• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.462-471
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• 2008

The quality control for DCM is based on the unconfined compressive strength of laboratory treated soils, the cement contents, setting and checking the strength of in-situ treated soils. Also the strength of in-situ is checked mainly by the core boring. In case of large size construction, it might be considered the distribution of DCM strength data as normal distribution, so it might be employed a statistical method to evaluate DCM strength easily. In Japan, it has been established correlation between the strength of laboratory treated soils, the strength of in-suit treated soil and the design strength. Also It has been employed domestically the correlation suggested by Japan. But the correlation, so called $\lambda$(ratio in the strength of laboratory treated soils and the in-suit) and $\gamma$(ratio in the strength of in-suit and the design strength), might be far different with the domestic due to different DCM system and soil properties. so it might be restrictive to use domestically. Therefore in this paper, It is presented correlation between the strength of laboratory treated soils and in-suit treated soil to be employed domestically by evaluating $\lambda$ based on the domestic in-suit illustrations.

• Geomechanics and Engineering
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• 제7권3호
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• pp.247-261
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• 2014

Analytical and numerical modeling of soft or problematic soils stabilized with lime and cement require a number of soil parameters which are usually obtained from expensive and time-consuming laboratory experiments. The high shear strength of lime and cement stabilized soils make it extremely difficult to obtain high quality laboratory data in some cases. In this study, an alternative method is proposed, which uses the unconfined compressive strength and estimating functions available in literature to evaluate the shear strength parameters of the treated materials. The estimated properties were applied in finite element model to determine which estimating function is more appropriate for lime and cement treated granular soils. The results show that at the mid-range strength of the stabilized soils, most of applied functions have a good compatibility with laboratory conditions. However, application of some functions at lower or higher strengths would lead to underestimation or overestimation of the unconfined compressive strength.

• 한국환경농학회지
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• 제20권5호
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• pp.317-324
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• 2001

Short-term effect of phosphogypsum on soil properties including acidification, salinity and metal availability were investigated under laboratory and field conditions. Phosphogypsum and mixtures of phosphogypsum and compost were added to soil and incubated in a laboratory condition with 15% moisture content. Phosphogypsum treatments were 2.5 and 5.0 g/kg soil and in the treatments of phosphogypsum and compost mixture 10 g of compost was added additionally. After the 30 days of incubation, an additional phosphogypsum and/or compost were added to the remaining soils at the same rates of the first treatments. pH, electrical conductivity, and available hazardous elements were measured periodically during the incubation. Field experiment was conducted in a plastic film house of mellon with four treatments of phosphogypsum and compost mixtures - 25+125, 50+125, 50+250 and 100+250 kg/165 $m^2$. pH, electrical conductivity, and hazardous elements in soil and total hazardous elements in leaf were measured. In the laboratory experiment, after 30 days of the first phosphogypsum application, soil pHs were lowered by 0.7-0.8 units. After the second treatment of phosphogypsum 0.2 units of additional acidification occurred. However, acidification was not observed in the soils treated with mixtures of phosphogypsum and compost. In the laboratory experiment, phosphogypsum treatments increased electrical conductivity very significantly. In field experiment, pH and electrical conductivity of soils treated with phosphogypsum were nearly the same as those of soil not treated with phosphogypsum. Since soil condition in the field study was an open system, the free acids and salts derived from phosphogypsum could be diffused down with water leaching through the soil profile and then any significant acidification or salt accumulation in the topsoil could not be observed. In both laboratory and field experiments, levels of available hazardous elements in soils treated with phosphogypsum were quite low and not different from the levels found in the control soil. Results obtained from this study suggest that application of phosphogypsum at appropriate rates on agricultural land appears of no concern in terms of acidity, salinity and hazardous element content of soil.

