문집
    • /
    • 제39권2호
    • /
    • pp.19-30
    • /
    • 2023
  • 연약지반 대책공법으로 적용되는 다짐모래말뚝과 같은 지중구조물은 주로 복합지반 설계법에 의해 침하 및 안정성을 분석한다. 복합지반 설계법의 기본원리는 아칭효과이며 말뚝의 보강효과는 응력분담비로 평가한다. 탄성적 특성을 갖는 그라우팅 말뚝을 지반보강공법으로 적용할 때 기존의 응력분담비 평가는 말뚝이 지표까지 설치되어 상재하중이 말뚝과 원지반에 같이 직접 재하되는 경우만을 고려해 왔다. 본 연구에서는 지반보강 말뚝의 설치를 지표까지 올리지 않고 지중 어느 위치에서 마감할 때에는 지금까지의 연구들에 의해 적용된 응력분담비 적용 방법이 달라져야 한다는 것을 보여주었다. 고강도 Jet grouting이 적용되었을 때 원지반에 대한 그라우팅 말뚝의 응력분담비(n)는 통상 30~50 범위의 값을 적용한다. 그러나 이는 지표까지 말뚝이 놓이는 경우이고 말뚝 상단의 위치가 지표로부터 멀리 깊게 위치될 경우 응력분담 효과가 급격히 저감되며 응력구(stress bulb) 경계가 되는 깊이부터는 정량적 값 1.5에 수렴했다.

지반변동성을 고려한 액상화 진동전단응력비의 확률론적 해석 (Probabilistic Analysis of Liquefaction Cyclic Stress Ratio Considering Soil Variability)

  • 허준
    • 한국농공학회논문집
    • /
    • 제60권2호
    • /
    • pp.95-101
    • /
    • 2018
  • The objective of this study is to evaluate the liquefaction cyclic shear stress ratio considering the soil uncertainty. In this study, the probabilistic ground response analysis and the cyclic shear stress ratio analysis for the liquefaction potential evaluation are performed considering the soil variability. The statistical properties of input ground parameters were analyzed to investigate the parameters affecting the seismic response analysis. The Probabilistic analysis was carried out by Monte Carlo Simulation method. The ground response analysis was performed considering the soil variability and the probability distribution characteristics of the ground acceleration. The probability distribution of the peak ground acceleration by seismic characteristics was presented. The differences of liquefaction shear stress ratio results according to soil variability were compared and analyzed. The maximum acceleration of the ground by the deterministic method was analyzed to be overestimation of the ground amplification phenomenon. Also, the shear stress ratio was overestimated.

평면연삭에서의 잔류응력 분포에 관한 연구 (A study on residual stress distribution in surface grinding)

  • 김경년;정재천;김기선
    • 오토저널
    • /
    • 제13권6호
    • /
    • pp.109-118
    • /
    • 1991
  • In this study, it is intended to investigate the effect of the grinding conditions such as table feed, down feed, cross feed of residual stress distribution. And this distribution is investigated upon the grinding direction and the its orthogonal direction at ground layers. The material is used carbon steel (SM20C) which usually used to motor axis. And in order to be considered as Bernoulli-Euler beam, the dimension of the specimen is appropriately designed. According as corroiding the ground surface, the residual stress layers are removed and strain which occured on account of unbalance of internal stress is detected by rosette-gate. Through A/D converter and computer, these values are saved and evaluated residual stress by stress-strain relation formula. Finally, these results are diagrammatized with Auto Cad. The results obtained are as follows. As the depth from the ground surface increases in grinding direction and its orthogonal direction, tensile residual stress exists in the surface, and subsequently it becomes compressive residual stress as it goes downward. As the table feed, the cross feed and the down feed increase, maximum residual stress is transformed form the tensile to the compressive.

  • PDF

점토지반 조건 및 쇄석말뚝 특성에 따른 응력분담비 산정 (Evaluation of Stress Distribution Ratio According to Clay Ground Condition and Stone Column Characteristics)

  • 김동은;박현일;이승래;유상호
    • 한국지반공학회논문집
    • /
    • 제24권11호
    • /
    • pp.35-41
    • /
    • 2008
  • 쇄석말뚝은 연약지반의 침하 억제 및 지지력 보강에 사용되는 연약지반 보강공법 가운데 하나이다. 본 연구에서는 연약지반의 침하저감효과를 평가하는데 영향을 미치는 중요한 인자인 응력분담특성을 살펴보기 위하여 쇄석말뚝으로 보강된 점토지반에 대한 실내실험을 수행하였다. 상재하중 재하 시 시간경과에 따라 쇄석말뚝의 응력비 값은 감소하는 것으로 나타났다. 점토지반의 강성도가 증가함에 따라 쇄석말뚝의 응력비는 증가하는 경향성을 보였다. 또한, 쇄석말뚝으로 보강된 연약지반의 응력분담율을 간편하게 예측하기 위하여 제안된 수정된 Baumann & Bauer의 해가 계측 결과와 잘 일치되는 결과를 보여주는 것으로 나타났다.

