| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 93 === Abstract
This study aims at investigating the ground vibrations induced by dynamic pile tests. The cases selected for studying are the Statnamic and drop-hammer tests conducted at the Shian-Du Extreme-highly Voltage Substation located at the western tip of the Guan-Du Plain of Taipei Basin. The Statnamic test of maximum load 2000ton was conducted on a bored-pile of diameter 1.1m and length 52m and the drop-hammer tests of weight 16.7ton and falling-heights of 0.5m, 1.0m and 1.5m, respectively, were conducted on the same pile. During the tests, a series of velocity sensors were deployed along a line to a distance of 100m from the pile center to measure the ground vibrations induced. Data collected were analyzed to deduce the 1/3-octave-band vibration amplitude spectrum and the coefficients of ground vibration attenuation with distance were also deduced.
In addition, numerical simulations for both tests are performed in this study by using the computer program ABAQUS. Axisymmetric analyses with 4-node soil and pile elements were adopted. Four types of model were selected for parameter studies. They are: (1) Linear soil elements without pile/soil interface elements; (2) Elasto-plastic soil elements without pile/soil interface elements; (3) Linear soil elements with pile/soil interface elements; and (4) Elasto-plastic soil elements with pile/soil interface elements. Both the piles responses and the ground responses obtained from numerical analyses are compared with the results in-situ of tests.
Based on the comparison studies, it is found that both the models with pile/soil interface elements (i.e., model 3 and 4) are acceptable to simulate the behavior of dynamic pile tests. The responses of pile obtained are quite close to the test results. However, the responses of ground vibrations obtained are not so satisfactory due to the complexity and uncertainties in the in-situ conditions.
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