• Title/Summary/Keyword: Strain wedge model

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Application on Pile Under Lateral Load in Multi Layered Ground Using the Strain Wedge Model (변형률 쐐기모델을 이용한 다층지반에서의 횡하중을 받는 말뚝의 적용성 평가)

  • Kim, Hongtaek;Lee, Jungjae;Chung, Jongmin;Yoon, Changjin
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.7
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    • pp.159-165
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    • 2009
  • The Strain Wedge Model is useful method for horizontal bearing capacity calculation considering interaction of pile and ground deformation. However, application case of the Strain Wedge Model is rare and the strain wedge model of plenty of verification is needed on multi layered ground in Korea. In this present study, to conduct laboratory model test and numerical analysis for verification of Strain Wedge Model, adapt model that could describe the interaction of pile and ground deformation on multi layered ground. In model test, it was performed to estimate the behavior characteristics on pile under lateral load and to analyze the relationship between load and deformation. In addition, it was fulfilled to measure the skin friction on pile using strain gauge and to decide the ground passive resistance wedge using skin friction. Numerical analysis was performed to verify laboratory model test results.

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Evaluation of Ultimate Lateral Resistance for Single Pile Using Strain Wedge Model in Sand (모래지반에서 쐐기모델을 이용한 단말뚝의 극한수평저항력 산정)

  • Kim, Ji-Seong;Kang, Gi-Chun
    • Journal of the Korean Geotechnical Society
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    • v.32 no.12
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    • pp.15-22
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    • 2016
  • The magnitude of the lateral resistance that resists the lateral movement of the pile is controlled by the amount of the pile movement and the strength and stiffness of soil. In this paper, we proposed an equation which produces the ultimate lateral resistance of the laterally loaded single pile in sand using the strain wedge model of the soil deformation. The ultimate lateral resistance in strain wedge model is composed of earth pressure of wedge rear, the shear resistance on the side of the wedge, and the frictional resistance between pile and ground. The ultimate lateral resistance determined by the proposed equation was compared with the Ashour, F.D.M., field test in sand. As a result, the error of the proposed equation and Ashour theory, field test, F.D.M were respectively 1.03%, 0.40~3.32%, 6.02%.

Lateral Resistance Analysis of Single Pile Using Strain Wedge Model in Sand (모래지반에서 쐐기모델을 이용한 단독말뚝의 수평저항력 해석)

  • Bae, Jong-Soon;Kim, Ji-Seong;Kim, Sung-Ho
    • Journal of the Korean Geotechnical Society
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    • v.26 no.11
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    • pp.39-46
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    • 2010
  • The magnitude of the lateral resistance that resists the lateral movement of the pile is controlled by the amount of the pile movement and the strength and stiffness of soil. In this paper, we proposed an equation which produces the lateral resistance of the laterally loaded single pile using the strain wedge model of the soil deformation. The results of this equation is compared with results of model test, field test, p-y curve and other methods. It is found that the result of proposed equation is smaller than the result of model test. The results of loading test considerably coincide with those of proposed equation; however, a few of deviations are generated as the displacement of pile head increases. Moreover, coincidences exist between the results of the proposed equation and those of finite difference method.

A Study on Interaction between Soil and Nail using SW Model (Strain Wedge Model을 이용한 지반-네일의 상호작용에 대한 연구)

  • 김홍택;강인규;김진홍;전찬우
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.153-158
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    • 1999
  • In the design and analysis of soil nailed slope, interaction between soil and nail is one of important problems. In the present analysis approaches for the interactions have developed a elastic analysis approach or a plastic analysis approach. However these approaches are not able to estimate the general interaction between soil and nail. In this study the general interaction between soil and nail using the strain wedge model is proposed. Also results of comparison between the proposed method and full scale test results by Gassler(1976) and large scale experimental results at Oxford University are shown in good agreements.

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A Study on the Characteristic Behavior of the Lateral Load Piles using the Strain Wedge Model and Laboratory Model Test (실내모형실험과 변형률 쐐기모델을 이용한 수평하중을 받는 말뚝의 거동 특성에 관한 연구)

  • Kim, HongTaek;Han, YeonJin;Kim HongLak
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.2
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    • pp.103-112
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    • 2012
  • The most of original horizontal bearing capacity theory of the pile is not efficiently to consider interaction between soil and pile because it is only to consider the earth pressure theory and separately the ground form pile. In recent, in order to improve the pile technology, it is necessary to confirm the real behaviour characteristics of pile under lateral load. Hence, to evaluate the behaviour characteristics of the single and group pile under lateral loads using the strain wedge model that could consider the interaction between soil and piles. Primarily, laboratory scale down model tests was carried out to predict the behaviour characteristics on real size piles using the strain wedge model. The comparative analyses between model test and numerical analysis for the evaluation of whole behaviour were conducted.

