• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.3
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• pp.74-83
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• 1994

A series of isotropic consolidation tests, undrained and drained triaxial compression tests was carried out to investigate the physical characteristics and behaviours of marine silty sands collected from the western coast of Korea. This study also included a theoretical development of the constitutive equation to evaluate stress-strain relationship and volume change of silty sands. The results and main conclusions of the study are summarized as follows; 1. Isotropic compression and swelling index are linearly decreased with an increase in relative density. 2. Both undrained shear strengh and elastic modulus are increased with an increase in relative density and confining pressure. 3. Internal friction angles obtained from drained and undrained compression tests of the soils are proportional to relative density. 4. The phenomenon of dilatancy of each sample is less profound when confining stress is increased but more profound when relative density is increased. 5. The slope of critical state lines is 1.78 for Saemangum, 1.70 for Siewha and 1.26 for Sukmoon sands. 6. In this study, Drucker-Praper type criterion is used and hardening function of Cap model is modified by hyperbolic fuction. This will improve a lack of physical meaning of hardening parameters in conventional Cap model. 7. A newly developed constitutive equation to the forementioned silty sands and checked its applicability. This is in good agreement with the measured data.

• Geotechnical Engineering
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• v.14 no.5
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• pp.235-247
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• 1998

The IIA(Inchon International Airport) which will function as the HUB airport in the northeast Asian region in the upcoming 21th century will be located in the reclaimed land with sand dredged in the vicinity of project area between Youngjong and Yongyu islands. The original ground is composed of soft clayey silt (ML) or silty clay (CL). The reclaimed land is classified as being SP-SM and having poor gradation of Cu<3 which resulted in the anticipation for difficulty in compaction (compaction index = 0.6~0.7). This anticipation shedded light on the necessity of performing test compactions for the thickness of 3~5meters of reclaimed land, aiming at the discovery of effective and economical compaction method. Upon the call for the test compaction performance 4 different compaction methods have been selected for trial from the research done on the international and local academic papers, past experience with compaction works, and their written materials. For the precise interparetation of test results, the ground survey and measurements have been performed. The Hydraulic Hammer Compaction has been chosen as the most optimum in accordance withe the test results.