Series of triaxial and shaking table tests were carried out to compare repeated liquefaction behavior. / 再液状化挙動を比較するため一連の三軸試験および振動台モデル実験を実施した.

Triaxial Test / 三軸試験

In triaxial testing, it was found that the liquefaction resistance increased with liquefaction stages. This increase was later discovered that it depended on the strain amplitude. The specimens subjected to low strain amplitude showed larger increase in resistance although an increase in relative density was smaller. It was even larger when the specimen was subjected to small strain.


Shaking Table Test / 振動台実験

For shaking table tests, series of repeated liquefaction tests were conducted with different starting input accelerations on flat ground models. The results showed that liquefaction resistance in the first shake event was always larger than the following event in every repeated liquefaction series. In addition, under the same input acceleration, the results revealed that future liquefaction resistance can be briefly predicted using current and previous maximum strain amplitude.


Comparison / 結果の比較

As stress and strain response cannot be controlled in shaking table, cumulative damage concept was employed to convert irregular cyclic stress response into equivalent uniform cyclic stress before comparing with triaxial results. Higher liquefaction and reliquefaction resistance was observed in shaking table test. Further investigation was also conducted using energy approach. It was found that relationship between dissipated energy during the previous liquefaction stage and the next liquefaction resistance was well defined for each test apparatus results.


More Details...

1)Teparaksa, J. and Koseki, J. “Behaviour of silica sand under repeated liquefaction using triaxial apparatus.” Proc. of the 18th International Summer Symposium, Japanese Society of Civil Engineers, 2016, pp.37-38
2)Teparaksa, J. and Koseki, J. “Comparison of silica sand behaviour under repeated liquefaction using shake table and triaxial test.” To be published in Proc. of the 18th International Summer Symposium, Japanese Society of Civil Engineers, 2017
3)Teparaksa, J. and Koseki, J. “Silica sand behavior under repeated liquefaction in cyclic triaxial test.” To be published in Proc. of the 19th International Conference on Soil Mechanics and Geotechnical Engineering, September, 2017