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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geotechnical Society
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Korean Geotechical Society
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Volume & Issues
Volume 26, Issue 12 - Dec 2010
Volume 26, Issue 11 - Nov 2010
Volume 26, Issue 10 - Oct 2010
Volume 26, Issue 9 - Sep 2010
Volume 26, Issue 8 - Aug 2010
Volume 26, Issue 7 - Jul 2010
Volume 26, Issue 6 - Jun 2010
Volume 26, Issue 5 - May 2010
Volume 26, Issue 4 - Apr 2010
Volume 26, Issue 3 - Mar 2010
Volume 26, Issue 2 - Feb 2010
Volume 26, Issue 1 - Jan 2010
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The Effect of Shear Direction on the Behavior of the Post-earthquake Settlement of GBFS
Baek, Won-Jin ; Hiroshi, Matsuda ; Park, Kyung-Hwan ; Kim, Jin-Young ;
Journal of the Korean Geotechnical Society, volume 26, issue 3, 2010, Pages 5~12
In this study, in order to clarify the effect of the direction of cyclic shear on the post-earthquake settlement the multi-directional shear tests were carried out for Toyoura Japan standard sand, Genkai natural sand, Kaolinite and the Granulated Blast Furnace Slag (GBFS). The diameter and the height of the specimen are 75 mm and 20 mm, respectively. In a series of tests, the number of strain cycles was adjusted as n=5, 20, 30, 100, 200 and the shear strain amplitudes were varied from 0.1% to 1.0%. The relative densities of each samples were also adjusted as Dr=50, 60 and 70%. From the test results for Toyoura sand and GBFS, it is clarified that the post-earthquake settlement is relatively large at the small relative density and becomes large with the shear strain amplitude. When the influence of difference on the direction of cyclic shear decreases, the post-earthquake settlement strain for Toyoura sand is converged to a constant value, but the GBFS increases with the number of strain cycles. In addition, the post-earthquake settlement is in the order of Kaolinite > Toyoura sand > Genkai sand > GBFS.
Centrifuge Model Tests on Trafficability of Very Soft Ground Treated with Geotextile and Sand Mat
Jun, Sang-Hyun ; Lee, Jong-Ho ; Yoo, Nam-Jae ;
Journal of the Korean Geotechnical Society, volume 26, issue 3, 2010, Pages 13~23
In this study, centrifuge model tests with 50 g gravitational condition were performed to evaluate the bearing capacity of very soft ground, improved by spreading geotextile and sand on the surface of ground, for the heavy machinery to be able to access. For undrained shear strength of ground model, prepared with the clay sampled from the field, being in the range of 3.1~11.7 kPa, bearing capacity tests were performed with the model footing and the loading system built to simulate the heavy machinery on the ground model treated with geotextile and sand. Test results were compared with theoretically and numerically evaluated ones. Test results about load-settlement curves showed that the bearing capacity increases with the increase of the undrained shear strength of ground. Punching shear or local shear failure was also observed. For a relatively low undrained shear strength of ground, settlement behavior is found to be crucial to evaluating the trafficability of machinery whereas bearing capacity becomes a dominant factor with the increase of undrained shear strength of ground. The method for assessing the bearing capacity of the ground related to trafficability of machinery is presented by acquiring the regression relationship between the contact pressure of machinery and settlements using load-settlement curves with the change of the undrained shear strength. Furthermore, results of numerical analyses about load-settlement relation are in relatively good agreement with those of centrifuge model test.
Numerical Simulation of Ground Expansion Induced by Pulse Discharge Technology
Park, Hyun-Ku ; Lee, Seung-Rae ; Kim, Seon-Ju ; Cho, Gyu-Yeon ;
Journal of the Korean Geotechnical Society, volume 26, issue 3, 2010, Pages 25~34
In the present paper, a numerical study was carried out to simulate ground expansion induced by an application of pulse discharge technology. Based on laboratory pulse discharge tests, the characteristics of shockwave were investigated, and then the laboratory tests were numerical1y simulated using underwater explosion model implemented in a coupled acoustic-structural finite element analysis. In addition, for clayey soils, the expansion of ground was also studied using soil properties obtained from empirical correlations with SPT N values. It was found that the calculation results well agreed with the field test results.
Punching Shear Failure in Pile-Supported Embankments
Hong, Won-Pyo ; Song, Jei-Sang ; Hong, Seong-Won ;
Journal of the Korean Geotechnical Society, volume 26, issue 3, 2010, Pages 35~45
The mechanism of load transfer by punching shear in pile-supported embankments is investigated. Based on the geometric configuration of the punching shear observed in sand fills on soft ground, a theoretical analysis is carried out to predict the embankment loads transferred on a cap beam according to punching shear developed in pile-supported embankments. The equation presented by the theoretical analysis was able to consider the effect of various factors affecting the vertical loads transferred on the cap beam. The reliability of the presented theoretical equation is investigated by comparing it with the results of a series of model tests. The model tests were performed on cap beams, which had two types of width; one is narrow width and the other is wide width. Sand filling was performed through seven steps. Two types of loading pattern were applied at each filling step; one is the long-term loading, in which sand fills at each filling step were kept for 24 hours, the other is the short-term loading, in which sand fills at each filling step were kept for 2 hours. The vertical loads measured in all model tests show good agreement with the ones predicted by the theoretical equation. Finally, the predicted vertical loads also show good agreement with the vertical loads measured in a well-instrumented pile-supported embankment in field, where cap beams were placed on too wide space.
A Study on the Development of a Stability Chart for Yield Seismic Coefficient of Soil Slope Using Limit Analysis
Choi, Sang-Ho ; Kim, Jong-Min ;
Journal of the Korean Geotechnical Society, volume 26, issue 3, 2010, Pages 47~57
Yield seismic coefficient plays an important role in the estimation of permanent displacement of a soil slope subjected to earthquake using Newmark's sliding block theory. However, yield seismic coefficients currently used in practices are not mechanically rigorous since most of them are estimated using limit equilibrium methods considering equilibrium condition only. Therefore, estimation of permanent displacement of a soil slope based on existing yield seismic coefficient may cause problems. Limit analysis estimating the range of mechanically rigorous solution is thought to be effective in evaluating the validity of existing yield seismic coefficient. In this study, a simple stability chart for yield seismic coefficient useful in practices is proposed by considering various slope conditions including stability number, slope inclination, strength parameters, etc.
Development of Risk Analysis Structure for Large-scale Underground Construction in Urban Areas
Seo, Jong-Won ; Yoon, Ji-Hyeok ; Kim, Jeong-Hwan ; Jee, Sung-Hyun ;
Journal of the Korean Geotechnical Society, volume 26, issue 3, 2010, Pages 59~68
Systematic risk management is necessary in grand scaled urban construction because of the existence of complicated and various risk factors. Problems of obstructions, adjacent structures, safety, environment, traffic and geotechnical properties need to be solved because urban construction is progressed in limited space not as general earthwork. Therefore the establishment of special risk management system is necessary to manage not only geotechnical properties but also social and cultural uncertainties. This research presents the technique analysis by the current state of risk management technique. Risk factors were noticed and the importance of each factor was estimated through survey. The systemically categorized database was established. Risk extraction module, matrix and score module were developed based on the database. Expected construction budget and time distribution can be computed by Monte Carlo analysis of probabilities and influences. Construction budgets and time distributions of before and after response can be compared and analyzed 80 the risks are manageable for entire whole construction time. This system will be the foundation of standardization and integration. Procurement, efficiency improvement, effective time and resource management are available through integrated management technique development and application. Conclusively decrease in cost and time is expected by systemization of project management.