Effects of Vibration History on Modulus and Damping of Dry Sand
Effects of Vibration History on Modulus and Damping of Dry Sand
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DOI：
10.1061/(asce)1090-0241(1998)124:11(1071
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发表时间：
1998-11
影响因子：
3.9
通讯作者：
X. S. Li;W. Yang
中科院分区：
文献类型：
--
作者：
X. S. Li;W. Yang
本文介绍了一种实验方案，旨在仔细检查的动态特性（剪切模量和阻尼比）的正常固结干砂的影响，以前的振动。使用新开发的能量注入虚拟质量共振柱系统进行测试。新系统允许应变以及应变速率在整个测试过程中同时保持恒定（连续振动小时），而不管土壤特性的变化。在测试过程中，在不中断振动的情况下连续监测模量和阻尼值。试验变量包括应变幅、预振次数、围压和相对密度。结果表明，当剪切应变超过某一阈值时，干砂的阻尼比明显地依赖于加载循环次数，而剪切模量随加载循环次数的变化相对平缓。试验结果还表明，在所测的砂土特性中存在明确的振动历史特征。这一新发现可能会导致某些应用。
This paper describes an experimental program aimed at a close examination of the dynamic properties (shear modulus and damping ratio) of a normally consolidated dry sand as affected by the previous vibration. Tests were performed using a newly developed energy-injecting virtual-mass resonant column system. The new system allows the strain as well as the strain rate be kept constant concurrently throughout a test (hours of continuous vibration), irrespective of changes in soil properties. During the tests, modulus and damping values were monitored continuously without interrupting vibration. The test variables include strain amplitude, number of previbration cycles, confining pressure, and relative density. The results confirm that the damping ratio of dry sand is evidently dependent on the number of loading cycles when the shear strain exceeds a threshold, while the variations of shear modulus as number of loading cycles increases are relatively moderate. The test results also show that there exists an unequivocal signature of vibration history in the measured sand properties. This new finding may lead to certain applications.