• Title/Summary/Keyword: Surcharge pressure

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Lateral earth pressure and bending moment on sheet pile walls due to uniform surcharge

  • Singh, Akshay Pratap;Chatterjee, Kaustav
    • Geomechanics and Engineering
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    • v.23 no.1
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    • pp.71-83
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    • 2020
  • Cantilever sheet pile walls are subjected to surcharge loading located on the backfill soil and at different distances from the top of the wall. The response of cantilever sheet pile walls to surcharge loadings at varying distances under seismic conditions is scarce in literature. In the present study, the influence of uniform surcharge load on cantilever sheet pile wall at varying distances from the top of the wall under seismic conditions are analyzed using finite difference based computer program. The results of the numerical analysis are presented in non-dimensional form like variation of bending moment and horizontal earth pressure along the depth of the sheet pile walls. The numerical analysis has been conducted at different magnitudes of horizontal seismic acceleration coefficient and vertical seismic acceleration coefficients by varying the magnitude and position of uniform surcharge from the top of the wall for different embedded depths and types of soil. The parametric study is conducted with different embedded depth of sheet pile walls, magnitude of surcharge on the top of the wall and at a distance from the top of the wall for different angles of internal friction. It is observed that the maximum bending moment increases and more mobilization of earth pressure takes place with increase in horizontal seismic acceleration coefficients, magnitude of uniform surcharge, embedded depth and decrease in the distance of surcharge from the top of the wall in loose sand.

Design charts for yield acceleration and seismic displacement of retaining walls with surcharge through limit analysis

  • Aminpoor, Mohamad Mahdi;Ghanbari, Ali
    • Structural Engineering and Mechanics
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    • v.52 no.6
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    • pp.1225-1256
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    • 2014
  • Calculating the seismic displacement of retaining walls has an important role in the optimum design of these structures. Also, studying the effect of surcharge is important for the calculation of active pressure as well as permanent displacements of the wall. In this regard, some researchers have investigated active pressure; but, unfortunately, there are few investigations on the seismic displacement of retaining walls with surcharge. In this research, using limit analysis and upper bound theorem, permanent seismic displacement of retaining walls with surcharge was analyzed for sliding and overturning failure mechanisms. Thus, a new formulation was presented for calculating yield acceleration, critical angle of failure wedge, and permanent displacement of retaining walls with surcharge. Also, effects of surcharge, its location and other factors such as height of the wall and internal friction angle of soil on the amount of seismic displacements were investigated. Finally, designing charts were presented for calculating yield acceleration coefficient and angle of failure wedge.

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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Numerical Analyses on Consolidation Promotion Effect of Soft Clay Ground by Prefabricated Vertical Drain (PVD에 의한 연약점토지반의 압밀촉진효과에 대한 수치해석)

  • You, Seung-Kyong
    • Journal of the Korean Geosynthetics Society
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    • v.8 no.1
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    • pp.19-24
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    • 2009
  • In this paper, a series of numerical analyses on soft clay ground improved by PVD were carried out, in order to investigate the consolidation promotion effect considering PVD width and surcharge pressure. In the numerical analyses, an elasto-viscoplastic three-dimensional consolidation finite element method was applied, in which the applicability of numerical analyses could be confirmed comparing with consolidation behavior simulated at the laboratory. And, through the results of the numerical analyses, consolidation behaviors of soft clay ground with elapsed time was elucidated, together with the effects of PVD width and surcharge pressure.

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Settlement Characteristics of Soft Ground Applying the Suction Drain Method (석션드레인공법을 적용한 연약지반의 침하 특성)

  • Han, Sang-Jae;Yoo, Han-Kyu;Kim, Byung-Il;Kim, Soo-Sam
    • Journal of the Korean Geotechnical Society
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    • v.29 no.3
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    • pp.15-27
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    • 2013
  • A vacuum pressure method has been developed to solve many problems in the conventional surcharge method such as embankments, and its application has increased in the country. Recently, to control target settlements in the field, there have been many studies on the comparison of settlements between vacuum pressure method and surcharge load method in the same conditions. In this study, the settlement characteristics of soil subjected to vacuum pressure and surcharge pressure are discussed. The results indicate that if vacuum pressure is applied to the improvement of soft ground, there will be inward lateral displacement and the vacuum pressure will induce generally less settlement than a surcharge load of the same magnitude. The range of settlement reduction ratio is 0.54~0.67 based on Hooke's law, 0.91 based on field cases, 0.81 based on laboratory oedometer tests, 0.75 based on the theory of elasticity and coefficient of volumetric compressibility and 0.77~0.93 in its recent applications to the thick soft ground.

