| Budget Amount *help |
¥18,590,000 (Direct Cost: ¥14,300,000、Indirect Cost: ¥4,290,000)
Fiscal Year 2018: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000)
Fiscal Year 2017: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2016: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000)
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| Outline of Final Research Achievements |
Repeated small shaking events due to earthquakes significantly enhance liquefaction resistance of soils. This study investigates the pre-shearing effects on the liquefaction resistance (RL) through laboratory tests and centrifuge tests. An attempt was made to explain the effects quantitatively with a single index parameter of the volumetric strain caused by pre-shearing. It was confirmed from triaxial tests that the RL of pre-sheared sand uniquely increased with increasing volumetric strain during the pre-shearing. To examine the pre-shaking effects on the RL of sand under a level ground condition, centrifuge tests were conducted. Sand models were subjected to small shaking events repeatedly, which were weak enough not to cause liquefaction. At the end of the test, the sand was subjected to a strong shaking event. The relationship between RL ratio of the ground and volumetric strain that occurred in the pre-shaking events coincides with that obtained from the triaxial tests.
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