| 摘要: | 橡膠粒砂土混合物（Rubber Sand Mixture）中所使用的橡膠粒來源廣泛，其中汽車廢棄輪胎是材料來源之一，根據中華民國環境部2022的統計資料，台灣於2022年產生約15萬公噸的廢棄輪胎，而RSM技術能有效再利用廢棄輪胎，作為建築物基礎，以緩解和減少建築物因地震導致的損壞，從而達到可持續發展。因此本研究採用石英細砂及D_50=0.55 mm及D_50=3.00 mm的橡膠粒為試驗材料，以不同橡膠粒配比及粒徑作為變因，進行壓密-不排水三軸試驗，探討砂土和橡膠粒砂土混合物在不同橡膠粒配比及粒徑條件下之力學性質及其關聯性，同時進行動力三軸試驗，探討砂土和橡膠粒砂土混合物降低液化發生的可能性之能力。
試驗結果顯示，抗剪強度、視凝聚力、磨擦角、單位重及最佳含水量均與橡膠粒粒徑及配比相關。橡膠粒砂土混合物的抗剪強度之主要影響因素為有效圍壓、橡膠粒配比及橡膠粒平均粒徑;以橡膠粒配比作為控制變因的條件下，橡膠粒平均粒徑為3.00 mm的橡膠粒砂土混合物具較高抗剪強度；單位重及最佳含水量與橡膠粒配比存在負相關，平均粒徑3.00 mm的橡膠粒砂土混合物具較高單位重及最佳含水量; 視凝聚力會以先升後降之3次方程式形態出現，而磨擦角則隨橡膠粒配比上升而下降，可以2次方程進行迴歸，橡膠粒平均粒徑較高的橡膠粒砂土混合物具較高視凝聚力及磨擦角。在彈性模數方面，E0，E50及E100均隨橡膠粒重量配比上升而下降。在 E50方面，橡膠粒平均粒徑0.55 mm的混合物，其E50會於混合物中的橡膠粒重量配比達20 %後趨向穩定。在降低液化發生的可能性之能力之能力方面，橡膠粒重量配比為40 %的混合物能有效降低CSR= 0.1、0.2及0.3的反覆加載所帶來的液化發生的可能性，但對於CSR=0.4的反覆加載其降低液化發生的可能性之能力較弱。在彈性模數方面，E0、E50及E100於CSR=0.1的反覆加載條件下，其下降幅度最低，而E0、E50及E100於CSR=0.2、0.3及0.4的反覆加載條件下，其下降幅度相似。
;The sources of rubber granules used in rubber sand mixture (RSM) are various, including discarded automobile tires. According to the data from the Ministry of Environment in Taiwan, there were about 150,000 tons of discarded automobile tires in 2022. However, RSM technology can effectively reuse waste tires while mitigating and reducing damage to buildings caused by earthquakes, thereby achieving sustainable development. Therefore, this study uses quartz fine sand and rubber particles of D50=0.55 mm and D50=3.00 mm as test materials, with different rubber content and particle sizes as variables to explore the mechanical properties of the rubber sand mixtures by conducting the consolidated undrained triaxial tests. On the other hand, the Cyclic triaxial tests are conducted to explore the liquefaction resistance of rubber sand mixtures.
The test results show that the main influencing factors of the shear strength of the rubber sand mixture are the effective confining pressure, the rubber content and the average particle size of the rubber particles. Under the same rubber content, the rubber sand mixture with 3.00 mm average particle size of the rubber particles has higher shear strength. The unit weight and optimal water content decrease as the rubber particle ratio increases. The rubber sand mixture with D50=3.00 mm has a higher unit weight and optimal moisture content; the apparent cohesion appears in the form of rising first and then falling, and the friction angle decreases as the rubber content increases. On the aspect of elastic modulus, E0, E50 and E100 indicate the rubber sand mixtures with D50=0.55 mm rubber granules have lower elastic modulus. Moreover, the E50 of the mixture with D50=0.55 mm tends to be stable in a lower rubber content. The rubber sand mixture with a higher average particle size of rubber particles has a higher apparent cohesion and friction angle. On the other hand, a rubber sand mixture with 40 % rubber content can effectively reduce the risk of liquefaction caused by the cyclic loading with CSR=0.1, 0.2 and 0.3, but its liquefaction resistance against cyclic loading with CSR=0.4 is weak. On the aspect of elastic modulus, the test condition with CSR=0.1, the decline in elastic modulus is the slowest in this test, and additionally, the tendency of the elastic modulus with test condition CSR=0.2, 0.3 and 0.4 respectively is close to one another. |