Earth Pressures Acting on the Rigid Wall under Incremental Load (점증하중에 의한 강성벽체에 작용하는 토압)

  • Chon, Yong-Baek;Kwon, Uk-Hwa
    • Journal of the Korean Society of Industry Convergence
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    • v.5 no.3
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    • pp.247-254
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    • 2002
  • This study has researched the following conclusion to compare to the existing theory and to examine lateral earth pressure, which have measured to add incremental load on sandy soil, and were different in types of compaction by modeling earth pressure test. Lateral earth pressure by incremental load shows that it is increasing at depth forty four centimeters as 2/3H point for wall high, and under 2/3 H point the variation of earth pressure on incremental load is not conspicuous. Therefor, the more a position of surcharge load is close with fixed wall, the more a variation of lateral earth pressure marks considerably. According to relative compaction density of soil, lateral earth pressure turns up larger effective value for layer compaction test to a thickness of thirty three centimeters than layer compaction test to a thickness of twenty centimeters by the roller.

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The Response of Buried Flexible pipe due to Surcharge Load and Uplifting Force. (상재하중 및 인발하중으로 인한 식중매설연성관의 거동 특성)

  • 권호진;정인준
    • Geotechnical Engineering
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    • v.3 no.3
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    • pp.31-48
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    • 1987
  • The vertical pressure due to soil prism load and surface surcharge load acts on buried pipe, and occasionally uplifting force due to earthquake or differential settlement acts on it. In this paper, study was performed to estimate the pressure acting on the buried pipe due to soil prism load through analyzing Marston-Spangler theory by new method. And loading tests on the buried flexible pipe were performed to study on the response of the pipe due to surface surcharge load. Also, through the estimation of uplifting resistance theory and uplifting test for buried pipe, the method to determine the maximum uplifting resistance of buried pipe was proposed.

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GROUND TREATMENT CASE HISTORY OFR SOFT CLAY LAYER AND EVALUATION OF ITS IMPROVEMENT (연약지반처리와 개량효과 평가사례)

  • Lee, Yeong-Nam;Lee, Hyeong-Ju;Sim, Dong-Hyeon
    • Proceedings of the Korean Geotechical Society Conference
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    • 1992.10a
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    • pp.113-120
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    • 1992
  • The construction of container terminal at Brani, Singapore required the improvement of soft clay layer having the thickness of about 6.5m, average moisture content of 79.4%, liquid limit of 90.4%, plastic limit of 21.8%, field vane strength of 10 to 25 KPa, pre-consolidation pressure of 225 to 60 KPa and compression index of 0.4 to 1.0. For the improvement of this layer, Colbon drains of 1.3m spacing in triangular pattern were installed to the bottom of the layer and surcharge of more than 11.25m high sand fill was later applied to the treated area. The settlement and lateral displacement of the ground were measured and the speed of surcharge filling was controlled, based on these readings. The removal of surcharge was determinied using the estimated time for the 90% degree of consolidation under the design pressure of 180KPa. The field and laboratory test results show that the soft clay layer has been improved substantially in its strength and consolidation characteristics: increase in strength of about 50KPa and pre-consolidation pressure and decrease in void ratio and compression index.

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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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Static and seismic active lateral earth pressure coefficients for c-ϕ soils

  • Keshavarz, Amin;Pooresmaeil, Zahra
    • Geomechanics and Engineering
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    • v.10 no.5
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    • pp.657-676
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    • 2016
  • In this paper, the active lateral earth pressure is evaluated using the stress characteristics or slip line method. The lateral earth pressure is expressed as the lateral earth pressure coefficients due to the surcharge, the unit weight and cohesion of the backfill soil. Seismic horizontal and vertical pseudo-static coefficients are used to consider the seismic effects. The equilibrium equations along the characteristics lines are solved by the finite difference method. The slope of the ground surface, the wall angle and the adhesion and friction angle of the soil-wall interface are also considered in the analysis. A computer code is provided for the analysis. The code is capable of solving the characteristics network, determining active lateral earth pressure distribution and calculating active lateral earth pressure coefficients. Closed-form solutions are provided for the lateral earth pressure coefficients due to the surcharge and cohesion. The results of this study have a good agreement with other reported results. The effects of the geometry of the retaining wall, the soil and soil-wall interface parameters are evaluated. Non-dimensional graphs are presented for the active lateral earth pressure coefficients.