• Title/Summary/Keyword: settlement characteristics

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Settlement Characteristics of Short-fiber Reinforced Soil under Dynamic Loading (동적하중에 의한 단섬유 보강토의 침하 특성)

  • Park, Young-Kon;Kim, Jung-Ki;Hwang, Seon-Keun;Shin, Min-Ho
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.321-324
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    • 2002
  • To analyze the settlement characteristics of short-fiber reinforced soil(SFRS) under dynamic loading, a series of tests with loading condition of 5 Hz frequency and 500,000 cycles were performed. The materials used for tests are a soil of SM type and short-fibers with polypropylene and monofilament or fibrillated type. From the tests, average plastic settlement of SFRS at PPF38(0.3%), PPF38(0.5%), PPM60(0.2%) is low. Elastic settlement of SFRS is low at PPM60(0.2%) and is high at PPF60(0.5% ).

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Settlement Characteristics of Short-fiber Reinforced Soil under Simulated Railroad Loading (열차모의하중에 대한 단섬유 보강토체의 침하특성)

  • 박영곤;김정기;김현기;황선근
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.596-600
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    • 2002
  • To analyze the settlement characteristics of short-fiber reinforced soil(SFRS), which will be used as a new backfill material of reinforced retaining wall, under simulated railroad loading, a series of tests with loading condition of 5 Hz frequency and 500,000 cycles were performed. The materials used for tests are soils with SM or ML type, and polypropylene short-fibers with mono-filament(PPM) or fibrillated type(PPF). From the tests, average plastic settlement is low at PPF38(0.3%)(abbreviation of PPF with 38mm length and mixing ratio 0.3%), PPF38(0.5%), PPM60(0.2%) for SFRS using SM soil and at PPF38(0.3%), PPF60(0.2%) for SFRS using ML soil. Elastic settlement is low at PPM60(0.2%) for SFRS using SM soil and at PPM60(0.5%) for SFRS using ML soil.

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A study on Gap Parameter and Influence Area of Ground Settlement Using Back Analysis Constructed by Shield TBM with Shallow Depth (천층터널 쉴드TBM에서 역해석을 이용한 Gap Parameter 및 지표침하 영향범위에 대한 연구)

  • Koh, Sung-Yil;Kwon, Sung-Ju;Hwang, Chang-Hee;Kim, Sang-In;Choo, Seok-Yeon
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1509-1518
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    • 2011
  • Shield TBM tunneling method has been getting the spotlight for urban tunneling. It can be minimized the civil complaint during construction and possible safe tunneling. But the settlement has occurred inevitably due to characteristics of shield TBM equipment. For this reason, the civil complaint can occur in urban areas when tunnel with shallow depth passes through neighboring building or residential area. In this study, the occurrence factors of settlement according to shield TBM tunneling and the tendency of ground settlement by strata condition had analyzed. It is suggested that the practical settlement estimation method and minimizing method of ground settlement under simultaneous backfill grouting condition through measurement results and back analysis data using gap parameter.

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Settlement Estimation of CFRD Considering Valley Shape During Construction Period (계곡형상을 고려한 CFRD의 축조 중 침하량 예측)

  • Park, Han-Gyu;Kim, Yong-Seong;Lim, Heui-Dae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.302-305
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    • 2005
  • In this study, settlement characteristics of 38 CFRD was investigated from monitoring data and the method to estimate the dam settlements considering valley shape during constructions was proposed. The construction modulus of dam was found to be dependent on void ratios and valley shape factor. The construction modulus varied with valley shape and decreased with increasing void ratio. Also, the modulus was increased when the shape coefficient was less than 4. The settlement investigation results showed that the total settlement was proportional to the value of the settlement coefficient multiplied by the shape coefficient divided by void ratio.

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Regional Revitalization and Settlement Improvement from the point of view of the Local Residents - A Case Study on the Nakathu-Mura of Wakayama Prefecture in Japan - (지역주민의 시각에 의한 정주환경개선과 지역활성화 - 일본 와카야마현 나카츠무라를 중심으로 -)

  • Kim, Young-Joo;Choi, Soo-Myung;TAKAHASHI, Tsuyoshi
    • Journal of Korean Society of Rural Planning
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    • v.10 no.3 s.24
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    • pp.19-26
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    • 2004
  • In this study, a new model for improving the settlement environment and revitalizing hilly and mountainous areas was presented. A case study was conducted in two rural villages of Nakatsu-Mura in Wakayama-Prefecture, Japan. The settlement environment was evaluated from the point of view of the local residents, and the expectation of the local residents about the regional revitalization of their village in the future was assessed. From the analysis, each factor used far the assessment displayed characteristics of the two rural villages well. The type of improvement in rural villages was classified by a combination of the degree of satisfaction over the current settlement environment and expectation about the regional revitalization of the villages in the future. A method for improving and revitalizing settlement environments was clarified.

Application of Scale Effect in Estimating Bearing Capacity and Settlement of Footing from Plate-Load Test (평판재하시험으로부터 실제기초의 지지력 및 침하량 산정시 Scale Effect)

  • 정형식;김도열
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.350-357
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    • 2002
  • The scale effect should be considered to determine the bearing capacity and settlement of footings from Plate-Load Test, because of the size difference between a footing and a loading plate. To analyze characteristics of bearing capacity and settlement according to the difference of loading plate sizes, model tests were peformed with four different sizes of square plate, which is B=10, 15, 20 and 25cm respectively, on five different kinds of subsoil, which is pure sand(100:0), sand-clay mixed soil(75:25, 50:50, 25:75), and pure clay(0:100). Based on the analyzed results, this paper also proposed a method of bearing capacity and settlement determination, where scale effect is considered depending on the mixing ratio of sand and clay. Applying the formular proposed in this research to field problems, it is expected that evaluation of bearing capacity and settlement of footings can be more reliable and more economic construction can be achieved.

