LIQUEFACTION TRIGGERING RESPONSE UNDER WAVE-INDUCED CYCLIC LOADING


Bilge H. T. , Unutmaz B., Yunatci A. A. , Yunatci I., Cetin K. O.

28th International Conference on Ocean, Offshore and Arctic Engineering, Hawaii, Amerika Birleşik Devletleri, 31 Mayıs - 05 Haziran 2009, ss.361-366 identifier identifier

  • Basıldığı Şehir: Hawaii
  • Basıldığı Ülke: Amerika Birleşik Devletleri
  • Sayfa Sayıları: ss.361-366

Özet

Cyclic response of saturated sands has become one of the most popular topics in geotechnical earthquake engineering due to the consequent damages of earthquakes. Related to this topic, detailed performance of offshore structures founded on saturated sands under the effect of cyclic loads carries vital economic importance. It is well-known that besides seismic loading; storm, wind and/or submarine slope failures have direct effect on the strength and deformation behavior of soils through induced sea-level variations. This study summarizes the results of a series of cyclic triaxial tests performed to simulate the behavior of fully-saturated coarse grained sands under wave-induced cyclic loading. Evaluating the excess pore water pressure generation and shear strain accumulation response along with the number of cycles required for liquefaction triggering for sands, having different relative densities, and being subjected to various cyclic shear stress ratios (CSR), the following observations are made; i) number of cycles to liquefaction increases with increasing relative density and decreasing CSR, ii) for medium dense foundation and backfill soils, liquefaction is not triggered for CSR values less than 0.1 under reasonable number of cycles, and iii) number of cycles to liquefaction decreases significantly for soils subjected to CSR values exceeding of 0.25. These results were used to express the effects of the variation in water level and liquefaction triggering response in terms of in-situ test data, wave height and number of waves for the granular backfill of a sample offshore structure.