• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.274-278
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• 2011

We present an innovative method of multi-physics application involving energetic materials. We use an Eulerian methodology to address these problems. We have devised a new level set based tracking framework that can elegantly handle large gradients typically found in energetic response of high explosive and metals. Proper constitutive relations are employed to model the transient phases of gas, lliquid, and solid in the high strain rate regime. We use the confined and unconfined rate stick results to validate against the experimental data.

• Geomechanics and Engineering
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• v.12 no.1
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• pp.85-109
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• 2017

The paper presents the laboratory study of clayey soil stabilized with Pond ash (PA), Rice husk ash (RHA), cement and their combination used as stabilizers to develop and evaluate the performance of clayey soil. The effect of stabilizer types and dosage on fresh and mechanical properties is evaluated through compaction tests, unconfined compressive strength tests (UCS) and Split tensile strength tests (STS) performed on raw and stabilized soil. In addition SEM (scanning electron microscopy) and XRD (X-ray diffraction) tests were carried out on certain samples in order to study the surface morphological characteristics and hydraulic compounds, which were formed. Specimens were cured for 7, 14 and 28 days after which they were tested for unconfined compression tests and split tensile strength tests. The moisture and density curves indicate that addition of RHA and pond ash results in an increase in optimum moisture content (OMC) and decrease in maximum dry density (MDD). The replacement of clay with 40% PA, 10% RHA and 4% cement increased the strength (UCS and STS) of overall mix in comparison to the mixes where PA and RHA were used individually with cement. The improvement of 336% and 303% in UCS and STS respectively has been achieved with reference to clay only. Developed stabilized soil mixtures have shown satisfactory strength and can be used for low-cost construction to build road infrastructures.

• Geotechnical Engineering
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• v.9 no.3
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• pp.5-22
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• 1993

A series of laboratory tests (physical and mechanical index and engineering design) were conducted on undisturbed granite soils of CW and RS weathering grades in Korea. From these testes it can be concluded that most of physical and mechanical index values are very sensitive to change in weathering grade from CW to RS. Engineering design tests indicate that the unconfined compressive strength and the shear strength parameters are significantly reduced and that the soil becomes ductile and plastic with increasing weathering and saturation. It was found that weathered granite soils have the special characteristics when water saturated: (i) they significantly lose their shear strength(especially cohesion) and unconfined compressive strength, (ii) they are fragile and their grains break down in water as observed in grain size analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.725-733
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• 2008

A thixotropic grout has been developed for the use of filling a tail void in the shield TBM and as well as various ground voids. The grout developed in this study is a mixture of inorganic substance, cement and some functional additives. Its engineering characteristics was investigated by measuring a viscosity and unconfined compressive strengths. The optimum mix proportion for an effective thixotropic grout was proposed through several repeated laboratory tests. The various physical properties such as thixotropy, unconfined compressive strengths, and durability of the thixotropic grout and the gels produced from the grout were compared with those of the well-known waterglass-type grout such as L.W.. The thixotropic grout developed in the study exhibited an excellent performance for back-filling of tail voids in the shield TBM based on experimental results compared to the existing waterglass grout.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.140-146
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• 2014

This study investigated the engineering characteristics of non-sintering binder-stabilized mixtures consisting of different ratios of a hardening agent(3%, 6%, 9%, 12%) for recycling industrial by-products through several series of laboratory tests. The hardening agents consisted of two kinds of non-sintering binders(NSB-1, NSB-2), which were developed by using inter-chemical reactions among blast furnace slag, phospho-gypsum, and an alkali activator. In addition, ordinary Portland cement(OPC) was used to compare the engineering characteristics of the stabilized mixture. An unconfined compressive test showed that the unconfined compressive strength increased with the curing time and mixing ratio. Experimental test results indicated that the 7-day strength of the NSB-1 mixture was similar to that of the OPC mixture. However, its 28-day strength was higher than that of the OPC mixture. The secant module of elasticity showed a range of $E_{50}=(42-109)q_u$ regardless of the agents. Based on the results of triaxial tests, the cohesion and friction angle increased with the mixing ratio.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.808-817
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• 2006

