• Title/Summary/Keyword: Surcharge loads

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Behavior of Piled Abutment adjacent to Surcharge Loads (측방유동을 받는 교대말뚝기초에 대한 거동분석)

  • 정상섬;서정주;장범수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.25-32
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    • 2000
  • In order to analyze the behavior of piled abutment adjacent to surcharge loads a numerical study was conducted. In 2D plane stalin analysis, the distribution of lateral soil movement was investigated by varying the thickness of clay layer and the magnitude of surcharge loads. In 3D analysis, the magnitude and distribution of lateral pile-soil movement were studied for different cap rigidity. Based on limited parametric studies, a simple method is proposed to identify the lateral pressure of piled abutment adjacent to surcharge loads.

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Model Test for The Behavior of Reinforced Earth Wall Associated with Surcharge Load (상재하중의 영향에 따른 보강토옹벽의 거동에 관한 모형실험연구)

  • 김명호;황의석;이봉렬;김학문
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.79-86
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    • 2000
  • Recently, application of the reinforced earth wall is in increasing trend. Although many investigations on the influence of the length and spacing of reinforcement and the values of surcharge load has been carried out in the past, but the research about the influence of the location and value of surcharge loads has been scarce. Therefore this study was necessitated. The model test were carried out by varying the location and value of surcharge loads for two types of the backfill soils.

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Behavior of Retaining wall near Rigid slopes (강성사면에 인접한 옹벽의 거동에 관한 연구)

  • Yoo, Nam-Jae;Lee, Myoung-Woog;Park, Byoung-Soo
    • Journal of Industrial Technology
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    • v.18
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    • pp.405-415
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    • 1998
  • This thesis is an experimental and numerical research on bearing capacity acting retaining walls close to rigid slopes with stiff angles. Experiments were performed with changing the roughness of adjacent slope to the wall, its inclination, distance between wall and slope. Vertical stress and applied surcharge loads were measured by miniature earth cells and a load cel respectively. Stress distribution Vertical Settlement of surcharge load of rigid model footing were measured by LVDTs. Bearing capacities of surcharge loads were compared with theoretical estimations by using several different methods of limit equilibrium and numerical analysis. For limit equilibrium methods, the modified silo and the wedge theories, proposed by Chung sung gyo and Chung in gyo (1994) were used to analyze test results Based on those modified theories, the particular solution with the boundary condition of surcharge loads on the surface of backfill was obtained to find the stress distributions acting in the backfill and to compare with test results. From results of surcharge test with model wall being very close to the slope, analyzed results by the modified silo theory and to be in the better agreements than other methods.

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A Numerical Study of Cantilever Retaining Wall Sliding Behavior due to Surcharge Loading Condition (과재하중 재하에 따른 역 T형 옹벽의 활동거동에 관한 수치해석)

  • Yoo, Nam-Jae;Lee, Myung-Woog;Park, Byung-Soo;Lee, Seung-Joo
    • Journal of Industrial Technology
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    • v.21 no.B
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    • pp.205-212
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    • 2001
  • This paper is experimental and numerical research about the sliding behavior of cantilever retaining walls resisting surcharge loads. In experimental research, centrifuge model tests at the lg and 40 g-level were performed by changing the location of model footing and its width. Bearing capacity of model footing and characteristics of load-settlement and load-lateral displacement of retaining wall were investigated. Test results of bearing capacity were compared with modified jarquio method, based on the limit equilibrium method with elasticity theory. For the numerical analysis, the commericially available program of FLAC was used by implementing the hyperbolic constitutive relationships to compare with test result about load-settlement and load-displacement of retaining wall, bearing capacity of strip footing.

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The Earth Pressure on the Effect of Surcharge Load at the Narrowly Backfilled Soil (좁은 공간 되메움 지반에서의 상재하 영향에 의한 토압)

  • 문창열;이종규
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.165-180
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    • 1997
  • The structure such as underground external walls of buildings, conduit and box culvert supports the surcharge loads (point, strip and line loads) . The vertical and horizontal stresses in a soil mass depend on the backfill width and wall friction, etc. The investigations described in this paper is designed to identify the magnitude and the distributions of the lateral and vertical pressure which is occurred by the narrowly backfilled soil in an open cut by the surcharge loads. For these purposes, model tests were performed for various width of backfill in a model test box by considering the wall friction using carbon rods. The results of test were compared with the theories of Weissenbach and VS Army Code and also with the results of the numerical analysis using finite difference method which introduces Mohr-Coulomb failure hypothesis.

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Evaluation of Surcharge toads Acting in Backfilled Space (되메움 공간의 상재하중 영향평가에 관한 연구)

  • Moon Chang-Yeul;Kim Hee-Dong;Choi Heon
    • Journal of the Korean Geotechnical Society
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    • v.20 no.9
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    • pp.167-176
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    • 2004
  • Underground structures will be affected by the additional surcharge loads such as traffic load et al. Terzaghi (1956) suggested the equation on the influences of surcharge loads in vertically backfilled spaces. In field, the shapes of backfill spaces are not always formed vertically. Then the Terzagi (1956) equation is not suitable to use because of boundary condition. This study suggests equation to calculate the stress in backfilled space caused by surcharge loads when the backfilled space is sloped symmetrically. The suggested equation is verified by carbon box test and numerical analysis. The experimental results show good agreement with the suggested equation but the numerical analysis result shows a little disagreement. The differences are estimated to be caused by the fact that ground made by carbon rod has become more dense and internal frction and wall friction has increased itself as surcharge load is added but that this increase can not be considered in the numerical analysis. The suggested equation shows good agreement with Terzaghi (1956) equation in case of sloped backfill ground. According to the results, it is considered that the suggested equation can be applied not only to sloped space but also to vertical space. Further investigation using full scale experiment is needed.

