| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 96 === The construction of highway embankment or earth dam requires compacting back-fill materials lay-by-layer. In practice, for the purpose of quality control, Proctor test and sand cone test are performed to measure the "relative compaction" of a compacted layer. However, the sand cone test is a destructive test and performing this test is labor intense and time consuming. The objective of this thesis to investigate the feasibility of evaluating the compaction quality of soils by stress wave propagation speeds. To achieve this goal, Proctor test, stress wave propagation velocity test, and California Bearing Ratio (CBR) test were performed in the laboratory on two different materials used in the earth dam of the Who-Shan Reservoir to obtain the calibration curve between the dry density and S-wave velocity. In addition, stress wave propagation velocity tests were also performed on the compacted layers in the field to back calculate the field density of these materials.
Results of laboratory tests indicate that the stress (P and S) wave velocities of the samples are proportional to their dry density for samples compacted at dry of optimum. On the other hand, the P-wave and S-wave velocities of the samples decrease as their water content increases. Finally, both the P wave and S wave velocities of the samples are proportional to their CBR values. However, the back calculated field densities using the measured S-wave propagation velocities with the laboratory calibration curve are slightly higher than values obtained from sand cone tests. Therefore, application of this technique to evaluate the compaction quality of soils should be further studied.
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