The first large scale geotechnical centrifuge in Korea has recently been developed at KAIST under the Korea Construction Engineering Development (KOCED) Collaboratory program. A 5 m platform radius, 240 g-tons state-of-the-art geotechnical centrifuge has been installed in a new facility. The centrifuge has the unique feature of an automatic balancing system and includes parts for general testing purposes such as fluid rotary joints, slip rings, a fiber optic rotary joint and an Ethernet network system. In addition, a four degree-of-freedom in-flight robot can be equipped to simulate complex construction or in-situ testing process during centrifuge flight. In order to simulate earthquake motion during operation, a self-balancing type biaxial shaking table has also been developed. Since the KOCED program promotes collaboration and remote use, tele-presence and tele-participation environments have been implemented in this facility.

A Newly Developed State-of-the-Art Geotechnical Centrifuge in Korea

Performance of an equivalent shear beam (ESB) model container for dynamic geotechnical centrifuge tests

Effect of underground tunnel on the ground surface acceleration

This paper performed centrifuge load tests of a tripod bucket foundation preliminarily designed as a supporting system of wind turbines and compared the results to those obtained from a test of a monopod bucket foundation. The tripod foundation prototype studied in this study has three bucket caissons, each of which is 6.5 m in diameter and 8.0 m in length. The center-to-center distance between the buckets was 26.9 m. The site is composed of an 11-m thick layer of dense silty sand overlying a thick sandy silt layer. The horizontal load was applied at a height of 33 m from the seabed floor according to the design load condition, and the vertical load was simulated by the self-weight of the model. The moment-rotation angle curves for the tripod foundations were compared with that of the monopod bucket foundation. The moment-rotation curve of the tripod was nearly bilinear, whereas that of the monopod showed a gradual decrease in slope. The yield moment for the tripod foundation was half that of the monopod, but the rotation angle for the yield moment was only 20% that of the monopod. The behavior of the tripod foundation under a cyclic load with respect to the accumulated plastic deformation has also been examined in this study. When the resultant moment of cyclic loading was smaller than the monotonic yield moment, negligible accumulated plastic deformation was observed for both one-way and two-way loading. However, when the resultant moment was higher than the monotonic yield moment, significant cumulated deformation resulted.

Investigation of Monotonic and Cyclic Behavior of Tripod Suction Bucket Foundations for Offshore Wind Towers Using Centrifuge Modeling

The present study was conducted to evaluate the metal pollution of groundwater in the vicinity of Tuticorin Corporation in Tamilnadu State, India, used by various pollution indices such as heavy metal pollution index (HPI), heavy metal evaluation index (HEI), and degree of contamination (DOC). Thirty-six groundwater samples were collected during the summer season (May 2013) and the concentration of metals Al, Cr, Fe, Cu, Mn, Ni, Zn, Cd, and Pb was analyzed. Consequences exhibited that groundwater was contaminated with Mn (59.12 ppb), Cu (162.41 ppb), Pb (196.15 ppb), Cr (187.12 ppb), and Cd (10.11 ppb). Correlation and factor analysis revealed that the sources of metals in groundwater in the study area are the same, and it may due to the leachates from the nearby sewage farm, industrial activity (State Industries Promotion Corporation of Tamil Nadu Limited (SIPCOT)), Buckle canal, and solid wastes dumped in the residential area. Groundwater pollution indices of HPI, HEI, and DOC revealed that most of groundwater samples belonged to the medium to high zones, which was adjacent to the polluted Buckle canal, SIPCOT industrial waste, and sewage fish farm in the coastal area. The present study points out that the metal pollution causes the degradation of groundwater quality around Tuticorin coastal corporation. These study results will be very helpful for sustainable management of groundwater resources, and they will enable planners and policymakers to evolve a strategy to solve similar problems elsewhere.

A GIS-based assessment of water quality pollution indices for heavy metal contamination in Tuticorin Corporation, Tamilnadu, India

KOCED Geotechnical Centrifuge Testing Center

Settlement prediction of large scale plate load test using shear wave velocity profile

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Evaluation of Shear Modulus of Sand Using Earthquake Records in Dynamic Centrifuge Tests

Time-Frequency Analysis for Impact Echo Method

Damages of large embankment dams by recent strong earthquakes in the world highlight the importance of seismic security of dams. Some of recent dam construction projects for water storage and hydropower are located in highly seismic zone, hence the seismic performance evaluation is an important issue. While state-of-the-art numerical analysis technology is generally utilized in practice for seismic performance evaluation of large dams, physical modeling is also carried out where new construction technology is involved or numerical analysis technology cannot simulate the behavior appropriately. Geotechnical centrifuge modeling is widely adopted in earthquake engineering to simulate the seismic behavior of large earth structures, but sometimes it can`t be applied for large embankment dams due to various limitations. This study proposes a dynamic centrifuge testing method for large embankment dams and evaluated its applicability. Scaling relations for a case which model scale and g-level are different could be derived considering the stress conditions and predominant period of the structure, which is equivalent to previously suggested scaling relations. The scaling principles and testing method could be verified by modified modeling of models using a model at different acceleration levels. Finally, its applicability was examined by centrifuge tests for an embankment dam in Korea.

Nam-Ryong Kim

Papers

KOCED Geotechnical Centrifuge Testing Center

Settlement prediction of large scale plate load test using shear wave velocity profile

Evaluation of Shear Modulus of Sand Using Earthquake Records in Dynamic Centrifuge Tests

Time-Frequency Analysis for Impact Echo Method

A Study on Geotechnical Centrifuge Testing Method for Seismic Performance Evaluation of Large Embankment Dams