• Elastomers and Composites
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• v.51 no.1
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• pp.17-23
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• 2016

In this study, the reclaimed polypropylene (RPP) and waste ground rubber tire (WGRT) were used to simulate the thermoplastic vulcanizate (TPV) for cost reduction and resources recycling. Also, we examined the effects of dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (DTBPH) as peroxide type cross-linking agents to enhance the properties of TPV's. The components of RPP and WGRT were fixed at 30 and 70 wt%, and DCP and DTBPH were added in the concentrations from 0.5 to 1.5 phr, respectively. RPP/WGRT composites with different contents of DCP and DTBPH were prepared by a modular intermeshing co-rotating twin screw extruder. The Young's modulus of composites were decreased with increasing peroxides contents. On the other hand, tensile strength, elongation at break, and impact strength of the composites were increased with peroxide contents. We also confirmed that interfacial adhesion between RPP and WGRT was considerably improved by adding the peroxides. Taken together, DTBPH added RPP/WGRT composites exhibited better mechanical properties rather than those of DCP added composites.

• Journal of the Korean Geotechnical Society
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• v.24 no.8
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• pp.61-79
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• 2008

Consolidation settlements on marine dredged clays are often greatly and potentially damaging to structures. Currently, large-scale projects are in planning or progressing in Korea. These projects have been performed on thick and soft clay layers. So, the evaluation of consolidation characteristics for dredged and reclaimed ground is very important in design and construction. Therefore, in this study, a series of conventional consolidation tests were performed to investigate the consolidation characteristics of marine dredged clays near Gwang-yang Port. Preconsolidation pressures were evaluated by applying previously proposed 8 methods for the conventional tests results in order to evaluate the legitimacy of these methods. In these methods, when estimating maximum past pressures for dredged and reclaimed ground, it was proved that Becker (1987), Silva (1970), Sridharan (1991)'s methods are excellent in legitimacy.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.640-648
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• 2009

Recently the truction of coastal reclaimation work has been extensively implemented in Korea. The Sondo New City is being established on the reclaimed land from the sea, construction companies of metro construction are planing to pull-out the sheet pile for saving the construction cost. In the case of soft marine clay, it is very difficult to pull-out the sheet pile by using the hydraulic hammer difficult. Therefore, the man of the field must be aware of vibration effect to the ground and the structure. For understanding the vibration effect to the ground during subway construction, the model was formulated with 1/25 braced-cut for subway construction. Scott and Iai(1989) proposed the law of the similarity for other experimental conditions. The laboratory model test was conducted under the vibration condition of sheet pile pulling out. The settlement on the ground surface was measured during the shaking table test. The pore water pressure was also monitored in the upper, middle, and lower layers of soil. The field settlement level and the pore water pressure can be predicted by using the results of the laboratory shaking table test.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.1
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• pp.27-38
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• 2000

The collapses and settlement of harbor facilities from earthquakes were known due mostly to liquefaction of reclaimed land. The most harbor quay wa1ls being designed as gravity types in Korea are known susceptible structures to liquefaction because reclaimed land was not treated resistant to earthquake. In this study, liquefaction susceptibility of reclaimed land behind a large quay walls under construction to earthquake was predicted and its stability was analyzed. In addition, liquefaction prediction methods in harbor facilities specification adopted by both Korea and Japan were compared by applying the methods to prediction of liquefaction susceptibility of reclaimed land, respectively.

• Korean Journal of Environment and Ecology
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• v.16 no.1
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• pp.1-9
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• 2002

This study was carried out to examine the tree-ring growth characteristics of Pinus thunbergii Parl. after replanting on the reclaimed land from the sea in Kwangyang bay, The factors, mostly affecting the growths of Pinus thunbergii Parl. , were the replanting stress and drought. The growth reduction due to replanting occurred in the replanting year and following year, but that due to drought after 2-3 years of replanting. The growth recovery after replanting differed with soil condition. The sites showing fast recovery were the covered ground of improve soil, the ground of medium mounding, the top and the slope ground of big mounding sites. The filled ground of improve soil and the lower ground of big mounding sites showed retarded growths. The mean sensitivity(year-to-year variation) and the coefficient of variation(tree-to-tree variation in a certain year) in tree rings of Pinus thunbergii Parl. were higher in the poor soil sites than in the favourable soil ones. The physical characteristics of the soil, especially soil hardness, were the most crucial. The mean sensitivity and the coefficient of variation were also low in the salty soil environment.

