• Title/Summary/Keyword: 수평토압

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Earth Pressure Acting on the Cylindrical Retaining Wall of a Shaft in Cohesionless Soils : Study on the Application by Model Test (사질토 지반의 원형수직구에 설치된 흙막이벽에 작용하는 토압 : 적용성 연구)

  • 천병식;신영완;문경선
    • Journal of the Korean Geotechnical Society
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    • v.20 no.4
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    • pp.75-88
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    • 2004
  • It is known that the earth pressure acting on the cylindrical retaining wall in cohesionless soils is small than that acting on the retaining wall in plane strain condition due to three dimensional arching effect. In this study, the earth pressure equation considering the earth pressure decrease by horizontal and vertical arching effects, overburden, wall friction, and failure surface slope is proposed. For the purpose of verifying the applicability of proposed equation, model test is performed with apparatuses that can control wall displacement, wall friction, and wall shape ratio. Influence of each factor on the active earth pressure acting on the cylindrical retaining wall is analyzed according to the model test in constant wall displacement condition. The comparison of calculated results with measured values shows that the proposed equations satisfactorily predict the earth pressure distribution on the cylindrical retaining wall.

Lateral Earth Pressure with The Shape of Narrow Space with Backfill (좁은 공간의 형상에 따른 되메움 토압에 관한 연구)

  • Huh, Kyung-Han
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.1
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    • pp.89-96
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    • 2008
  • The study, with regard to unsymmetrically inclined backfilled wall, was intended to estimate the lateral earth pressure, develop the equation for lateral earth pressure and eventually identify the mutual behavior, based on the modified Kellogg theory, while changing the width between the walls, wall angle, relative density and wall friction angle. To verify the geostatic pressure obtained from the study, the results in the wake of 62 kinds of model tests performed were compared and evaluated with the behaviors based on theoretical equations. As a result, the wall inclination angle was found to be the factors affecting the earth pressure the most, when both walls were inclined unsymmetrically. And the narrower the backfill space and the larger the wall inclination angle to the horizontal level, the greater the effect of the wall friction. The equation considering the wall friction reaction indicated the value, which was closer to the actually-measured earth pressure, and when the width between the warts was narrow, the arching effect appeared to be great, thereby indicating the difference between the measured earth pressure, theoretically calculated earth pressure and the geostatic pressure proved to be insignificant.

Numerical Investigation into Behavior of Retaining Wall Subject to Cycles of Freezing and Thawing (동결-융해 반복작용에 노출되는 옹벽의 거동에 관한 수치해석 연구)

  • Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.29 no.1
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    • pp.81-92
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    • 2013
  • This paper presents the results of a numerical investigation into the behavior of retaining wall subject to cycles of freezing and thawing due to seasonal temperature change. The thermo-hydro-mechanical coupled finite element modeling strategy was first established to simulate the wall behavior. A series of finite element analyses were then performed on a range of conditions representing seasonal temperature change characteristics. The results indicated that the average freezing temperature and the number of cycles of freezing and thawing were the primary influencing factors for the wall behavior. Also revealed was that the duration of freezing period does not significantly affect the wall displacement and the lateral earth pressure, and that the earth pressure on the wall does not significantly change due to the freezing and thawing action suggesting that the increase in the wall displacement during the freezing and thawing action may be attributed to degradation of backfill due to the freezing and thawing action.

An Experimental Study on the Earth Pressure on the Underground Box Structure (지하 박스구조물에 작용하는 토압에 관한 실험적 연구)

  • 김은섭;이상덕
    • Journal of the Korean Geotechnical Society
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    • v.15 no.4
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    • pp.235-246
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    • 1999
  • Some of the underground structures such as subway tunnels are constructed by open cut method, in which the ground is excavated, a structure installed, and after that the excavated space is backfilled. In this case, because of their narrow and constrained boundary conditions, the earth pressure induced by self-weight of the backfilled soil acting on the underground structures is different from that of the classical theory. The vertical and horizontal earth pressures acting on upper slab and side wall of the underground structures constructed by open cut method are affected by the backfill geometry. The laboratory model tests were performed in the conditions of a variety of the shapes of backfill geometry and wall friction. And their results were compared with those from theories. As a result, it was observed that the distribution of the earth pressure acting on the underground structure is affected by the shapes of backfill geometry, the width of backfill, the angle of excavation and the wall friction.

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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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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.

Estimation of Ultimate Lateral Load Capacity Using CPT Results Considering Lateral Soil Pressure Distribution (수평토압분포를 고려한 CPT 기반의 말뚝극한수평지지력 산정)

  • Kim, Min-Kee;Kyung, Doo-Hyun;Hong, Jung-Moo;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.25 no.2
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    • pp.37-44
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    • 2009
  • In this study, estimation methodology for the pile of ultimation lateral resistance, pu, and ultimate lateral capacity, Pu, is based on the CPT cone resistance $q_c$. Preexistent methodologies for ultimate lateral resistance and ultimate lateral capacity have been generally represented with relative density, vertical effective stresses, and various $K_0$ values which are important for analyzing sandy soil. These methodologies, however, did not consider the horizontal effective stress and the effects of construction site conditions. Therefore, CPT-based methodology for the estimation of the ultimate lateral pile load capacity Hu was proposed. Calibration chamber test results were analyzed and compared with calculated results. The proposed estimation methodology for the pile of $p_u$ can be effectively utilized as alternative to preexistent methods.

The Mechanical Behavior of Steel Circular Caisson by Horizontal Load (水平載荷에 따른 鋼製圓筒 케이슨의 力學的 擧動)

  • 장정욱
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.10 no.3
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    • pp.141-150
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    • 1998
  • Model tests were performed to examine the mechanical behavior of steel circular caisson by horizontal load. It was generally found that displacements and bottom pressure of the caisson model were increased rapidly at the local plastic load. The maximum displacement was measured at the loading point, whereas the less displacement was measured at the upper part of the caisson model. The bottom pressure was getting higher, as it was nearer the loading side. Furthermore, the increase ratio of the bottom pressure was higher as the load was increased.

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Passive Force Acting on the Kicker Block Used to Support a Raker in Soft and Weathered Soil (연약지반과 풍화토지반에서 경사고임대 지지블록의 수동토압 산정)

  • Kim, Tae Hyung;Park, Lee Keun;Kim, Tae O;Jin, Hyun Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.5
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    • pp.801-813
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    • 2017
  • Passive force acting on the kicker block used to support a raker is different dependent on soil's type. The passive force incorporating a factor of safety is considered for design of the retaining wall. However, an actual passive force developing on the kicker block is overestimated and it may lead to an unsafe design. In this study, the actual passive forces acting on the kicker block in soil ground are evaluated using 3-D Finite Element Program, PLAXIS. Soft and weathered soils are selected as a soil ground. The relation curves between horizontal displacement and actual passive force of the kicker block for each soil ground are obtained through numerical analyses. From the curves, the actual passive forces are determined as a yielding point, which are about 55.5% and 66% of Rankine's passive forces in soft and weathered soils, respectively.