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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Geotechnical Society
Journal Basic Information
Journal DOI :
Korean Geotechical Society
Editor in Chief :
Seong Wan Park
Volume & Issues
Volume 28, Issue 12 - Dec 2012
Volume 28, Issue 11 - Nov 2012
Volume 28, Issue 10 - Oct 2012
Volume 28, Issue 9 - Sep 2012
Volume 28, Issue 8 - Aug 2012
Volume 28, Issue 7 - Jul 2012
Volume 28, Issue 6 - Jun 2012
Volume 28, Issue 5 - May 2012
Volume 28, Issue 4 - Apr 2012
Volume 28, Issue 3 - Mar 2012
Volume 28, Issue 2 - Feb 2012
Volume 28, Issue 1 - Jan 2012
Selecting the target year
Behavior of Geotextile Tube for Erosion Control
Chang, Yong-Chai ; Son, Ka-Young ; Lee, Seung-Eun ; Kim, Sang-Jin ; Kim, Suk-Woo ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 5~12
DOI : 10.7843/kgs.2012.28.5.5
Geotextile tube method is the latest application process to construct a variety of civil structures such as river and coastal structures by using geotextile which is a high polymer synthetic fiber. In this paper, laboratory tests and field tests were conducted in order to identify the behavior, stability and application possibility of geotextile tube which prevents the erosion of coastal sand. As a result of large-scale direct shear test, which is one of laboratory tests, the increase in friction angle was shown as the relative density increased, and friction angle of sand/geotextile was larger than that of sand/sand. As a result of field test, the behavior and stability during construction and after construction were identified through measurement, and the effect of preventing erosion was confirmed.
Temperature Compensation of Optical FBG Sensors Embedded Tendon for Long-term Monitoring of Tension Force of Ground Anchor
Sung, Hyun-Jong ; Kim, Young-Sang ; Kim, Jae-Min ; Park, Gui-Hyun ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 13~25
DOI : 10.7843/kgs.2012.28.5.13
Ground anchor method is one of the most popular reinforcing technology for slope in Korea. For the health monitoring of slope which is reinforced by permanent anchor for a long period, monitoring of the tension force of ground anchor is very important. However, since electromechanical sensors such as strain gauge and V/W type load cell are also subject to long-term risk as well as suffering from noise during long distance transmission and immunity to electromagnetic interference (EMI), optical FBG sensors embedded tendon was developed to measure strain of 7-wire strand by embedding FBG sensor into the center king cable of 7-wire strand. This FBG sensors embedded tendon has been successfully applied to measuring the short-term anchor force. But to adopt this tendon to long-term monitoring, temperature compensation of the FBG sensors embedded tendon should be done. In this paper, we described how to compensate the effect in compliance with the change of underground temperature during long-term tension force monitoring of ground anchors by using optical fiber sensors (FBG: Fiber Bragg Grating). The model test was carried out to determine the temperature sensitivity coefficient (
) of FBG sensors embedded tendon. The determined temperature sensitivity coefficient
was verified by comparing the ground temperatures predicted from the proposed sensor using
with ground temperatures measured from ground thermometer. Finally, temperature compensations were carried out based on
value and ground temperature measurement from KMA for the tension force monitoring results of tension type and compression type anchors, which had been installed more than 1 year before at the test site. Temperature compensated tension forces are compared with those measured from conventional load cell during the same measuring time. Test results show that determined temperature sensitivity coefficient (
) of FBG sensors embedded tendon is valid and proposed temperature compensation method is also appropriate from the fact that the temperature compensated tension forces are not dependent on the change of ground temperature and are consistent with the tension forces measured from the conventional load cell.