• Journal of Industrial Technology
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• v.30 no.B
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• pp.25-32
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• 2010

In this paper stability about lateral soil movement of bridge abutment constructed on the soft ground, reinforced with the sand compaction pile (SCP) and the preconsolidaton methods, was evaluated by using the centrifuge testing facility which stress conditions in field could be reconstructed in the laboratory. The layouts of model such as ground condition, sand compaction piles and abutment was determined on the basis of similitude law with the reduced scale of 1/200. Construction sequences of installing SCP, preparing reclaimed ground, preconsolidating ground and building the piled bridge abutment were reconstructed during centrifuge modelling and measurements of movement were followed in each sequence. From analyzing the results of measuring movements of the model abutment and the ground, measured lateral movement of model abutment was found to be within the allowable value so that stability of abutment against lateral sliding was secured.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.509-514
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• 2006

Considering the risk management, there are many examples and various studies for the corporation risk. However, I have never seen the project risk management that applied a construction site for practical approach. Therefore, I have developed a chart (I-Chart) for the project risk management, and also built a model (I-Chart scenario analysis) that I could use. I applied this model to container yard reclaimed land in harbor construction with approaching of geotechnical engineering.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.425-434
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• 2007

In this paper, the stability standards of slopes reclaimed by soils mixed with stone dust were proposed to manage the stone dust as recovery soils. First of all, the mixed ratio between stone dust and natural soil is classified into 5 groups, and a series of soil test was performed in each group. As the results of tests, the shear strength and the maximum dry unit weight were increased in decrease of the mixed ratio of stone dust. On the basis of the investigation to the safety factor standards of embankment slopes in and outside the country, a slope stability rank of slopes reclaimed by mixed soils were divided into 3 stages such as unstable stage, attention stage and stable stage. The slope angle, the slope height and the mixed ratio with stone dust were proposed by the result of stability analysis of slopes reclaimed by mixed soils. As the result of slope stability analysis, the slope angle of 1 : 1.8 at the reclaimed slope should be constructed in case of the slope height of 10 m. Also, the slope angle of 1 : 1.8 and the mixed ratio of stone dust less than 50% should be constructed in case of the slope height of 15 m. The analysis result of reclaimed slope constructed inside the quarry is similar to that of reclaimed slope constructed on the open ground in same conditions of the slope angle, the slope height and the mixed ratio with stone dust. The proposed stability standards of slopes reclaimed by soils mixed with stone dust can be used practically at the quarrying site.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.87-96
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• 2023

There are a lot of difference between the surface settlement and the differential settlement measured at the Busan New Port, where the dredged and reclaimed clay layer exists and below the clay is originally thickly distributed. To find the cause and solution of this, the actual conditions of each differential settlement used for the soft ground improvement, characteristics, installation method, measurement frequency, measurement data management, and data analysis of each type were considered. In the deep soft ground improvement work where large deformation occurs, the bending deformation of the screw-type differential settlement gauge is less than that of other types of measuring instruments, so there is less risk of loss, and the reliability of data is relatively high as the instruments are installed by drilling for each stratum. Since the greater the amount of high-precision settlement measurement data, the higher the settlement analysis precision. It is necessary to manage with higher criteria than the measurement frequency suggested in the standard specification. For the data management of the differential settlement gauge, it is desirable to create graphs of the settlement and embankment height of the relevant section over time, such as surface, differential, and settlement of pore water pressure gauge for each point. In the case of multi-layered ground with different compression characteristics, it is more appropriate to perform settlement analysis by calculating the consolidation characteristics of each stratum using a differential settlement data.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.109-120
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• 2004

There has been outstanding research on the soil-water characteristic curves of unsaturated soils over the past several decades. Unfortunately, unsaturated soil mechanics has not been considered as an important factor in Korea. In this paper, laboratory test and numerical analysis(SoilVision Professional ver 3.04) were performed to investigate the prediction method of soil-water characteristic curve and unsaturated permeability coefficient in reclaimed ground. The pressure cell, desiccator, and tensiometor tests were conducted on three types of reclaimed soils(dredged soil, sand, weathered granite soil). Numerical analysis was executed to compare the results with the laboratory test results and also compared with the results of each prediction method. Based on the laboratory test, three different types of soils have shown different soil-water characteristic curves. The hysteresis fir these soils is clearly defined. As a result of numerical analysis, Fredlund & Xing's method and Fredlund & Wilson's model proved to worke out well for reclaimed ground soils in Korea. Also, predicting method based on the soil-water characteristic curves from the particle-size distributions is flirty reliable for estimating unsaturated permeability coefficient.