| dc.description.abstract | Soil type, moisture content, compaction methods and other factors will affect the effectiveness of compaction. In order to measure the dry unit weight of soil in field, the sand cone method or the rubber balloon method are used frequently, but those are still not convenient enough. The purpose of this study is to explore a new detection method by impact test. The impact test uses a special test apparatus, by setting an accelerometer on the hammer, the variation of acceleration during the impact of hammer can be measured. The peak value of acceleration in the acceleration time history is defined as Impact acceleration. In this study, the lateritic soil sampled from NCU campus was used in the tests. The engineering properties of soil in the dry side and within 90-100% of the relative compaction is examined to obtain the relationships among impact acceleration, moisture content, dry unit weight and impact height. These experimental results revealed that under various conditions of compaction energy, the impact acceleration and the dry unit weight has a linear relationship. If the impact accelerations is normalized by compaction energy, these two factors will still have a good linear relation. Therefore, by using the data of impact acceleration, the dry unit weight of compacted soil can be obtained. Furthermore, prepared some specimens with the same conditions to perform the cone penetration tests, and the relationships between cone resistance and impact acceleration were examined. The relationships between cone resistance and dry unit weight are similar to that of the acceleration and dry unit weight. Acceleration and cone resistance have a linear relationship also.
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