• Geomechanics and Engineering
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• 제32권3호
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• pp.293-305
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• 2023

To ensure the safety of underground infrastructures, ground can sometimes be first treated by cement slurry and then stabilized using artificial ground freezing (AGF) technique before excavation. The hydration heat produced by cement slurry increases the soil temperature before freezing and results in an extension of the active freezing time (AFT), especially when the Metro Jet System (MJS) treatment is adopted due to a high cement-soil ratio. In this paper, by taking advantage of an on-going project, a case study was performed to evaluate the influence of MJS and AGF on the ground temperature variation through on-site measurement and numerical simulation. Both on-site measurement and simulation results reveal that MJS resulted in a significant increase in the soil temperature after treatment. The ground temperature gradually decreases and then stabilized after completion of MJS. The initiation of AGF resulted in a quick decrease in ground temperature. The ground temperature then slowly decreased and stabilized at later freezing. A slight difference in ground temperature exists between the on-site measurements and simulation results due to limitations of numerical simulation. For the AGF system, numerical simulation is still strongly recommended because it is proven to be cost-effective for predicting the ground temperature variation with reasonable accuracy.

• 한국토양환경학회지
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• 제3권3호
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• pp.45-53
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• 1998

본 연구의 목적은 석유계탄화수소 오염토양의 처리에 있어서 초기농도 및 영양소의 영향을 평가하는 것이었다. 본 연구에서 이용한 반응기는 용기형태의 슬러리상 생물반응기였다. 디이젤연료 오염토양의 처리 및 미생물성장에 대한 수행결과는 실험실규모에서 얻어졌다. TPH(총 석유계 탄화수소)의 거동 및 미생물성장은 생물학적 제거율과 연관하여 평가되었다. 50,000및 100,000 mg TPH/kg soil의 초기부하수준에 대한 영향이 연구되었다. 두 반응기에서의 수행결과는 각각 90.5%와 90.8%의 총체적인 TPH제거율 나타내었다. 그러나 50,000mg TPH/kg soil의 초기농도가 적용된 반응기가 초기농도 100,000mg TPH/kg soil이 적용된 반응기에 비하여 휘발에 의한 제거를 제외한 순수한 생물학적 TPH제거율에 있어서 우수한 결과를 보여주었다. 다른 영양소량이 두 반응기에 적용되었음에도 불구하고 미생물성장율에 있어서 현저한 차이를 보이지는 않았다. 그러나 본 결과에서 고려되어야 할 중요한 요소는 두 반응기에 대하여 초기농도가 다르게 적용되었다는 것이다. 초기농도가 영양소가 첨가되지 않은 반응기에 비하여 두배나 높았음에도 불구하고 총체적 및 생물학적 TPH제거율에 있어서 영양소가 첨가된 반응기는 그렇지않은 반응기에 비하여 뛰어난 결과를 보여주었다.

• 한국축산시설환경학회지
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• 제8권2호
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• pp.99-106
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• 2002

This study was conducted to improve utilization efficiency of slurry and choose a suitable type of tractor power which can be attached by manure spreader in the paddy field. In the paddy field, the pulling force for the spreader was measured by using a measurement system installed between tractors with and without the spreader. The soil moisture contents at the 0${\sim}$10cm and 10${\sim}$20cm depth of test soil(SiCL) were 28.45% d.b. and 23.47% d.b., respectively in average while Cone Index at l0cm and 15cm depth were 14.5kPa and 16.2kPa, respectively. It was impossible to measure the soil moisture contents and Cone Index below 20cm depth of the soil because the hardness of the soil increased greatly. Thereafter, hard pan of the sampled soil was found at 15${\sim}$20cm depth. While the required power only for the dragged tractor was found to be 3.44kW in the test field, the required pulling powers of tractor considering the pumping were 8.48${\sim}$12.48kW, 12.19${\sim}$16.19kW, 16.96${\sim}$20.96kW, respectively for 2 tons, 3 tons, and 4 tons of tank capacity. As the tank capacity increased, the sinkage of soil were also increased to 7cm, l0cm, and 12cm, respectively for the tractors with 2 tons, 3 tons and 4 tons of tank capacity. Considering about 60% of pulling efficiency of tractor, a tractor which had lower than 25.74kW of pulling power was suitable to pull the spreader and spread the slurry simultaneously for manure spreader with 2 tons of tank capacity. 29.42kW${\sim}$36.78kW of pulling power was found to be optimum for the tractor with 3 tons of tank capacity while over 40.45kW for 4 tons of tank capacity.

