• Title/Summary/Keyword: 뒤채움 방식

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Analysis on Design Change for Backfilling Solution of the Disposal Tunnel in the Deep Geological Repository for High-Level Radioactive Waste in Finland (핀란드 고준위방사성폐기물 심층처분시설 처분터널 뒤채움 설계 변경을 위한 연구사례 분석)

  • Heekwon Ku;Sukhoon Kim;Jeong-Hwan Lee
    • Tunnel and Underground Space
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    • v.33 no.6
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    • pp.435-444
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    • 2023
  • In the licensing application for the deep geological disposal system of high-level radioactive waste in Finland, the disposal tunnel backfilling has been changed from the block/pellet (for the construction) to the granular type (for the operation). Accordingly, for establishing the design concept for backfilling, it is necessary to examine applicability to the domestic facility through analyzing problems of the existing method and improvements in the alternative design. In this paper, we first reviewed the principal studies conducted for changing the backfill method in the licensing process of the Finnish facility, and identified the expected problems in applying the block/pellet backfill method. In addition, we derived the evaluation factors to be considered in terms of technical and operational aspects for the backfilling solution, and then conducted a comparative analysis for two types of backfill methods. This analysis confirmed the overall superiority of the design change. It is expected that these results could be utilized as the technical basis for deriving the optimum design plan in development process of the Korean-specific deep disposal facility. However, applicability should be reviewed in advance based on the latest technical data for the detailed evaluation factors that must be considered for selecting the backfilling method.

Numerical Approach to Evaluate the Behavior of Concrete Panel Considering Construction Method (수치해석을 이용한 시공방법에 따른 판넬식 옹벽의 거동 분석에 관한 연구)

  • Junhee, Kang;Hoki, Ban
    • Journal of the Korean GEO-environmental Society
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    • v.23 no.12
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    • pp.17-23
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    • 2022
  • This paper analyze the precast panel retaining wall's safety factor changes based on the numerical analysis using PLAXIS 2D software. Numerical analysis conditions include construction method, nail and panel fixing method, backfill material compaction conditions, rainfall conditions. The classification according to the construction method of the precast panel retaining wall includes the top-down and bottom-up methods. The difference between the top-down and bottom-up methods is the presence or absence backfill material and the ground excavation method. The top-down method involves vertically excavating the ground and attaching the panel using mortar, but in the bottom-up method, the ground is vertically excavated and harden the backfill material. As a result of numerical analysis, the top-down method secured a higher safety factor in all cases except the rainfall conditions.

Deformation Characteristics of Underground Pipe with In-situ Soil CLSM (현장발생토 CLSM을 이용한 지하매설관의 변형특성)

  • 박재헌;이관호;조재윤;김석남
    • Journal of the Korean Geotechnical Society
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    • v.20 no.3
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    • pp.129-139
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    • 2004
  • During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the small-scaled model test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM.. From the model test in the lab, it was found out that the use of CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the gound surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was smaller than those in the other cases, and the absolute value was almost zero. Judging from the small-scaled model test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing failure of the underground pipes.

Evaluation of Construction Operation and Design Properties of CLSM for Corrugated Pipe in Underground (파형강관을 이용한 지하매설물용 뒤채움재 설계 및 시공성 평가)

  • Lee Kwan-Ho;Park Jae-Heon
    • International Journal of Highway Engineering
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    • v.8 no.2 s.28
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    • pp.63-74
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    • 2006
  • During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the full-scaled field test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM. From the full-scaled test in field, the use of in-situ CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the ground surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was the smaller than the other cases, and the absolute value was almost zero. Judging from the full-scaled field test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing the failure of the underground pipes.

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A Study on Effect of Earth Pressure Reduction and the Silo Earth Pressure of the Retaining Wall by CLSM Backfill with Waste Foundry Sand (폐주물사를 이용한 유동성 채움재의 절토구간 옹벽 뒤채움시 사일로토압 및 토압경감효과 연구)

  • Cho, Jae-Yun;Lee, Kwan-Ho;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.4 no.2 s.12
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    • pp.19-31
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    • 2002
  • The recycling of waste foundry sand(WFS) and fly ash as by-products of industry is one of the urgent problem to deal with. For the recycling of these materials, CLSM(controlled low strength materials) concept was adopted. This research has been done for last three years. In this research, couple of selected waste foundry sand and fly ash were used as fine aggregate. Also, WFS modified by Proper chemical liquid was used for the comparison. The main focus is to evaluate the silo earth pressure and the reduction effect due to the use of CLSM instead of normal fine aggregate. Silo effect, which occurs at short distance between retaining wall and backfill, was not detected because the characterization of CLSM is highly different from that of normal aggregate. Therefore, the theory for earth pressure, like Rankine theory or Coulomb theory, should be carefully used for CLSM. The reduction of earth pressure for modified WFS is higher than the others. But, the final earth pressure is converged at very small value, even though the reduction effect depends on the curing time.

