• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.5-18
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• 2009

In construction of buildings in Korea, the buildings are frequently founded on the weathered ground (weathered soil/rock, fractured rock). In this case, to make a full use of a bearing capacity of a weathered ground for economic design, the shallow mat foundation system could be used. In this study, we have researched three cases of mat foundations on the weathered ground in Korea, and analyzed and considered the design procedures and the reinforcing methods. That is, we have considered the detail design, analysis proceedings, the ground settlement evaluation proceedings, the rock face mapping evaluations after excavation and reinforcing methods of the mat foundation on the weathered ground. And large scale plate load tests on the weathered ground supporting the mat foundation were performed and also load bearing capacity and settlement of actual mat foundation, considering the scale effect, were evaluated.

• Journal of the Korean Geophysical Society
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• v.2 no.2
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• pp.111-122
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• 1999

한반도 남동부 경상분지에 위치한 양산단층의 지전기학적 구조를 밝히기 위하여 경주시 이조리와 울산시 서하리, 양산시 삼감리와 회산리 사이에서 전기비저항 탐사를 수행하였다. 단층파쇄대는 낮은 전기비저항값을 가지며 단층파쇄대에 분포하는 풍화대는 남쪽으로 향할수록 두꺼워지는 것으로 나타났다. 풍화대의 깊이는 서하리와 회산리에서 약 100 m 이며 다른 지역에서는 약 50-70 m 정도이다. 단층파쇄대에 위치하는 풍화대의 전기비저항값은 회산리에서 얻어진 약 10 Ωm의 매우 낮은 값을 제외하고는 약 40-300 Ωm 정도이다. 연구지역 내에서는 풍화대 하부에 위치하는 기반암의 깊이가 양산단층을 따라 남쪽으로 향할수록 깊어지는 특징적인 변화 양상을 갖는 것으로 보인다. 수평탐사 결과는 양산단층에 가까워질수록 겉보기 비저항값이 감소함을 보여준다

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.114-118
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• 2004

울산지역의 대수층 분포특성과 지하수 유동특성에 관해 연구하기 위해 크리깅 기법을 이용하였다. 울산지역의 시추자료 1,783개 지점과 지하수위자료 총 1,171개 지점에 대하여 2년간(2002년～2003) 자료를 획득하여 분석하였다. 본 연구지역의 표고 충적층 하부경계 심도, 충적층, 하부경계 심도, 충적층 층후, 풍화대 층후, 충적층-풍화대 층후, 대수층 단면, 지하수위 그리고 지하수유동 분석을 하기 위해 베리오그램 분석한 결과 풍화대 하부경계 심도에 지수형모델(exponential model), 나머지 지하수위를 포함한 성분들은 모두 구상형모델(shperical model)이 가장 적합하게 나타났다. 울산지역 대수층의 경우 산악지역은 얕은 충적층과 풍화대 분포가 나타나는 반면, 남구는 충적층, 북구는 풍화대 발달이 우세하게 나타났다. 그리고 울산지역의 충적층과 풍화대 층후 분포특성이 울산단층을 따라 층후가 두껍게 나타났다. 지하수 유동은 고지형의 북구와 동구 산악지역에서 바다에 인접한 내륙지역으로 지하수 유동특성을 보였으며, 울산의 4개구는 산악지역, 태화강, 동천강, 울산단층 그리고 충적층과 풍화대가 잘 발달된 대수층을 따라 지하수유동 특성이 잘 나타났다.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.517-523
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• 2007

Geophysical surveys(seismic refraction, electrical resistivity, and ground penetrating radar) were performed to delineate the weathering zone associated with vadose water in Chojeong area and investigate the fault related fracture zones. On the basis of seismic velocity structures, weathering layer for the southwestern part is interpreted to be deeper than for the northeastern part. The depth to bedrock(i.e., thickness of weathered zone) from seismic refraction data attempted to be correlated with drill-core data and groundwater level. As for the investigation of geological discontinuities such as fault related fracture zone, seismic refraction, electrical resistivity, and ground penetrating data are compositely employed in terms of velocity and resistivity structures for mapping of surface boundary of the discontinuities up to shallow depth. Surface boundaries of fracture zone are well indicated in seismic velocity and electrical resistivity structures. Accurate estimation of weathered zone and fracture zone can be successfully available for mapping of attitude of vadose water layer.