• 한국초지조사료학회지
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• 제21권4호
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• pp.203-210
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• 2001

To establish the recycling system of animal manure(AM) for environmental preservation and improve the utilization of AM, this study was to investigate the effects of the types and nitrogen application rate of AM on herbage productivity, efficiency of nitrogen utilization, nutritive value and an increase of soil fertility and in mixed grassland. This sudy was arranged in split plot design. Main plots were the types of AM(Cattle feedlot manure, CFM; Pig manure fermented with sawdust, PMFS; cattle sluny, CS) and subplots were the application rate of animal manure, such as 100, 200 and 300kgNiha. I. DM yields of herbage were the highest with CS and decreased by application over ZOOkgNiha AM. 2. Crude protein(CP) ontent was the highest with CFM and followed by CS, and the lowest with PMFS, and increased as application rate of AM increased. 3. Nitrogen(N) yields of CS treatment was higher than that of CFM and CS. and increased significantly as application rate of AM increased(P<0.05). 4. The contents of NDF, ADF and TDN was hardly influenced by the types and application rate of AM. 5. Organic matter(0M) content in the soil was the highest with PMFS and followed by CFM and the lowest with CS. OM content increased significantly as application rate of AM increased(P<0.05). 6. Total nitrogen content of the soil was not affected by the type of AM, but increased significantly as application rate of AM increased(P<0.05). (Key words : Animal manure, Grassland, Cattle feedlot manure, Pig manure fermented with sawdust, Cattle slurry, Soil fertility)

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1245-1252
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• 2010

Many industrialized countries are confronted with a difficulty about reuse of closed waste landfill. facilities. Especially, the demand of closed waste landfill maintenance and reuse nearby urban area has been increased, because of the shortage of usable land and extend of urban area. For the safe reuse of closed waste landfill, the most important check point is the effect of waste landfill on environment abound them. However, the non-sanitary closed waste landfill generally have no leachate lining system, therefore, the in-situ lining system such as sheet-pile, and vertical slurry wall etc. was needed to prevent the leachate outgoing from the waste landfill. In this paper present the case history of performance evaluation of vertical slurry wall by tracer tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1455-1460
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• 2005

This paper presents the results of an experimental study on the ground deformation by trench excavation for Diaphragm Wall construction. The model tests are performed to investigate the back ground deformation by lowering of slurry level in trench after excavating. Through these, the deformation characteristic of the back ground due to stress release of excavated space was investigated. This study considered relative density of soil mass and the distance between trench and surcharge. An experiment was performed in order to observe the failure pattern of a slurry-supported trench excavated in sandy ground. From model tests, in order to predict reasonably the deformation behavior of the adjacent ground due to the underground excavation, it is significantly recommended that the ground settlement by trench excavation should be considered.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1504-1511
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• 2005

The efficiency of the hydraulic transport of soil-water mixtures is an important factor in designing and operating a pump & pipeline system and is directly connected with dredging cost and working period. However, the hydraulic transport mechanism in the slurry flow inside the pipeline such as frictional losses, specific energy consumption, deposition velocity has not been well established. In this study a new dredging test loop system was designed and built. It is composed of a slurry pipeline with pipes of different diameters, a centrifugal slurry pump and a diesel engine connected with the slurry pump. and equipped with modern measuring facilities that enable to measure all important characteristics of a transportation system. The objective of this paper is to discuss the efficiency of the hydraulic transport of the Jumoonjin sand-water mixtures in the dredging test loop and to present simple equations induced from the test results of the loop that can express the transport product and the transport productivity.

