• Title/Summary/Keyword: Lateral earth pressures

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Suitability Evaluation of Lateral Earth Pressure for Design Diaphragm Walls applied to the Top-Down Construction Method (Top-Down 공법이 적용된 지중연속벽의 설계시 측방토압의 적합성 평가)

  • Hong, Won-Pyo;Kang, Chul-Joong;Yun, Jung-Mann
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.1
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    • pp.11-21
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    • 2012
  • The Rankine(1857)'s earth pressure and the Hong and Yun(1995a)'s earth pressure was applied to analyze the lateral displacement of diaphragm wall applied to the Top-Down construction method using the computer program, which is a common design program for diaphragm wall. The lateral displacement estimated by the computer program was compared with the lateral displacement measured by inclinometer. The Rankine's earth pressure has been widely used to design the diaphragm wall in the analysis of computer program. As the result of comparison, the lateral displacement of diaphragm wall was predicted differently according to the applied earth pressures. The behavior of lateral displacement predicted by the Rankine's earth pressure was different with displacement measured by inclinometer and the lateral displacement at the bottom part was overestimated. However, the lateral displacement predicted by the Hong and Yun's earth pressure is similar to the behavior and maximum value of real displacement. Therefore, the Hong and Yun's earth pressure is more suitable than the Rankine' earth pressure to design the diaphragm walls applied to the Top-Down Construction Method.

The Stability of Foundation Piles for Abutment (교대기호말뚝의 안정)

  • 홍원표;안종필
    • Geotechnical Engineering
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    • v.7 no.2
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    • pp.67-82
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    • 1991
  • When bridge abutments are constructed on pile foundations in unstable slope, horizontal deflections may be developed in the piles and the abutments due to lateral soil movements arisen from backfills. In most of the above mentioned cases, the piles are situated in a soft layer where lateral earth pressures are developed between the piles and the soils. The undesirable lateral earth pressures decreases the stability of the piles. However, the piles may have a preventive effect against lateral soil movements and improve the stability of the slope. For the stability problem of such slope containing piles in a row, two kinds of analyses for the slope-stability and the pile-stability have to be performed. The whole stability of bridge abutments on pile foundation can be obtained only by the stabilization for both the slope and the piles. A reasonable analytical method for the bridge abutments on pile foundation was established in this study By use of the analytical method for an example, several factors which influence affect the stability of bridge abutment were investigated. Finally, for the bridge abutment subjected to lateral deflections damage, the fixity condition of pile head was investigated.

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Estimation of Earth Pressures Acting on Box Structures Buried in Ground (지중에 매설된 박스구조물에 작용하는 토압 산정)

  • Hong, Won-Pyo;Yun, Jung-Mann;Song, Young-Suk
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.2
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    • pp.23-33
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    • 2015
  • The earth pressure acting on underground structure was measured by application of the instrumentation system in the subway construction site constructed by the method of cut-and-cover tunnel. The measured earth pressure was compared with the earth pressure obtained from the existed theoretical equation, and the actual earth pressure diagram acting on the underground structure was investigated. As a result of investigation, the vertical earth pressure is mainly affected by the embankment height, and the lateral earth pressure is significantly affected by whether the existence of earth retaining structures or not. The measured vertical earth pressure is very similar to the theoretical earth pressure proposed by Bierbaumer. The measured lateral earth pressure is closed to the active earth pressure proposed by Rankine rather than the earth pressure at rest. The coefficient of earth pressure in soil deposit layer is about 0.35, and the coefficient in soft rock deposit layer is about 0.21. For design and construction the underground structures, therefore, it is reasonable estimation that the lateral earth pressure acting on structures installed in soil deposit layers is an average value between active earth pressure and earth pressure at rest. In rock deposit layers, the lateral earth pressure acting on structure is an active earth pressure only.

