| dc.description.abstract | The plain of west Taiwan is formed of soft alluvium ground with a high groundwater level. As Taiwan is located on the Circum-Pacific Seismic Belt, earthquakes occur frequently and can lead to soil liquefaction on the alluvium ground. Sheet pile walls are often used as a retaining system at riverbanks, harbors, and piers due to their cost-effectiveness, convenience, and constructability. Near the river, soil deposits are composed of alluvial soils and groundwater levels are very high, therefore soil liquefaction are usually more common around this area. When soil liquefaction occurs, the sheet pile walls would fall or become damaged as a result of soil deformation.
Both the intensity and duration of the earthquake are positively correlated with the severity of the earthquake disaster. In order to understand the seismic response behavior of sheet pile walls in saturated soil caused by these two variations, four dynamic centrifuge tests were conducted to simulate the sheet pile wall in liquefiable ground, and used the centrifugal model scaling law to simulate the seismic response of the sheet pile wall in a mixed soil layer of saturated silica sand with relative density of 90% and 60%, and thicknesses were 1m and 4m, respectively. In the 24 times gravitational field, frequency of input motion is 1 Hz. The maximum acceleration of input motion and the cycles of the maximum acceleration of the motion are 0.2 g-5 cycles, 0.17 g-10 cycles, 0.14 g-19 cycles, 0.11 g-36 cycles of ramped sine waves, respectively. In this test, accelerometers, linear variable differential transformers, pore water pressure transducers, spaghetti and surface marker were arranged to measure the response of the model. The test results show that 1. Liquefaction depth and the intensity of input motion are positively correlated; 2. As the input motions have the same AI, if the amplitude is big enough to lead to front wall soil liquefaction occur, the wall will tilting angle much more than other smaller motion; 3. In the stage of dissipation period, the sheet pile wall will no longer continue to move, and the backwall soil will continue to settle.
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