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Mechanical characteristics + differential settlement of CFG pile and cement-soil compacted pile about composite foundation under train load

  • Cheng, Xuansheng;Liu, Gongning;Gong, Lijun;Zhou, Xinhai;Shi, Baozhen
    • Geomechanics and Engineering
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    • v.20 no.2
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    • pp.155-164
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    • 2020
  • In recent years, the stability, safety and comfort of trains has received increased attention. The mechanical characteristics and differential settlement of the foundation are the main problems studied in high-speed railway research. The mechanical characteristics and differential settlement of the foundation are greatly affected by the ground treatment. Additionally, the effects of train load and earthquakes have a great impact. The dynamic action of the train will increase the vibration acceleration of the foundation and increase the cumulative deformation, and the earthquake action will affect the stability of the substructure. Earthquakes have an important practical significance for the dynamic analysis of the railway operation stage; therefore, considering the impact of earthquakes on the railway substructure stability has engineering significance. In this paper, finite element model of the CFG (Cement Fly-ash Gravel) pile + cement-soil compacted pile about composite foundation is established, and manual numerical incentive method is selected as the simulation principle. The mechanical characteristics and differential settlement of CFG pile + cement-soil compacted pile about composite foundation under train load are studied. The results show: under the train load, the neutral point of the side friction about CFG pile is located at nearly 7/8 of the pile length; the vertical dynamic stress-time history curves of the cement-soil compacted pile, CFG pile and soil between piles are all regular serrated shape, the vertical dynamic stress of CFG pile changes greatly, but the vertical dynamic stress of cement-soil compacted pile and soil between piles does not change much; the vertical displacement of CFG pile, cement-soil compacted pile and soil between piles change very little.

A Study on the Settlement Characteristics of Fill Dam (FILL DAM의 침하특성(沈下特性)에 관(關)한 연구(硏究))

  • Moon, Tae Wan;Kang, Yea Mook
    • Korean Journal of Agricultural Science
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    • v.12 no.2
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    • pp.282-291
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    • 1985
  • In order to investigate the settlement characteristics of fill dam with decomposed granite is used as a embankment material instead of conventional clay collected behavoir of Andong dam and analyzed. Andong dam is the use of decomposed granite in the embankment material, and various type of gauges were installed in dam to measure a pore pressure, interval vertical settlement, dam crest settlement, relative settlement, surface settlement and internal horizontal movement. The results were summerized as follows; 1. With the increase of embankment loading, the settlement of core zone during construction increased with linear and under the effective stress $7kg/cm^2$ vertical settlement ratio ranged between 0.1 and 0.8% approximately and showed smaller value than that of fill dam with clay were used as a embankment material. 2. Though embankment loading was increased with about over central part of embankment height, the settlement of core zone in the lower part of the embankment was influenced slightly. 3. Pore pressure responsed sensitively with the increase of coefficient of permeability in core zone and settlement increased with pore pressure were dispersed. 4. During construction relative settlement in the lower part of the embankment has the largest influence on magnitude of the relative density and after construction settlement showed larger value in the core zone which has the largest compression height. 5. Settlement distribution of dam crest showed larger value in the central part, maximum section of dam, but smaller value in near the abutment.

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A Study on the Characteristics of Consolidation Settlement of Soft Ground in the Plains of the Central Region (중부지방 평야지역의 연약지반에 대한 압밀침하특성 분석 연구)

  • Joon-Seok Kim
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.706-712
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    • 2022
  • Purpose: In this study, field experimental research was conducted to analyze the settlement characteristics of soft ground in the central inland region of Korea and use it in practice. Method: The design predicted values and comparative analysis were performed using the ten settlement measurement data actually measured in the field experiment. For the design prediction value, Terzaghi's one-dimensional consolidation settlement analysis was used. In the experiment, the surface subsidence plate was used for field measurement. Result: The settlement behavior of the predicted value and the actual value was generally similar, but in the settlement value, the actual settlement value showed a settlement behavior of 30% or less compared to the predicted settlement value. The rate of consolidation settlement in this study area was in the range of 9.6% to 27.0%, and the average value was 18.21%. It is analyzed that the prediction of the settlement amount of the silty soils distributed in the inland plains of the central region of Korea can be relatively overestimated. Conclusion: It is judged that precise ground investigation and detailed prediction are necessary because there is a possibility of over-design in the design for predicting the amount of settlement of the silty soils distributed in the inland plains of the central region of Korea.

Load-Settlement Characteristics of Concrete TOP-BASE Foundation on Soft Ground (팽이기초공법(Top-Base Method)의 하중-침하량 분석)

  • Kim, Jae-Young;Jeong, Sang-Seom;Lee, Jae-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.210-221
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    • 2009
  • A new foundation type which is called Top-Base method has been used frequently in engineering practices in Korea. In this study, the settlement behavior of concrete Top-Base foundation on soft ground is investigated since the consolidation settlement of the embedding depth and the effect of footing dimensions are not included in current Korean criterion (2007). To obtain detailed information, the model tests of the Top-Base foundation are performed using the PLAXIS 3D finite element analysis. It is shown that in-situ measurements and finite element analysis of the behavior of foundations indicate that consolidation settlement is reduced up and bearing capacity of the foundation increases up to 50%~100%, compared to the primary non-treated ground. Based on this study, it is found that the Top-Base foundation prevents the lateral deformation of soft ground and reduces its negative dilatancy to the surface settlement, and that the foundation creates rather uniform stress distribution under it to increase its bearing capacity. It is also found that the total settlement of Top-Base foundation was highly dependent on the consolidation settlement and footing configurations.

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