• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.665-670
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• 2006

In this paper, the results of empirical methods and the numerical analysis were compared and investigated on the lateral displacement due to embankment in soft soil. The empirical methods gave different results so the possibility of lateral displacement could not be determined only by the empirical methods. The numerical analysis could be used so effectively that its result showed useful lateral and vertical displacements with depth and distance.

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.37-42
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• 2001

생석회말뚝공법은 연약점토에 대한 유용한 지반개량공법으로서 그 개량효과는 매우 빨리 나타난다. 본 연구에서는 생석회말뚝 타설 면적비에 따라 연약점토지반의 함수비나 전단강도 등의 특성이 어떻게 변화하는가를 규명하고자 하였다. 이를 위하여 철제상자에 연약점토로 모형지반을 조성하고 소요 면적비로 생석회말뚝을 타설한 후 적당한 시간간격을 두고 함수비와 전단강도를 측정하는 실내 모형시험을 수행하였다. 그 결과 면적비가 증가함에 따라 함수비의 감소량과 전단강도의 증가량은 커지지만 면적비가 약 10%를 초과하면 별 차이를 보이지 않으며 같은 면적비에서 생석회말뚝의 지름이 작고 간격이 좁으면 함수비의 감소량과 전단강도의 증가량은 더 크다는 것을 규명하였다. 또한 같은 양을 사용했다면 생석회말뚝공법보다 생석회혼합공법을 적용한 흙의 전단강도 증가량이 더 크다는 것을 알 수 있었다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.5
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• pp.80-90
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• 1998

The EPS construction method-one kind of the load reducing methods-utilizes the EPS blocks, ultra-light materials whose unit weight is about 1/100 of soils and has been applied to many soft ground sites. It needed 3,000 days to get the 90% degree of the consolidation for the case of 12m high soil embankments on the 30m thick soft clayey foundations. The N value of SPT at this deposit was less than 5. The pack drain was installed to promote the radial consolidations. Although staged embankments were planned, designers failed to get a sufficient stability of the foundation ground. Therefore, the EPS fill method was selected to reduce the load and the construction period. EPS blocks(D-20 model) replaced the upper part of the soil embankments. These complex embankments reduced the ground settlement and the construction period. The possibility of lateral movements of the bridge abutments was checked and the design scheme was reviewed.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.408-415
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• 2001

Hardening agent has been the traditional material for surface soil stabilization of soft ground. The aim of this study if to determine optimal mixture ratio of hardening agent in accordance with the required design specifications. Hardening agent consists of fly ash, gypsum, slag and cement for the ettringite hydrates and if effective for early stabilization of unconsolidated soil. The raw ground material is the clay that is widely found here and there in Korea. In this study, preliminary tests were performed to get optimal mixture ratio of stabilizer ingredient and marine clay in Jinhae was used to get physical and chemical properties. Laboratory tests of 50 stabilized soils were performed to get optimal mixture ratio for 16-stabilizer materials of 6 types, and mixture ratio of stabilizer ingredient and marine clay was determined.

• International Journal of Railway
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• v.6 no.3
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• pp.90-94
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• 2013

Cement or lime is generally used to improve the strength of soil. However, bacteria were utilized to produce cementation of loose soils in this study. The microo rganism called Bacillus, and $CaCl_2$ was introduced into loose sand and soft silt and $CaCO_3$ in the voids of soil particles were produced, leading to cementation of soil particles. In this study, loose sand and soft silt typically encountered in Korea were bio-treated with 3 types of bacteria concentration. The cementation (or calcite precipitation) in the soil particles induced by the high concentration bacteria treatment was investigated at 7 days after curing. Based on the results of Scanning Electron Microscope (SEM) tests and EDX analyses, high concentration bacteria treatment for loose sand was observed to produce noticeable amount of $CaCO_3$, implying a significant cementation of soil particles. It was observed that higher calcium carbonate depositions were observed in poorly graded distribution as compared to well graded distribution. In addition, effectiveness of biogrouting has also been found to be feasible by bio-treatment without any cementing agent.

• Journal of Ocean Engineering and Technology
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• v.15 no.1
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• pp.92-97
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• 2001

Hardening agents have been the traditional material for surface soil stabilization of soft ground. This study aims at determining the optimal mixture ratio of the hardening agent in accordance with the required design specifications. Hardening agents which consists of fly ash, gypsum, slag and cement for the ettringite hydrates is effective for early stabilization of unconsolidated soil. The raw ground material is the clay that is widely found in Korea. In this study, preliminary tests were performed to get an optimal mixture ratio of the stabilizer ingredient and marine clay from Jinhae was used to get physical and chemical properties. Laboratory tests of 50 stabilized soils were performed to get an optimal mixture ratio for 16-stabilizer materials of 6 types, and a mixture ratio of the stabilizer ingredient and marine clay was determined.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.329-336
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• 1998

Sandmats are used to dissipate trapped water rapidly from the embankment built on marine soft ground. At present, however, it becomes difficult to obtain qualified sands since natural resources such as river sand are to exhausted. Also, low permeability of sand may cause low degree of consolidation and instability of embankment. In this study, design and construction methods was discussed. Drainage capacities of prefabricated horizontal drains which were installed in highway construction site are investigated in order to find possible substitution for river sands as drainage materials. On the basis of measurement data at the construction site, it was concluded that use of the prefabricated horizontal drains shows satisfactory drainage capacity without instability of embankment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.219-223
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• 2006

In this paper, the criteria of the lateral displacement in soft soil due to embankment were evaluated. The lateral displacement was measured at a pier structure in a new harbor construction site, and the measurement was compared with the criteria. The results by the measurement such as the critical pressure causing lateral movement in terms of undrained strength, the lateral movement index by Japan Highway Co., the lateral displacement index by Japan Construction Ministry, the modified index by Korean Highway Co. were estimated to be lower than the respective index values.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.582-587
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• 1999

This study has been done to investigate the characteristics of synthetic fiber reinforcement sol with fully satruated . To this end, consolidated undrained triaxial test was performed on synthetic fiber reinforcement soil using the soft clay and plypropylene fiber . From the results of test, it was formed that the mixing ratio for weight and the aspect ratio of synthetic fiber have an effect on the shear characteristic of synthetic fiber rinforcement soil. Especially shear paramter C has line relationship for mixing ratio of fiber, and øhas parabolic relationship for mixing ratio of fiber.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.614-619
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• 2002

Since 1980's in U.S.A and Japan, the studies on increasing the bearing capacity of railway roadbed using geocell have been conducted for repair and reinforcement of railways constructed on soft soils. In this study, the railway roadbed system reinforced with geocells has been analyzed and investigated results of the previous studies were conducted in Korea and other nations, And the method for estimating the railway roadbed thickness was developed based on the equivalent method using the multi-layer theory and the deformation modulus Ev.