• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.33-40
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• 2000

The horizontal drain method is one of the soil improvement methods in reclamation works using dredged soils. In this method, plastic drain boards are installed horizontally in the ground, and a seepage pressure or negative pressure is applied through one end of these drains. In this study, a basic consolidation test using horizontal drains was conducted to investigate the effectiveness of this method. The configuration of soil box which was used in this test is 100cm(B)${\times}$100cm(L)${\times}$85cm(H). The drain board was reduced to 25mm${\times}$5mm. The variations in settlement and volume of drain water during the consolidation process were measured, and the distribution of water content and the transpormation of horizontal drain were investigated.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.129-138
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• 2002

This paper presents a study on the discharge capacity of geotextiles as a horizontal drain layer placed between the layers of earth fill and natural soft ground. Required discharge capacity of geotextiles as drain layers estimated by consolidation analysis is proportional to the consolidation coefficient of the ground soils and the width of the earth fills. The field discharge capacity of the geotextiles are measured by the hydraulic transmissivity test. And the results show wide variation according to the material characteristics of geotextiles, water content of the soils, vertical pressure, and etc. For the short horizontal drain length, geotextile filter mat can be used for the horizontal drain layer. And f3r the long drain($25{\sim}55m$), it is used for the drain together with Bord Drain.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.82-88
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• 2013

There are the stirring test and drain test in the daily performance test to determine the thermal performance of a domestic solar hot water system. The drain test is a test that measures the discharge heating rate while drain the hot water from the top of the storage tank and supply the city water to the bottom of the tank. From the perspective of the user, this drain test is more effective than the stirring test. In this study, the thermal performance were compared through the drain test for a passive type and an active type domestic solar hot water systems consisting of the same storage tank and collectors. At this point, a passive type was used the horizontal storage tanks, and an active type was used vertical storage tank. In the drain test, when the hot water drained up to the reference hot water temperature, an active type which have vertical storage tank represents excellent daily performance than a passive type which have horizontal storage tank regardless of weather conditions. The reason for this is because the vertical storage tank is advantageous to thermal stratification in the tank. After the drain test, the residual heat for the horizontal storage tank was much more than the vertical storage tank, but in the next day the amount of discharged heat were less than the those of vertical storage tank neither. Thus, the solar water heating system which have horizontal storage tank should be adopted preheating control method rather than separate using control method when connected with auxiliary heat source device.

• Journal of the Korean Geosynthetics Society
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• v.3 no.1
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• pp.17-25
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• 2004

A horizontal drain method, which applies vacuum pressure at the end of a horizontal drain for discharging pore water, is used often for improving surface reclaimed clay in the field. In this study, to examine the effectiveness of improving consolidation or shear strength depends by varying vacuum pressure, laboratory chamber horizontal drain test using vacuum pressure is performed and the results is compared with that of self-weight consolidation. The results show that water content reduces with the increase of soil depth in case of self-weight consolidation, while it reduces near the horizontal drain and increases with the increase of the distance from the horizontal drain in case of applying vacuum pressure. The shear strength of dredged soil was improved as well, when the vacuum pressure is applied. The optimized consolidation was achieved at the vacuum pressure range of 30 to 50kPa in the laboratory box test of 50cm wide, considering the range of drain interval in the field was between 0.7 and 1.2m.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.563-570
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• 2001

In this study, the charactersistics of horizontal drains used to stabilize the dredged fill are investigated experimentally by doing tensile strength test, discharge capacity test, and filter clogging test. The types of the drains selected for the study are filament type (Tyre-E), embossed type(Type-P) and heat bonded cubic type with the thickness 10mm(Type-010) and 5mm(Type-05). The results of tensile strength and discharge capacity test show that the performance of drain Type-O10 was better than the other drains. This is caused by the fact that the lattice shape core of drain Type-O10 has strong rigidity and minimizes the loss of the sectional area of discharge with increased confining pressure. Analyzing the compatibility of filters by the results of the strength characteristics test and clogging test, the filter of filament type drain produced with polyester clothed polyamide performed well.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.109-118
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• 2003

