• Title/Summary/Keyword: earth pressure

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Earth Pressuroes of Tieback Walls in Sand (사질토에 시공된 앵커토류벽의 토압분포에 관한 연구)

  • 김낙경
    • Geotechnical Engineering
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    • v.14 no.5
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    • pp.17-28
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    • 1998
  • The design of a ground anchor wall calculating the design anchor force and anchored walls depends primarily on the earth pressure acting on anchored w deflection of the wall, the wall stiffness, distribution exists for anchored walls. In the apparent earth pressure envelope design of anchored walls. In this study, full scale anchored w pressure distribution was obtained from function. Earth pressures obtained from pressure and with the apparent earth pre the anchored wall in sand. It is conclude is appropriate for the anchored wall design.

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Passive earth pressure for retaining structure considering unsaturation and change of effective unit weight of backfill

  • Zheng, Li;Li, Lin;Li, Jingpei;Sun, De'an
    • Geomechanics and Engineering
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    • v.23 no.3
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    • pp.207-215
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    • 2020
  • This paper presents a kinematic limit analysis for passive earth pressure of rigid retaining structures considering the unsaturation of the backfill. Particular emphasis in the current work is focused on the effects of the spatial change in the degree of saturation on the passive earth pressure under different steady-infiltration/evaporation conditions. The incorporation of change of effective unit weight with degree of saturation is the main contribution of this study. The problem is formulated based on the log-spiral failure model rather than the linear wedge failure model, in which both the spatial variations of suction and soil effective unit weight are taken into account. Parametric studies, which cover a wide range of flow conditions, soil types and properties, wall batter, back slope angle as well as the interface friction angle, are performed to investigate the effects of these factors on the passive pressure and the corresponding shape of potential failure surfaces in the backfill. The results reveal that the flow conditions have significant effects on the suction and unit weight of the clayey backfill, and hence greatly impact the passive earth pressure of retaining structures. It is expected that present study could provide an insight into evaluation of the passive earth pressure of retaining structures with unsaturated backfills.

Analysis of Influencing Factors for Calculation of the Coulomb Earth Pressure of Cantilever Retaining Wall with a Short Heel (뒷굽 길이가 짧은 캔틸레버 옹벽의 Coulomb 토압 산정에 대한 영향 인자 분석)

  • Yoo, Kun-Sun
    • Journal of the Korean Geotechnical Society
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    • v.33 no.11
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    • pp.59-72
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    • 2017
  • In this study, the calculation method of the active earth pressure acting on the imaginary vertical plane at the end of the heel of the wall is proposed. For cantilever retaining wall, a change of shear zone behind the wall affects the earth pressure in the vertical plane at the end of heel of the wall depending on wall friction and angle of ground slope. It is very complicated to calculate the earth pressure by a limit equilibrium method (LEM) which considers angles of failure planes varying according to the heel length of the wall. So, the limit analysis method (LAM) is used for calculation of earth pressure in this study. Using the LAM, the earth pressures considering the actual slope angles of failure plane are calculated accurately, and then horizontal and vertical earth pressures are obtained from them respectively. This study results show that by decreasing the relative length of the heel, the slope angle of inward failure plane becomes larger than theoretical slope angle but the slope angle of outward failure plane does not change. And also the friction angle on the vertical plane at the end of the heel of the wall is between the ground slope angle and the wall friction angle, thereafter the active earth pressure decreases. Finally, the Coulomb earth pressure can be easily calculated from the relationship between friction angle (the ratio of vertical earth pressure to horizontal earth pressure) and relative length of the heel (the ratio of heel length to wall height).

Behavior Analysis of Earth Retaining Walls on the Excavation for Contact Structure (인접 구조물의 터파기로 인한 흙막이 벽체의 거동 분석)

  • Kim, Young-Muk;Jung, Young-Soo;Hong, Chang-Pyo;Shin, Youn-Sub
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1496-1503
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    • 2005
  • The study on the lateral earth pressure is briskly preformed for various conditions such as type of retaining walls, ground condition, and type of supporting systems. It is not simple to determine the distribution of lateral earth pressure accurately, however, because the lateral earth pressure is affected by various factors. This study is performed to analyze the behavior of earth retaining walls for new excavation contacting with existing excavation by comparing with the site measuring values before and after new excavation. On the base of observation, the distribution of strut axial forces is similar to that of ganeral earth retaining walls, but strut axial forces is increased by removal of existing earth anchors. When new excavation is performed contacting with existing excavation, the axial force of strut is decreased because of soil exclusion in the behind walls, but that force is increased after new exeavation. The analysis result show that the installation of strut in middle part makes a effect to not only 1 adjacent strut, but 3-5 adjacent struts. Also during new excavation strut axial forces is decreased by relaxation of total earth retaining wall system.

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Reduction of Horizontal Earth Pressure on Retaining Structures by a Synthetic Compressible Inclusion (압축성재료를 이용한 콘크리트 옹벽의 수평토압 저감방안에 대한 연구)

  • Yoo, Ki-Cheong;Paik, Young-Shik;Kim, Ho-Bi;Kim, Khi-Woong
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.1
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    • pp.19-28
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    • 2003
  • Current methods for lateral thrust calculations are based on the classical formulations of Rankine or Coulomb. However, the previous studies indicate that lateral earth pressures acting on the wall stem, which is the function of deformation parameters of the backfill, are close to the active condition only in the top half of the wall stem and in the lower half of the wall stem, the lateral earth pressures are significantly in excess of the active pressures. This paper presents the compressible inclusion function of EPS which can results in reduction of static earth pressure by accomodating the movement of retained soil. A series of model tests were conducted to evaluate the reduction of static earth pressure using EPS inclusion and determine the optimum stiffness of EPS. Also, field test was conducted to evaluate the reduction of static earth pressure using EPS inclusion. Based on field test it is found that the magnitude of static earth pressure can be reduced about 20% compared with classical active earth pressure.

