• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.599-615
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• 2022

In order to excavate underground tunnel most safely such as Han river, the slurry shield TBM method is applied to cope with face of high water pressure for many metro projects. In downtown subway project most of excavated soil is discharged externally whereas in road construction excavated soil is used as filling materials so it becomes important factor for success of the project. After excavated soil, weathered rock and soft rock are discharged with bentonite through discharge pipe to slurry treatment plant then those soils are separated in separation plant according to those size. Fine grained soil has been discarded together with filter cake but it is not toxic and can be mixed with coarse aggregate in proper ratio so this study is performed to find use of qualified filling material to meet quality standard. Therefore, in this study, legal standards and quality standards for the utilization of excavated soil of the slurry shield TBM method were examined and test was conducted to derive recycling way for filter cake and aggregate. And a plan for using it as a filling material for road construction was derived. Because bentonite is a clay composed of montmorillonite, and the excavated soil in the tunnel is also non-toxic, disposal of this material can waste social cost so it is expected to be helpful in the underground space development project that carries out the TBM project by recycling it as a valuable resource.

• Economic and Environmental Geology
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• v.52 no.3
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• pp.213-221
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• 2019

The Wugang banded iron formation (BIF) is located within the Taihua complex at the southern margin of the North China Craton (NCC). In this study, we analyzed major elements and rare-earth elements in iron ores from the Wugang BIF, to study the type of BIFs and their formation mechanism in combination with previously-published data from the literature. We found that the iron ores from the Wugang BIF display two types of banding textures, which can be described as weak banding or no banding. The samples are composed of coarse-grained magnetite, quartz, pyroxene, and amphibole. Based on our geochemical results, mixing of a hydrothermal fluid with sea water led to the precipitation of the Wugang BIF, and there is evidence of crustal contamination. These results, combined with previous literature data, almost all of the iron ores lack Ce anomalies, though some samples show negative Ce anomalies. Our results indicate that the Wugang BIF was formed in a dominantly reducing environment, although the surfaces were relatively oxidized. Geochemical evidence suggests that the Wugang BIF iron ores were formed in a near-shore continental-shelf environment or in a back-arc basin. The BIF is known as interbedded with migmatite, amphibole gneiss, minor quartz and marble, which indicating lack of volcanic materials input. This study, combined with previous results on geochemical interpretation of related wall rock of Wugang BIF, demonstrated that Wugang BIF belongs to Superior-type BIF.

• Journal of the Korean Geotechnical Society
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• v.39 no.10
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• pp.5-18
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• 2023

The construction timeline for earthworks can be significantly reduced by substituting the conventional layer-by-layer compaction using a vibratory roller with single-layer compaction through the rapid impact compaction (RIC) method. Dynamic load compaction is well-suited for coarse-grained soils like sand. However, as the supply of sand, the primary reclamation material, becomes scarcer, the utilization of soil with fines is on the rise. To implement the dynamic load compaction, such as RIC, with reclaimed materials containing fines, it's imperative to determine the effective improvement depth. In this study, we assess the impact of the RIC method on the effective improvement depth for clean sand and public fill with fines, comparing field test results before and after RIC application. Our focus is on the cone resistance (q_c) as it pertains to compaction quality control criteria. In conclusion, it becomes evident that standardizing the cone resistance is vital for the quality control of various reclaimed soils with fines. We have evaluated the compaction quality control criteria corresponding to a relative density (Dr) of 70% for clean sand as Q_tn,cs = 110. As a result of this analysis, we propose new quality control criteria for q_c, taking into account the fines content of reclaimed soils, which can be applied to RIC quality control.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.212-223
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• 2022

