• 한국지반공학회논문집
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• 제20권1호
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• pp.75-82
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• 2004

본 연구에서는 지지대상층이 아닌 투수 대상층으로서의 풍화토 지반에 초점을 맞추어 불교란 풍화토 시료를 이용해 다양한 구속압 조건에서 동수경사를 변화 시켜가면서 연성벽체 투수시험을 수행하였다. 동수경사 및 구속압이 풍화토의 투수특성에 미치는 영향을 투수계수를 이용하여 분석하였으며, 사질토에 대해서도 유사한 시험을 수행하여 사질토와는 구별되는 풍화토만의 침투 특성을 평가하였다. 또한 풍화토 지반의 파이핑 특성을 분석하기 위하여 모형 파이핑 시험을 수행하였다. 실험결과로부터 동수경사의 범위에 따라 풍화토는 서로 다른 투수특성을 보임을 알 수 있으며, 파이핑에 대하여 사질토에 비해 매우 높은 저항 능력을 가짐을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.743-750
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• 2002

Unsaturated soil has a possibility to induce a negative pore water pressure. Until now, saturated soil is mainly focused on the research of soil mechanics. Recently, soil mechanics is researched on two major parts such as saturated and unsaturated soil mechanics. Negative pore water pressure has a non-linear relationship with the water content changes. Soil-water characteristic curves of soil in Korea are not determined. There is no proper characteristic value such as air-entry value and residual water content. In this study, the characteristic curves of reclaimed soil, sand, and weathered granite soil were determined by laboratory tests. Air-entry value and residual water content were determined by fitting methods. Soil-water characteristic curves were estimated based on the particle-size distribution and compared with the laboratory test results. The results of soil-water characteristic curves estimation indicated that Fredlund and Wilson's model is excellent for sand and weathered granite soil. Arya and Paris's model is excellent for reclaimed soil.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.423-430
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• 1999

A weathered residual soil is a soil-like material derived from the in situ weathering and decomposition of rock which has not been transported from its original location. Undisturbed sampling of residual soils is extremely difficult, which has an important effect on investigating the strength and compression characteristics. Thus, a special undisturbed sampling device (direct shear box with shoe) was developed and undisturbed samples were successfully obtained for direct shear tests, Direct shear testing was conducted under unsoaked and soaked condition. As a result, the shear strength of soaked samples was less than that of unsoaked samples, and it was verified that direct shearing of undisturbed samples can evaluate reasonably the shear strength and the slope stability.

• 산업기술연구
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• 제17권
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• pp.119-124
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• 1997

This thesis is an experimental research of shear behavioral characteristics and shear behavioral coefficient of weathered residual soil which is mostly contained in soil of Korea. Using the weathered residual soil from mountain near Kangwon National University, this experimental research were contained the physical properties of sample in term of the basic test method such as specific gravity, plastic and liquid limit, grain-size distribution, density and water content. Experimental results obtained from direct shear test sand triaxial compression tests show that according to step loading, linear strain and linear stress increase continually and angle of internal friction decreases just little according to incresing of water content in case of ignoring the cohesion, and angle of internal friction appears the maximum angle near a optimum moisture content in case of considering the cohesion.

• 한국농공학회지
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• 제41권2호
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• pp.80-91
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• 1999

This paper presents the stress-strain , volumetric strain characteristics of the Pocheon weathered residual granite soil with variation of the initial water content under drained conditions. A series of consolidated drained triaxial compressiion tests and isotrpc compression tests with various initial water content on specimens were performed. All material parameters of Lade's double work hardening model were determined by using the results of tests. Most aspects of the soil behavior measured in the triaxial compression tests were reproduced with good accuracy by the constitutive model . Therefore double work hardening model has been shown to be applicable to weathered residual granite soil.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.28-33
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• 2006

Shallow failures of slopes in weathered soils are caused by infiltration due to prolonged rainfall. These failures are mainly triggered by the deepening of the wetting band accompanied by a decrease in suction induced by the water infiltration. In this paper, hysteresis on soil-water characteristic curve(SWCC) of granite and gneiss weathered soils are investigated using transient flow analysis respectively. Each case was subjected to artificial rainfall intensities and time duration depending on the laboratory-based drying and wetting processes. The results show that the unsaturated seepage on weathered slopes are very much affected by the initial suction of soils and unsaturated permeability of the soils. In addition, a granite weathered soil has a lower air-entry value, residual matric suction, and wetting front suction and less hysteresis loop than a gneiss weathered soil.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.360-372
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• 2005

The weathering degree and shear wave velocity, $V_S$, were evaluated for decomposed granite layers in Hongsung, where earthquake damages have occurred. The subsurface geological layers and their $V_S$ profiles were determined, respectively, from boring investigations and seismic tests such as crosshole, downhole and SASW tests. The subsurface layers were composed of 10 to 40 m thickness of weathered residual soil and weathered rock in most sites. In the laboratory, the weathering indexes with depth were estimated based on the results of X-ray fluorescence analysis using samples obtained from field, together with the dynamic soil properties determined from resonant column tests using reconstituted specimens. According to the results, it was examined that most weathering degrees represented such as VR, Li, CIA, MWPI and WIP were decreased with increasing depth with exception of RR and CWI. For weathered residual soils in Hongsung, the $V_S's$ determined from borehole seismic tests were slightly increased with increasing depth, and were similar to those from resonant column tests. Furthermore, the $V_S$ values were independent on the weathering degrees, which were decreased with depth.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 봄 학술발표회 논문집
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• pp.93-100
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• 1998

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.711-716
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• 2002

When judging the ground by core-logging, depth of coring might be stopped by coming into view of the moderately weathered rock and also considered as bedrock line. However, highly weathered rock may appear again, if coring more, because there are core-stones in the residual soil and highly weathered rock by the effect of hydraulic-thermal differentiation and does the irregular rock weathering or metamorphic rock region. Therefore, there are room for misunderstanding of diagnosing the moderately weathered rock. Even though the irregular ground where the corestones were come out will show clear geotechnical differences between the ground and the gradually weathered bedrock, nowadays, the construction sites do not take into account the characteristic of core-stone region. In conclusion, to study the failure-strength characteristics of soil layers containing core-stones, we made artificial core-stones and varied percentage of corestones, and measured cohesion and friction factors to adjust them to construction sites containing corestones such as slope, tunnel, and underground.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 가을 학술발표회 논문집
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• pp.65-72
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• 1998