Lateral Earth Pressure against Gravity Walls Backfilled by $C-\phi$ Soil ($C-\phi$ 흙으로 뒤채움한 중력식 옹벽에 작용하는 정적토압)

  • Jeong, Seong-Gyo;Heo, Dae-Yeong;Lee, Man-Ryeol
    • Geotechnical Engineering
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    • v.12 no.4
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    • pp.47-60
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    • 1996
  • Of the classical theories on lateral earth pressure, the Coulomb's and the Rankine's theories, which have been usually used in practice for design of retaining walls, assumed that the lateral earth pressure was a triangular distribution. However, the experimental results obtained by Terzaghi(1934), Tsagreli(1967), Fang & Ishibashi(1986), etc showed that lateral pressure were not triangular distribution. ' In this study, for rigid walls with inclined backfaces and inclined surfaces backfilled by $C-\phi$ soils, an analytical method of earth pressure distribution has been newly suggested by using the concept of the flat arch. The results calculated by the newly suggested equations were compared with ones by the existed theories. And'the influence factors of the earth pressures by the suggested equations were investigated. As a result, the thrusts obtained by this method agree well with those by the existing theories, except the Rankine's solution. It was showed that the height to the centre of pressure(h) depends mainly upon the inclinations of the backface and the backfilled surface, the angle of internal friction, and the adhesion between the wall and the backfilled soil, instead of 0.33H, where H is the wall height.

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A Study on the Design Method of the Reinforced Earth Structures Considering Compaction Induced Stresses (다짐 유발응력을 고려한 보강토 설계방법에 관한 연구)

  • 임철웅;백영식
    • Geotechnical Engineering
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    • v.8 no.4
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    • pp.5-16
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    • 1992
  • The main purpose of this the sutdy is to develop the reinforced earth structure design method considering induced stresses and deflections resulting from placement and compaction of soil. In this paper, the new reinforcement Geolog developed by the author is also introduced which is being used as one of the effective earth reinforcing structure against compaction induced stresses. This study adopted the Seed's bilinear model in the estimation of the com paction induced stresses and compute the peak lateral stresses during compaction by doubled Boussinessq's elastic solution of mirror image theory, thereafter, calculate the residual compaction induced lateral stresses from the above peak lateral stress by the residual fraction. It is considered to be reasonable that the compaction induced stresses be added to the lateral earth pressures estimated from conventional gravity analysis considering the actual stresses during service life of the structures. "GEOLOG", a composite of steel bar and attached concrete stopper is found to be effective against tension and pull - out failure. In this paper, the design method considering the compaction induced stresses and the effect of Geolog reinforcement is suggested for the remforced earth structures where backkfill settlement on displacements are not allowed as in the cases of the bridge abutments or double faced reinforcement earth structures.tructures.

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Excavation Behavior of an Earth Retaining Wall Supported by Large Diameter Soil-cement Blocks (대구경 소일-시멘트 교반체로 보강한 토류벽의 굴착 시 거동 분석)

  • Kim, YoungSeok;Choo, Jinhyun;Cho, Yong Sang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.2C
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    • pp.65-74
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    • 2011
  • This paper presents an analysis of excavation behavior of an earth retaining wall supported by large diameter soil-cement blocks at a field trial site. The concept and design philosophy of the large soil-cement block reinforcement are described first. The wall behavior during sequential excavations up to 9.8 m is analyzed based on the measured lateral wall movements and earth pressures. The settlements of adjacent ground are examined by field measurements and inverse numerical analysis. The results indicate that, when the lengths of the soil-cement blocks were over 0.45 H (H: wall height), the displacements and the earth pressures induced by the excavations were similar to those supported by conventional methods such as soil nailing.

Static Lateral Active Earth Pressures with Various Wall Movements (벽체변위에 따른 초유벽의 정적 주동 토압)

  • 채영수;김영진
    • Geotechnical Engineering
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    • v.4 no.2
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    • pp.25-32
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    • 1988
  • This paper first presents the distributions of static lateral earth pressure in case of translational o.all movement (ATRA) , obtained respectively by the Dubrova method and by the method where Chang's idea is applied to the former, acting on the rigid retaining vertical wall with horizontal sand backfill. Total active resultant forces and the points of application of those forces, calculated results by the two methods, are compared with the experimental results recently published by Fang Y.S. and Ishibashi I. A comparative study about the distribution of static lateral earth pressurein each case of rotation about top(AT) and base (AB), on which the writer studied previously, is also conducted along with the above experimental results. The following results are obtained 1) In case of AT and ATRA, the experimental results are in good agreement with the calculated results by the Dubrova's method. 2) In case of AB, the results of the Dubrova's method are very inconsistent with those of model test, where as th method 9.here Chang's idea is applied, corresponds well, even though there is a small deviation.