There were huge damages of human beings and their properties in many areas of the basin of the Nak-Dong river by the unusual weather and the localized downpour recently. In this research against disasters, we want to know the special quality of strength of the cemented sand that is mixed with cement and poor-graded sand which is the materials of riverbed in the basin of the Nak-Dong river as levee's material. For that, we want to provide the fundamental data which need in the examination of adaptation of levee's material, design and analysis by investigating compressive strength by curing period and cement ratio, elastic modulus and stress by transformation from compaction test, CBR test, unconfined compression test, triaxial compression test as changing ratio of sand and cement from 2% to 8% at two points in the basin of the Nak-Dong river.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1283-1290
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• 2005

A thixotropic grout has been newly developed for the use of back-filling a tail void in the shield tunnel and filling up ground voids. The grout developed in the study is a mixture of colloidal silica, cement and some functional additives. Its engineering characteristics was investigated by measuring a viscosity and unconfined compressive strengths. The optimum mixing proportion for an effective thixotropic grout was proposed through several repeated laboratory tests. The various physical properties such as thixotropy, unconfined compressive strengths, and durability of the thixotropic grout and the gels produced from the grout were compared with those of the well-known waterglass grout such as L.W.. The thixotropic grout developed in the study exhibited an excellent performance for back-filling of tail voids, based on experimental results compared to the existing waterglass grout.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.73-80
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• 2009

This paper is to investigate effect of B.G.I (Best Grouting Innovation) method on reinforcing ground. In this thesis, extensive literature review was performed to summarize theoretical backgrounds of grouting and to compare the applicability of different grouting methods. Unconfined compression test with specimen prepared by injecting different grouts of B.G.I, S.G.R and L.W methods and by changing the curing time were carried out to figure out characteristics of initial unconfined compression strength mobilized in the early stage. As results of test, the compression strength increases with curing times and specimen prepared with grouts of B.G.I method show greater values than others. On the other hands, the measured values of pH are in the range of 7-10 during tests. In field, preliminary construction to main construction at several sites were performed to confirm the effect of reinforcing the ground by application of B.G.I method. From the results of permeability test in field, SPT test and phenol reaction test, it was found that N values after grouting are greater than those before grouting and values of permeability in grouted ground is reduced significantly.

• Geomechanics and Engineering
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• v.8 no.5
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• pp.687-706
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• 2015

Methods commonly used to evaluate the improvement of lime-treated expansive soil include swelling characteristics and unconfined compressive strength. In the field, lime-treated expansive soils are in compacted unsaturated state. Soil water characteristic curves (SWCCs) represent a key parameter to interpret and describe the behavior of unsaturated expansive soil. This paper investigates the use of SWCC as a technique to evaluate improvements acquired by expansive soil after lime treatment. Three different lime contents were considered 2%, 4% and 6% by dry weight of clay. Series of tests were performed to determine the SWCC for the different lime content under curing periods of 7 and 28 day. Correlations between key features of the soil water characteristic curves of lime treated expansive soils and basic engineering behavior such as swelling characteristics and unconfined compression strength were established. Test results revealed that initial slope ($S_1$), saturated water content ($w_{sat}$), and air entry value (AEV) play an important role in reflecting improvement in engineering behavior achieved by lime treatment.

• Geomechanics and Engineering
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• v.8 no.5
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• pp.649-661
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• 2015

This research provides insight on the laboratory investigation of the engineering properties of a lateritic soil modified with the mucilage of Opuntia ficus-indica cladodes (MOFIC), which has a history of being used as an earthen plaster. The soil is classified, according to AASHTO classification system, as A-2-6(1). The Atterberg limits, compaction, permeability, California bearing ratio (CBR) and unconfined compressive strength of the soil were determined for each of 0, 4, 8 and 12% addition of the MOFIC, by dry weight of the soil. The plasticity index, optimum moisture content, swell potential, unconfined compressive strength and permeability decreased while the soaked and unsoaked CBR increased, with increasing MOFIC contents. The engineering properties of the natural soil, which only satisfies standard requirements for use as subgrade material, became improved by the application of MOFIC such that it meets the standard requirements for use as sub-base material for road construction. The effects of MOFIC on the engineering properties of the soil resulted from bioclogging and biocementation processes. MOFIC is recommended for use as a modifier of the engineering properties of soils, especially those with similar characteristics to that of the soil used in this study, to be used as a pavement layer material. It is more economical and environment-friendly than conventional soil stabilizers or modifiers.