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A Case Study of Evaluating Inertial Effects for Inverted T-shape Retaining Wall via Dynamic Centrifuge Test (동적원심모형실험을 이용한 지진 시 역T형 옹벽의 관성력 영향 분석 사례 연구)

  • Jo, Seong-Bae;Ha, Jeong-Gon;Choo, Yun-Wook;Kim, Dong-Soo
    • Journal of the Korean Geotechnical Society
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    • v.29 no.4
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    • pp.33-44
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    • 2013
  • Mononobe-Okabe (M-O) theory is widely used for evaluating seismic earth pressure of retaining wall. It was originally developed for gravity walls, which have rigid behavior, retaining cohesionless backfill materials. However, it is used for cantilever retaining wall on the various foundation conditions. Considering only inertial force of the soil wedge as a dynamic force in the M-O method, inertial force of the wall does not take into account the effect on the dynamic earth pressure. This paper presents the theoretical background for the calculation of the dynamic earth pressure of retaining wall during earthquakes, and the current research trends are organized. Besides, the discrepancies between real seismic behavior and M-O method for inverted T-shape retaining wall with 5.4m height subjected to earthquake motions were evaluated using dynamic centrifuge test. From previous studies, it was found that application point, distribution of dynamic earth pressure and M-O method are needed to be re-examined. Test results show that real behavior of retaining wall during an earthquake has a different phase between dynamic earth pressure and inertial force of retaining wall. Moreover, when bending moments of retaining wall reach maximum values, the measured earth pressures are lower than static earth pressures and it is considered due to inertial effects of retaining wall.

A Numerical Study on Safety Evaluation of Prefabricated Sewage-Pipe Plastic Foundation Based on Pipe Diameters and Buried Soil Depths (하수관거 직경과 심도를 고려한 하수관거 플라스틱 받침기초의 안전성 평가를 위한 해석연구)

  • Park, Rae-Jin;Park, Jong-Sup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.6
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    • pp.4322-4327
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    • 2015
  • Improper backfill materials and compaction controls under pipelines have become one of the major causes of failure in many sewage pipeline systems. A study on backfill materials and compaction controls has been considered for a long time. However, structural supporters under the pipe were recently concerned because of pipeline repair and maintenance. This paper presents a prefabricated plastic foundation for supporting a sewage pipe system and increasing the performance function of the pipes. Several analytical models for the plastic foundations were investigated using finite-element program, ABAQUS, for checking safety. Comparing with the results of analyses, some of economic design sections based on the sizes of pipe diameters, 600mm, 700 and 600mm, were evaluated. These results could be applied to a pipeline system with a prefabricated plastic foundation with respect to pipe diameters and buried depths.

Basic Study on Historical Repair Techniques for Landscape Architectural Facilities - Focusing on Government-managed Spaces in Joseon Dynasty - (전통조경 시설물의 역사적 수리기법에 관한 기초연구 - 조선시대 관영공간을 중심으로 -)

  • Kim, Min-Seon;Oh, Jun-Young
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.41 no.4
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    • pp.8-20
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    • 2023
  • Although the landscape architectural facilities need to be repaired according to historical and authentic techniques, the repair criteria of the standard specification for repairing cultural heritages still remain at a theoretical level, and there are little research analyzing detailed techniques from specific cases. This study discussed the repair techniques based on historical facts, around terraced flower beds, ponds, waterways and pavement in the government-managed spaces in the Joseon Dynasty. It analyzed the materials and finish of stone wall elements, the structural reinforcement and backfill materials, and topsoil surface protection measures, and drew out stones for foundation reinforcement, plastering material for agglutination, and stone processing techniques for the terraced flower beds. It examined the materials and structures of the rock revetment, foundation reinforcement and waterproofing techniques and drew out the outstanding characteristics of the foundation work, the recycle of used elements and the management of water quality, for the ponds. It primarily investigated the materials, foundation reinforcement and waterproofing techniques and discovered the repair techniques such as cover stone finishing methods, foundation and backfill materials, and flow reduction methods, for the waterways. Finally, it provided actual cases of the foundation composition, auxiliary materials and tools, and the use of cyperaceae and highlighted the existence of professional craftsmen called Bangjeonjang(方磚匠), for the pavement. This study is expected to be a staring point for discovering the repair techniques for landscape architectural facilities and used as basic data for revising specifications in the future.