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Lateral Earth Pressures on Buried Pipes due to Lateral Flow of Soft Grounds (연약지반의 측방유동으로 인하여 매설관에 작용하는 측방토압)

  • Hong, Byungsik;Kim, Jaehong
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.9
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    • pp.27-38
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    • 2010
  • A series of model test as well as numerical analysis by FEM was performed to investigate lateral earth pressure acting on a buried pipe in soft ground undergoing horizontal soil movement. A model test apparatus was manufactured so as to simulate horizontal soil movement in model soft ground, in which a model rigid buried pipe was installed. The velocity of soil deformation could be controlled as wanted during testing. The model test was performed on buried pipes with various diameters and shapes to investigate major factors affected the lateral earth pressure. The result of model tests showed that the larger lateral earth pressure acted on the buried pipes under the faster velocity of soil movement. The result of numerical analysis, which was performed under immediate loading condition, showed a similar behavior with the result of model tests under 0.3mm/min to 1.0mm/min velocity of soil deformation. Most of model tests showed the soil deformation-lateral load behavior, in which the first yielding load developed at small soil deformation and elastic behavior was observed by the yielding load. Then, lateral load was kept constant by the second yielding load, in which plastic behavior was observed between the first yielding load and the second yielding one. Beyond the second yielding load, the compression behavior zone was observed. When the velocity was too fast, however, the lateral load was increased with soil deformation beyond the first yielding load without showing the second yielding load. The buried pipes with the larger diameter was subjected to the larger lateral load and the larger increasing rate of lateral load. At small soil deformation, the influence of diameter and shape of buried pipes on lateral load was small. However, when soil deformation was increased considerably, the influence became more and more.

Lateral Wall Movements and Apparent Earth Pressures for In-situ Walls during Deep Excavations in Multi-Layered Grounds with Rocks (암반을 포함한 다층토 지반에서의 깊은 굴착시 흙막이벽체의 수평변위 및 겉보기토압)

  • 유충식;김연정
    • Journal of the Korean Geotechnical Society
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    • v.16 no.4
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    • pp.43-50
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    • 2000
  • This paper presents the measured performance of in-situ walls using the measured data collected from various deep excavation sites in urban area. A variety of in-situ wall systems from 57 sites were considered, including H-pile walls, soil cement walls, cast-in-place pile walls, and diaphram walls. The examination included lateral wall movements as well as apparent earth pressure distributions. The measured data were thoroughly analyzed to investigate the effects of various components of in-situ wall system, such as types of wall and supporting system, on the lateral wall movement as well as on the apparent earth pressure distribution. The results wee then compared with the current design/analysis methods, and information is presented in chart formes to provide tools that can be used for design and analysis. Using the measured data, a semi-empirical equation for predicting deep excavation induced maximum lateral wall movement is suggested.

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Estimation Method of Earth Pressures Acting on a Row of Piles due to Lateral Soil Movements (측방변형지반속 줄말뚝에 작용하는 토압의 산정법)

  • 홍원표;송영석
    • Journal of the Korean Geotechnical Society
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    • v.20 no.3
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    • pp.13-22
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    • 2004
  • In case of the lateral movement accurring at soft ground where a row of piles are installed, the crown failure at external arch zone of soil arching is firstly developed, and the cap failure at wedge zone in front of piles is lastly developed. Therefore, the lateral earth pressure acting on a row of piles due to soil movement should be calculated in each condition of crown and cap failures around piles. A theoretical equation of crown failure can be proposed using a cylindrical cavity expansion theory. The theoretical equation of crown failure is mainly affected by two factors. One is related to soil properties such as internal friction angle, cohesion and horizontal pressure, and the other is related to pile factors such as diameter, installation interval. Meanwhile, the yield range of lateral earth pressure is established in the estimation of theoretical equation based on crown and cap failures around piles. The theoretical values based on crown and cap failures are compared with the experimental values. The experimental values are located in the range proposed by theoretical values. Thus, it is confirmed that the theoretical values proposed in the study are very reasonable.