• Journal of the Korean Institute of Gas
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• v.12 no.3
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• pp.75-80
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• 2008

According to the Integrated Notice on City Gas Safety Management Standards, materials for bedding and foundation which are around the pipe should be sands or fine grade soil without large particle that is more than 19 mm size. However, sands are mostly used at gas pipeline construction sites and this causes a shortage of sands and an increase of construction costs. It even causes the disruption of natural environment. In order to improve the standards of backfill material, we have researched regulations in other countries and investigated the pipeline construction sites to survey the present state of backfilling. We also have studied what the bedding and foundation materials affect on buried gas pipelines. Lastly, we have suggested suitable materials for bedding and foundation besides sands. We are sure this paper help the government amend the Notice about backfill materials.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.63-73
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• 1986

The model was developed by applying the principles of Bacot and Vidal to measure the behavior of deformation of the reinforced earth wall, and various tasts were performed by using the plastic fabric filter and the galvanized steel plate as a strip. The results obtained are as follows; 1. When the reinforced earth wall is deformed by the load, the strip is completely reinforced by the backfill materials and changed to the rigid block state, under the state of failure which permits sliding only, the next theoretical equation is formed. (H/L) . tan$\theta$ [cosO-sinOtanO] =2sinO[tan($\theta$ +0) +tanO] 2.The degree of the mutual reinforcement of the backfill material and the strip depend on the physical characteristics of the each material especially the angle of shearing resistance of the backfill material is desirable over 20$^{\circ}$ and, if it is over 400, its function could be a maximum. 3.The distribution of the maximum tensile strain of the reinforcement is changing with the height of reinforced earth wall, and when the height from bottom of the reinforced earth wall is 1.85 to 3. 35m, the maximum tensile strain appears at 2m from the skin element. The maximum tensile strain is increased by the depth of the reinforced earth wall from surface, and increased with the lapse of time after construction. 4.The failure surface of the reinforced earth wall by the concrete skin was about 60$^{\circ}$and the failure behavior of the reinforced earth wall in which the fabric filter was buried was slow, and so the pore pressure could be decreased. 5.It is possible to construct the fabric retained earth wall by the plastic fabric filter only. And the reinforcing effect between the steel plate and the plastic fabric filter is not largely different. however, in the aspect of the economic durability, the plastic fabric filter is more advantageous. 6.The reinforcing action mainly depends on the width and the length of the reinforcing materials, if possible, the full width is advantageous to enlarge the contact area with backfill. but considering the economic aspect, it is neccessary to develop the method controlling the space of the strip.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.303-312
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• 2006

This study is to evaluate the mechanical characteristics of flowable backfill and offer a guide line of mixture proportion based on soil types for constructing underground power utilities. Flowable backfill is known as soil-cement slurry, void fill, and controlled low-strength material(CLSM). The benefits of CLSM are reduced equipment costs, faster construction, re-excavation in the future, and the ability to place materials in confined spaces, which are narrow parts or perimeters of underground power cables nearly impossible for compaction. The flowable slurry mixed with 17 soils and 6 accelerated mixtures in the laboratory were evaluated for flowability and unconfined compressive strength to meet the target values of this study.

• Journal of the Korean Geotechnical Society
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• v.22 no.1
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• pp.63-72
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• 2006

Coulomb's theory has traditionally been used for the estimation of active earth pressure acting on rigid walls. However, many experimental data show that active earth pressures on rough, rigid walls are nonlinearly distributed. This is due to the arching effects produced by friction between the wall and backfill materials when the wall translates away from the backfill. Although there are analyses that take arching into consideration f3r a horizontal backfill surface and a vertical rigid wall, these analyses were derived for homogeneous backfill. Therefore, it is not possible to use these analyses for a caisson backfilled with crushed rock and sand, a common type of rigid wall for harbor structures. In this study, a new formulation for calculation of the nonlinear active earth pressure acting on a caisson backfilled with crushed rock and sand is proposed considering both internal friction angles and unit weights of the crushed rock and sand.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1061-1064
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• 2010

뒷채움재료의 선정기준으로 구조물과 연이은 토공부 사이의 부등침하를 최소화하기 위해 맞물림(Interlocking)효과 및 다짐성이 우수하고 배수가 원활히 될 수 있는 입상재료인 선택층 재료를 사용하는 것으로 규정 및 설계하고 있다. 일률적으로 정해진 현재의 뒤채움재료 선정기준은 건설초기에 손쉽게 구할 수 있었던 선택층 재료인 SB-1의 공급이 어려워져 적절하게 현장여건을 고려하기 곤란하다. 공학적 측면에서 지나치게 안전측으로 선택 및 설계되는 경우가 있어 공사비의 상승 등 시공성과 경제성 측면에서 많은 문제점을 가지고 있다. 본 연구에서는 실내 모형토조를 이용하여 뒤채움 완료 후 뒤채움부 상단에서 교통하중에 의한 장기동적토압을 모사해 뒤채움부의 장기 침하량과 수직, 수평토압을 측정 비교해 교대 뒤채움부 재질 변경을 위한 기초자료로 활용하고자 한다.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.656-661
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• 2009

In this study, theoretical analysis and evaluation tests were performed to assess the pipe stability against compaction equipments and vehicle loads when conventional construction criteria for pre-insulation heating pipes are applied and the alternative material, crushed sand, are used for backfills. The research outcomes shows that (1) the conventional code criteria for pre-insulated heating pipes is well established to support compaction equipments and vehicle loads, (2) the crushed sands as an alternative is usable as backfill materials for pre-insulated heating pipes based on the suitability evaluations of various types of pipes, and (3) the crushed sand agree well with the design consideration of pre-insulated heating pipes construction in the points of economical efficiency and construction criteria.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.599-605
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• 1999

An experimental investigation was carried out to study the feasibility of using the stabilized sludge, as a backfill and cutoff-water materials for embanckment structures. for stabilizing of sludge, hydrated lime and quick lime was used as additive , and a series of tests was performed on the sludge and the stabilized sludge to examine their physical properties, compaction, compressive strength, hydraulic conducivity and consolication characteristics. From the test results, the physical and mechanical properteis of the stabilized sludge weremore improved as compared with the sludge. Especially from the viewpoint of physical porperty , consolidation or settlement and cutoff-water , quick lime is more effective than the hydraged lime as tabilizatio addtivie. But , viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as stabilization additive. As a result of this study, it was founded that the stabilized sludge can be developed the backfill and cutoff-water materials , improved the stabilizing method of sludge.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.6
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• pp.97-104
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• 1999

An experimental investigation was carried out to study the feasibility of using the stabiliozed sludge, as a backfill and cutoff-water materials for embankment structures. For stabilizing of sludge, hydrated lime and quick lime were used as additive, and a series of tests were performed on the sludge and the stabilized sludge to examine their physical and mechanical properties , compaction, compressive strength, hydraulic conuctivity and consolidation characteristics. From the test results, physical and mechanical properties of the stabilized sludge were improved as compared with the sludge. Especially from the viewpoint of physcial property, consolidation or settlement and cutoff-water, quick lime is more effective than the hydrated lime as a stabilization addtive. But, viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as a atabilization additive. As a result of this study, it was found that the stabilized sludge can be developed the backfill and cutoff-water materials, improved the stabilizing method of sludge.

• 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.

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.211-216
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• 2008