• Proceedings of the Korean Geotechical Society Conference
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• 2001.06a
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• pp.33-44
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• 2001

The generally known vertical drain methods for improvement of soft ground are Sand Drain, Sand Compaction Pile, Plastic Drain Board, and Pack Drain. Recently, Plastic Drain Board method application in soft ground is widely used. In this case study, it is compared with each other vertical drain methods from the results of monitorning and test embankment. The results of the analysis and the study show that Plastic Drain Board method is relatively acceptable as vertical drain method.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1165-1172
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• 2006

In this study, an aspect of settlement, developed from different ground improvement method like suction drain method using vacuum pressure and vertical drain method using overburden pressure, was compared each other. In order to analyze settlement tendency of each method exactly, the finite element analysis program was used. The analyses of vertical settlement and lateral displacement for suction drain method and vertical drain method were conducted independently during the solving stage. The initial condition of drainage zone was fixed with 25m depth and 21m width. After the program analyses, the settlement condition had a different tendency with the ground improvement method. Especially, in the results of vertical drain method, the disparity of settlement between the middle of improved zone and unimproved zone. In the case of suction drain method, however, the difference of settlement was smaller than that of vertical drain method.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1126-1131
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• 2009

Suction Drain Method is soft ground improvement technique, in which a vacuum pressure can be directly applied to the Vertical Drain Board to promote consolidation and strengthening the soft ground. This method does not require a surcharge load, different to embankment or vertical drain method. In this study, Using Suction-CAIN program, which optimize th Suction Drain method, estimate validity Suction Drain method on deep soft ground

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.373-382
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• 2007

In the vertical drain method, discharge capacity is generally one of the most important factor which affect on the estimation of the drain efficiency. However, adopting the drain considering discharge capacity only is not sufficiently considered method so that systematic criteria for adoption is necessary to choose the most suitable drain. Therefore, this study represents the application method considering behavior of the ground and vertical drain which is coupled together and ground improvement efficiency analyzing various cases of discharge capacity test performed in the recent soft ground improvement projects. According to the analysis, most drains tend to satisfy the required discharge capacity. It presents that deformed shape of the drains and well resistance estimation along the ground settlement, improvement efficiency by water content ratio along the depth and shear strength obtained after ground improvement should be considered altogether with the discharge capacity to select the proper drain. Also, appropriate adoption of drain material considering the ground condition is vital through analyzing the field measured data and comparing the result of the discharge capacity test as various vertical drain materials are being constructed continuously.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.692-701
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• 2009

The use of vertical drain method to improve the soft soil ground has been continuously increased in Korea such as Busan New Port, Saemangeum reclamation project and so on in Korea. Especially PBD(Plastic Board Drain), one of the vertical drain, has been widely used due to the economic feasibility, construction compatibility and quality control. However in case of using PBD, discharge capacity reduction caused by creep deformation of the PBD filter, bending, kinking and so on can be occurred. Therefore the purpose of this study is to solve these problems by developing Deformation-Compatible Vertical Drain, DCVD which allows to deform with consolidation settlement without bending and kinking of vertical drain. In order to investigate the performance of DCVD developed in this study, discharge capacity test, centrifuge model test and complex discharge capacity test for both PBD and DCVD are performed and the results are compared.

• Journal of the Korean Geosynthetics Society
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• v.9 no.2
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• pp.11-20
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• 2010

This paper studies the discharge capacity of vertical drain boards that is controlling hydraulic gradient among many factors in the specification. The KS K 0940(2008), a testing method based on the conventional Delft type method for measuring the discharge capacity of a vertical drain, was specified in Korea Standard recently. In this test method, the variation in hydraulic gradient can result in large differences in the discharge capacity for the same vertical drain board.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1148-1154
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• 2006

Composite discharge capacity tests and smear effect tests are carried out to estimate the parameters for the reliability-based design of vertical drain method. Also the probabilistic and deterministic solutions of radial consolidation theory are presented. It compared to the result of reliability-based design and that of deterministic design using the tested and estimated parameters. The results indicated that the drain spacing is larger the deterministic method than the probabilistic method because the former is not considered the uncertainties in the properties of soil. The divergence of methods is dependent on the probability of achieving target degree of consolidation by a given time and the coefficient of variation(COV) of the coefficient of horizontal consolidation$(c_h)$.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1167-1174
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• 2008

Vertical drain method, which is one of the soft ground improvement methods, shorten s drain path to accelerate consolidation process and is applied in many sites. At a recent, composite discharge capacity experiment that analyze discharge amount by consolidation behavior with overburden pressure of soft ground in laboratory, simulates similarly with actuality. Geotechnical engineering problems such a s soft ground improvement are solved by numerical analysis by development of computer and numerical analysis techniques. Numerical analysis does that result is contrary by user's inexperience for choice of constitution model and application of analysis method. Therefore, this thesis experiments on composite discharge capacity test and study discharge capacity of drain and consolidation behavior of soft ground installed prefabricated vertical drain boards. Also, This thesis studied reasonable input parameters and constitution model by compare results of composite discharge capacity test and numerical analysis using PLAXIS that is 2D finial element numerical analysis program.

• Journal of the Korean Geotechnical Society
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• v.27 no.4
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• pp.77-87
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• 2011

To investigate the effect of drainage spacing and smear on the rate of consolidation and the efficiency of vertical drain method, a series of consolidation tests with a large consolidation chamber and special equipment for inserting mandrels were conducted. As the smeared region increases, total settlement in over-consolidated clay increases whereas apparent change in settlement does not appear in normally consolidated clay. Vertical drain generally accelerates the rate of consolidation, while it could also deteriorate the efficiency of vertical drain method even for the decreasing drainage length and spacing ratio.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.69-77
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• 2009

The shortage of bearing capacity and settlement, shear deformation may occur when constructing a structure such as harbor, airport and bridge on soft ground such as marine clay, silty clay, sandy soil because it is very soft. The various ground improvement methods were applied to obtain preceding settlement of soft ground and strength increase. The vertical drain method has been used to reduce the required time for consolidation of the soft ground. Especially, the PBD (Plastic Board Drain) has been widely used among in the vertical drain method. In this study, a behavior of characteristic was evaluated by operating a compound drainage capacity test about the PBD (Plastic Board Drain) method applied in soft clay in deep depth. As a result, the settlement gradually occurred with increase of surface load. The consolidation settlement was processed with dissipation of pore pressure after surface load of $500kN/m^2$. Accordingly, it was found that change of settlement through load steps was resulted from dissipation of pore pressure. It was also found that the drainage capacity of vertical drains was considerably reduced with pressure increase and time elapse.