Dynamic shear modulus of soil using a random vibration method.
Dynamic shear modulus of soil using a random vibration method.
复制标题
使用随机振动方法计算土壤的动态剪切模量。
DOI：
10.3208/sandf1972.17.1
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发表时间：
1977
影响因子：
3.7
通讯作者：
R. D. Japp
中科院分区：
文献类型：
--
作者：
R. Yong;T. Akiyoshi;R. D. Japp
利用Hardin研制的土动剪切模量仪，提出了用随机振动法测定土体的动剪切模，并与标准正弦试验结果进行了比较。根据土样-承台耦合系统的共振频率计算土体的正弦振动剪切模数，根据窄带过程理论推导出随机振动的期望频率，计算土体的剪切模数。在本研究中，剪切应变幅值很小(小于10-5)，土的等效阻尼常数小于0.05。如果试验装置-试件耦合系统的频率响应函数相对于共振频率产生明显的不对称性，则系统响应特性的信息在很大的频率范围内的变化将导致随机振动和正弦振动试验的剪切模数计算不一致。在低围压条件下，两种方法测得的剪切模量相差较大。
The random vibration method is proposed in this study for evaluation of the dynamic shear modulus of soil using the apparatus developed by Hardin, and the results are compared with that obtained by the standard sinusoidal test.The soil specimen made of two kinds of clay and sand were placed in the triaxial cell, and twisted at the top by sinusoidal or random forces through the magnetic coils under uniform confining pressure and drained condition. The shear modulus of soil by sinusoidal vibration was computed from the resonant frequency of the soil specimen-top cap coupling system, and that by random vibration was from the expected frequency which was deduced from the narrow-band process theory. In this research study, shear strain amplitude was very small (less than 10-5), and the equivalent damping constant of soil was less than 0.05.If the test apparatus-specimen coupling system produces an apparent nonsymmetry in the frequency response function with respect to the resonant frequency, variations in the evaluation of the informations on the response characteristics of the system over a wide range of frequency result creating the inconsistencies in computation of the shear moduli from the random and sinusoidal vibration tests. Larger differences between the shear moduli by both methods are observed at low confining pressures.