• 제목/요약/키워드: Surcharge Load

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자연친화적인 보강토 옹벽의 철판망 gabion 보강재 타당성 분석 (A Feasibility Analysis on Steel Net Gabion Reinforcement of Reinforced Earth-retaining Wall)

  • 정대석
    • 한국환경과학회지
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    • 제17권2호
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    • pp.135-140
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    • 2008
  • Steel net gabion is eco-friendly retaining wall structure showing favorable ability to overcome construction and environmental restriction and also to resist corrosion, chemical attack and degradation. This paper is dealt with the applicability of gabion metal net as a substitution of existing strengthening material. Pull out test was carried out to verify the applicability of gabion metal net. According to results, the increase of surcharge loading and horizontal load resulted in a yield of metal net. The stress at the time of yield was in the range of elasticity. Accordingly, gabion metal net can be substituted for existing geogrid and there is a need for experiment and analysis of arrangement direction and durability of gabion steel net.

Suction Drain 공법에서 양방향 압력재하에 의한 효율 평가에 관한 연구 (A study on evaluation of duplex loading pressure in Suction Drain Method)

  • 안동욱;채광석;한상재;윤명석;김수삼
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 춘계 학술발표회
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    • pp.1256-1263
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    • 2010
  • Suction Drain Method is soft ground improvement technique, in which a vacuum pressure can be directly applied to the Vertical Drain Board to promote consolidation and strengthening the soft ground. This method does not require a surcharge load, different to embankment or Preloading Method. In this study, ground improvement efficiency of suction drain method was estimated when duplex loading pressure with vacuum and pressure. During suction drain method process, surface settlement and pore pressure were monitored, and cone resistance test as well as water content were also measured after the completion of Suction Drain Method treatment.

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Teaching learning-based optimization for design of cantilever retaining walls

  • Temur, Rasim;Bekdas, Gebrail
    • Structural Engineering and Mechanics
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    • 제57권4호
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    • pp.763-783
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    • 2016
  • A methodology based on Teaching Learning-Based Optimization (TLBO) algorithm is proposed for optimum design of reinforced concrete retaining walls. The objective function is to minimize total material cost including concrete and steel per unit length of the retaining walls. The requirements of the American Concrete Institute (ACI 318-05-Building code requirements for structural concrete) are considered for reinforced concrete (RC) design. During the optimization process, totally twenty-nine design constraints composed from stability, flexural moment capacity, shear strength capacity and RC design requirements such as minimum and maximum reinforcement ratio, development length of reinforcement are checked. Comparing to other nature-inspired algorithm, TLBO is a simple algorithm without parameters entered by users and self-adjusting ranges without intervention of users. In numerical examples, a retaining wall taken from the documented researches is optimized and the several effects (backfill slope angle, internal friction angle of retaining soil and surcharge load) on the optimum results are also investigated in the study. As a conclusion, TLBO based methods are feasible.

Optimum PVD installation depth for two-way drainage deposit

  • Chai, J.C.;Miura, N.;Kirekawa, T.;Hino, T.
    • Geomechanics and Engineering
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    • 제1권3호
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    • pp.179-191
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    • 2009
  • For a two-way drainage deposit under a surcharge load, it is possible to leave a layer adjacent to the bottom drainage boundary without prefabricated vertical drain (PVD) improvement and achieve approximately the same degree of consolidation as a fully penetrated case. This depth is designated as an optimum PVD installation depth. Further, for a two-way drainage deposit under vacuum pressure, if the PVDs are fully penetrated through the deposit, the vacuum pressure will leak through the bottom drainage boundary. In this case, the PVDs have to be partially penetrated, and there is an optimum installation depth. The equations for calculating these optimum installation depths are presented, and the usefulness of the equations is studied by using finite element analysis as well as laboratory model test results.

토목섬유보강 성토지지말뚝의 설계조건별 침하억제 효과 (Effect of the Settlement Reduction to each Geosynthetic Reinforced Pile Supported Embankments Design Condition)

  • 이일화;이성진;이수형;문인호
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2009년도 춘계학술대회 논문집
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    • pp.1519-1524
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    • 2009
  • Construction of high-speed concrete track embankments over soft ground needs many of the ground improvement techniques. Drains, surcharge loading, and geosynthetic reinforcement, have all been used to solve the settlement and embankment stability issues associated with construction on soft soils. However, when time constraints are critical to the success of the project, another measures should be considered. Especially, since the design criteria of residual settlement is limited as 30mm for concrete track embankment, it is very difficult to satisfy this allowable settlement by using the former construction method. Pile net method consist of vertical columns that are designed to transfer the load of the embankment through the soft compressible soil layer to a firm foundation and one or more layers of geosynthetic reinforcement placed between the top of the columns and the bottom of the embankment. In this paper, three cases with different embankment height and number of geosynthetic reinforcement, were studied through FEM analysis for efficient use of pile net method.

