• Title/Summary/Keyword: geo-material

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Integrated Experimental-Numerical Approach to Investigate the Heat Transferring Effect of Carbon Nanotube on the Concrete Slab (실내실험 및 수치해석을 통한 Carbon Nanotube의 콘크리트슬래브 열전달 효과 검증)

  • Kim, Hee Su;Ban, Hoki
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.1
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    • pp.51-56
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    • 2019
  • This paper presents a method to deice concrete pavement with carbon nanotube(CNT) as an heating material so as to avoid the adverse effects of conventional deicing method such as salt on the structure, function and environment. To this end, laboratory tests integrated with numerical simulations were conducted. In the laboratory tests, the CNT was embedded inside the concrete slab and generated the heat up to the target temperature of $60^{\circ}C$ in the freezer at temperature of $-10^{\circ}C$. Then, the surface temperature was measured to investigate how far the heat transfers on the surface at temperature of above $0^{\circ}C$. Also, three different spacings of 15, 20 and 30cm between CNTs were conducted to determine the maximum allowable spacing of CNT. Along with these experimental tests, heat transferring analysis conducted to validate the test results.

Estimation of Vertical Load Capacity of PCFT Hybrid Composite Piles Using Dynamic Load Tests (동재하시험을 통한 긴장력이 도입된 콘크리트 충전 강관말뚝을 사용한 복합말뚝의 연직지지력 평가)

  • Park, Nowon;Paik, Kyuho
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.3
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    • pp.31-38
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    • 2019
  • To determine the optimum dynamic load test analysis for PCFT (Prestressed Concrete Filled steel Tube) hybrid composite piles that PCFT piles are connected to the top of PHC piles, the dynamic load tests and CAPWAP analyses were performed on two hybrid composite piles with steel pipe and PCFT piles as upper piles. The results of the dynamic load tests and CAPWAP analyses showed that the particle velocity measured in PCFT hybrid composite piles was equal to the wave speed of PHC piles when the strain gauges and accelerometers are attached to the surface of inner composite PHC pile after removing the steel pipe in the upper PCFT pile. In addition, when assuming that the material of that upper PCFT pile was the same as that of the lower PHC pile and the cross-sectional area of the steel pipe in upper PCFT pile was converted to that for concrete through the pile model (PM) in CAPWAP analysis, the accuracy of the CAPWAP analysis result for PCFT hybrid composite piles was very high.

Model Experiments and Behavior Analyses of The Tunnel Support Using TDR Sensor (TDR센서를 이용한 터널 지보재의 모형 실험과 거동해석)

  • Park, Min-Cheol;Han, Heui-Soo;Cho, Jae-Ho;Yang, Nam-Young
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.9
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    • pp.35-45
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    • 2011
  • This paper is to analyze the behaviors of tunnel support by TDR(Time Domain Reflectometry) sensor using electrical pulse. To analysis the behaviors of tunnel support, Copper tape as sensing materials was studied for on-site installation. Copper tape to the top of the glass tape, foam tape, and shielding the lower part was used electromagnetic shield sheet. For a high sensitivity to load and fill out the measurement noise emissions has been developed for the production of materials. This sensing material through the tunnel model tests for the change by surcharge load in TDR data were analyzed. Varing stiffness and support of conditions were determined the change of TDR data through PVC pipe tunnel section model tests. By comparing TDR data and finite element analysis, the behaviors of the tunnel support materials were analyzed qualitatively.

Study on Solidification and Strength of Soft Soils by Using Waste Magnesia-Carbon Powder (폐 Magnesia-Carbon Powder를 이용한 연약지반 고형화 및 강도 증진에 대한연구)

  • Choi, Hun;Song, Myong Shin;Kang, Hyung Ju;Jung, Eui Dam;Kim, Ju Seng
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.1
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    • pp.35-40
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    • 2011
  • Magnesia-carbon brick is used to refractory material in Converter and/or Ladle furnace for molten steel manufacturing. The rapid growth of steel making industry, molten steel industry is increased. Therefore, growth of molten steel industry lead to make waste magnesia-carbon brick by repair of Converter and/or Ladle furnace. These waste magnesia-carbon brick is abandoned all. Besides, as it is loosely composed of silt and clay including sand falling according to the type of gangue, rainwater inflows and outflows relatively easily, but silt or clay particles absorb water for a long period, weakening ground. This study tried to show that when colluvial soil is solidified using waste magnesia-carbon brick powder as a way to solidify strengthen the rigidity of colluvial soil.

An Experimental Research About Settling and Consolidation Characteristic of Dredged Soil in West Coast (서해안 준설토의 침강압밀특성에 관한 실험적 연구)

  • Lee, Seung-Ho;Lee, Jeong-Hak
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.5
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    • pp.29-36
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    • 2011
  • In this study, settling experiment was performed about cohesive and sandy soils among representative sample expected to dredge and dump for analysis of settling and consolidation characteristic. The analysis showed the definite difference between cohesive soils and sandy soils of relationships with settling and consolidation coefficient, a water content, interfacial heights. But directly after a dredged reclamation, prediction results about a initial volume change showed that cohesive soil of a water content change was decreased rapidly as time goes by, but sandy soils made no difference in a water content change. Results were compared and analyzed with the settling and consolidation coefficient and a initial settling velocity by real soil amounts for a feasibility check about test conditions applied to these experiment: we judge that test conditions are appropriate, each material by such these analyses suggests the scope of settling and consolidation coefficient, average and the representative relational formula.