Experimental Investigation of Wedge Slamming Impact (쐐기 슬래밍에 관한 실험적 연구)

  • Di, Ren;Ahn, Gang-Su;Kwon, Sun-Hong
    • Journal of Ocean Engineering and Technology
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    • v.29 no.2
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    • pp.163-168
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    • 2015
  • This paper presents the results of experimental work on the wedge slamming impact problem. An experiment was done with a wedge model. The deadrise angle of the wedge was $4^{\circ}$. The model was made in two parts: the outside part was made of a 5-mm-thick steel plate that could be assumed to be a rigid body, and the inside part was made of a thin SUS plate that could be assumed to be an elastic body. Thin SUS plate thicknesses of 2 mm and 3 mm were used to determine the effect of plate rigidity. The drop height was varied from 0.25 m to 1 m to determine the effect of a large deformation.

Experimental Study on Wedge Slamming Considering Fluid-Structure Interaction (유체-구조 상호 간섭을 고려한 쐐기 슬래밍에 대한 실험적 연구)

  • Ahn, Kang-Su;Kwon, Sun-Hong
    • Journal of Ocean Engineering and Technology
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    • v.31 no.1
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    • pp.22-27
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    • 2017
  • This paper presents the results of an experimental study on the wedge slamming impact problem, including the fluid-structure interaction. A free drop test was performed to estimate the hydroelasticity. Three wedges were fabricated of 5 mm thick steel plate. The deadrise angles were $15^{\circ}$, $20^{\circ}$, and $25^{\circ}$. Plate thicknesses of 2 mm and 3 mm were used to determine the effect of the structural rigidity. The drop heights were 25 cm, 50 cm, 75 cm, and 100 cm. The pressure on a rigid part of the wedge and strain of the elastic plate were measured at four different locations. The pressure was compared using the Wagner theory and generalized Wagner theory.

Behavior of Back Ground of the Laterally Loaded Pile Group (수평하중이 작용하는 무리말뚝 배면지반의 저항거동 특성)

  • Kim, Ji-Seong;Bae, Jong-Soon
    • Journal of the Korean Geotechnical Society
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    • v.32 no.1
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    • pp.5-18
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    • 2016
  • In this study, we grasped the resistance state of the back ground which had a notable influence on computing the lateral resistance of the laterally loaded pile group in the homogeneous ground by the model test. Resistance state was grasped as the depth of rotation-point, wedge failure angle, and wedge wing angle. The model experiment is performed by varying the width, spacing and number of piles and the relative density of sand in this study. According to the observation of the rear ground surface deformation of the piles in lateral load, rotation point ratio, wedge failure angle, and wedge wing angle of the front row were similar to those of the middle row; however, those of the back row were relatively smaller. The rotation point ratio, wedge failure angle and wedge wing angle of the piles in parallel were the same as those of a single pile. Based on the model test results, equations for estimation of the rotation-point, wedge failure angle, and wedge wing angle are proposed.

Experimental and numerical studies of mono-strand anchorage

  • Marceau, D.;Bastien, J.;Fafard, M.;Chabert, A.
    • Structural Engineering and Mechanics
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    • v.12 no.2
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    • pp.119-134
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    • 2001
  • This paper deals with an experimental and numerical study of a mono-strand wedge anchor head mechanism. First, the experimental program is presented and monitored data such as wedge slippage, anchor deflection and strain distributions along external peripheral surfaces of the anchor head are presented and discussed. In accordance with the experimental set up, these data concern only the global behaviour of the mechanism and cannot provide valuable information such as internal stress-strains distributions, stress concentrations and percentage of yielded volume. Therefore, the second part of this paper deals with the development of an efficient numerical finite element model capable of providing mechanism of the core information. The numerical model which includes all kinematics/material/contact non-linearities is first calibrated using experimental data. Subsequently, a numerical study of the anchorage mechanism is performed and its behaviour is compared to the behaviour of a slightly geometrically modified mechanism where the external diameter has been increased by 5 mm. Finally, different topics influencing the anchorage mechanism behaviour are addressed such as lubrication and wedge shape.

A new analytical model to determine dynamic displacement of foundations adjacent to slope

  • Varzaghani, Mehdi Imani;Ghanbari, Ali
    • Geomechanics and Engineering
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    • v.6 no.6
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    • pp.561-575
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    • 2014
  • Estimating seismic displacements has a great importance for foundations on or adjacent to slope surfaces. However, dynamic solution of the problem has received little attention by previous researchers. This paper presents a new analytical model to determine seismic displacements of the shallow foundations adjacent to slopes. For this purpose, a dynamic equilibrium equation is written for the foundation with failure wedge. Stiffness and damping at the sliding surface are considered variable and a simple method is proposed for its estimation. Finally, for different failure surfaces, the calculated dynamic displacement and the surfaces with maximum strain are selected as the critical failure surface. Analysis results are presented as curves for different slope angles and different foundation distances from edge of the slope and are then compared with the experimental studies and software results. The comparison shows that the proposed model is capable of estimating seismic displacement of the shallow foundations adjacent to slopes. Also, the results demonstrate that, with increased slope angle and decreased foundation distances from the slope edge, seismic displacement increases in a non-linear trend. With increasing the slope angle and failure wedge angle, maximum strain of failure wedge increases. In addition, effect of slope on foundation settlement could be neglected for the foundation distances over 3B to 5B.