• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.10a
• /
• pp.174-187
• /
• 2005

Recently, because of environment, cost, supply and demand factors, though applying sea-sand as horizontal drains is getting difficult that usage of Gravel has been growing in large size of construction sites, Study on engineering properties and behavior characteristics of Gravel stratum is not thoroughgoing enough. We have applied Gravel Mat as the horizontal drains in O O construction site. We also conducted several field tests such as Material property test, Geosynthetics damage test with Repeated load, Discharge capacity test performed by inflow of upper soil and In-situ PBD Penetration test to review the application of Gravel Mat. Test results show that Gravel Mat is not only advantageous in Trafficability and Water drainage by Consolidation due to its great Internal friction angle and Permeability, but also easy to penetrate with Mandrel and has great discharge capacity and guarantee of the stability against geosynthetics damage at the same time. With these benefits Gravel Mat shows great application in fields.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.3
• /
• pp.37-46
• /
• 2011

To investigate the applicability of Precious Slag Ball as the alternative material such as vertical drains, it is necessary to check the drainage effect of it in the field construction. In order to attain an successful design it is important to predict problems encountered in field construction. Accordingly, in this study the laboratory tests were executed under different conditions before applying of the field. 4 cases including Precious Slag Ball, sand+Precious Slag Ball, pack Precious Slag Ball and sand as vertical drains were conducted, and under the base of the laboratory tests the field test was executed and analyzed. By the upper results it is apposite to use Precious Slag Ball as vertical drains.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.54 no.5
• /
• pp.103-111
• /
• 2012

In this study, the full-scale laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use an alternative material of sand in soft ground is performed. The settlement and pore water pressure were measured to evaluate the discharge capacity and filed application, and the results were compared and analyzed through the finite element method. The measured and estimated settlement in all vertical drain materials decreases gradually with the load increase. The measured settlement 6.55~8.63 mm, and the estimated by the Hyperbolic model was 7.45~7.92 mm. So the model used for the analysis can be applied to the settlement estimation of the actual field. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. The pore water pressure was similarity to that of sand after rapid drawdown. Therefore, it was applicable to the field because discharge capacity was enough to be an alternative material to the sand which had been being used as the vertical drains.

• Economic and Environmental Geology
• /
• v.38 no.5 s.174
• /
• pp.563-570
• /
• 2005

The purposes of this study are to examine a field test on heavy metal removal efficiency for AMD(Acid Mine Drainage) using fish bone and apatite, and to compare those results of the laboratory & the field tests. The duration of the field test was about one month and flow rates of AMD varied from 2.53 l/min to 12.8 l/min. From the result of the field test, removal efficiencies of apatite and those of fish bone are high for As, Fe, and Pb while those of fish born is higher than those of apatite far Al, Cd, Cu and Zn which are similar to the result of the previous laboratory test. In particular, average arsenic removal efficiency of apatite is higher$(84\%)$ than that of fish bone$(75\%)$ like the result of the previous laboratory test. In case of precipitates of phosphate compounds which are generated from chemical reaction between apatite/fish bone and AMD, those generated from apatite/AMD reactionform powder-shape while those created from fish bone/AMD reaction seem to be sludge. Therefore, apatite will be used as a precipitant for mine drainages having wide range of pH based on previous studies while fish bone will be applied as a precipitantfor AMD having lower PH and high concentration of heavy metals.

• Journal of Soil and Groundwater Environment
• /
• v.16 no.2
• /
• pp.52-60
• /
• 2011

Although facilities for the passive treatment of AMD (Acid Mine Drainage) are currently operating in Korea, their removal efficiency for heavy metals is relatively low in average (only 80%). Passive treatment system is composed of oxidation tank, SAPS (Successive Alkalinity Producing System), and wetland. In the treatment system adopted in korea, SAPS (Successive Alkalinity Producing System) plays a major role to remove about 65% of heavy metals through a precipitation. However, the efficiency of SAPS is limited due to the use of mushroom compost (MC) as a organic material and of limestone as a neutralizer. Therefore, this research was performed to search for alternative organic materials through the field test. We tested two types of mixed organic materials: 1) cow manure and spent oak (herein, CO) and 2) cow manure and sawdust (herein, CS). For comparison mushroom compost (herein, MC) was also tested. The result showed that the average Fe removal efficiency was 91.38% with CO, 85.19% with CS, and 91.58% with MC. Thus, CO can be effectively used as an alternative of MC in the SAPS system for heavy metals removal.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.259-262
• /
• 1999