연약점토층위 이층지반 지표면 재하시 지중응력 특성연구 (A Study on the Distribution Stresses beneath Loaded Ground Surface Area of Double Strata Ground on Soft Clay Layers)

  • 이인형;임종석
    • 한국농공학회논문집
    • /
    • 제47권6호
    • /
    • pp.47-57
    • /
    • 2005
  • Stress distribution in soils is the very important element to design and to solve the problems of settlement, safety of foundations and trafficability of constructing vehicle in civil engineering. This research presents the comparative estimation of the actual and theoretical measurement on the underground stress of outer layer for each soil after the observation of each top soil layer fur its vertical and horizontal stresses in (1) homogeneous sand ground (2) weak stratum with the sand soil (3) weak stratum with gravel of the soil model, and it also investigates the effect of subsidence of ground by the repeated load. The underground stresses fumed out to be different in the value of theoretical and actual measurement after the trial examination of model. This study has the purpose of suggesting the better construction method of running equipment on weak stratum by comparing the estimated value of trial experiment and theory on underground stress of the weak ground surface area and of raising up the necessity of the continuous research hereafter.

지표면 재하시 토층구성에 따른 지중응력분포에 관한 연구 (A Study on the Stress Distribution in Soil According to the Composition of the Soil Layer in Case of Surface Loading)

  • 임종석;정상균;하혁
    • 한국지반공학회:학술대회논문집
    • /
    • 한국지반공학회 2005년도 지반공학 공동 학술발표회
    • /
    • pp.510-516
    • /
    • 2005
  • This research aims to verify the stress distribution in soil according to the composition of the soil layer in case of surface loading. For this purpose, loading tests with measurement of stresses in the soil on four kinds of layered model ground in laboratory were performed. Those are (1)homogeneous sand, (2)gravel underlain by sand, (3)sand underlain by clay and (4)gravel underlain by clay. Test results are compared and analysed for the compositions of the soil layers. based on the results obtained, it is found that the larger the difference of the strengths of upper and lower layer is, the smaller the stress in the soil in case of surface loading is.

  • PDF

응력 -간극수압 연계해석을 이용한 흙막이 굴착시 지하수저하에 따른 지반침하에 관한 연구 (Urban Excavation - Induced Ground Movement in Water Bearing Ground Using Stress-pore Pressure Coupled Analysis)

  • 최고니;유충식
    • 한국지반공학회논문집
    • /
    • 제27권5호
    • /
    • pp.17-31
    • /
    • 2011
  • 본 연구에서는 흙막이 굴착 공사시 지하수저하에 의한 주변 지반의 공학적 거동에 관한 수치해석 연구내용을 다루었다. 먼저 2차원 간극수압-응력 연계해석을 통하여 굴착공사가 지반침하 거동에 미지는 영향을 알아보았으며 그 결과를 토대로 벽체 수평변형, 벽체배변 변형, 소성변형률 분포, 유효응력분포 및 버팀보 축력분포 등을 분석을 수행하였다. 한편 다양한 지층조건과 초기 지하수위 조건에 대한 매개변수 연구를 통하여 주변지반 및 버팀보의 거동을 분석하였으며 해석 결과를 토대로 특정조건의 최대 지반변형범위를 제안하였다.

상수도용 도복장간관의 용접 및 외부하중에 의한 응력 특성에 관한 연구(II) - 복합외부하중 및 후열처리에 따른 용접부의 응력분포 특성 - (A Study on the Stress Distribution of Steel Water Pipes(II) - Characteristics of Stress Distribution by External Forces and PWHT -)

  • 윤석환;이승기;나석주;고명환
    • Journal of Welding and Joining
    • /
    • 제19권3호
    • /
    • pp.292-297
    • /
    • 2001
  • One of the major characteristics that affects the life of welded steel water pipes is the stress distribution caused by welding and external forces. Some studios have bean carried out on the residual stress of steel water pipes. But the results on the stress distributions by welding and complex external forces are rare, because real water pipes operate under the ground and many kinds of external forces act simultaneously on the joints. To understand the complex stress distributions of welded joints, therefore predictions by numerical or analytic methods are required. In this study, temperature and stress distributions in steel water pipes produced by welding are predicted by a three-dimensional finite element method(FEM). Based on these results, stress distributions by welding and complex external forces are evaluated by adopting the same numerical method. The influence of some post weld heat treatments on residual stress distributions is also investigated.

  • PDF

확률론적 하중에 따른 실트질 모래지반 내 지중응력의 변동계수 특성 (The Coefficients of Variation Characteristic of Stress Distribution in Silty Sand by Probabilistic Load)

  • 봉태호;손영환;김성필;허준
    • 한국농공학회논문집
    • /
    • 제54권6호
    • /
    • pp.77-87
    • /
    • 2012
  • Recently, Load and Resistance Factor Design (LRFD) based on reliability analysis has become a global trend for economical and rational design. In order to implement the LRFD, quantification of uncertainty for load and resistance should be done. The reliability of result relies on input variable, and therefore, it is important to obtain exact uncertainty properties of load and resistance. Since soil stress is the main reason causing the settlement or deformation of ground and load on the underground structure, it is essential to clarify the uncertainty of soil stress distribution for accurately predict the uncertainty of load in LRFD. In this study, laboratory model test on silty sand bed under probabilistic load is performed to observe propagation of upper load uncertainty. The results show that the coefficient of variation (COV) of soil stress are varied depending on location due to non-linear relationship between upper load increment and soil pressure increment. In addition, when the load uncertainty is transmitted through ground, COV is decreased by damping effect.