• 한국지반공학회논문집
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• 제19권5호
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• pp.69-78
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• 2003

화강풍화토의 동결-융해 전후의 동적 거동을 구명하기 위하여 반복삼축압축시험을 수행하였다. 화강풍화토의 실트 함유량 20%이내에서 동결-융해를 받지 않은 공시체와 동결-융해를 받은 공시체를 구속압력을 변화시켜 동적 물성치인 전단탄성계수와 감쇠비의 변화 특성을 고찰하였다. 또한 점성토의 함유량을 각각 다르게 하여 소성지수의 변화에 따른 동결-응해 후의 동적 거동의 변화를 고찰하였다. 연구결과, 화강풍화토의 실트함유량이 증가할수록 전단탄성계수는 감소하였다. 그러나 동일한 밀도, 구속압력의 조건에서 동결-융해를 받은 화강풍화토의 전단탄성계수는 실트함유량에 관계없이 전단탄성계수에 큰 차이가 없었다. 점토를 함유한 소성지수 20이내의 화강풍화토의 전단탄성계수는 소성지수가 클수록 증가하였으며 동결-융해를 받게되면 전단탄성계수의 감소가 뚜렷하게 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.831-838
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• 2004

To study on mechanical characteristics of weathered granite masses are difficult because of undisturbanced sampling and in-situ test. Generally, pressuremeter test is widely used to investigate the behavior of weathered rock masses. However, it has many problems to get a limit pressure because of cavity collapse, membrane damage, ete. This study aims to evaluate the mechanical characteristics of weathered granite masses using in-situ pressuremeter test and numerical analysis depending on the ratio of length and diameter of the membrane(L/D=5, 8, 10, 15, 20). Test results and data are shown that strength parameters are reduced exponentially varing weathering degree, and numerical analysis results are approximately coincided with the test results. And the ratio of length and diameter of the membrane arc not affected the parameters such as modulus of pressuremeter, shear modulus, etc. But limit pressure is increased decreasing membrane length based on numerical analysis. On the other hand, increasing the membrane length, yield pressure is decreased and plastic radius is increased in the case of same weathering degree.

• 한국안전학회지
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• 제25권2호
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• pp.55-64
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• 2010

Since various weathered soils are encountered in many domestic construction sites, it is necessary to estimate characteristics of natural weathered soils. However, the remolded sample of weathered soils are commonly used to estimate their characteristics because it is very difficult to sample weathered soils in undisturbed states. However, it is well known that the behavior of remolded sample is different from that of the undisturbed sample particularly in the dynamic response, because the particle structure of undisturbed sample maintains its original structure from the mother rock. Thus, to evaluate the influence of sampling method and preparation method on stress-strain behavior, the resonant column tests were performed on the block, tube samples, remolded samples with static compression and remolded samples with tamping of the weathered granite soils. The shear modulus of the remolded sample with tamping is larger than the other samples presumably due to the high tamping pressure enough to induce particle breakage. The tube samples show larger damping ratios than other samples. Furthermore, one-dimensional ground response analysis was performed to compare the results qualitatively.

• 한국농공학회지
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• 제21권2호
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• pp.81-103
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• 1979

The weathered granite soil involves problems in its stability in soil structures depending upon the reduction of soil strength due to the water absorption, crushability, and content of colored mineral and feldspar. As an attemt to solve the problems associated with soil stability, the crushability of weathered granite soil was investigated by conducting tests such as compaction test, CBR test, unconfined compression test, direct shear test, triaxial compression test, and permeability test on the five soil samples different in weathering and mineral compositions. The experimental results are summarized as follows: The ratio of increasing dry density in the weathered granite soil was high as the compaction energy was low, while it was low as the compaction energy was increased. The unconfined compressive strength. and CBR value were highest in the dry side rather than in the soil with the optimum moisture content, when the soil was compacted by adjusting water content. However, the unconfined compressive strength of smples, which were compacted and oven dried, were highest in the wet side rather than in soil with the optimum moisture content. As the soil becomes coarse grain, the ratio of specific surface area increased due to increased crushability, and the increasing ratio of the specific surface area decreased as the compaction energy was increased. The highest ratio of grain crushability was attained in the wet side rather than in the soil with the optimum moisture content. Such tendency was transforming to the dry side as the compaction energy was increased. The effect of water on the grain crushability of soil was high in the coarse grained soil. The specific surface area of WK soil sample, when compacted under the condition of air dried and under the optimum moisture content, was constant regardless of the compaction energy. When the weathered granite soil and river sand with the same grain size were compacted with low compaction energy, the weathered granite soil with crushability had higher dry density than river sand. However, when the compaction energy reached to certain point over limitation, the river sand had higher dry density than the weathered granite soil. The coefficient of permeability was lowest in the wet side rather than in the optimum moisture content, when the soil was compacted by adjusting soil water content. The reduction of permeability of soil due to the compaction was more apparent in the weathered granite soil than in the river sand. The highly significant correlation coefficient was obtained between the amount of particle breakage and dry density of the compacted soil.

