• Geotechnical Engineering
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• v.14 no.4
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• pp.61-76
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• 1998

Various kinds of reinforced soil methods have been developed by many researchers or companies for their economic merits mainly. These methods have generally used sandy soils which have high permeability as embanking or backfill material. That is because, if poor embanking materials, especially like a clayey soil which has very low permeability, are used in a reinforced soil embanking, and if excessive pore water pressure is produced by external factors, the friction resistance between reinforcing members and Boils decrease, as a result possible damage or collapse of the body of a reinforced embankment. In fact, clayey Boils can also be used as a embanking materials with reinforcement which has high permeable capacity, and are expected to be able to dissipate the excess pore water pressure effectively. In this study reinforcing effects have been examined through a serries of direct shear tests in which clayey soils are reinforced with nonwoven geotextiles of which permeability is very high and tensile strength is relatively weaker than geogrids which are usually used in reinforced soil wall. Even though such nonwoven geotextile are used as reinforcement of high saturated clayey soils. the test results show the possibility that nonwoven geoteztiles could be used as a reinforcement for reinforced soil walls effectively.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.121-129
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• 2017

There have been a number of water and sewer pipe breakdown reports followed by ground subsidence. Also, the excavating works for construction due to overcrowding of city have been common. Particularly, in urban areas ground becomes unstable because of the lowered lifeline sinkage followed excavation and backfilling. In order to solve the problem, some reinforcement works for ground by rod tamping or grouting have been applied. However, it is hard to predict when the buried utilities in underground will be damaged. Also, there is a limit for the underground exploration and investigation methods. Therefore, in this study, the estimated about the water soluble polymer pouch including poor mixed admixture which is designed to eliminate the dangerous factors. The reinforcement strength of this method was confirmed by verifying three points: meltiness in a certain period, water solubility in the ground water level, and characteristics of the pouch, which can be stored in daily conditions. It is also proved that this method allows to keep the ground from getting weakened in the installation of water and sewer pipe along with back filling materials.

• Journal of the Korean Geosynthetics Society
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• v.6 no.3
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• pp.39-46
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• 2007

Many industrialized countries of the world have many problems about the reuse of waste landfill area because the increase of terminated waste disposal landfill. Especially, the effective use of the terminated waste disposal landfill nearby the urban area has been demanded, because of the lack of the usable land. However, the reuse of terminated waste disposal landfill site is needed an adequate stabilization of ground for increasing the bearing capacity and reduce the allowable settlement for the given structure. This study is to evaluate the applicability of geosynthetics for the increment of bearing capacity of solid waste landfill ground. The in-situ cyclic plate loading tests were performed to determine the dynamic and static behaviors of reinforced ground with geosynthetics. Four series of test were conducted with variations of geosynthetics, number of geogrid layer. Based on the cyclic plate load test results, the bearing capacity ratio, subgrade modulus of ground, and the elastic rebound ratio were determined.

• Journal of the Korean Geotechnical Society
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• v.21 no.1
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• pp.81-91
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• 2005

This paper is the results of experimental and numerical works on the investigating design factors influencing the bearing capacity, the ratio of stress concentration, and the failure mechanism of the clay ground improved with sand compaction piles (SCP). In order to find the behavior of the clay ground improved with SCP, extensive centrifuge model experiments were carried out for each of the SCP replacement ratio of 20, 40, and $70\%$, the non-plastic fine contents in sand of 5, 10, and $15\%$, and the ratio of the improved width to the loaded area (W/B) of 1, 2, and 3. The commertially available software of FEM, CRISP, was used to analyze test results by performing numerical estimations. In these numerical analyses the sand compaction piles and the clay ground were simulated as a linear elastic and plastic constitutive model and the modified Cam-clay model, based on Critical State Soil Mechanics, respectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.638-645
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• 2010

This study introduces a reinforcement work case using Twin-Jet Method. The area is located behind the abutment of the bridges built on soft clay along the $\bigcirc\bigcirc$ Express Highway. Its foundation was constructed by installing EPS blocks on the original ground to reduce the embankment load under the highway. However, the ground deformation has continuously occurred due to the settlement of the foundation soft cohesive soils. The amounts of subsidences at the surface turned out to be 20~30.0mm, After the pavement patch work on April 23, 2009, a drastic subsidence occurred together with 10mm swell, For this reason, Twin-Jet grout column construction was applied by passing through the EPS banking blocks without closing traffic flows on the express highway. The outcomes of core sample tests after reinforcing the ground turned out to be TCR 92.5%, RQD 64.6% and unconfined compressive strength 2.3~8.6Mpa. The test results showed that the condition of the ground foundation had improved using Twin-Jet grouting in most layers of ground including the cobble and gravel layer.

• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.5-13
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• 2010

Low slump mortar grouting is widely used in reinforcement of structural foundation and ground improvement in soft ground, and has advantage which construction is possible in insufficient space. However it has been not yet studied sufficiently to estimate the effect of ground improvement in design step and to prove the estimating method. So the method must be developed in order to use the low slump mortar grouting method in various cases. In this study, the field tests were performed in the reclaimed soils to measure the effect of ground improvement. Then it was compared with what was calculated by the existing formula that was formerly suggested. The results show that the value from the formula was similar with the value from the field tests. Also it was proved that the formula was available to estimate the effect of ground improvement in the loose granular soils.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.119-124
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• 2008

Due to the recent development of instruments which enabled the measurements of subtle IP effect in the ground and analysis algorithms, complex resistivity (CR) method was expanding its application to various field. In this study, we applied the CR method to the test site where the ground reinforcement had been done by injecting the cement mortar for investigating the effect of ground reinforcement. For this site, resistivity monitoring and tomography survey was carried out while the ground reinforcement had been made by the grouting. From the result, the anomalous region that was shown on the result of resistivity 4D monitoring was coincident with those of phase section in the CR method, because the cement grouting material had the strong IP effects. It might be expected that the CR method should be very powerful surveying tool for the similar purpose.

• Journal of the Korean Geosynthetics Society
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• v.10 no.1
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• pp.43-51
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• 2011

Pile-supported embankment is one of the reinforcing methods to minimize damage due to the severe subsidence and lateral flow when soft clay ground is supported with embankment. pile-supported embankment mainly penetrates soft ground into the bearing stratum in order to support surcharge load which minimizes the subsidence and lateral flow due to the surcharge load. The aim of this research is to review quantitatively reinforcing effect of pile-supported embankment which is installed in soft clay ground. From the model test, it reproduced the ground movement with regard to the non-reinforced and reinforcing embankment-pile and also analyzed stabilizing effects of lateral flow due to the pile-supported embankment. With regard to the case of installing pile-supported embankment, its were analyzed stabilizing effects of lateral flow in cases of quick-load and slow-load to make different surcharge load.

• Journal of the Korean Geotechnical Society
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• v.21 no.7
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• pp.21-29
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• 2005

This paper presents the results of a numerical investigation on the behavior of a geosynthetic reinforced two-tier segmental retaining wall (GR-SRW) on a yielding foundation. A hypothetical 10 m high two tier GR-SRW to be constructed on an incompetent foundation containing a layer of relative soft soil deposit was considered. A verified finite-element procedure was employed to get insights into the effect of foundation yielding on the wall behavior including the wall deformation and the reinforcement load. It is shown that the effect of foundation yielding is to increase the wall deformation as well as the reinforcement load, thus influencing both the internal as well as the external stability of the wall. Practical implications of the findings obtained from this study are highlighted in this paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2C
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• pp.133-141
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• 2008

Theoretical analysis are developed to estimate the load transfer by soil arching in geosynthetic-reinforced and pile-supported(GRPS) embankment systems. According to the results of analyses, the efficiency of embankment pile systems increases when the geosynthetics are installed with piles. Especially the increment of efficiency is more remarkable in the low embankment height, where soil arching can not be fully developed. The factors affecting the load transfer in GRPS embankment systems are the pile spacing, the height and properties of embankments, and the strength of geosynthetics. The efficiency decreases with increasing the pile spacing, while it increases with the height and internal friction angle of embankment fills, and the strength of geosynthetics. These results of analyses show the proposed analysis method is resonable to estimate the soil arching in GRPS embankment systems.