For the remediation and restoration of contaminated sediment at the West Sea-Byeong dumping site, dredged materials was dumped in 2013, 2014, 2016, and 2017. The physicochemical properties and benthic fauna in surface sediments of the capping area (5 stations) and natural recovery area (2 stations) were analyzed annually from 2014 to 2020 to evaluate the capping effect of the dredged materials. The natural recovery area had a finer sediment with a mean particle size of 5.91-7.64 Φ, while the sediment in the capping area consisted of coarse-grained particles with a mean particle size of 1.47-3.01 Φ owing to the capping effect of dredged materials. Considering that the contents of organic matters (COD, TOC, and TN) and heavy metals in the capping area are approximately 50 % lower (p<0.05) than that in the natural recovery area, it is judged that there is a capping effect of dredged materials. As a result of analyzing macrobenthic assemblages, the number of species and ecological indices of the capping area were significantly lower than that of the natural recovery area (p<0.05). The number of species and ecological indices at the capping area were increased for the first four years after the capping in 2013 and 2014 and then tended to decrease thereafter. It is presumed that opportunistic species, which have rapid growth and short lifetime, appeared dominantly during the initial phase of capping, and the additory capping in 2016 and 2017 caused re-disturbance in the habitat environment. In the natural recovery and capping areas, Azti's Marine Biotic Index (AMBI) was evaluated as a fine healthy status because it maintained the level of 2^nd grades (Good), whereas Benthic Pollution Index (BPI) remained at the 1^st and 2^nd grade. Therefore, capping of dredged materials for remediation of contaminated sediment in the dumping site has the effect of reducing the pollution level. However, in terms of the benthic ecosystem, it is recommended that the recovery trend should be monitored long-term. Additionally, it is necessary to introduce an adaptive management strategy when expanding the project to remediate the contaminated sediment at the dumping area in the future.

• Korean Journal of Heritage: History & Science
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• v.51 no.3
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• pp.4-31
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• 2018

It is difficult to ascertain exactly when the Hongjuupseong (Town Wall) was first constructed, due to it had undergone several times of repair and maintenance works since it was piled up newly in 1415, when the first year of the reign of King Munjong (the 5th King of the Joseon Dynasty). Parts of its walls were demolished during the Japanese occupation, leaving the wall as it is today. Hongseong region is also susceptible to historical earthquakes for geological reasons. There have been records of earthquakes, such as the ones in 1978 and 1979 having magnitudes of 5.0 and 4.0, respectively, which left part of the walls collapsed. Again, in 2010, heavy rainfall destroyed another part of the wall. The fortress walls of the Hongjuupseong comprise various rocks, types of facing, building methods, and filling materials, according to sections. Moreover, the remaining wall parts were reused in repair works, and characteristics of each period are reflected vertically in the wall. Therefore, based on the vertical distribution of the walls, the Hongjuupseong was divided into type I, type II, and type III, according to building types. The walls consist mainly of coarse-grained granites, but, clearly different types of rocks were used for varying types of walls. The bottom of the wall shows a mixed variety of rocks and natural and split stones, whereas the center is made up mostly of coarse-grained granites. For repairs, pink feldspar granites was used, but it was different from the rock variety utilized for Suguji and Joyangmun Gate. Deterioration types to the wall can be categorized into bulging, protrusion of stones, missing stones at the basement, separation of framework, fissure and fragmentation, basement instability, and structural deformation. Manually and light-wave measurements were used to check the amount and direction of behavior of the fortress walls. A manual measurement revealed the sections that were undergoing structural deformation. Compared with the result of the light-wave measurement, the two monitoring methods proved correlational. As a result, the two measuring methods can be used complementarily for the long-term conservation and management of the wall. Additionally, the measurement system must be maintained, managed, and improved for the stability of the Hongjuupseong. The measurement of Nammunji indicated continuing changes in behavior due to collapse and rainfall. It can be greatly presumed that accumulated changes over the long period reached the threshold due to concentrated rainfall and subsequent behavioral irregularities, leading to the walls' collapse. Based on the findings, suggestions of the six grades of management from 0 to 5 have been made, to manage the Hongjuupseong more effectively. The applied suggested grade system of 501.9 m (61.10%) was assessed to grade 1, 29.5 m (3.77%) to grade 2, 10.4 m (1.33%) to grade 3, 241.2 m (30.80%) and grade 4. The sections with grade 4 concentrated around the west of Honghwamun Gate and the east of the battlement, which must be monitored regularly in preparation for a potential emergency. The six-staged management grade system is cyclical, where after performing repair and maintenance works through a comprehensive stability review, the section returned to grade 0. It is necessary to monitor thoroughly and evaluate grades on a regular basis.