The Evaluation of Seepage Characteristics in Reinforced Embankment Constructed on Low Permeable Clay Layer Through Centrifuge Model Tests
Jin, Seok-Woo ; Choo, Yun-Wook ; Kim, Young-Muk ; Kim, Dong-Soo ; Im, Eun-Sang ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 27~39
DOI : 10.7843/kgs.2012.28.5.27
In this paper, a series of centrifuge tests were performed to evaluate the seepage characteristic of reinforced embankment. The centrifuge models simulated an actual embankment reinforced by enlargement of levee cross-section. The centrifuge models have the same conditions except the locations of enlargement with low permeable material : water-side and land-side. In addition, the prototype embankment is constructed on low permeable clay layer. In the case of water-side reinforcement, the reinforced zone makes water head down and the saturated zone of embankment propagates slowly. In the case of land-side reinforcement embankment, the saturated zone enlarged relatively faster but the amount of exit water at land-side toe was very small because of the land-side reinforcement zone. The low permeable clay foundation layer was being continuously saturated by the inflow from the embankment as well as the uplift flow from the permeable layer induced by the excess pore water pressure.
A Study on the Chemical Index of Alteration of Igneous Rocks
Choi, Eun-Kyeong ; Kim, Sung-Wook ; Kim, In-Soo ; Lee, Kyu-Hwan ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 41~54
DOI : 10.7843/kgs.2012.28.5.41
The weathering process of rocks leads to the reduction of geotechnical bearing capacity. The weathering of granite is frequently used to refer to the degradation of geotechnical property in the design and construction of infra-structure. In this study, the range of values of CIA (chemical index of alteration) and the change of mineral compositions by weathering have been analysed with igneous rock, which covers 45.5% in South Korean territory. Several weathering indices were studied for various rocks found in Korea and significant relationships between different indices were delineated via statistical analysis. The applicability of CIA was found to be the most significant among all weathering indicies. The composition of illite, the secondary weathering residual, generally increases for the felsic rock, and swelling clay material is not included. The weathering of felsic rock will follow a sequential process, starting from bed rock, illite, and chlorite to kaoline. The mafic rock will show weathering process, from bed rock, smectite, and chlorite to kaoline. The intermediate rocks such as andesite and tuff will show similar weathering procedure and the composition of kaoline, chlorite, and smectite tends to increase more than that of illite when the mafic rock is dominated. This means the increase of rock material which has high CEC (cation exchange capacity) during secondary weathering process. However, the characteristics of a specific rock cannot be completely analyzed using merely CIA, since it is exclusively based on chemical composition and corresponding alteration. The CIA can be used to quantify the weathering process in a limited range, and further considerations such as rock composition, strength characteristics will be required to configure the comprehensive weathering impact on any specific region.
Real-time Seismic Damage Estimation for Harbor Site Considering Ground Motion Amplification Characteristics
Kim, Han-Saem ; Yoo, Seung-Hoon ; Jang, In-Sung ; Chung, Choong-Ki ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 55~65
DOI : 10.7843/kgs.2012.28.5.55
The purpose of this study is to estimate seismic damage for harbor site considering dynamic amplification characteristics. First of all, a series of ground response analysis is performed and then correlation equations between rock outcrop accelerations and peak ground accelerations (PGAs) are determined. These equations are saved into DB and when an earthquake occurs, PGAs are determined by them as soon as possible. For earthquake events, seismic damage grades of harbor structures are determined by using the correlated PGAs and fragility curves of harbor structures in real time. In this study, seismic damage was estimated and classified into several grades by applying two hypothetical earthquakes.
A Study on the Arrangement Design of Shield-TBM Cutter Bit
Kim, Sang-Hwan ; Kim, Ji-Tae ; Lim, Chae-Ho ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 67~76
DOI : 10.7843/kgs.2012.28.5.67
This study is a research about cutter bits arrangement of shield-TBM and carried out a scale model test and numerical analysis according to a space of cutter bits. A cutter head pressures and an advance time are measured to be followed by the space of cutter bits with an advance speed through the scale model test. We conducted the numerical analysis to verify the result of the scale model test, and to compare with the scale model test. There are three cases of space : unification 1.0D and 1.5D. In case TBM is excavated and space is 1.0D, the advance speed is much faster than the other cases, and pressure of face of ground deformation and cutter head is maintained stably. If additional researches about bits arrangement of cutter head of sand ground based on the result of this research are performed, substantial results may be obtained.