3D stability of pile stabilized stepped slopes considering seismic and surcharge loads

  • Long Wang;Meijuan Xu;Wei Hu;Zehang Qian;Qiujing Pan
    • Geomechanics and Engineering
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    • v.32 no.6
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    • pp.639-652
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    • 2023
  • Stepped earth slopes incorporated with anti-slide piles are widely utilized in landslide disaster preventions. Explicit consideration of the three-dimensional (3D) effect in the slope design warrants producing more realistic solutions. A 3D limit analysis of the stability of pile stabilized stepped slopes is performed in light of the kinematic limit analysis theorem. The influences of seismic excitation and surcharge load are both considered from a kinematic perspective. The upper bound solution to the factor of safety is optimized and compared with published solutions, demonstrating the capability and applicability of the proposed method. Comparative studies are performed with respect to the roles of 3D effect, pile location, pile spacing, seismic and surcharge loads in the safety assessments of stepped slopes. The results demonstrate that the stability of pile reinforced stepped slopes differ with that of single stage slopes dramatically. The optimum pile location lies in the upper portion of the slope around Lx/L = 0.9, but may also lies in the shoulder of the bench. The pile reinforcement reaches 10% universally for a looser pile spacing Dc/dp = 5.0, and approaches 70% when the pile spacing reaches Dc/dp = 2.0.

Optimum design of cantilever retaining walls under seismic loads using a hybrid TLBO algorithm

  • Temur, Rasim
    • Geomechanics and Engineering
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    • v.24 no.3
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    • pp.237-251
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    • 2021
  • The main purpose of this study is to investigate the performance of the proposed hybrid teaching-learning based optimization algorithm on the optimum design of reinforced concrete (RC) cantilever retaining walls. For this purpose, three different design examples are optimized with 100 independent runs considering continuous and discrete variables. In order to determine the algorithm performance, the optimization results were compared with the outcomes of the nine powerful meta-heuristic algorithms applied to this problem, previously: the big bang-big crunch (BB-BC), the biogeography based optimization (BBO), the flower pollination (FPA), the grey wolf optimization (GWO), the harmony search (HS), the particle swarm optimization (PSO), the teaching-learning based optimization (TLBO), the jaya (JA), and Rao-3 algorithms. Moreover, Rao-1 and Rao-2 algorithms are applied to this design problem for the first time. The objective function is defined as minimizing the total material and labor costs including concrete, steel, and formwork per unit length of the cantilever retaining walls subjected to the requirements of the American Concrete Institute (ACI 318-05). Furthermore, the effects of peak ground acceleration value on minimum total cost is investigated using various stem height, surcharge loads, and backfill slope angle. Finally, the most robust results were obtained by HTLBO with 50 populations. Consequently the optimization results show that, depending on the increase in PGA value, the optimum cost of RC cantilever retaining walls increases smoothly with the stem height but increases rapidly with the surcharge loads and backfill slope angle.

Characteristics of Vertical Stress Distribution in Soil according to the Relative Density of Sandy Soil in case of Surface Loading (지표면 재하시 사질토 지반의 상대밀도에 따른 지중 연직응력분포 특성)

  • 임종석;이인형;정원중
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.422-426
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    • 2003
  • Model soil tank tests were conducted in sandy soil to investigate the effect of surcharge strip loads on vertical stress distribution in soil. A total number of 6 tests were performed using one loading plate and two relative density(55%, 65%). The soil was considered as an elastic material, while no friction was allowed between the wall and the soil. Measured stress values were compared to predictions defined by Frohlich, Boussinesq and Westergaard. The comparison of measured values and predictions used the ratio between the soil pressure and load value. Results of this study demonstrated that experimental values were generally larger than predictions. The Frohlich analysis provided the best prediction, while the Boussinesq analysis and Westergaard theory not presented a satisfactional result.

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Wall Displacement of Geosynthetic Reinforced Soil Walls with Different Surcharge Loads - Model Test (상재하중 변화에 따른 토목섬유 보강토옹벽의 벽체변위)

  • Lee, Kwang-Wu;Cho, Sam-Deok
    • Journal of the Korean Geosynthetics Society
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    • v.7 no.2
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    • pp.41-47
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    • 2008
  • This paper describes the results of model experiments in the laboratory, which were conducted to assess the behavior characteristics of geosynthetic reinforced soil walls according to different surcharge loads and reinforcement types. The model walls were built in the box having dimension, 100 cm tall, 140 cm long, and 100cm wide. Three types of geosynthetics, geonet, geogrid A and geogrid B, are used as the reinforcements. Decomposed granite soil (SM) was used as a backfill material. Seven model walls are constructed and tested. After the construction of the model wall, the LVDTs are installed to obtain the displacements of the wall face. As the results of the model tests, the maximum horizontal displacements of the model walls occurred due to uniform surcharge pressure were measured at the 0.7H from the bottom of the wall. The more the reinforcement strength increases, the more the wall displacements decrease, and also the reduction ratio of the wall displacement decrease with increasing the surcharge pressure.

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