• Korean Journal of Heritage: History & Science
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• v.38
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• pp.387-419
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• 2005

Material characteristics and provenance interpretation of the raw materials for the stone moulds of bronze artifacts excavated in Galdong Prehistoric site were studied. The stone moulds are made of igneous hornblendite with coarse-grained holocrystalline textures. The surface color shows greenish grey to dark green with greasy luster. The value of magnetic susceptibility of the moulds ranges from 19.2 to 71.0 (mean ; $39.2{\times}10^{-3}$ SI unit).High value of magnetic susceptibility indicates high contents of magnetite as a ferromagnetic mineral and the wide range of the values are due to heterogeneous distribution of magnetite. These are characteristics of basic igneous rocks. The rock-forming minerals of the moulds mainly consist of amphibole, plagioclase and biotite. Pyroxene, chlorite and opaque minerals are also rarely present. A large quantity of carbon was detected on the dark black crust near the surface of the moulds by quantitative analysis. Geological field survey was carried out to identify a source of the raw materials of the stone moulds around Galdong site. Hornblendite or gabbroic rocks being similar to the moulds forming rock occur at Daeseongri, Sikcheonri and Gyodongri in Jangsoo, and Illdaeri in Namwon about 50 kilometers away from the site in a straight line. They have similarity with the moulds forming rock in magnetic susceptibility ranging from 16.1 to 72.4 (mean ; $39.9{\times}10^{-3}$ SI unit). Among those hornblendite or gabbroic rocks, one in Jangsoo area is the most similar to the moulds forming rock on the basis of petrological and mineralogical characteristics. Comparing normalized patterns of major, minor, rare earth and immobile elements contents of the moulds to them of hornblendite in Jangsoo area, geochemical evolution trend and behavior characteristics show affinities between them. It suggests that the moulds forming rock and hornblendite in Jangsoo area have been originated from cogenetic magma. This hornblendite is easy to engrave an inscription or detail graphics on the surface because of its softness, and has good thermal conductivity. Hornblendite in Sikcheonri, Jangsoo is particularly produced and used for stone wares until the present day. Therefore, it is probable that the stone materials of the moulds has been imported from Daeseongri, Sikcheonri and Gyodongri in Jangsoo area. However, it cannot be completely excluded the possibility that the material of the moulds was supplied from Illdaeri in Namwon area appearing the same type of hornblendite on a small outcrops. It is necessary to carry out further archaeological studies to identify several possibilities of migration process of raw materials.

• The Journal of the Petrological Society of Korea
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• v.13 no.1
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• pp.34-45
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• 2004

This paper describes the textural relations of mantle xenoliths and fluid inclusions in mantle-derived rocks found in alkaline basalts from Jeju Island which contain abundant ultramafic, felsic, and cumulate xenoliths. Most of the ultramafic xenoliths are spinel-lherzolites, composed of olivine, orthopyroxene, clinopyroxene and spinel. The felsic xenoliths considered as partially molten buchites consist of quartz and plagioclase with black veinlets, which are the product of ultrahigh-temperature metamorphism of lower crustal materials. The cumulate xenoliths, clinopyroxene-rich or clinopyroxene megacrysts, are also present. Textural examination of these xenoliths reveals that the xenoliths are typically coarse grained with metamorphic characteristics, testifying to a complex history of evolution of the lower crust/upper mantle source region. The ultramafic xenoliths contain protogranular, porphyroclastic and equigranular textures with annealing features, indicating the presence of shear regime in upper mantle of the Island. The preferential associations of spinel and olivine with large orthopyroxenes suggest a previous high temperature equilibrium in the high-Al field and the original rock-type was a Al-rich orthopyroxene-bearing peridotite without garnet. Three types of fluid inclusions trapped in mantle-derived xenoliths include CO$_2$-rich fluid (Type I), multiphase silicate melt (glass ${\pm}$ devitrified crystals ${\pm}$ one or more daughter crystals ＋ one or more vapor bubbles) (Type II), and sulfide (melt) inclusions (Type III). C$_2$-rich inclusions are the most abundant volatile species in mantle xenoliths, supporting the presence of a separate CO$_2$-rich phase. These CO$_2$-rich inclusions are spatially associated with silicate and sulfide melts, suggesting immiscibility between them. Most multiphase silicate melt inclusions contain considerable amount of silicic glass. reflecting the formation of silicic melts in the lower crust/upper mantle. Combining fluid and melt inclusion data with conventional petrological and geochemical information will help to constrain the fluid regime, fluid-melt-mineral interaction processes in the mantle of the Korean Peninsula and pressure-temperature history of the host xenoliths in future studies.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.222-241
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• 2020