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Analysis of Monitoring Results and Back Analysis for Rigid Diaphragm Wall Supported by Ground Anchor (지반앵커로 지지된 강성 지하연속벽체의 상세계측 결과분석 및 역해석 평가)

  • Lee, Jong-Sung;Hwang, Eui-Suk;Cho, Sung-Hwan;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.25 no.5
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    • pp.39-46
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    • 2009
  • In this study, behavior of a rigid continuous wall, earth pressure distribution with construction stage, and axial force of earth anchors were evaluated based on field monitoring data and numerical analysis results. For this purpose, a construction site excavated using the diaphragm wall was selected and full instrumentation system was introduced. From monitoring results, it was found that the values of horizontal displacement of the wall measured from the inclinometers, which were installed within the diaphragm wall were similar to analytical value. The earth pressure increased with excavation progress due to jacking force of the ground anchors installed in previous excavation stages. When the excavation depth reached 60% of the final depth, observed earth pressure distribution was similar to that estimated from Peck's apparent earth pressure distribution. When the excavation depth was around 90% of the final depth, values of observed earth pressure showed middle values between those of Peck's and Tschebotarioffs apparent earth pressures. It was also observed that, when excavation depth is deep, values of the earth pressures from the rigid wall were similar to those estimated from conventional earth pressure distribution shape proposed for flexible walls.

Effect of Step-Wise Excavation Depth on the Earth Pressure against an Excavation Wall in Rock Mass (암반지층 굴착벽체 발생토압에 대한 단계별 굴착깊이의 영향)

  • Son, Moorak;Adedokun, Solomon
    • Journal of the Korean Geotechnical Society
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    • v.30 no.2
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    • pp.43-52
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    • 2014
  • This paper examined the effect of step-wise excavation depth on the earth pressure against an excavation wall in rock mass. Numerical parametric studies were conducted based on the Discrete Element Method (DEM) to carry out the problems in rock mass. Controlled parameters included step-wise excavation depth, rock types, and joint conditions (joint shear strength and joint inclination angle). The magnitude and distribution characteristics of the induced earth pressure in a jointed rock mass were investigated and compared with Peck's earth pressure for soil ground. The results showed that the earth pressure against an excavation wall in rock mass were highly affected by different rock and joint conditions, and the effect of step-wise excavation depth increased as a rock type is deteriorated more. In addition, it was found that the earth pressure against an excavation wall in rock mass might be considerably different from Peck's empirical earth pressure for soil ground.

Nonlinearly Distributed Active Earth Pressure on a Translating Rigid Retaining Wall : II. Application (평행이동하는 강성옹벽에 작용하는 비선형 주동토압 : II. 적용성)

  • 백규호
    • Journal of the Korean Geotechnical Society
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    • v.19 no.1
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    • pp.191-199
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    • 2003
  • It is known that the distribution of the active earth pressure against a rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the farmer paper, a new formulation was proposed for the nonlinear distribution of active earth pressure on a translating rigid retaining wall considering arching effects. In this paper, parametric study is performed to investigate the effect of ${\phi}, {\delta}$ and wall height on the magnitude and distribution of active earth pressure calculated from the proposed equations. In order to check the accuracy of the proposed formulation, the predictions from the equation are compared with both existing full-scale test results and values from existing equations. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict both the earth pressure distribution and the lateral active earth force on the translating wall. Simplified design charts are also proposed for the modified active earth pressure coefficient and fur the height of application of the lateral active force in order to facilitate the use of the proposed equation.

Earth Pressure on the Underground Box Structure (지중 박스구조물에 작용하는 토압)

  • 이상덕
    • Journal of the Korean Geotechnical Society
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    • v.16 no.1
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    • pp.243-250
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    • 2000
  • The mechanical behavior of the underground box culvert constructed by the open cut method depends mainly on the earth pressure acting on it. In this study, the earth pressure on the underground box culverts constructed by the open cut method during and after the construction sequence was numerically analysed by using FLAC. The results are compared with those of the Marston-Spangler's theory, silo theory, and the model tests. The results showed that the vertical earth pressure on the upper slab of the box structure was not uniform. It was as large as the overburden in the middle part of the slab but was smaller or larger than that at its end part depending on the slope of the excavation, the depth of the cover, and the width of the side refill. The horizontal earth pressure on the side wail was much smaller than the earth pressure at rest and grew nonlinearly with the depth.

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Evaluation of Lateral Earth Pressure on Buried Pipes in Soft Ground Undergoing Lateral Movement (측방유동지반속 지중매설관에 작용하는 토압식 산정)

  • 홍원표;한중근;배태수
    • Journal of the Korean Geotechnical Society
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    • v.18 no.5
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    • pp.55-65
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    • 2002
  • Model tests were performed to investigate the mechanism of lateral earth pressure on a buried pipe, which was installed in a plastic flowing soil mass undergoing lateral movement. On the basis of failure mode tests, the equation of lateral earth pressure to apply Maxwell's visco-elastic model was proposed to consider the soil deformation velocity. Through a series of model tests of differential soil deformation velocity, lateral earth pressure of theoretical equation was compared with experimental results. When lateral soil movement was raised, the lateral earth pressure acting on buried pipe increases linearly with the soil deformation velocity. It shows that the lateral earth pressure on buried pipe is largely affected by soil deformation velocity. When plastic soil movement was raised, lateral earth pressure predicted by theoretical equation showed good agreement with experimental results. Also, coefficient of viscosity by theoretical equation had a good agreement with direct shear test results.