• 한국환경복원기술학회지
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• 제18권4호
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• pp.1-14
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• 2015

A manipulation of zoysiagrass's lateral stems and soil-media; used for slope revegetation, is expected to facilitate the production of high-quality grass. To study the influences on the growth of zoysiagrass depending upon various soil-media conditions, two different types of soil are used. The results obtained - through investigation of its cover rates, leaf color and number - are summarized as follows. In mountain regions soil, there are no significant differences in growth and development of grass in treatments: zoysiagrass's lateral stems treatments with 1cm, 2cm, and 3cm soil-media and treatment with only seeding. Zoysiagrass, in most of the treatments, show about the same growth rates, and at the end, fair visual quality. Zoysiagrass's lateral stems treatments with 2cm, 3cm show slightly better growth, however, thickness of soil-media need not be more than 1cm to obtain an expected quality of lawn. In decomposed granite soil, there appears statistical significance in growth of the grass in treatments: zoysiagrass's lateral stems treatments with 1cm, 2cm, and 3cm soil-media and treatment with only seeding. The thicker the soil-media, the better the growth of grass, and that in treatment with seeding-only shows poor quality in general. And therefore, it is efficacious to plant in 3cm soil-media when quick formation of lawn is necessary; however, using 2cm soil-media is ultimately the most cost-efficient way of formation. But, when time allows - that is, more than three months - 1cm soil-media in decomposed granite soil is reasonable to formate just as effective lawn. And so when performing seeding, additional covering, fertilization or increasing the quantity of seed must be considered.

• 한국토양비료학회지
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• 제47권4호
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• pp.284-289
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• 2014

Farmers in highlands in South Korea pile up 20 to 30 cm of saprolites, mostly granite- or granite-gneiss-weathered materials, on surface of arable lands every three to five years to compensate eroded soil and sometimes to discontinue soil-borne diseases. Immediate increases of infiltration and percolation rates are expected with coarse textured saprolites while soil drainage becomes poorer in a long-term. In this study, we analyzed mineralogical characteristics and micro-morphology of plow pan to investigate processes making impermeable layers. Soil samples were collected from plow pan, usually located at approximately 20 cm soil depth and at the lower part of piled saprolites, in arable lands in Hoenggye 5-ri, Daekwanryeong-myeon, Gangwon-do (N37.7, E128.7) in which saprolites were added 2, 4, and 8 years ago; saprolites were transported from similar areas. The saturated hydraulic conductivity decreased over time. Based on soil thin section pedography, quartz and feldspar accounted for a majority of minerals. The size of feldspar decreased and macropores became filled with clay or silt particles over time, which implies that macropores were packed with particles weathered from feldspar. The X-ray diffraction (XRD) analysis indicated that intensity of feldspar decreased over time and the reverse was true for kaolinite and illite, indicating that feldspar and mica weathering induced formation of kaolinite and illite. Conclusively, deteriorated drainage by formation of impermeable layers in farms with piled saprolites was caused by accumulation of clay minerals such as kaolinite and illite in macropores; illite and kaolinite can be formed by weathering of mica and feldspar, respectively.

• 지질공학
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• 제18권4호
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• pp.523-535
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• 2008

강우재현장치를 제작하고, 강우 및 사면조건에 따라 강우재현 모형실험과 함수특성곡선실험(SWCC Cell Test)을 실시하여 불포화 특성에 관해 연구하였다. 그 결과를 이용하여 강우에 따른 침투거동 특성과 함수특성곡선 모델들의 불포화된 화강암질 풍화토에 대한 적용을 검토하였다. 강우재현 모형실험의 습윤과정(강우재현)과 건조과정(방치)에서 계측된 체적함수비와 모관흡인력을 비교한 결과 체적함수비는 $2{\sim}5%$, 모관흡인력은 $3{\sim}10\;kPa$ 정도 값의 차이를 보여 이력현상을 확인 할 수 있었다. 또한, 모관흡인력의 값이 체적함수비의 값에 비해 상대적으로 큰 차이를 보여 모관흡인력에 이력거동이 더 큼을 확인할 수 있었다. 강우재현 모형실험과 함수특성곡선실험에서 얻은 결과로부터 구한 함수특성곡선을 비교하면, 습윤과정과 건조과정에서 두 방법 모두 근접한 함수특성곡선을 얻을 수 있었으나, 두 방법 모두 습윤과정과 건조과정에서의 결과는 차이가 있었다. 이로써 불포화토의 특성을 고려한 보다 합리적인 설계나 안정검토에 함수특성곡선을 적용시킬 때에는 습윤과정에서는 습윤과정 함수특성곡선을 건조과정에서는 건조과정 함수특성곡선을 적용하는 것이 합당할 것으로 여겨진다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.277-284
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• 1999

This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

• 한국농공학회지
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• 제22권3호
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• pp.60-74
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• 1980

Soil-cement mixtures involve problems in it's durability in grain size distribution and mineral composition of the used soils as well as in cement content, compaction energy, molding water content, and curing. As an attempt to solve the problems associated with durability of weathered granite soil with cement treated was investigated by conducting tests such as unconfined compression test, it's moisture, immers, wet-dry and freeze-thaw curing, mesurement of loss of weight with wet-dry and freeze-thaw by KS F criteria and CBR test with moisture curing on the five soil samples different in weathering and mineral composition. The experimental results are summarized as follows; The unconfined compressive strength was higher in moisture curing rather than in the immers and wet-dry, while it was lowest in freeze-thaw. Decreasing ratio of unconfined compressive strength in soil-cement mixtures were lowest in optimum moisture content or in the dry side rather than optimum moisture content with freeze-thaw. The highly significant ceofficient was obtained between the cement content and loss of weight with freeze-thaw and wet-dry. It was possible to obtain the durability of soil-cement mixtures, as the materials of base for roads, containing above 4 % of cement content, above 3Okg/cm$_2$ of unconfined compressive trength with seven days moisture curing or 12 cycle of freeze-thaw after it, above 100% of relative unconfined compressive strength, 80% of index of resistance, below 14% of loss of weight with 12 cycle of wet-dry and above 1. 80g/cm$_2$ of dry density.