This paper is results of numerical works of investigating effects of horizontal drain arrangements on vacuum consolidation. Extensive numerical analyses were carried out to find the appropriate arrangements of horizontal drain of vacuum consolidation. Commercially available program of CRISP, well known to be good to modelling the behavior of clay material, was used Cam-clay model, based on the Critical State of Soil Mechanics(CSSM), was used to simulate the geotechnical engineering behavior of clay. Model test results carried out previously in the laboratory were compared with numerically estimated results and it was found that results about consolidational settlement with times were in good agreements. Based on this confirmation, parametric numerical study was performed to investigate effects of horizontal drain arrangements on vacuum consolidation with changing the vertical and horizontal spacings between drains for the given soil properties and vacuum. The effect of distance of drain located in top layer from the surface of the ground on the settlement due to vacuum was also investigated. As a results of numerical analyses, appropriate arrangements of horizontal drain to maximize the consolidation settlement due to vacuum were found. The mechanism of vacuum consolidation about the vacuum pressures being transferred to the effective stresses around drains was also evaluated.

• Journal of the Korean GEO-environmental Society
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• v.13 no.3
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• pp.77-83
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• 2012

The most of horizontal drainages, which is composed of the aggregates made of sand and crushed stone, are used to improve the soft ground. However, where the aggregates are used as the horizontal drainage, it often brings about the delay of consolidation. For this reason, the horizontal drain pipe system is applied to properly improve the soft ground using a drainage pipe instead of horizontal drainage. This system is direct drain method for disappearing the excess porewater pressure which is caused by placing of fill on the soft ground. The large-scale field test was conducted in order to evaluate the applicability and constructability of the horizontal drain pipe system. The settlement characteristics of improved ground with horizontal drain pipe system was observed. It is also compared to the conventional soft ground improvement method to confirm its effectiveness.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.551-558
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• 2001

The horizontal drain method is one of methods improving reclamation ground. This method reduces consolidation time by using drained installed horizontally, and negative pressure is applied on end of these drains by vacuum pump. But, effective negative pressure still wasn't evaluated in applying this method to reclamation ground. To estimate optimum negative pressure, soil box test that make a model the in-situ by installing horizontal drains in the center is performed pressing different vacuum pressure In the laboratory, and the variations in settlement and volume of drained water through the drains during consolidation process were measured. Also, water content with distance from drain and with depth is measured after the test.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.293-301
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• 2001

This paper is experimental results of investigating the efficiency of horizontal vacuum drainage system. Effects of size and shape of drain on horizontal vacuum drainage were studied. Model tests in the laboratory with soft marine clay were carried out with drain pipe of having three different diameters and PBD (Plastic Board Drain) of strip shape so that consolidation settlement of soft clay due to applied vacuum pressure, amount of discharge, ground settlement and distributions of pore pressure and undrained shear strength were measured during testing. From results of model test, amount of discharge due to vacuum pressure was increased with the diameter of pipe drain whereas the drain efficiency of pipe in per unit area of drain surface was decreased with diameter of pipe. The rate of discharge per unit time was reduced very fast with diameter of pipe. Settlement of ground surface with time was increased with diameter of pipe as a result of increase of discharge to drain pipe.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.35-44
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• 2016

PET aggregates were produced by mixing heated PET flakes with frictional soils. Using these artificially-made PET aggregates, horizontal drain tests in the laboratory, pilot scale model tests were conducted for the evaluation of the drainage characteristics of PET aggregates. Laboratory horizontal drain tests were conducted under twenty different conditions varying mixing ratios and surcharged pressures. Moreover, by utilizing the aggregates with a mixing ratio producing the lowest variation in terms of permeability against applied load, large scale tests were performed. Reliability of the test results was evaluated from comparison with the results of the laboratory horizontal drain test.