• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.90-94
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• 1999

Waste gypsum is produced about 2.6million tons per year as a by-product in the process of TiO$_2$production. Geotechnical properties such as natural water content, specific gravity, Atterberg limits were determined to figure out the engineering characteristics waste gypsum. Grain-size distribution, compaction, CBR tests, and unconfined compression test for various mixing ratios between waste gypsum and decomposed granite soil 8t dredged soil. The environmentally adverse effect for mixed specimen with waste gypsum is far below than those of regulatory requirement.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.83-89
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• 2004

The analysis about consolidation characteristic in soft clay has been depending one-dimension consolidation analysis. but, drain and undrain zone are explicated as homogeneous by consolidation behavior following consoli- dated settlementsoft in soft clay. 1) Established sand drain in soft clay in many types, and measured water content, unconfined compression strength, vertical stress, horizontal stress, vertical settlement, pore water pressure. 2) Arranged the result from the test and numerically explicated effective stress, total stress, and effective stress path at the drain and undrain zone. 3) We also analyzed and comparied elastic and elastic-plastic in soft clay using measured data. The result analyzed does not approach to a special theory, but, it is well in accord with the result of other investigator's study in the same condition.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.511-518
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• 2009

In this study, by the consideration of in situ curing conditions, cemented sand with cement ratio less than 20% is prepared by air dry condition and then wetted. A series of unconfined compression tests are carried out to evaluate the effect of wetting on the strength of cemented soils. Strength of air dry cured specimen drops to maximum 30% after wetting at the end of curing period when cement ratio is low. However, regardless of cement ratio, strength of repetitively wetted specimens during curing increases as the number of wetting increases. The results of this study can predict the strength variation of cemented sand depending on wetting conditions in the field, which can guarantee the safety of geotechnical structures such as dam.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.31-36
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• 2010

This paper introduces a practical determination method for soil parameters adopted in the new performance based design code for port and harbour facilities in Japan. In the new port-design code, the depth profile of the derived values is modeled as the profile of the estimated values so as to be either the mean value or the regression line, then the correction factors are multiplied to the estimated value according to the coefficient of variation (if COV > 0.1) and the number of the data entries (if n < 10). The new port-design code is applied to the unconfined compression test results for the Hiroshima Port clay in order to evaluate the undrained shear strengths. From the discussion, it is emphasized that not only the statistic treatment but also the engineering judgment are required in the procedure of the soil parameter determination for the reliability design.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.43-53
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• 2008

The rock mass classification systems used in Korea are not standardized. And also the criteria values differ between agencies. So different opinions for rock mass classification can occur among engineers who participate in each design process. In this research, a new rock mass classification system was suggested to correct these problems. For this purpose, the criteria used in the Korean agencies were compared with the criteria used in foreign agencies and standard criteria were selected. Thereafter rational and objective criteria values were suggested quantitatively for the new classification system.

• Journal of the Korean Geosynthetics Society
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• v.7 no.2
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• pp.1-5
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• 2008

The differential settlement on ordinary concrete buildings and paved roads are often occurred and which caused the failure of structure. The grouting method can be used for correcting the settlement of the structure. However, the grouting method has a disadvantage like that it takes a long time period to get a desired strength, and it is not a continuous in the phase of reinforced effect. In this paper, as an injecting material called GPCON to complement disadvantage, it is estimated about the characteristic that has a high-density expansion. With the changing of ground conditions and amount of injection, the change of physical strength on compression, the stability against chemical material are studied through the filming of SEM. The physical strength with compression is developed to high strength due to mixing with other material. It is not react with most of the material on chemical conditions except the component of alcohol. Through the SEM test. it is confirmed that the strength of material was increased as formation is being densified.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.115-123
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• 1989

