• Geomechanics and Engineering
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• v.25 no.2
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• pp.99-109
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• 2021

Tunnel provide faster, safer and convenient way of transportation for different objects. The region where it is construction and surrounding medium has significant influence on the overall stability and performance of tunnel. The present simulation has been carried out in order to understand the behaviour of rock tunnel under static loading condition. The present numerical model has been validated with the laboratory scaled model and field data of underground tunnels. Both lined and unlined tunnels have been considered in this paper. Finite element technique has been considered for the simulation of static loading effect on tunnel through Abaqus/Standard. The Mohr-Coulomb material model has been considered to simulate elastoplastic nonlinear behaviour of different rock types, i.e., Basalt, Granite and Quartzite. The four different stages of rock weathering are classified as fresh, slightly, moderately, and highly weathered in case of each rock type. Moreover, extremely weathered stage has been considered in case of Quartzite rock. It has been concluded that weathering of rock and overburden depth has great influence on the tunnel stability. However, by considering a particular weathering stage of rock for each rock type shows varying patterns of deformations in tunnel.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.183-194
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• 2002

Biotite and its weathering Products in the weathering Profile of Andong granite were examined using X-ray diffraction, chemical analysis, and electron microscopy. Major weathering product of biotite was oxidized biotite, which is decomposed into kaolinite in the upper part. Discrete vermiculite or hydrobiotite was not detected although minor vermiculite (5%) was randomly interstratified with oxidized biotite. Excess positive charge induced by iron oxidation was balanced by release of Fe (16%) and Mg (12%) from octahedral site and K (13%) from interlayer site. After slight chemical and structural modification induced by iron oxidation, oxidized biotite persists through the weathering profiles with partial decomposition in the upper part of the profile. Formation environments and dissolution experiments of oxidized biotite highly resistant to weathering are required to understand the elemental behavior in the surface environments on the biotite-bearing bedrocks.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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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.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.101-109
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• 2008

In order to investigate the influence of the water on compression characteristic of decomposed granite soils, a single particle crushing test and one-dimensional compression tests were carried out on three decomposed granite soils and Silica sand. The initial fracture strength for single particle reduced and variability of the strength increases due to weakening by existing water. Moreover, it was recognized that one-dimensional compression characteristic was related to the initial fracture strength characteristic, and the initial fracture strength also has the effect of weathering.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.1
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• pp.61-68
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• 2008

It is essential to analyze and classify the physical characteristics of weathered granite for engineering purposes. This paper is to suggest a physical method to determine the degree of weathering of weathered soils. A new classification method for determining the degree of weathering is suggested, based upon the results from laboratory tests including fall cone test. According to the proposed physical method using fall cone apparatus, the measured values of the samples from the same area show distinctive difference of weathering. The water content tends to increase with increasing the degree of weathering at the same penetration in fall cone test. And relationship between CWI and water content are expressed one equation in Hwaseong area and Ilsan area.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.484-486
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• 2004

• Journal of the Korean Geographical Society
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• v.41
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• pp.1-18
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• 1990

• Geotechnical Engineering
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• v.12 no.4
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• pp.115-130
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• 1996

The definition of laterite or lateritic soils is discussed on a climatic condition of tropical and semitropical regions, and the weathering index is indicated by the chemical composition. The chemical composition of$(Fe_2O_3+Al_2O_3)$ of the weathered granite residual soils in tropical and the temperate regions which shelus laterization usually ranges from 0.2 to 0.5. This study shows that the chemical ratio of the Chonju Ajung site is about 0.2U, and that of the regions along the shore of the western sea of Hongsong and Taechon is about 0.33. The chemical ratio of the non-laterite is less than 0.2, and the Kyougju Pulguksa site confirmed about 0.17, The X-Ray diffraction test shows that the clay mineral of the laterite soils is made of kaolinite, this X -Ray result indicates the same characteristics compared with the wrathered granite residual soils of other sites.

• Structural Engineering and Mechanics
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• v.74 no.6
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• pp.757-769
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• 2020

Granite is commonly used in the construction of the ancient stone pagodas of Korea. The material has excellent weathering resistance and durability, as well as high compressive strength. Most of the stone-made state-designated architectural heritage of Korea is made of granite. Therefore, the understanding of the structural feasibility of stone-made architectural heritage is crucial. Even though, until now, experimental studies for the reinforced stone have been rarely performed. This study intends to suggest a new methodology for the reinforcement of granite using a threaded titanium bar. Through the experimental study, the flexural behavior of the reinforced granite depending on the reinforcement ratio is investigated. Based on the test results, a moment-displacement relationship for the design of reinforced granite is suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.431-443
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• 2006

As part of a fundamental characterization for subsurface layers in Korea, the weathering degree and shear wave velocity ($V_S$) were evaluated from the X-ray fluorescence analyses and the site investigations containing boring and in-situ seismic tests, respectively, for decomposed granite layer in Hongsung. The subsurface layers at Hongsung were composed of 10 to 40 m thickness of weathered layer in most sites. According to the results of weathering degree analyses in Hongsung, it was examined that three chemical weathering indexes such as MWPI, VR and WIP generally increased with decreasing depth. From the in-situ seismic tests, the $V_S$ was determined as the range between 200 and 500 m/s in weathered layer. Based on the $V_S$ and N value at borehole seismic testing sites, N-$V_S$ correlations were established for weathered layer. Furthermore, the relationships of three representative weathering indexes with the $V_S$ and N value indicated that the MWPI, WIP and 100/VR increased linearly as increasing $V_S$ and exponentially as increasing N value.