• 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.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.626-632
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• 2002

Geogrid is widely used as the reinforcement materials in railway earth structures in order to achieve efficient land utilization as well as securing safety in railway service lines in other countries. In this study, the real scale test was carried out to investigate the application of geogrid reinforced soil segmental retaining walls(SRWs) in railway. For this goal, the vibration transfer characteristics of reinforced soil segmental retaining walls was evaluated. The resonant frequencies of SRWs, vertical ground vibration in backfill and vertical/horizontal vibration at segmental units were acquired. This experimental data and analysis result can contribute to understand the vibration response behavior of SRWs.

• Geotechnical Engineering
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• v.12 no.1
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• pp.73-86
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• 1996

In this study, the possibility of the utilization of coal ash as earthwork materials is investigated. For this purpose, some laboratory experiments were carried out. The samples used in these tests are fly ash(FA), bottom ash(BA), coal ash dropped into ash pond(FA:BA=8:2), and mixed coal ash(FA:BA=5:5), which were discharged as a by-product at Yong-Yeul thermoelectric power plant, and general road filling materials. And for the deformation analysis of coal ash reclamation ground, several hyperbolic model parameters were determined by triaxial compression test. As a result of this study, coal ash has excellent engineering properties such as strength parameters comparing with general soils of the same grain size, especially in case of being used as backfill materials and reclamation materials on soft ground, and coal ash is superior to general earthwork materials in engineering properties becasuse of self hardening behaveiour, light weight property, etc.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.43-50
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• 2000

This paper presents the engineering property of light weight soil made of soil mixed with recycled stylofoam and stabilizer. Recycled stylofoam beads is able to use by lightweight fill materials because it is light, adiabatic, and effective for vibration interception. Especially, recycled stylofoam beads is easy to supply because stylofoam have been recycle item in 1996. In this study, physical and geotechnical properties of the light weight mixed soil(weathered granite soil mixed with Stylofoam Beads) were analyzed by laboratory experiments to examine its suitability for backfill materials. Laboratory tests were performed to evaluated strength, bearing capacity, weight, permeability, microphotograph analysis with variation of mixing ratio. Based on the results, it is concluded that the use of recycled stylofoam beads is acceptable lightweight fill.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4005-4012
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• 2022

As high-level radioactive waste (HLW) generated from nuclear power plants is harmful to the human body, it must be safely disposed of by an engineered barrier system consisting of disposal canisters and buffer and backfill materials. A gap exists between the canister and buffer material in a HLW repository and between the buffer material and natural rock-this gap may reduce the water-blocking ability and heat transfer efficiency of the engineered barrier materials. Herein, the basic characteristics and thermal properties of granular bentonite, a candidate gap-filling material, were investigated, and their effects on the temperature change of the buffer material were analyzed numerically. Heat transfer by air conduction and convection in the gap were considered simultaneously. Moreover, by applying the Korean reference disposal system, changes in the properties of the buffer material were derived, and the basic design of the engineered barrier system was presented according to the gap filling material (GFM). The findings showed that a GFM with high initial thermal conductivity must be filled in the space between the buffer material and rock. Moreover, the target dry density of the buffer material varied according to the initial wet density, specific gravity, and water content values of the GFM.

• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.5-12
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• 2012

Recently the installation of reinforced earth retaining walls in the domestic construction site has increased, surpassing conventional RC walls. These reinforced walls have various types depending on the reinforcing material, installation method and the form of face panel. However, there are difficulties in design and construction management due to the unproved safety of construction method. In case of reinforcing materials, despite the fact that they come in all different sizes and types produced by small businesses or partially imported with cheap price and low quality, no proper standards for designing the walls have been suggested. In order to apply reinforced retaining wall system to broad cases and design the walls effectively considering site conditions, specific design and construction guidelines for efficient construction management are needed. In conclusion, this study verified that reduction factors can be greatly affected by grain sizes and stiffness of backfill materials and granularity range, therefore in case of relatively large construction site, it is required to redesign the reinforced retaining wall by evaluating site installation resistance test, applying respective reduction factors to each backfill material and select the right geogrid depending on the usage of retaining wall so as to enhance the safety of reinforced earth retaining walls with efficiency.