• 자원환경지질
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• 제31권5호
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• pp.415-424
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• 1998

In order to investigate soil-gas $^{222}Rn$ concentrations, Kwanak Campus (Seoul National University), Boeun (Choong-buk) and Gapyung (Kyonggi) areas were selected and classified depending on their base rock types. Radon risk indices of these study areas decrease in the order of Gapyung>Kwanak Campus>Boeun areas, and in the order of rock type as banded gneiss>granite gneiss>granite>black slate-shale>mica schist>shale-lirnestone>phyllite-schist. Radon emanating trends with water content and grain size of soils were assessed by modified Morse 3 min. method. Radon emanation increases with the increase of water content in soils which is lower than 6~16 wt.%, and decreases in the range of higher than 6-16 wt. %. It shows that Rn emanation increases with the decrease of soil grain size. Radioactivity analysis of radionuclides of 238U series in some soil samples shows that radioactive disequilibrium state between $^{226}Ra$ and $^{238}U$ exists owing to different geochemical behavior of each radionuclide, and, it is necessary to carry out radioactive isotope geochemical approach for soil-gas $^{222}Rn$ study.

• 한국지반환경공학회 논문집
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• 제13권4호
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• pp.71-76
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• 2012

흙의 전단강도는 흙 속의 임의의 면을 따라 발생하는 파괴와 활동에 저항하는 힘으로 흙의 공학적 특성 중에 가장 중요한 요소 중의 하나이다. 전단강도는 앝은 기초나 말뚝의 지지력 해석방법과 같은 기초공학의 문제나 댐 및 절 성토 후의 사면안정, 그리고 토류 구조물의 횡토압과 같은 흙의 안정 문제 해석 등에 이용된다. 본 연구는 화강풍화토에서 점성토 성분을 제거하고 건조시킨 후, 2 00mm(10번체)와 0 85mm(20번체), 0 475mm(40번체)로 분류한 시료로 직접전단시험기를 이용하여 전단강도 변화를 파악하고자 하였으며, 또한 산호모래를 선정하여 비교 시험을 실시하였다. 따라서 본 연구는 입자의 크기에 따른 전단강도 특성을 비교한 연구에 도움이 될 것으로 판단된다.

• Advances in concrete construction
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• 제9권6호
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• pp.537-545
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• 2020

In order to reduce the usage of cement slurry in grouting engineering and consume the tunnel excavation waste soil, a new geopolymeric grouting material (GGM) was prepared by combine completely weathered granite (CWG) and blast-furnace slag (BFS), which can be applied to in-situ grouting treatment of completely weathered granite strata. The results showed CWG could participate in the geopolymerization process, and GGM slurry has the characteristics of short setting time, high flowability, low viscosity, high stone rate and high mechanical strength, and a design method of grouting pressure based on viscosity evolution was proposed. By adjusted the content of completely weathered granite and alkali activator concentration, the setting time of GGM were ranged from 5 to 30 minutes, the flowability was more than 23.5 cm, the stone rate was higher than 90%, the compressive strength of 28 days were 7.8-16.9 MPa, the porosity were below 30%. This provides a novel grouting treatment and utilizing excavated soil of tunnels in the similar strata.

• 한국환경복원기술학회지
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• 제6권5호
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• pp.48-58
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• 2003

This study was carried out to select proper species for early stage replantation in granite forest road cut-slope. From one to thirteen year elapsed forest roads in five regional areas of Chungcheong-do and Kyungsangbuk-do, sample plots were selected, and their vegetations and environmental factors were investigated. Soil organic matter, total nitrogen, soil moisture content, and bulk density in the granite weathering soils were below 0.5%, 0.02%, 10%, and above 1.2g/$cm^3$, respectively. The environmental factors affecting distribution of species in the granite forest road were the elapsed year, elevation, cut-slope aspect, and cut-slope. Sowing plants of Dactylis glomerata, Lolium perenne, and Eragrostis curvula were found in the early stage of forest road-cut. Annual herbs of Youngia denticulata, Erigeron annuus, etc. were found in the 2-3 years elasped forest road-cut. Perennial herbs of Artemisia princeps var. orientalis, Miscanthus sinensis, etc., parachute woody plants of Weigela subsessilis, Pinus densiflora, etc., and gravitative trees of Prunus sargentii, Lindera obtusiloba, Quercus sp., etc. were found in the forest road cut-slope after 3 years of road-cut. Leguma of Lespedeza cureata, Amorpha fruticosa, Lespedeza bicolor, Pueraria thunbergiana, Albizzia julibrissin, etc., herbs of Artemisia keiskeana, Artemisia princeps var. orientalis, Miscanthus sinensis, etc., and woody plants of Rubus crataegifolius, Weigela subsessilis, Zanthoxylum schinifolium, Pinus densiflora, etc. were considered as proper species for replantation in granite forest road cut-slope.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.47-50
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• 2001

The laboratory tests were peformed to investigate the relationship between electrical resistivity and the unsaturated subsurface condition and to evaluate the contamination due to leachate based on measuring electrical resistivity. For weathered granite soil, the electrical resistivity of soil decreases as moisture density increases. The electrical resistivity of soil decreases as the concentration of leachate in pore fluid increases since leachate contains various ionic constituents. And the modified Archie's equation for applying to unsaturated sand is derived by regression analysis.