The Taereung Royal Tomb from the Joseon Dynasty is the tomb of Empress Munjeong, the second queen of King Jungjong, and it contains various types of stone artifacts. All of these stone artifacts were constructed using coarse- to medium-grained biotite granite. The major types of deterioration of the stone artifacts are identified as surface weathering and biological contaminants. Exfoliation (145 sculptures), granular decomposition (138 sculptures), and repair materials (156 sculptures), along with biological contaminant algae (154 sculptures), lichen (165 sculptures) and moss (97 sculptures), have a high occurrence frequency. In particular, it is deemed that immediate conservation treatment is required, as biological deterioration (algae) represents the most serious condition (grade 3 or higher in 94% of all stones), and it is thought that exfoliation and granulation decomposition are required for long-term conservation management. As a result of equo -tip hardness and ultrasonic measurement, more than 70% of stones were found to have very weak physical properties. Through hyperspectral analysis, organisms were shown to inhabit more than 80% of the surface of burial mound stone artifacts, and P (phosphorus), S (sulfur), Cl (chlorine), and Ca (calcium) were detected in this area. This is because Taereung Royal Tomb has been exposed to the outdoors for hundreds of years and has been weathered by physical, chemical, and biological factors. Therefore, among the stone artifacts in the Taereung Royal Tomb, those with high physical weathering grades are considered to require consolidation to reinforce them physically. Since organisms are highly likely to cause stone damage, they must be removed via dry and wet cleaning. In addition, in order to delay the reoccurrence of organisms following conservation treatment, it is necessary to regularly clean up the soil that has flowed into the burial mound, and to monitor conservation conditions over the long term.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.647-659
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• 2023

This study is to analyze the lithological similarities between railing stones of Gwanghwamun Woldae and stone blocks stored in Donggureung Royal Tombs, Guri, to interpret the provenance of the stones, and to suggest the most suitable quarry for a new stones supply among the rocks in the Seoul-Pocheon area in order to select stones for the restoration of the Gwanghwamun Woldae. The railing stones in Donggureung are medium to coarse-grained pink biotite granite, and their lithological characteristics, magnetic susceptibility(Average 5.20 ×10^-3 SI unit), and gamma spectrometer data(K 5.00~6.38%, U 4.92~8.56 ppm, Th 27.60~36.44 ppm) show similarities with the remaining railing stones in Gwanghwamun Woldae(Average 5.38). Therefore, the railing stones in Donggureung can be reused for the restoration of Gwanghwamun Woldae. They have similar lithological and geochemical charateristics to the pink biotite granite found the Suraksan Mt. and Buramsan Mr. areas in Seoul, suggesting that these areas are the source of the stone. However, since the Suraksan Mt. and Buramsan Mt. areas are currently unavailable for quarrying, lithological and geochemical analyses on granite from the Yangju and Pocheon areas are conducted to determine the suitability of the new stone for restoration. As a result, a pink biotite granite similar to the Woldae stones was identified in the Pocheon area, and it is suggested that the stones similar in grain size and colour to the railing stones of Gwanghwamun Woldae should be selected and used for the restoration of Gwanghwamun Woldae.