In underground reinforced concrete structures, such as drainage structure, water and chloride ion penetrated into concrete through the cracks of concrete and its permeable property, cause the corrosion of reinforcing steel bar, which accelerates the expansive cracks and deterioration of concrete. It is necessary to control those deterioration of underground structure by improving its permeability and durability through the reasonable solutions in design, construction and materials. In the present study, fly ash concrete, which has good material properties in long-term period, was compared and studied with plain concrete using ordinary portland cement in terms of fundamental mechanical properties, permeability, drying shrinkage and durability. Also, the mix design and field test of low permeable concrete using fly ash were performed. From this study, fly ash concrete can control the penetration of water and chloride ion effectively by forming dense micro-structure of concrete. Therefore, fly ash concrete may increase the long-term function, performance and serviceability of underground structures.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.10a
• /
• pp.133-145
• /
• 2001

This paper presents quality and measure controls of Plastic Board Drains(PBD) for improvement of soft ground. Laboratory and field tests has been carried out to evaluate the quality of PBD focussing on : discharge capacity of flow area; permeability of filter sleeve; migration of fine particles; deformed shape of PBD; consolidation of clay in the close vicinity of PBD; tensile strength of PBD; long-term consolidation behavior of clay-PBD. Test results show that the quality of PBD is sufficient to perform the improvement of soft silty and clayey ground. But, geotechnical engineer must make efforts minimizings of PBD damage and ground disturbance, continuity of drainage system during construction. Adequate monitoring system should apply at ground focussing on number, location, and accuracy of geotechnical instrumentation, measurement and evaluation of data for ground behaviour.

• Proceedings of the KIEE Conference
• /
• 2003.11a
• /
• pp.382-384
• /
• 2003

In case of parallel running with underground gas pipeline and subway, stray current of subway makes a interference on gas pipeline. This interference is one of the reason of gas pipeline corrosion. So, the high speed response rectifier was developed in order to mitigate a interference. In this paper, the field test result of proposed rectifier is presented. The effect of an alternative in stead of the forced drainage system is also presented.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.52 no.6
• /
• pp.111-123
• /
• 2010

In this study, laboratory model test on utilization of recycled aggregates and crushed stone as horizontal drains to use alternative material of sand in soft ground is practiced. The coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~5.1 times and 2.0~3.3 times greater than sand, respectively. The horizontal coefficient of permeability in case of installing the horizontal perforated drain pipe showed largely 1.9~6.8 times more than the case of not installing. The drainage distance showed 1.7~1.8 times greater than sand. When a degree of consolidation is 90 %, there is no delay of consolidation in SCP and PVD improvement sections. Therefore, it is proven that the field applicability is excellent. Also, the suitable quality management criterion is presented to make use of a horizontal drains in soft ground on the basis of analysis of the physical and environmental characteristics.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.9
• /
• pp.13-23
• /
• 2005

The prefabricated vertical drains (PVDs) are one of the most widely used techniques to accelerate the consolidation of soft clay deposits and dredged soil. Discharge capacity is one of the factors affecting the behavior of PVDs. In the field, a PVD is confined by clay or dredged soil, which is normally remolded during PVD installation. Under field conditions, soil particles may enter the PVD drainage channels, and the consolidation settlement of the improved subsoil may cause 131ding of the PVD. These factors will affect the discharge capacity of the PVDs. In this study an experimental study was carried out to estimate the discharge capacity of three different types of PVDs by utilizing the large-scale laboratory model testing and small-scale laboratory model testing equipments. The several factors such as confinement condition (confined by soft marine clay or dredged soil) and variations of the discharge capacity were studied with time under soil specimen confinement, The test results indicated that discharge capacity decreases with increasing load, time, and hydraulic gradient. With load application, the cross-sectional area of the drainage channel of PVD decreases because the filter of PVD is pressed into the core. The discharge capacity of the soft marine clay-confined PVDs is much lower than that of the dredged soil-confined PVDs.