• 한국토양비료학회지
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• 제44권4호
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• pp.559-564
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• 2011

Soil microbial functions are considered to be effective in assessing the severity of heavy metal pollution. Therefore, this study was carried out to examine the effect of heavy metals on nitrogen mineralization by measuring the releasing pattern of inorganic nitrogen ($NH_4^+$-N and $NO_3^-$-N) in a soil treated with heavy metals. A factorial combination of two heavy metals (Zn and Cd) treated with three concentrations (50, 100 and $150{\mu}mol\;g^{-1}$ soils) was used in a laboratory incubation. Nitrogen mineralization was determined at 3, 7, 14, 21, 28, 42 and 56 days after the treatments replicated four times. Soil sample free from heavy metals was served as the control. The amount of nitrogen mineralization from heavy metal treated soils was found to be decreased at an increasing rate during the first 21 days of incubation. However, as the incubation progressed, nitrogen mineralization was found to be decreased at decreasing rates. Furthermore, during this period, nitrogen mineralization in Cd treated soils was significantly lower ($P{\leq}0.05$) than that of the control. Soils treated with Cd at the concentration of $150{\mu}mol\;g^{-1}$ showed the lowest N mineralization throughout the incubation. Nitrogen mineralization in Zn treated soils ($50{\mu}mol\;g^{-1}$) was found to be higher than the other heavy metal treated soils. On the base of present findings, nitrogen mineralization of soil could be considered as a viable assessment of the degree of heavy metal pollution.

• 한국토양비료학회지
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• 제45권4호
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• pp.551-554
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• 2012

The present laboratory investigation was conducted to assess the effect of heavy metals on carbon mineralization. Soil was treated with three concentrations (50, 100 and $150{\mu}mol\;g^{-1}$ soil) of two heavy metals (Cd and Zn) in a factorial combination of treatments replicated four times. Determination of carbon mineralization was carried out at 3, 7, 14, 21, 28, 42 and 56 days after metal treatments.. The amount of $CO_2$-C released from heavy metal treated soils was found to be decreased at an increasing rate during the first 28 days, followed by slow release as incubation progressed. The total amounts of $CO_2$-C released were 448, 382 and $348mg\;kg^{-1}$ soil respectively for soils treated with 50, 100 and $150{\mu}mol\;g^{-1}$ soil of Zn. The corresponding figures for Cd treated soils were 406, 354 and $282mg\;kg^{-1}$ soil implying that dose-dependent reduction in cumulative $CO_2$-C released from soils. The inhibition of carbon mineralization was found to be high in Cd treated soils than that of Zn treated. Therefore, tolerance and adaptation of the microbial community is likely to be related to the concentration and the type of metal. According to the results, carbon mineralization can be considered as possible indicator of soil pollution by means of heavy metals.

• Environmental Engineering Research
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• 제10권6호
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• pp.294-305
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• 2005

The effectiveness of fly ash-, quicklime-, and quicklime-fly ash-based stabilization/solidification(S/S) in chromium(Cr) contaminated soils was investigated using modified semi-dynamic leaching tests. Artificial soil samples composed of kaolinite or montmorillonite contaminated with chromium nitrate(4000 mg $Cr^{3+}\;kg^{-1}$ of solid) were prepared and then subjected to S/S treatment using quicklime, fly ash, or quick lime-fly ash. The effectiveness of the treatment was evaluated by assessing the cumulative fraction of leached $Cr^{3+}$ as well as, by computing the effective diffusivity ($D_e$) and the leachability index (LX) of the treated samples. The reduction in $Cr^{3+}$ release for the untreated samples was more pronounced in the presence of montmorillonite, which was attributed to sorption. Treatment with quicklime, fly ash, or quick lime-fly ash was significantly effective in reducing $Cr^{3+}$ release most probably due to the formation of pozzolanic reaction products and $Cr(OH)_3$ precipitation. The most effective treatment was observed in montmorillonite-sand soil samples treated with quicklime-fly ash (99.8% removal). The mean $D_e$ decreased significantly and the mean LX was greater than 9 for all treated samples, indicating that the treated soils were acceptable for "controlled utilization". The mechanism controlling $Cr^{3+}$ leaching from all treated samples during the first 5 days appeared to be diffusion.

• 한국재난정보학회 논문집
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• 제2권1호
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• pp.53-64
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• 2006

This study presents the laboratory properties on the frost heave under various moisture contents and compaction efforts in pavement subgrade soil. Many researches were conducted on the frost heave. However, the researches with the domestic soils have not been so active until now. In particular, the evaluation of the frost heave in pavement subgrade soils was not established by many researchers. The problems relating with the frost heave have been serious causes in the distresses of pavements. The study was performed using an appropriate field simulation. The research results revealed that the drainage conditions in earth work should be treated cautiously.

