| Summary: | 碩士 === 中原大學 === 土木工程研究所 === 100 === According to the literature, sands in Taiwan could contain mica particles. Most researches on micaceous sand focused on compressibility, and shear strength characteristics of the micacous sand are still rarely explored. This study explored the shear strength of muscovite-sand mixtures. Mailiao sand and Ottawa sand were used with different contents of coarse or fine muscovite to prepare direct shear test specimens to measure shear strength. It is hoped that the results will be useful for engineering design involved with micaceous sand.
Test results show that dry unit weight of the Mailiao sand in dry state (12.94 kN/m3, Dr=11.09%) is slightly higher than that in the saturation state by about 0.3 kN/m3. When the coarse muscovite content increases from 5% to 10% in dry state, the dry unit weight decreases by about 1.5 kN/m3, and thereafter it decreases by about 0.5 kN/m3 for each 5% increase. When the fine muscovite content increases 5%, the dry unit weight does not change, and thereafter it decreases by about 0.5 kN/m3 for each 5% increase. The dry unit weight of saturated coarse muscovite-Mailiao sand mixtures is lower by about 2.6、3.0、or 3.0 kN/m3 than that of fine muscovite-Mailiao sand mixtures for muscovite contents 10%、20%、or 30%, respectively.
Dry unit weight of the Ottawa sand in dry state (15.52kN/m3, Dr=18.51%) is slightly higher than that in the saturation state by about 0.3 kN/m3. When the coarse muscovite content increases by 10% in dry state, the dry unit weight decreases by about 3.5 kN/m3, and thereafter it decreases by about 1 kN/m3 for each 10% increase. When the fine muscovite content increases 10%, the dry unit weight does not change, and thereafter it decreases by about 1.5kN/m3 for each 10% increase. The dry unit weight of saturated coarse muscovite-Ottawa sand mixtures is lower by about 2.6、3.2、or 3.3 kN/m3 than that of fine muscovite-Ottawa sand mixtures for muscovite contents 10%、20%、or 30%, respectively.
In dry state, the linear regression internal friction angle for the fine muscovite-Mailiao sand mixtures is higher by about 0.8° to 1.9° than that for the coarse muscovite-Mailiao sand mixtures. For each 5% increase in muscovites contents, the friction angle decreases by 0.5° to 1.2° for the fine muscovite and by 0.3° to 1.5° for the coarse muscovite. In saturated state, the linear regression internal friction angle for the muscovites-Mailiao sand mixtures are nearly the same, and it decreases by 1.1° to 3.5° for each 10% increase in muscovite content.
In dry state, the linear regression internal friction angle for the fine muscovite-Ottawa sand mixtures is higher by about 1.7° to 2.5° than that for the coarse muscovite-Ottawa sand mixtures. For each 10% increase in muscovites contents, the friction angle decreases by 0.6° to 1.7° for the fine muscovite and by 1.2° to 3.1° for the coarse muscovite. In saturated state, the linear regression internal friction angle decreases by 1.3° to 4° for coarse muscovite-Ottawa sand mixtures and by 1.4° to 2.2° for fine muscovite-Ottawa sand mixtures for each 10% increase in muscovite content.
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