A Study on the Consolidation Settlement Properties of Reclaimed Soil in Yun-Lin Offshore Area
| Autor: | Cheng, Chich-Ching, 鄭志清 |
|---|---|
| Rok vydání: | 1996 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 84 Hydraulic sand fills is one of the most important reclamation method for near shore area. The structure and fines content of the reclaimed soil are related with the consolidation and mechanism. The reclaimed soil is formed by precipitation. The aggregates of the reclaimed soil have soft and loose structure. In the hydraulic fill process, the loss of fine content is due to the operation of machines and transportation of soil. Thus, the properties of filled soil will change according to the fine content. Therefore, to simulate the accumulate of soil in the laboratory, and to evaluate the effect of fine content on properties of reclaimed soil, is important research topic. In this study, the filled material in Yun-Ling near shore area was used as test samples and sea water were adopted as the pore media. Using hydraulic sand fill simulation method in the laboratory to prepare the specimen, to discuss the accumulate properties of the soil aggregates. Using traditional moist tamping method, the specimens were prepared with different relative density (Dr=35%,55%,75%) and fine content (0%,10 %,20%,30%).One dimensional consolidation test and Rowe type consolidation test were conducted. The parameters Cv, Cc and mv are obtained to evaluate the consolidation properties of the reclaimed soil. The influence factors such as packing properties, fines content, relative density, pore media, load boundary and size effect are discussed. By using the Rowe type consolidation system, seepage test is conducted to evaluate the seepage parameter k, and to prove the reliability of the seepage parameter adopted by consolidation test. In this study, to evaluate the influence of earthquake or cyclic load on the reclaimed soil, Rowe type consolidation cell is adopted for dynamic load test. By using the traditional consolidation results of Lin(1995), the test result obtained from Rowe consolidation test are compared. The influence of different test method on the consolidation prerties of reclaimed soil are discussed. As shown in the test results, fines content has great influence on the consolidation properties of reclaimed soil. The parameters Cc, av and mv increases as the fines content increases. This show that the soil with higher fines content has greater shrinkage properties. For the reclaimed soil with higher fines content, the seepage parameter k adopted from the consolidation test are close to the k adopted from seepage test. To simulate the hydraulic sand fill process, the hydraulic sand fill simulation system developed by Chien(1993) are adopted to prepare the specimen. The specimens prepared by hydraulic sand fill method are fill with 2%. The specimens prepared by moist tamping method and hydraulic sand fill method have different results. As shown in the test results, the consolidation parameters (Cc, mv and k) adopted from the specimen prepared by moist tamping method have larger value compared to the specimen prepared by hydraulic sand fill method. In this study, different pore media (sea water and tap water) are adopted. As shown in the test results, the consolidation properties of the reclaimed soil are influence by the pore media. For the specimen using sea water as pore media, the reclaimed soil would have larger settlement value. Both rigid and soft loading boundaries are adopted for the consolidation test. As shown in the test results, the specimens conducted by soft loading boundary, the irregular stress are transmitted in the soil. The specimens conducted by rigid loading boundary, the regular stress are transmitted in the soil. The consolidation parameters Cc, av, mv and k) adopted from the specimens conducted by rigid loading boundary have larger value compared to the specimens conducted by soft loading boundary (about 20%). In this study, three different specimen size (3inch, 6inch and 10 inch) are discussed. As shown in the test results, the size would not have great influence on the results adopted from the specimens conducted by rigid loading boundary. As for the specimens conducted by soft loading boundary, the results show greater variation(average of 20% greater). This shows that size effect would influence the consolidation properties of the reclaimed soil. As shown in the test results, the seepage parameter k adopted from the seepage experiment are about 3. As shown in the test results, the load applied system for the traditional consolidation test can be influenced by human manual and frictions. The specimen would not be saturated. Thus, the tests adopted from traditional consolidation test and Rowe consolidation test would show different results. For the influence of the cyclic loading on the consolidation properties, the settlement caused by cyclic loading are 1~5 times greater than static loading. This show that earthquake has great inflence on the consolidation properties of the reclaimed soil. For the cyclic loading less than 60, the cyclic load settlement are 2 times grater than the static load settlement. Concluding the results and figures, the results can be a reference for the fonudation stability analysis. The consolidation properties of the reclamation area can be estimated, for the design, stability analysis and related research. Keyword: hydraulics sand fill, Rowe type consolidation test, soil aggregate, fines content, load boundary, size effect, cyclic dynamic load. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|