• Geotechnical Engineering
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• v.12 no.2
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• pp.59-70
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• 1996

The EPS has the unit weight of only 20~30kg/m3 and is used as one of the methods of reducing road embankment loads. Parts of it's applications are for backfill materials of structures like abutment, retaining wall, etc., to reduce horizontal earth pressure and for banking materials to secure the safety of settlement and bearing capacity by minimizing the stress Increment. However, the Korean Standards (KS) has not yet proposed any testing method for use of EPS as a engineering banking material. Only its testing and quality ordinance as a heat insulation material has been standardized. Therefore, in Korea, EPS is used as banking material without any systematic testing data as a civil engineering material. In this point of view, this paper deals with the engineering characteristics of EPS through many laboratory tests on strength, strain, absorption, and creep. from the results achived through tests, this paper proposes the enactment of a suitable quality testing ordinance and the criteria of unconfined design strength of EPS for use as engineering material.

• Computers and Concrete
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• v.17 no.6
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• pp.787-799
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• 2016

Climate anomalies in recent years, numerous natural disasters caused by landslides and a large amount of entrained sands and stones in Taiwan have created significant disasters and greater difficulties in subsequent reconstruction. How to respond to these problems efficaciously is an important issue. In this study, the sands and stones were doped with recycled materials (waste LCD glass sand, slag powder), and material was mixed for recycled ready-mixed soil. The study is based on security and economic principles, using flowability test to determine the water-binder ratio (W/B=2.4, 2.6, and 2.8), a fixed soil: sand ratio of 6:4 and a soil: sand: glass ratio of 6:2:2 as fine aggregate. Slag (at concentrations of 0%, 20%, and 40%) replaced the cement. The following tests were conducted: flowability, initial setting time, unit weight, drop-weight and compressive strength. The results show that the slump values are 220 -290 mm, the slump flow values are 460 -1030 mm, and the tube flow values are 240-590 mm, all conforming to the objectives of the design. The initial setting times are 945-1695 min. The unit weight deviations are 0.1-0.6%. The three groups of mixtures conform to the specification, being below 7.6 cm in the drop-weight test. In the compressive strength test, the water-binder ratios for 2.4 are optimal ($13.78-17.84kgf/cm^2$). The results show that Recycled ready-mixed soil materials (RRMSM) possesses excellent flowability. The other properties, applied to backfill engineering, can effectively save costs and are conducive to environmental protection.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.81-87
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• 2010

As enormous construction projects of land development are carried out around Korea, useful construction materials are needed to perform the construction projects. However, there are no more enough of fill and reclamation materials in our country. That is why the coal ash is expected to be utilized as an alternative material. Since the coal ash has the characteristics of a pozzolan and a selfhardening material, it is adjudged that coal ash has a great possibility to be used as a fill and reclamation material. In this study, grain size analysis, Atterberg limit test, and specific gravity test were performed to examine the physical characteristics of the coal ash about a self-hardening material before utilizing the coal ash in the construction. Compaction test, unconfined compression test were conducted to investigate the engineering characteristics according to mixture ratios of fly ash and bottom ash. As a result of the tests, it was confirmed that the mixing ratio 1:1 of fly ash and bottom ash is the most effective to use as a fill and reclamation material. If the mixture of coal ash is used as a backfill material with light weight around structure, it is expected to play a significant role in reducing earth pressure on the back of the structure. As described above, the coal ash should be considered as an alternative material of fill and reclamation materials since the result of the tests indicates that the coal ash is suitable to a useful material on the construction design.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.97-105
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• 2004

The purpose of this study is to provide the ways of recycling of by-product limes as lightweight fill, backfill materials, and lightweight blocks by performing experimental study. New lightweight fill materials and blocks were devised by mixing by-product lime, weathered granite soil, small pieces of waste EPS, and Portland cement. Physical, geotechnical, and environmental properties of the lightweight mixed soils and blocks were analysed by laboratory experiments for mixed samples manufactured with various mixing ratios. KMS tests were also performed to evaluate the concentration variation of the chemical components of the light weight blocks leachates. It is expected that this study will contribute to resolving the problem of by-product lime disposal as well as to recycling the by-product limes as fill materials and blocks.