• Journal of the Korean Geotechnical Society
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• v.35 no.12
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• pp.15-24
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• 2019

Weathered granite zone exists in most regions of Korea and it is often used as a bearing stratum of geotechnical structures. So it is very important to estimate the characteristics of weathered granite zone. SPT (Standard penetration test) is usually performed to investigate the characteristics of the weathered zone because undisturbed samples suitable for laboratory testing are hardly retrieved. PMT (Pressuremeter test) can reliably evaluate the in situ stress-strain behavior, but it is rarely conducted because of their high cost and time-consuming procedure. In this study, the correlation between the SPT-N values and the PMT results, obtained from the weathered granite zone, was analyzed. Empirical equations for pressuremeter modulus (E_m) and limit pressure (P_L) were suggested and compared with the previous research.

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.97-108
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• 2014

Naesung stream famous for 'sandy river', a tributary to the Nakdong River, flows through Yeongju-Bonghwa Basin, its drainage. If the dismantlement of granitic hills in basin is in final stage, weathering materials from hills into stream are finer materials like silty or sandy loam than coarse sand, because sand as weathering mantles is provided from granitic hills, in general. So the granitic hills in Yeongju-Bonghwa basin is dissecting present. As a results of the CIA analysis(A-CN-K and A-CNK-FM ternary diagram), chemical weathering of granitic grus in Yeongju-Bonghwa basin is too very weak for calcium and sodium to be dissolved and go as far as to be more weak than that of Jeongeup, Nonsan and Namwon, common granitic grus in Korean Peninsula. Therefore, the chemical characteristics of granitic hills in Yeongju-Bonghwa basin show that the alteration of weathering mantles just finished disintegration and is dissected at a standstill. Plenty of sands provided from granitic hills is filling the channel of Naesung stream.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.23-35
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• 2004

The weathering characteristics of periodically submerged sedimentary rocks in the Sayeon dam, Ulsan was examined by field work, electron probe micro-analysis, X-ray diffraction, and X-ray fluorescence spectrometry. Analysis of fracture zone and exfoliation showed the submerged sedimentary rocks have undergone severe mechanical weathering. Mechanical weathering in the water-rock interface accelerated chemical weathering, such as dissolution and alteration of the most of minerals except for quartz in the weathering zone. The dissolution of carbonates specially calcite, is remarkable creating the cavities, whereas formation of minerals including clay minerals is not active. The sedimentary rocks have been periodically submerged for a certain period of time, and have repeated freezing and thawing. This mechanical weathering favored infiltration, which accelerated mineral dissolution. The high content of easily soluble carbonate of the sedimentary rocks is likely the major cause of intense chemical weathering. The dissolved elements within the infiltrated water interrupted the occurrence of clay and weathering minerals, and expend fractures by infiltrated water accelerated weathering process.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.160-189
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• 2023

The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.670-670
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• 2007

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.18-25
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• 2005

We derive refraction statics for seismic data recorded in a hard rock terrain, in which there are large and rapid variations in the depth of weathering. The statics corrections range from less than 10 ms to more than 70 ms, often over distances as short as 12 receiver intervals. This study is another demonstration of the importance in obtaining accurate initial refraction models of the weathering in hard rock terrains in which automatic residual statics may fail. We show that the statics values computed with a simple model of the weathering using the Generalized Reciprocal Method (GRM) and the Refraction Convolution Section (RCS) are comparable in accuracy to those computed with a more complex model of the weathering, using least-mean-squares inversion with the conjugate gradient algorithm (Taner et al., 1998). The differences in statics values between the GRM model and that of Taner et al. (1998) systematically vary from an average of 2ms to 4ms over a distance of 8.8 km. The differences between these two refraction models and the final statics model, which includes the automatic residual values, are generally less than 5 ms. The residuals for the GRM model are frequently less than those for the model of Taner et al. (1998). The RCS statics are picked approximately 10 ms later, but their relative accuracy is comparable to that of the GRM statics. The residual statics values show a general correlation with the refraction statics values, and they can be reduced in magnitude by using a lower average seismic velocity in the weathering. These results suggest that inaccurate average seismic velocities in the weathered layer may often be a source of short-wavelength statics, rather than any shortcomings with the inversion algorithms in determining averaged delay times from the traveltimes.