• Journal of the Korean Geotechnical Society
• /
• v.22 no.1
• /
• pp.15-23
• /
• 2006

During earthquake, force components acting on quay walls consist of inertia force, earth pressure and water pressure. The earth pressure is largely influenced by the backfill condition such as soil density and the installation of gravel backfill. Therefore, shaking table tests were performed by using four different model sections, which were designed by varying the soil density and the backfill materials. The magnitude and the phase of force components acting on quay wall were analyzed. Test results showed that the gravel backfill and the soil compaction were effective to reduce the excess pore pressure in backfill and the magnitude and phase of backfill thrust were much influenced by the excess pore pressure in backfill. When the input acceleration was 0.10g, the average ratios of the inertia force, the front dynamic water force and the thrust to the total force were $64\%,\;21\%\;and\;16\%$, respectively. As the excess pore pressure increased, the ratio of the thrust to the total force increased.

• Journal of the Korean Geosynthetics Society
• /
• v.17 no.1
• /
• pp.85-93
• /
• 2018

A existing standard design section of transitional zone between bridge and earthwork section in high speed railway should be designed to gradually change support stiffness from bridge abutment to backfill side that were placed on cemented stabilized gravel, general gravel, soil materials. The larger the backfill slope of the general gravel and soil was more structurally stable, but there is no clear reason about them. In this study, it was compared with settlement and bearing capacity of backfill area in currently design and alternating backfill slope section using large centrifuge tester. As the experimental results, it was showed that the 1:2 slope and 1:1.5 slope have almost similar bearing capacity behavior under the load stage as railway loading level.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.1
• /
• pp.13-26
• /
• 2011

Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need for cable backfill materials to be maintained at a low thermal resistivity during the service period. Temperatures greater than $50^{\circ}C$ to $60^{\circ}C$ may lead to breakdown of cable insulation and thermal runaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aimed at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. The results of Dong-rim river sand (relatively uniform) show that as water content level increases, thermal resistivity tends to decrease, whereas the thermal resistivity on dry condition is very high value($260^{\circ}C-cm/watt$). In addition, other materials(such as Jinsan granite screenings, A-2(sand and gravel mixture), E-1(rubble and granite screenings mixture) and SGFC(sand, gravel, fly-ash and cement mixture)) are well-graded materials with low thermal resistivity($100^{\circ}C-cm/watt$ when dry). Based on this research, 4 types of improved materials were suggested as the environmentally friendly backfill materials with low thermal resistivity.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.04a
• /
• pp.112-119
• /
• 2000

the shaking table tests for 5 different model sections are performed to investigate the behaviors of quay walls during earthquakes and to evaluate the seismic performance of quay walls with countermeasures. 5 different model sections describe the cases of dense soil and loose soil in the foundation repectively the case to which gravel backfill was applied and the cases to which light material replacement method and sand compction pile method was applied repectively for sesmic countermeasure methods. Pore water pressures accelerations and deformations in quay walls and grounds are analyzed. As a result the softening of foundation and backfill soils have much influence on the behaviors of quay walls. Also light material replacement method and sand compaction pile method are effective in improving the seismic performance of quay walls.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.9
• /
• pp.5-11
• /
• 2011

This paper recommends the alternative back-fill material for the pre-insulated pipe based on the results of tests performed using different kinds of backfill material. In this study, laboratory tests were preformed to determine the behavior of the pre-insulated pipe caused by variation on grain size distribution, friction characteristics and earth pressure characteristics of different types of backfill material. Two types of natural sand (fine-grained and coarse-grained sand) and crushed sand, and two types of gravel (10mm, 20mm) were used as backfill material in the laboratory tests. The laboratory test results were analyzed and compared with the pre-insulated pipe backfilled with the standard medium-grained sand. Based on the evaluation and comparison of laboratory test results, it was determined that crushed sand is the most suitable back-fill material that can be used as an alternative for medium grained sand for pre-insulated pipes.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.1C
• /
• pp.1-6
• /
• 2012

