Undrained dynamic behaviour of peaty organic soil under long-term cyclic loading, Part I: Experimental investigation
Undrained dynamic behaviour of peaty organic soil under long-term cyclic loading, Part I: Experimental investigation
复制标题
长期循环荷载下泥炭有机土的不排水动力行为，第一部分：实验研究
DOI：
10.1016/j.soildyn.2018.01.012
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发表时间：
2018-04-01
影响因子：
4
通讯作者：
Yin, Song
中科院分区：
文献类型：
--
作者：
Chen, Cheng;Zhou, Zhengming;Yin, Song
为研究泥炭有机土在长期循环荷载作用下的不排水循环特性，进行了一系列不排水循环三轴压缩试验。研究了循环加载过程中的永久轴向应变、累积超孔压和割线剪切模数，总结了它们与围压、循环偏应力和静偏应力等变量的关系。与温州软粘土相比，泥炭有机土在长期循环荷载作用下表现出明显的特征。对于给定的应力状态，由于泥炭有机土具有较高的静力强度，泥炭有机土在初始极限加载循环期间的永久应变小于无机软粘土。在长期循环荷载作用下，泥炭有机土表现出明显的粘性和较高的永久应变率。由于泥炭有机土中的有机成分高度分解且往往是无定形的，导致结构强度较弱，永久应变的发展对围压不敏感。此外，对于给定的剪切应变，泥炭有机土的割线模数随着有机质含量和分解程度的降低或围压的增加而增大。而等效阻尼比一般随围压、有机质含量或分解程度的增加而减小。
To investigate the undrained cyclic behaviour of peaty organic soil under long-term cyclic loading, a series of undrained cyclic triaxial compression tests was conducted. The permanent axial strain, accumulated excess pore pressure as well as secant shear modulus during the loading cycles were studied and their dependencies on variables such as confining pressure, cyclic deviator stress and static deviator stress were summarized. Distinctive characteristics of the peaty organic soil under long-term cyclic loading were presented in comparison to a soft clay from Wenzhou. For a given stress state, the permanent strain over the initial limited loading cycles was smaller for the peaty organic soil than for the inorganic soft clay for the higher static strength of peaty organic soil. The peaty organic soil displayed distinct viscous nature and higher permanent strain rate under long-term cyclic loading. Due to the highly decomposed and often amorphous organic components in the peaty organic soil, which results in a weak structure strength, the development of permanent strain was found to be insensitive to confining pressure. In addition, for a given shear strain, the secant modulus of peaty organic soils increased with decreasing organic content and degree of decomposition or with increasing confining pressure. While the equivalent damping ratio was found to generally decrease as the confining pressure, organic content or degree of decomposition increased.