• 한국토양비료학회지
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• 제40권1호
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• pp.51-56
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• 2007

유기성폐기물을 농경지에 투여하기 위하여 작물에 미치는 영향, 토양에 축적되는 중금속 농도 분석이 이루어지고 있으나, 토양에 축적된 총 오염물질이 지렁이에게 얼마나 독성을 갖고 있는지가 구명되어 있지 못한 실정이다. 본 연구는 4종류 유기성 슬러지(생활하수슬러지, 공단하수슬러지, 피혁슬러지, 주정슬러지)와 돈분퇴비를 8년 동안 매년 ha당 12,5톤, 25.0톤, 50.0톤으로 처리한 토양에 대한 지렁이의 독성을 측정하였다. 공단하수슬러지를 처리한 토양를 돈분퇴비와 비교해 보면, 축적된 구리는 18.9~26.2배, 크롬은 7.7~34.7배, 니켈은 14.8~18.8배로 나타났고, 피혁슬러지의 크롬은 35.7~268.0배, 니켈은 14.8~18.8배가 축적되었다. 이렇게 오염된 토양에 지렁이를 8주와 16주 동안 각각 노출시켰다. 8주 노출에서 생활하수슬러지와 주정슬러지의 모든 처리토양과 피혁슬러지 25.0톤 처리 토양은 돈분퇴비와 비슷한 낮은 독성을 나타냈으나, 나머지 공단슬러지와 피혁슬러지의 지렁이 치사율은 26.7~96.7%으로 높게 나타났다. 16주 노출에서 주정슬러지 12.5톤, 25.0톤의 토양만 돈분처리 토양과 비슷한 낮은 지렁이 독성을 보였고, 나머지 처리토양들은 모든 53.3~100%의 지렁이 치사율를 나타냈다. 이러한 결과들은 주정슬러지 50.0톤 처리 토양을 제외한 다른 슬러지 처리 토양은 지렁이에게 독성을 가지는 것으로 나타났다.

• Environmental Engineering Research
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• 제10권3호
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• pp.112-121
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• 2005

The effectiveness of quicklime-based stabilization/solidification (S/S) in immobilizing lead (Pb) was assessed by performing semi-dynamic leaching tests (ANS16.1). In order to simulate landfill leaching conditions, the ANS 16.1 test was modified by using 0.014 N acetic acid (pH = 3.25) instead of distilled water. Artificial soil samples as well as field soil samples contaminated with Pb were tested. The effectiveness of quicklime treatment was evaluated by determining diffusion coefficients ($D_e$) and leachability indices (LX). A model developed by de Groot and van der Sloat was used to elucidate the controlling Pb leaching mechanisms. Overall, upon quicklime treatment Pb leachability was significantly reduced in a]l of the samples tested. The mean LX values were higher than 9 for an artificial soil sample containing 30% kaolinite treated with 10% quicklime and for a field soil sample treated with 10% quicklime, which suggests that S/S treated soils can be considered acceptable for "controlled utilization". Moreover, quicklime treatment was more effective in artificially contaminated soil with high kaolinite content (30%), indicating the amount of clay plays an important role in the success of the treatment. The controlling Pb leaching mechanism was found to be diffusion, in all quicklime treated samples.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1130-1134
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• 2005

To monitor the possibility of horizontal gene transfer between transgenic potato and bacteria in the environment, the gene flow from glufosinate-tolerant potato to bacteria in soils was investigated. The soil samples treated with the leaf tissue of either glufosinate-tolerant or glufosinate-sensitive potato were subjected to PCR and Southern hybridization to determine possible occurrence of glufosinate-resistant soil bacteria and to detect the bar (phosphinothricin acetyltransferase) gene, conferring tolerance to glufosinate. The bar gene was not detected from genomic DNAs extracted at different time intervals from the soil samples, which had been treated with the leaf tissue of either transgenic or non-transgenic potato for 2 to 8 weeks. In addition, the level of glufosinate-resistant bacteria isolated from the soil samples treated with the leaf tissue of transgenic potato was similar to that of the samples treated with non-transgenic potato after 4 months of incubation at $25^{\circ}C$. The bar gene was not detected in the genomic DNAs extracted from colonies growing on the plate containing glufosinate, indicating that the bacteria could acquire the resistant phenotype to glufosinate by another mechanism without the uptake of the bar gene from glufosinate-tolerant potato.