The Experimental Study on the Reclaimed Soils Subjected to Various Impact Energy
| Autor: | Chun-Wei Lu, 呂俊緯 |
|---|---|
| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 This thesis presents an experimental study on the impact effectiveness on reclaimed soils through a single-point impact system and automatic cone penetration system. By controlling the water levels, drained conditions and impact energies, the effectiveness of improvement is investigated and presented in two scopes, i.e. Tests with dry soil samples, and soil samples with water levels. For dry condition, two types of tampers weighting 1 kgf and 2 kgf are used to perform impacts under three different energy efforts and those indexes, such as effective dynamic stresses, cone resistances, penetration work and improvement ratios are obtained and discussed. For soil samples with water levels, impact conditions are same as those for dry soil samples, except the additional controls on water levels and drained conditions. A discussion on comparison of effectiveness between “light tamper with more impacts” and “heavy tamper with fewer impacts” is presented. The test results indicate that after impacts, the effectiveness of dry soils is greater than that of soils with water levels; and the effectiveness of soils with lower water level are better than those with higher water levels. According to the relationship between impact energy and dynamic stress, the increments of impact-induced dynamic stresses in soils using tampers of 1 kgf and 2 kgf are both increasing with the impact energy. The increments of impact-induced effective dynamic stresses from high water level down to lowered water level are ranging from 2 % to 5.5 %. However, under same conditions, the increments of penetration work and peak cone resistances are the ranges of 0.57% ~1.49% and 0.72 % ~ 1.55%, respectively. In addition, the maximum values of Improvement Ratios appear at dry soils above the water levels and maintains near constant below the water level. Based on the post-impact cone resistances qc, increments of qc, penetration works and improvement ratios, the tesults show that the impact effectiveness increases with the impact energy. Under the same impact energy, the performance of impacts using 1 kgf tamper in general better than that using 2 kgf tamper. Therefore, if the minimum weight of tamper to achieve the improvement target can be confirmed, it is recommended, that under the same impact energy, by using a proper weight of tamper instead of a very heavy tamper to perform the dynamic compaction in the field. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|