In this study, field tests were performed to evaluate the stability of pre-insulated pipe during the compaction operation and to recommend an alternative backfill material. Three types of natural sand (fine-grained and medium-grained, coarse-grained sand), crushed sand and two types of gravel (10 mm, 20 mm) were used as backfill material in the field tests. Field tests were performed to determine the behavior (earth-pressure and deformation, installation damage) of the pre-insulated pipe due to variation of different types of backfill material. Based on the evaluation and comparison of field test results, it was determined that crushed sand is the most suitable back-fill material that can be used as an alternative for medium grained sand for pre-insulated pipes with respect to the engineering behavior and material supply.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.7
• /
• pp.37-46
• /
• 2013

Various sizes of gravels are included in the most field soils that are utilized for civil constructions. Especially, the small amounts of gravel are often included in selected soils for backfill materials, earth dams, and subbase ground. In such cases, the small amounts of mixed gravel and its shape may influence the determination of dry density of soils, which results in an inaccurate degree of compaction for soils in the field. In this study, a dry density of sand with various gravel contents (0, 10, 17, 23, 29 and 33%) and three different sizes (2.0-2.36, 3.35-4.75, 5.6-10.0 mm) was experimentally investigated for compacted or loosely packed conditions. The loosely packed sand with gravels was simulated by pouring sand into compaction mould and its density was determined. When a 33% of gravel content was mixed with sand, its dry density increased up to 15-20% for compacted specimen and 20-23% for loosely packed specimen. When a gravel content and size were the same, a dry density of compacted specimen was $0.1-0.16g/cm^3$ higher than that of loosely packed specimen. Even though the same gravel content was used, a dry density of sand with big gravels was $0.04-0.08g/cm^3$ higher than that of sand with small gravels for compacted specimen and $0.03-0.05g/cm^3$ for loosely packed specimen.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.25-32
• /
• 2001

Doosan Construction & Engineering Co., Ltd is building a railway tunnel beneath the Soo-Young River connecting MinLak Station and Centum City Station, a section 230, subway line 2, Pusan City, Korea. When completed the tunnel will have a finished inner diameter of 6.5m(21.311) throughout its total length of 840m(420m = 0.52 miles, Two Single Track Tunnel : 420m＋420m). The ground profile of the face toward shield machine is composed of multi layers, silty clay, clayey gravel, soft rock etc. This research paper is to predict ground deformation and variation of stresses around tunnel using Hyperbolic model, and to reflect the works on the next shield tunneling project. And this research paper is analyzed data of measuring instrument (such as settlement gauge, inclinometer, Multiple extensometer, etc.) which is installed along tunnel line for safety of tunnel. For calculations, the finite difference Method is applied. Backfill grouting material is supposed to have instantly strength of 10kg/$\textrm{cm}^2$ above, although its strength is available after 24 hours passed.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.5
• /
• pp.209-220
• /
• 2002

Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need for cable backfill materials that can maintain a low thermal resistivity (less than 5$0^{\circ}C$-cm/watt) even while they are subjected to high temperatures for prolonged periods. Temperatures greater than 5$0^{\circ}C$ to 6$0^{\circ}C$ may lead to breakdown of cable insulation and thermal nlnaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aiming at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. Tests were called out for DonUing river sand, a relatively uniffrm sand of very high thermal resistivity (5$0^{\circ}C$ -cnuwatt at 10% water content, 26$0^{\circ}C$-cm/watt when dry), and Jinsan granite screenings, and A-2(sand and gravel mixture), E-1 (rubble and granite screenings mixture), a well-graded materials with low thermal resistivity (about 35$^{\circ}C$ -cm/watt when at 10 percent water content, 10$0^{\circ}C$-cm/watt when dry). Based on this research, 3 types of backfill materials were suggested for improved materials with low thermal resistivity.

• Journal of the Korean Geosynthetics Society
• /
• v.20 no.4
• /
• pp.151-163
• /
• 2021

This paper is dealt with railway slope stability for slope reinforcement using a geosynthetic concrete composite mat(GCCM). Recently, according to a change in weather caused by global warming, train operation has been restricted by the loss of backfill slope at the roadbed, which is consists of gravel, due to typhoons and heavy rainfall. In addition, the amount of damage is getting more significant than the cost of restoration, and the safety of workers is worried. In order to improve this limitation, a slope stability analysis was applied with a rapid hardening composite mat so that it can quickly secure a construction surface with increased workability and work stability and reduce maintenance costs by preventing re-loss in case of heavy rain and fundamentally blocking vegetation. As a result of the analysis, it was confirmed that the increase in safety factor was confirmed when the rapid harding composite mat was applied.