• Geophysics and Geophysical Exploration
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• v.9 no.3
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• pp.225-230
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• 2006

Fluid replacement and conductivity logging have been applied to three boreholes in coastal aquifer in order to identify permeable fractures and to estimate the origin of saline groundwater. Fluid replacement technique measures and monitors the change of borehole fluid conductivity with depth under ambient or pumping condition after replacing the original borehole fluid with different one (by pumping out original one and injecting simultaneously new one at the hole bottom). After the replacement of borehole fluid, the change of fluid conductivity can be the direct indicator of the intake flow of formation water through aquifer such as permeable fractures or porous formations. The conductivity profiles measured with times therefore indicate the locations of permeable zone or fractures within the open hole or the fully slotted casing hole. As a result of fluid conductivity logging for three boreholes at coastal area in Yeonggwang, Jeonam Province, it is interpreted that the seawater intrusion in this area is not by remnant saline groundwater after land reclamation but mainly by intrusion of saline water through fractured rock. This approach might be useful for assessing the characteristics of seawater intrusion, the design of optimal pumping, the mitigation of seawater intrusion using freshwater injection, and estimating the hydraulic characteristics in coastal aquifer.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.29-36
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• 2004

Batch and column tests were performed to develop the design factors for permeable reactive barriers(PRBs) against the contaminated groundwater with ammonium from unsanitary landfill. Clinoptilolite, one of natural zeolites having excellent cation exchange capacity(CEC), was chosen as the reactive material. In batch test, the reactivity of clinoptilolite to ammonium was examined by varying the initial concentration of ammonium and the particle size of clinoptilolites. One gram of clinoptilolite showed removal efficiency about 80% against the ammonium except in very high initial concentration of 80 ppm, but the effect of particle size of clinoptilolite was not noticeable. Permeability test was performed for the specimens made of clinoptilolite and Jumunjin sand with 20 : 80 weight ratio. Flexible wall permeameter was employed far permeability test. The specimen containing the washed 0.42-0.85mm clinoptilolite showed the highest permeability of about $10^{-3}$/s. In column test, the reactivity of mixed materials against ammonium in flowing condition was examined with the landfill leachate. With the test results, clinoptilolite was found to be a suitable material for PRBs against the contaminated groundwater with ammonium.

• Geotechnical Engineering
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• v.10 no.3
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• pp.33-40
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• 1994

The effects of smear and well resistance should be taken into account for the design of sand drains. Practically, simple design, which employs the method using 112 reduced diameter of drains or assuming the coefficient of consolidation in horizontal direction equals to that in vertical direction, based on the theory neglecting these effects, has been used. In this study, the reliability of existing simple design methods as well as the influences of smear and well resistance was investigated with the equations proposed by Hansbo and Onoue. It is shown that the consolidation time is chiefly governed by the effect of smear for drains with highly permeable sands. For general soil condition and placing type of sand drain, consolidation time is underestimated for simple design wi어. 1/2 reduced diameter of drains, and it is overestimated for that with the assumption that the coefficient of consolidation in horizontal direction equals to that in vertical direction. Through the investigations on different reduced diameter, it was shown that simple design with 1/4 reduced diameter of drains yielded the reliable results with errors less than 6%.

• The Journal of Engineering Geology
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• v.30 no.3
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• pp.279-288
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• 2020

Sand dams are formed by installing beams across rivers and filling the secured space with water and a permeable material, such as sand, which stores the water in available pore space. These structures have mainly been reported in Kenya, Africa. This study proposes a sand dam design that improves structural safety and water intake. First, to increase the stability of the concrete wall of the dam, steel barbed wire connections are proposed for construction. Second, by using geotextile fabrics, evaporation may be reduced from 45% to 8%, and horizontal permeable discharge could be reduced markedly, therefore improving water storage capabilities. In addition, the water intake increased by ~2.4 times that of the previous design. Third, filtration efficiency is improved by selecting a sedimentary site for improved water quality. Finally, the installation of a tensiometer is suggested for monitoring the sand dam.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.39-53
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• 2007

Generally, fractured medium can be described with some key parameters, such as hydraulic conductivities or random field of hydraulic conductivities (continuum model), spatial and statistical distribution of permeable fractures (discrete fracture network model). Investigating the practical applicability of the well-known conceptual models for the description of groundwater flow in fractured media, various types of hydraulic tests were applied to studies on the highly fractured media in Geumsan, Korea. Results from single-hole packer test show that the horizontal hydraulic conductivities in the permeable media are between $7.67{\times}10^{-10}{\sim}3.16{\times}10^{-6}$ m/sec, with $7.70{\times}10^{-7}$ m/sec arithmetic mean and $2.16{\times}10^{-7}$ m/sec geometric mean. Total number of test interval is 110 at 8 holes. The number of completely impermeable interval is 9, and the low permeable interval - below $1.0{\times}10^{-8}$ m/sec is 14. In other words, most of test intervals are permeable. The vertical distribution of hydraulic conductivities shows apparently the good correlation with the results of flowmeter test. But the results from the cross-hole test show some different features. The results from the cross-hole test are highly related to the connectivity and/or the binary properties of fractured media; permeable and impermeable. From the viewpoint of the connection, the application of the general stochastic approach with a single continuum model may not be appropriate even in the moderately or highly permeable fractured medium. Then, further studies on the investigation method and the analysis procedures should be required for the reasonable and practical design of the conceptual model, with which the binary properties, including permeable/impermeable features, can be described.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1239-1251
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• 2015