• Geomechanics and Engineering
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• 제23권2호
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• pp.151-163
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• 2020

Grouting method is an effective way of reinforcing cracked rock masses and plugging water gushing. Current grouting diffusion models are generally developed for horizontal cracks, which is contradictory to the fact that the crack generally occurs in rock masses with irregular spatial distribution characteristics in real underground environments. To solve this problem, this study selected a cement-sodium silicate slurry (C-S slurry) generally used in engineering as a fast-curing grouting material and regarded the C-S slurry as a Bingham fluid with time-varying viscosity for analysis. Based on the theory of fluid mechanics, and by simultaneously considering the deadweight of slurry and characteristics of non-uniform spatial distribution of viscosity of fast-curing grouts, a theoretical model of slurry diffusion in an oblique crack in rock masses at constant grouting rate was established. Moreover, the viscosity and pressure distribution equations in the slurry diffusion zone were deduced, thus quantifying the relationship between grouting pressure, grouting time, and slurry diffusion distance. On this basis, by using a 3-d finite element program in multi-field coupled software Comsol, the numerical simulation results were compared with theoretical calculation values, further verifying the effectiveness of the theoretical model. In addition, through the analysis of two engineering case studies, the theoretical calculations and measured slurry diffusion radius were compared, to evaluate the application effects of the model in engineering practice. Finally, by using the established theoretical model, the influence of cracking in rock masses on the diffusion characteristics of slurry was analysed. The results demonstrate that the inclination angle of the crack in rock masses and azimuth angle of slurry diffusion affect slurry diffusion characteristics. More attention should be paid to the actual grouting process. The results can provide references for determining grouting parameters of fast-curing grouts in engineering practice.

• 한국축산시설환경학회지
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• 제1권2호
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• pp.173-178
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• 1995

장기간 액상분뇨 시용으로 인하여 질소가 과다하게 축적된 초지생태계에서 환경보호의 원인에 의하여 액상분뇨 시용량을 경감이 질산태 질소 용탈이 미치는 영향을 검토하기 위하여 독일 남서부에 위치한 알고이 지방에서 1991년 부터 1993년 까지 포장시험을 수행하였다. 처리는 액상분뇨 시용수준과 비료종류 처리구를 두었다. 용탈수를 채취하기 위하여 토양 120cm 길이에 ceramic cup을 설치하였다. 용탈수는 0.3~0.5 bar압력에서 2주 간격으로 채취하여 Tecator 자동 분석기로 NO$_3$함량을 분석하였다. 용탈수의 질산태질소 함량은 년중 심한 변이를 나타내었다. 시험기간 중의 평균 질산태 질소 농도는 무비구에서 8.5mg/$\ell$이었으나 이지방 관행액비시용구(년간 240kg N/ha)는 25.3mg/$\ell$로 높아졌다. 년간 질산태질소 용탈량은 관행액 비시용구, 액비감량시용구, 무비구에서 각각 ha당 29kg, 23kg, 12kg이었다. 이 지방의 관행 젖소사육밀도에 의한 관행액상분뇨 환원량은 너무 많은 양의 질산태질소를 지하수로 용탈시켜 환경에 과도한 부하를 주었다. 그러나 액비 감량 시용구는 지하수의 질산태질소 용탈을 뚜렷이 경감시킬 수 있어 환경보호 측면에서 액비시용량 경감정책은 실효를 거둘 수 있을 것으로 결론 내려진다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.49-53
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• 2006

The possibility of removal of PCBs (Polychlorinated Biphenyls) in soil was studied using biological method. The effects of soil and co-substrate on both PCBs reduction rate and chloride ion concentration in soil were investigated. It was shown that PCBs concentration of all the soils used in this study were reduced from 5ppm to below 1ppm after 60days, also chloride ion concentration in slurry increased, Results showed that leaf mold and humic acid as co-substrate do not seem to be effective for biological treatment of PCBs in soil,