This paper probabilisticly analyses the variance of the soil parameters on kinds of soil by conducting statistical analysis through the Unified Soil Classification System. Data used are the result of soil test which the Korea National Housing Corporation conducted in 176 sites of 74 cities throughout the country during the past 13 years from 1974 to 1986. In this paper, soil parameters such as natural water contents, specific gravity of soil particle, Atterberg limits, N-values, unconfined compression strength, compression index and shear strength parameter etc., is analysed. The result of the analysis is as follows. 1) The variance in physical properties of the soil is, when compared with coefficient of variation which is statistical variable, comparatively small. 2) The shear strength parameter is proved to be about 40% and compression index is about 32%. 3) The variance in specific gravity is 0.87-2.49% in granular soil and 0.91~5.03% in cohesive soil respectively. So, the degree of the variance is very small.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.125-131
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• 2004

A series of unconfined compression tests were carried out firstly to investigate mechanical behaviors of Lightweight Foamed Soil (LWFS) which is composed of dredged soils, cement and air foam. And secondly, to compare the difference of mechanical characteristic of LWFS with previous research conclusions (Yoon & Kim,2004) by using different dredged soils sampled at Joong-Ma in Gwangyang harbor area. Based on numberous laboratory experiments, it was found that deformation coefficient $(E_{50})$ of LWFS increases with increasing cement contents but decreases with increasing initial water contents of dredged soils. Appropriate regression formula (normalizing factor scheme) which considers relationship between LWFS composing elements, initial water contents of dredged soils, cement, air foam, and uniaxial compression strength or LWFS is proposed for practical applications. Finally, it was clear that, to apply LWFS method to practical projects, certain laboratory test would be necessary to take considerations of soil locality because mechanical charac-teristics of LWFS were surely dependent upon their sampled locations and properties.

• Geomechanics and Engineering
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• v.22 no.3
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• pp.227-236
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• 2020

Expansive soils are renowned for their swelling-shrinkage property and these volumetric changes resultantly cause huge damage to civil infrastructures. Likewise, subgrades consisting of expansive soils instigate serviceability failures in pavements across various regions of Pakistan and worldwide. This study presents the use of polypropylene fibers to improve the engineering properties of a local swelling soil. The moisture-density relationship, unconfined compressive strength (UCS) and elastic modulus (E₅₀), California bearing ratio (CBR) and one-dimensional consolidation behavior of the soil treated with 0, 0.2, 0.4, 0.6 and 0.8% fibers have been investigated in this study. It is found that the maximum dry density of reinforced soil slightly decreased by 2.8% due to replacement of heavier soil particles by light-weight fibers and the optimum moisture content remained almost unaffected due to non-absorbent nature of the fibers. A significant improvement has been observed in UCS (an increase of 279%), E₅₀ (an increase of 113.6%) and CBR value (an increase of 94.4% under unsoaked and an increase of 55.6% under soaked conditions) of the soil reinforced with 0.4% fibers, thereby providing a better quality subgrade for the construction of pavements on such soils. Free swell and swell pressure of the soil also significantly reduced (94.4% and 87.9%, respectively) with the addition of 0.8% fibers and eventually converting the medium swelling soil to a low swelling class. Similarly, the compression and rebound indices also reduced by 69.9% and 88%, respectively with fiber inclusion of 0.8%. From the experimental evaluations, it emerges that polypropylene fiber has great potential as a low cost and sustainable stabilizing material for widespread swelling soils.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.43-51
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• 2014

Organic matter in dredged soil has a lot of engineering problem in ground including a large settlement, crack propagation, low bearing capacity and low friction angle. From an agricultural point of view, however, organic matter contributes greatly soil quality and plant health. This paper investigated the relationship between engineering and germination characteristics of stabilized mixture consisting of different ratios of organic content (0 %, 10 %, 20 %, 30 %) for recycling dredged soil including organic matter. Several series of laboratory tests such as flow test, unconfined compressive test and consolidation test were performed to find out engineering characteristics. pH, percent of germination and growth of plants were also measured to investigate the germination characteristics. The experimental results indicated that, as organic content increased, unconfined compressive stress decreased and compression and swelling indices increased. However, percent of germination and plant growth increases as organic content increases.