• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1132-1141
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• 2006

Recently it is difficult to secure sand used in the improvement of soft ground, and so it is necessary to find alternative materials. For this reason many researchers are studying and trying to find new substitute materials. One of the materials is considered as converter slag by wind fracture which is generated in the production of steel manufacture by electric circuit. It is environment friendly since it is a recycled material and economical since it is cheaper than sand. To investigate the applicability of converter slag by wind fracture as the alternative material such as vertical drains, it is necessary to check the drainage effect of this 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 test was executed under different conditions in advance of applying of the field. A total of 4 cases including slag, sand+slag, pack slag and sand as vertical drains was conducted, and at the base of the laboratory test the field test was executed and analyzed.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.623-630
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• 2000

In this study, it was to investigate the possibility to use the converts slag, by product in producing steel as a substitute material with sand that is used fur a civil construction materials, in developing techniques to use converts slag to improve soft clay ground. To do this, it was investigated the physical and mechanical properties of the converts slag as a civil construction material. For this, cylindrical cell consolidation with a single vertical drains and large scale soil box test were performed. Through large scale soil box test, the applicability of the converts slag to the present vertical drain techniques which is dependent on sand and plastic drains was studied. As a result of that, it was found that the shape of inserted drains was maintained after completing a consolidation process of a soft clay with slag drains. In addition, we could find that the slag drains showed the similar results with sand drains in soft clay by analyzing the effect of acceleration of consolidation.

• Journal of the Korean GEO-environmental Society
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• v.12 no.3
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• pp.37-46
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• 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 Industrial Technology
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• v.29 no.A
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• pp.127-134
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• 2009

In this paper, an numerical approach is performed to investigate the effects of smear zone, occurred by penetrating vertical drains, on consolidation behavior of soft clay deposits. Such a numerical analysis is applied to the field condition to confirm its applicability. Parametric numerical analyses is carried out to study influencing factors such as permeability in smear zone, boundary of smear zone and discharge capacity of vertical drains on the consolidation of soil. As results of analyses, for the given conditions of soil, degree of consolidation is getting faster with increase of permeability of vertical drain. Degree of consolidation is delayed with decrease of permeability of smear zone. As the ratio of drain width to smear zone increases, the degree of consolidation decreases. Proposed values of influencing factors by previous researchers is found to be reliable from results of numerical analyses with Cam-clay model.

• Journal of the Korean Geosynthetics Society
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• v.7 no.4
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• pp.37-45
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• 2008

A pilot test using environmentally friendly drains, was carried out to evaluate their applicability potential in the field. The pilot test site was divided into 5 different areas, with several combinations of vertical and horizontal drains installed for evaluation. Conventional natural fiber drains (FDB), new developed straw drain board (SDB) and plastic drain board (PDB) were used as vertical drains, while sand and fiber mats were used as horizontal drains. Surface settlement rates and excess pore pressure generation/dissipation tendency of PDB and FDB are almost identical except those of SDB. Cone tip resistance obtained from cone penetration test measured at the end of 1st consolidation stage for upper soft layer definitely increased irrespective of types of vertical drains. The monitoring and site investigation test data obtained at the pilot test site prove the vertical natural fiber drains can be used as substitutes of conventional plastic and sand material.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.720-728
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• 2009

This thesis is results of numerical analyses about test results of discharge capacity apparatus using penetration method. Applicability of numerical approach with FEM technique, using Cam-clay model, was confirmed by analyzing the results of standard consolidation test before analyzing test results of discharge capacity apparatus using penetration method. Thus, input parameters for the model was convinced to be appropriate. For numerical analyses about test results of discharge capacity apparatus using penetration method, identical initial and loading conditions during tests were applied to simulate test results correctly. Effects of ground disturbance resulted from installment of vertical drains on the behaviors of consolidation were also simulated. Applicability of numerical approach was investigated by comparing test results with numerical ones. As results of them, both of consolidation settlement were found to be in good agreements so that its applicability was confirmed. As results of numerical estimation, degree of consolidation with the condition of considering smear zone was found to be delayed, compared with results without smear zone. On the other hands, parametric numerical analyses of changing parameters related to smear zone such as permeability and size of smear zone and permeability of vertical drain were also carried out.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5C
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• pp.313-320
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• 2008

The discharge capacity testing apparatus using penetration method, being able to simulate in laboratory the condition of embedding plastic board drains in field, was developed to investigate consolidation characteristics of ground and to figure out discharge capacity of drains. The developed apparatus with a mandrel and penetrating device was designed to insert PBD into the ground prepared by previously applied pressure, being different from the conventional testing method that the drain was installed and the ground material was poured subsequently. Discharge capacity tests with the conventional apparatus as well as the newly developed one were performed to assess the applicability of the latter. As a result of tests, the conventional method showed delayed consolidation due to overall disturbance of ground and local deformation of drain caused by inhomogeneity of ground. Therefore discharge capacity of drain with the conventional apparatus was measured more or less larger than the expected values whereas discharge capacity with new one could be measured similar to the actual value in field.