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원심모형실험에 의한 모래다짐말뚝의 지지력 산정식 연구 (A Study on Estimation of Bearing Capacity of Sand Compaction Pile by Centrifuge Model Tests)

  • 유남재;홍영길;전상현;김경수
    • 산업기술연구
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    • 제27권A호
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    • pp.121-130
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    • 2007
  • Centrifuge model tests were performed to find appropriate equations proposed previously of estimating the bearing capacity of the composite clayey soil reinforced with sand compaction pile. Model tests were carried out with changing the replacement ratio of SCP (20%, 40%, 70%), contents of fine materials (5%, 10%, 15%) and ratio of treated width to loading width (1B, 2B, 3B). Test results about bearing capacity of the composite ground were obtained by performing the surcharge load tests with measurements of applied loads and vertical displacement. Bearing capacities against bulging and shear failures were estimated by the existing equations. As results of comparing the estimated bearing capacity with experimental values the bearing capacities estimated by Greenwood's equation (1970) for bulging failure mode were similar to the test results.

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모래다짐말뚝 개량폭에 따른 보강효과에 관한 연구 (A Study on Effect of Ground Improvement by Sand Compaction Pile Changing Replacement Width)

  • 김시운;정길수;박병수;유남재
    • 산업기술연구
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    • 제25권A호
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    • pp.67-73
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    • 2005
  • In this research, centrifuge model experiments and numerical approach of finite element method to analyze experimental results were performed to investigate the behavior of improved ground with sand compaction piles. One of typical clay minerals, kaolinite powder, were prepared for soft ground in model tests. Jumunjin standard sand was used to sand compaction pile installed in the soft soil. In order to investigate the characteristics of mechanical behavior of sand compaction piles with low replacement ratios, centrifuge model experiments with the replacement ratio of 40%, changing the width of improved area with respect to testing results the width of surcharge loads, were carried out to obtain of bearing capacity, characteristics of load-settlement, vertical stresses acting on the sand pile and the soft soil failure mechanism in improved ground.

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풍화암 지반에 정착된 앵커의 인발저항 특성 (Pull - out Capacity of Ground Anchor in Weathered Rock)

  • 이승환;황의석;이봉열;김학문
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 가을 학술발표회 논문집
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    • pp.435-442
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    • 2002
  • Fluid Confirmation Tests(FCT) on 1500 ground Anchors install in weathered rock were carried out to investigate upper and lower limit of elastic elongation, frictional resistant of fixed anchor body, mobilized angle between anchor body and soil. All the measured data were analysed and compared with theoretical equations. The frictional angles of diaphragm wall and anchorage system in weathered rock showed nonlinear curve between upper and lower limit of standard elongation. The FCT results indicated that the frictional resistant angles increased with higher values of surcharge load. The quality assurance on the fixed anchor location was investigated by means of measuring elastic elongation during the FCT, and comparing these with theoretical design length, the quality of anchors in this particular site found to be above average standard. The results of this research works with provide valuable guide line on quality assurance of anchors system as well as resonable prediction of friction resistance between the fixed anchor body and the weathered rock.

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대심도 연약지반에 적용한 Suction Drain 공법의 수치해석 사례 (A Case analysis for Suction Drain method on deep soft ground)

  • 김성호;한상재;안동욱;김병일;김수삼
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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    • pp.1126-1131
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    • 2009
  • Suction Drain Method is soft ground improvement technique, in which a vacuum pressure can be directly applied to the Vertical Drain Board to promote consolidation and strengthening the soft ground. This method does not require a surcharge load, different to embankment or vertical drain method. In this study, Using Suction-CAIN program, which optimize th Suction Drain method, estimate validity Suction Drain method on deep soft ground

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Underground cavity remediation using membrane grouting method

  • Seung-Hyun Kim;Young-Hoon Jung;Jong-Ho Shin
    • Geomechanics and Engineering
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    • 제38권5호
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    • pp.455-466
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    • 2024
  • Ground collapse may occur around the tunnel when the cavity caused by groundwater runoff cannot resist the surcharge load. Any cavities or subsidence must be managed to avoid dangerous situations by stabilizing the ground through appropriate remedial measures. Trench and trenchless grouting methods can generally be used for the cavity restoration. The trench method is difficult to properly control the injection range and may cause environmental problems due to grout leakage and damages to the adjacent structures due to grouting pressure. In this study, Membrane-grouting method (MGM) is proposed, which, can be an appropriate trenchless grouting method that fills the void tightly and effectively controls the injection range. This method can be an alternative to eliminating the influence of adjacent structures and environmental pollution by inserting a membrane into the cavity and filling the membrane with grout. The membrane blocks the outflow of grout. In addition, it is easy to control the injection pressure to avoid heaving failure. This paper investigates the principle and application of the MGM using a theoretical method, model test and numerical analysis.