Impervious areas have been expanded by urbanization and the natural structure of water circulation has been destroyed. The limits of centralized management for controlling storm water runoff in urban areas have been suggested. Low impact development (LID) technologies have been promoted as a crucial alternative, establishing a connection with city development plans to build green infrastructures in environmentally friendly cities. Thus, the improvement of water circulation and the control of nonpoint source were simulated through XP-SWMM (storm water and wastewater management model for experts) in this study. The application of multiple LID combination practices with permeable pavements, bioretention cells, and gutter filters were observed as reducing the highest runoff volume by up to 70%. The results from four different LID installation scenarios indicated that permeable paving is the most effective method for reducing storm water runoff. The rate of storm water runoff volume reduced as the rainfall duration extended. Based on the simulation results, each LID facility was designed and constructed in the target area. The LID practices in an urban area enable future studies of the analysis of the criteria, suitable capacity, and cost-efficiency, and proper management methods of various LID techniques.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.343-350
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• 2009

In the present study, a new seismic retrofitting method that employs both a stainless steel wire mesh and a permeable polymer concrete mortar was proposed for reinforced concrete bridge piers with nonseismic design details. For this purpose, a total of six nonseismically designed bridge piers were tested under lateral load reversals. The test results reveal that nonseismically designed piers with lap splices need to be retrofitted to resist earthquake induced forces. In addition, it was proven that the proposed retrofitting method can be useful in improving the strength, stiffness, and energy dissipation capacities of bridge piers designed nonseismically. It is thus expected that the proposed method may provide an improved ductility capacity without sudden softening of strength for bridge piers excursing inelastic displacement range.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.435-442
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• 2000

Batch test and column test were performed to develop the design factors for permeable reactive barriers(PRBs) against ammonium and heavy metals, Clinoptilolite, a kind of natural zeolites having excellent cation exchange capacity(CEC), was choosen for the reacting materials through the ion-exchange mechanism. In the batch test, the reactivity of clinoptilolite for ammonium, lead, and copper was examined varying the initial concentration of contaminants(ammonium: 20, 40, 80 ppm, heavy metals: 10, 20, 40 ppm) and the particle size of clinoptilolites(0-0.15, 0.42-0.85, 1-1.25 mm). The reactivity is increasing as the initial concentration decrease and particle size decrease. In the column test, the permeability and the reactivity of the specimens were examined using flexible-wall permeameter. Specimens were made of clinoptilolite and Jumunjin-sand with 20 : 80 weight ratio varying particle size of clinoptilolite. The maximum permeability(1${\times}$10$\^$-4/-5${\times}$10$\^$-5/cm/s) was achieved in the specimen made of 0.42-0.85 mm clinoptilolite and sand.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.826-832
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• 2016

Reduced greenhouse gas effect induced by LID (Low Impact Development) technique application in tramway construction was quantified to increase environmental benefit as part of an overall economic assessment. In addition, by application of penetration type permeable blocks, the effect of the urban water cycle was examined as a special assessment item in the policy analysis. The carbon emission ratios of the permeable turf block, according to the turf coverage rate (100%, 50% granite, and 50% HDPE), against the concrete track construction were -184.7%, -127.3%, and -116.3%, respectively. The carbon emission ratios of permeable blocks with granite and HDPE were 30.1% and 52.5%. In the case of the penetration type permeable block, it was possible to store rainfall in the block until 90mm/hr of rainfall intensity (94.3% of water reserve rate); therefore, this method was effective as part of the urban water cycle system. As a result, an increased environmental benefit from LID technique application is expected in tramway construction; this needs to be considered as a policy factor in AHP analysis.

• Korean Journal of Agricultural Science
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• v.26 no.2
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• pp.49-55
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• 1999

This study is performed to evaluate the properties of permeable polymer concrete with blast furnace slag and fly ash. The following conclusions are drawn: 1. The highest strength is achieved by 50% filled blast furnace slag powder and fly ash permeable polymer concrete, it is increased 36% by compressive strength and 217% by bending strength than that of the normal cement concrete, respectively. 2. The static modulus of elasticity is in the range of $100{\times}10^3{\sim}130{\times}10^3kgf/cm^2$, which is approximately 43~51% of that of the normal cement concrete. 3. The dynamic modulus of elasticity is in the range of $102{\times}10^3{\sim}130{\times}10^3kgf/cm^2$, which is approximately less compared to that of the normal cement concrete. The highest dynamic modulus is showed by 50% filled blast furnace slag powder and fly ash permeable polymer concrete. The dynamic modulus of elasticity are increased approximately 0~4% than that of the static modulus. 4. The water permeability is in the range of $4.612{\sim}5.913l/cm^2/h$, and it is largely dependent upon the mix design.