Engineering Characteristics of Diatom Modified Soil Mixture
Kim, Kyu-Sun ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 77~84
DOI : 10.7843/kgs.2012.28.5.77
The engineering characteristics of natural sediments containing diatom microfossils have been investigated for their abnormal deformation and strength behavior for a few decades. The presence of disk or hollow shape diatoms causes low compressibility, high hydraulic conductivity, and high shear strength of sediments. Some of these unusual differences show the characteristic of diatom owing to the interlocking of large interparticle porosity and angular particles. This phenomenon implies the possible use of diatom as modification materials to change the engineering performance of soil mixtures. This paper describes the engineering characteristics of diatom-kaolin mixture to investigate the engineering properties of diatom modified soils using conventional geotechnical tests and elastic and electromagnetic wave propagation tests. Experimental test results show the performance improvement by increasing diatom contents and the performance degradation by the breakage of interlocking between diatom particles under high effective stress.
Mechanical Constitutive Model for Frozen Soil
Shin, Ho-Sung ; Kim, Ji-Min ; Lee, Jang-Guen ; Lee, Seung-Rae ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 85~94
DOI : 10.7843/kgs.2012.28.5.85
Recently, growing interests in frozen ground have stimulated us to advance fundamental theories and systematic researches on soil behavior under freezing conditions. Unlike the well-established soil mechanics theory, temperature variation and phase change of pore-water cause water migration to cold side, ground heaving, sharp increase in earth pressure, etc., which bring about serious problems in frozen geotechnical structures. Elasto-plastic mechanical constitutive model for frozen/unfrozen soil subjected to fully coupled THM phenomena is formulated based on a new stress variable that is continuous in frozen-unfrozen transitional regions. Numerical simulations are conducted to discuss numerical reliability and applicability of the developed constitutive model: one-dimensional heaving pressure, tri-axial compression test, and one-side freezing tests. The numerical results show that developed model can efficiently describe complex THM phenomena of frozen soil, and they can be utilized to analyze and design the geotechnical structures under freezing conditions, and predict their long-term behavior.
Development of Stress Based on Pore Pressure Model
Park, Du-Hee ; Ahn, Jae-Kwang ; Kim, Jin-Man ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 95~107
DOI : 10.7843/kgs.2012.28.5.95
Even though the importance of predicting build-up of pore pressure under cyclic loading is recognized, effective stress analysis is rarely performed due to difficulties in selecting the parameters for the pore pressure model. In this paper, a new stress based numerical model for predicting pore pressure under cyclic loading is developed. The main strength of the model is that it is easy-to-use, requiring only the CSR-N curve in selecting the parameters. Another advantage of the model is that it can be used for any loading pattern and therefore can be implemented in an effective stress time-domain dynamic analysis code. The accuracy of the model is validated through its comparisons with measurements in literature and laboratory test data collected in Korea. Further comparisons with another stress based pore pressure model highlighted the superiority of the proposed model.
Geostatistical Integration of Borehole and Geophysical Data for Design of Offshore-foundation
Kim, Han-Saem ; Kim, Min-Gi ; Kim, Joon-Young ; Kim, Kwang-Lae ; Chung, Choong-Ki ;
Journal of the Korean Geotechnical Society, volume 28, issue 5, 2012, Pages 109~120
DOI : 10.7843/kgs.2012.28.5.109
In marine site surveys, drilling boreholes are restrictively conducted, while geophysical surveys are used with ease. To overcome the limitations of marine site survey, various site survey data should be collected and analysed by adopting complementary pros and cons. In this study, the integration assessment was established to digitize 2D geo-layer based on the overlapping of a few borehole data to seismic refraction tomography and to determine 3D geo-information based on the kriging for the design of offshore-foundation. And the overlapping method was proposed considering spatial variability of the tomography and separation distance from borehole position to determine the 2D geo-layer. Finally, the integration assessment was applied to offshore wind-turbine site in Jeju-do, and its applicability was verified based on the cross-validation.