A Study on The Scale Effect of Landslide Model Tests (산사태 모형실험에서의 Scale Effect에 관한 연구)

  • Jeong, Jisu;Ji, Younghwan;Kim, Yootae;Lee, Seungho
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.8
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    • pp.5-12
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    • 2011
  • This study was performed to analyze the degree of rainfalls, the duration time of rainfalls, the inclination of slopes and other damage causes depending on the ground condition, when the landslide occurs by the rainfall. Based on that, a big and a small model soil box were compared to examine the features of landslides, which is ultimately for forecasting landslides. An artificial rainfall device was installed in the model box, and the large model box has a real-size slope in it. Also, various measures were fulfilled such as collapse forms, a pore pressure, an earth pressure and moisture contents in order to analyze the effect of the model box size on the landslide mechanism and to test the usability of a small model box as a material for landslide experiments.

Increase of CO2 Injection Ratio Using Surfactants Based on the Micromodel Experiment (마이크로모델 실험 기반 계면활성제를 활용한 이산화탄소 주입효율 향상)

  • Seokgu, Gang;Jongwon, Jung
    • Journal of the Korean GEO-environmental Society
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    • v.23 no.12
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    • pp.55-61
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    • 2022
  • Carbon dioxide is one of the greenhouse gases in the atmosphere and much research is underperforming in reducing carbon dioxide. Geological carbon dioxide storage is considered the primary technique for global warming prevention. So, technic development for storing carbon dioxide is required. Using surfactant is considered an effective material for geological carbon dioxide storage. However, research on using surfactants for carbon dioxide sequestration is not enough. In this study, a 2D micromodel experiment depends on the surfactant type (sodium dodecyl sulfate and sodium dodecylbenzene sulfonate), concentration and carbon dioxide injection rate. As result, geological carbon dioxide sequestration efficiency is increased according to surfactant concentration and carbon dioxide injection rate increase. However, efficiency no more increases after critical concentration and rate.

Prediction of Long-term Behavior of Tunnel in the Presence of Geological Anomalies (지질이상대가 존재하는 구간에서의 터널의 장기거동 예측)

  • Hoki Ban;Heesu Kim;Jungkuk Kim;Donggyou Kim
    • Journal of the Korean GEO-environmental Society
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    • v.24 no.8
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    • pp.13-20
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    • 2023
  • Tunnelling through the geological anomalies has widely known to have many difficulties such as bottom heave, crack of lining, squeezing and so on. To stabilize the tunnel during the construction or after construction, various reinforcing methods have been introduced and applied such as micropiling at the bottom of tunnel to prevent the bottom heave. In this study, long-term behavior of tunnel in the presence of geological anomalies was predicted using numerical analyses. To this end, material properties for swelling rock model capable of representing the rock swelling behavior was obtained using matching process with measured data to validate the adopted model. After the model validation, simulations were performed to predict the long-term behavior of tunnel in the geological anomalies.

[Retracted]Analysis of Minimum Penetrated Depth of Pile bent of IPM Bridge ([논문철회]토압분리형 일체식 교대 교량의 파일벤트에 대한 최소근입깊이 해석)

  • Kim, Hongbae;Kim, Taesu;Park, Jongseo;Han, Heuisoo
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.5
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    • pp.45-53
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    • 2017
  • IPM bridge was developed to revise the problems of IAB bridge by Nam et al, (2016). This research conducted the p-y analysis to examine the parameter traits among the protruded length (H), penetrated length (L) of pile bent and soil conditions. From the results, the maximum bending moment happened in the top segment of pile bent, because it is integrated to the upper structure. Also, the maximum shear force was shown in the boundary of the sand and weathered soil zones according to the analysis soil conditions. The maximum member force and unbraced length is converged when the ratio (L/H) of protruded length (H) and penetrated length (L) is 1.0. The larger material force is happened, if the pile bent is penetrated shallowly compared to the protruded length. The definite inflection points were shown in the horizontal displacement curve from the p-y analysis, also the smaller penetrated length made the curve grade slower.

Axial Stress Evaluation of Bundle Nails in Smart Construction (스마트 건설기반 번들네일의 축응력 평가)

  • Donghyuk Lee;Jaekoo Ryu
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.6
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    • pp.13-17
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    • 2024
  • The general soil nailing method, which is currently used domestically and internationally to stabilize the slopes of sandy slopes, is to form a kind of gravity-type retaining wall by drilling the ground and grouting it with a single steel bar. This method can reduce construction costs, ease of construction, relative strength and displacement, and is highly efficient. The difference between grouting and rebar adhesion to the yield pullout force and the difference between the amount of deformation in relation to the same pullout resistance was analyzed through field tests to identify engineering excellence, and in terms of construction cost, the reduction effect was evaluated by analyzing the difference in the number of drillings and the impact on the overall construction cost, such as material cost, when the same strength constant is applied to the ground with the same resistance.