• Korean Architects
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• no.5 s.99
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• pp.2-14
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• 1977

• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.309-313
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• 2002

• 한국문화재보존과학회:학술대회논문집
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• 2003.03a
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• pp.19-19
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• 2003

• Korean Journal of Heritage: History & Science
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• v.42 no.2
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• pp.170-183
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• 2009

• Journal of the Korean Geophysical Society
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• v.5 no.3
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• pp.199-209
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• 2002

We have carried out a nondestructive close examination for the purpose of the structural safety diagnosis of the Dabo Pagoda of Bulkuk temple located in Kyungju, Kyungbuk Korea. For estimating the mechanical properties of each rock block of the pagoda, ultrasonic measurements were conducted at 641 points of 255 blocks. The P-wave velocity ranges from 584m/sec through 5,169m/sec, and averages 2,901m/sec Based on this result, the uniaxial compressive strength was estimated to be $93{\sim}1,943kg/cm^2\;with\;396kg/cm^2$ of average, and the index of weathering is $0.07{\sim}0.88$ with 0.43 of average, which means the moderate degree of weathering. The comparison of the rock strength of each block with the overburden acting on the block reveals that the rock blocks related to the structure of the pagoda are relatively sound for uniform stress, but it is highly possible for a concentrated stress to lead to a partial failure. We suggest a monitoring of cracks due to the concentrated stress. The parapets of 1st and 2nd floors composed of small rock pieces are severely weathered. However, this is not directly related to the structural safety of the pagoda.

• 한국문화재보존과학회:학술대회논문집
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• 2003.03a
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• pp.20-21
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• 2003

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.79-80
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• 2002

경주시는 신라 천년의 고도로서 신라의 역사와 문화가 아직도 곳곳에 남아 있는 국내 최대의 역사도시이자 유적도시로 잘 알려져 있으며, 세계적으로 역사적인 문화가치를 인정받아 유네스코에 의해 세계문화유산으로 지정된 불국사, 석굴암, 남산 및 고분군 등의 문화재가 분포하고 있다. 특히, 경주시 지역에는 다보탑, 석가탑, 석굴암 및 불상 등 세계적으로 유명한 석조문화재가 고 밀도로 분포되어 있다. (중략)

• Journal of the Korean Geophysical Society
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• v.5 no.2
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• pp.143-151
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• 2002

Bulku temple in the city of Kyungju, Korea, built in 791 and reconstructed in the 20th century, is the home of seven national treasures including two three-story stone pagodas, Dabotap (height 10.4m, width 7.4m, weight 123.2ton) and Seokgatap (height 10.8m, width 4.4m, weight 82.3 ton). An earlier archaeological investigation shows that stone pagodas have experienced severe weathering process which will threaten their stability. At the base part of Dabotap, an offset of the stone alignment is also observed. For the purpose of the structural safety diagnosis of two pagodas, we introduce the nondestructive geophysical methods. Site characteristics around the pagodas are determined by the measurement of multiple properties such as seismic velocity, resistivity, image of GPR(ground-penetrating radar). Near the pagodas, the occurrence of high resistivity (up to 2200 Ωm) is obvious whereas their outskirts have as low as 200 Ωm. For the velocity of the P wave, the site of Dabotap has the range of 500~800 m/s which is higher than counterpart of Seokgatap with the velocity of 300~500m/s, indicating the solider stability of Dabotap site. Consequently, in addition to GPR images, the foundation boundaries beneath each stone pagodas are revealed. The Dabotap site is in the form of an octagon having 6-m-long side with the depth of ~4m, whereas the Seokgatap site the 9m × 10m rectangle with the depth of 3m. These subsurface structures appear to reflect the original foundations constructed against the stone load of ~8 ton/㎡. At the subsurface beneath the northeast of each pagoda, low seismic velocity as well as low resistivity is prominent. It is interpreted to represent the weak underground condition.

• Journal of the Mineralogical Society of Korea
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• v.19 no.1 s.47
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• pp.31-38
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• 2006

Site environments bring about various different deterioration forms of stone cultural properties. The aim of this study is to document the influence of coarse grained sandy soil on the deterioration of stone cultural properties. Bulguksadabotap is a good example that demonstrates the problem with coarse grained sandy soil. The ground around the Bulguksadabotap is covered with coarse grained sandy soil and the pagoda is surrounded by the corridors. Coarse grained sandy soil float easily in the air and deposit in the complicated stone structure caused by strong wind in Gyeongju and numerous visitors. To explain the influence of coarse grained sandy soil on the deterioration, the coarse grained sandy soil and weathered stone pieces of Bulguksadabotap were analyzed by XRD, optical microscopy, SEM for mineralogical component and IC and ICP-AES for the soluble salts. The soil and weathered stone pieces include clay minerals, such as smectite and kaolinite, can expand with water and exert pressure on the stone. Small size of the clay minerals in the coarse grained sandy soil can easily penetrate into the weathered surfaces of the Bulguksadabotap. The weathered stone pieces also contain NaCl, which is known to contribute to increase the expandibility of clay minerals by providing with $Na^{+}$ or by dropping the equilibrium of relative humidity. These results indicates that coarse grained sandy soil is not proper to site environment for weathered stone cultural properties.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.70-83
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• 2004

The safety diagnosis of cultural assets is Primarily focused on its non-destructiveness. Research on the nondestructive diagnosis and conservation of masonry cultural heritage is the key which is considered by technologic kernel. Geophyscial Prospecting as nondestructive diagnostic technology plays an important role in the characterization of the foundation of stone pagodas. It is natural that understanding of shallow subsurface condition beneath them is essential for their structural safety diagnosis. As an example, the nondestructive geophysical methods were applied to two three-story stone pagodas, Seokgatap (height 10.8 m, width 4.4 m, weight 82.3 ton) and Dabotap (height 10.4 m, width 7.4 m, weight 123.2 ton) which were built in 791 at Bulkuksa temple. An earlier archaeological investigation shows that stone pagodas have experienced severe weathering process and are slightly leaning, which will threaten their stability At the base part of Dabotap, an offset of the stone alignment is also observed. Direct measurements of ultrasonic velocities was introduced for the mechanical properties of the stone The velocity ranges of ultrasonic waves for Dabotap and Seokgatap are 1217${\~}$4403 m/s and 584${\~}$5845 m/s, respectively, and the estimated averages of the uniaxial compressive strength are 463 kg/$cm^2$ and 409 kg/$cm^2$, respectively. Site characteristics, around the pagodas are determined by the measurement of multiple properties such as seismic velocity, resistivity, image of ground-penetrating radar, On the basis of the higher velocity structure, the site of Seokgatap appears to have solider stability than the Seokgatap site. Near the pagodas, higher(up to 2200 $\Omega$m) resistivity is present whereas their outskirts have as low as 200 $\Omega$m. By the combined results of each geophyscial methods, the subsurface boundaries of two stone pagodas are revealed. The Dabotap site is in the form of an octagon having 6-m-long side with the depth of ${\~}$4 m, whereas the Seokgatap site is the 8 ${\times}$ 10 m rectangle with the depth of 3 m. These subsurface structures appear to reflect the original foundations constructed against the stone load of ${\~}8 ton/m^2$. At the subsurface beneath the northeast of each pagoda, low seismic velocity as well as low resistivity is prominent. It is interpreted to represent the weak underground condition which Is the possible cause of the slightly leaning pagodas toward the NNW.