• 한국지반공학회논문집
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• 제35권12호
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• pp.15-24
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• 2019

국내 다수의 지역에 분포하는 화강 풍화대 지반은 지반구조물의 주요 지지층으로 활용되고 있으므로 화강 풍화대의 지반특성을 평가하는 것은 중요하다. 풍화대 지반은 실내시험을 위한 불교란 시료를 채취하는 것이 어렵기 때문에 일반적으로 표준관입시험(SPT: Standard penetration test)을 통해 지반특성을 평가하고 있다. 프레셔미터시험(PMT: Pressuremeter test)은 풍화대 지반의 응력 - 변형률 거동을 신뢰도 높게 평가하는 대표적인 현장시험이지만 소요 시간과 비용의 제약으로 제한적인 시험만을 수행하고 있다. 본 연구에서는 화강 풍화대에서 수행된 SPT-N₆₀ 값과 PMT 결과의 상관성 분석을 수행하였으며, N₆₀ - E_m(E_m: Pressuremeter modulus)과 N₆₀ - P_L(P_L: Limit pressure) 관계식을 제안하였고 선행 연구 결과와 비교 분석하였다.

• 한국농공학회지
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• 제41권3호
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• pp.91-100
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• 1999

Tow constitutive models for weathered granite soil, Yasufuku's constitutive model with a single yield surface and Lade's constitutive model with two intersectiong yield surface compared in terms of their capabilities to accurately capture the observed behavior of compacted weathered grainite soil for various stress-paths. Both the single surface and the double surface models capture the experimentally observed behavior at a variety of stress-paths with good accuracy. The double surface model may model the observed compacted weathered granite soil behavior with better accuracy for proportational loading with increasing stress, but the single surface model may model dilatancy property with better accuracy for p-constant loading with increasing stress ratio.

• 자원환경지질
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• 제6권2호
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• pp.115-122
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• 1973

The writer intended to observe the relative mobility of elements in weathering process of granite, on the outskirts of IRI city at Jeollabukdo KOREA. He analysed fresh granites and weathered ones of Hwang-Dung granite mass and had following conclusions by the triangular diagrams and the oxidized variation diagrams of the analysis. 1) The increasing phenomena of $H_2O$ observed clearly in early and late stage of weathering processes. 2) Granites was weathered by physical weathering in early stage, and it was weathered by chemical weathering in late stage. 3) The ratio of $FeO/Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3$ decreased uniformly from early to late stage of weathering processes. 4) It was proved that weathering potential of granite was larger than that of basaltic rock. 5) The order of mobility in major elements was Ca, Na, K>Si>Mg>Fe, Al.

• 터널과지하공간
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• 제6권3호
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• pp.223-233
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• 1996

Geotechnical Information System (GTIS) for efficient management of three dimensional borehole data has been developed. Geotechnical maps in the vicinity of Bulkwangdong, Seoul station, Itaewon, Han river near Yuido, and Jungrangchon were constructed by Kriging method. In Bulkwangdong and Jungrangchon area where boundary between granite and gneiss is present, gneiss has been more weathered than granite, but in Seoul station and Itaewon area where the boundary is also present, granite has been more weathered than gneiss. It has been inferred that when Seoul granite intruded, the strength of gneiss in Bulkwangdong and Jungrangchon area was lowered by the attitude of foliation plane than in Seoul station and Itaewon area, so the gneiss has been easily fractured and weathered in Bulkwangdong and Jungrangchon area. Geotechnical map in the vicinity of Yuido showed that there is an NW-SE trend weakness zone that might be affected by major faults under Han river and it is expected that the fault zone may be present in construction area of Kyoungbu Highspeed Railway that lies below the Han river like the Subway Line No.5.

• 한국지반신소재학회논문집
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• 제6권3호
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• pp.1-7
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• 2007

풍화토의 특성은 다양한 풍화환경, 풍화도 및 영향인자에 따른 거동의 특이성 때문에 정밀한 접근에 있어서 한계를 가진다. 특히 국내 외의 연구는 퇴적토에 집중되어 있고 풍화토의 역학적 거동을 퇴적토의 관점에서 분석하려 하기 때문에 이러한 결과가 풍화토의 실제 거동과 일치하는지 판단하는데 무리가 있다. 본 연구에서는 인공적으로 풍화도를 변화시키는 실험의 초보단계로서 온도 변화에 따른 강도변화 특성을 규명하고자 한다. 이를 위하여 동결 융해 반복작용 후의 시료를 대상으로 실내시험을 실시하여 풍화도에 대한 화강풍화토의 모암별, 지역별, 특성변화를 살펴보았다.

• 지질공학
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• 제12권4호
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• pp.459-469
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• 2002

재성형된 해성점토 시료를 연직·수평방향으로 채취하여 표준압밀시험(SCT)과 일정변형률속도 압밀시험(CRSC)을 실시하여 연약 해성점토지반에 대한 압밀정수들의 구성관계를 확인하였다. 또한, 불교란 교란 화강암질 풍화토의 표준·일정변형률속도 압밀시험을 통하여 화강암질 풍화토에 대한 압밀 정수들의 특성과 적용성을 고찰하였다. 그 결과 해성점토 시료의 연직·수평방향과 표준·일정변형률속도압밀시험 방법에 따라 선행압밀응력, 압축지수, 과잉간극수압, 간극수압비 등이 달리 산정됨을 알 수 있었다. 또한, 불교란·교란 화강암질 풍화토 시료에서도 해성점토와 유사하게 과압밑·정규압밀 구간에서 압밀정수들의 변화를 확인하였다.