Long-term Non-linear creep and swelling behavior of Hong Kong marine deposits in oedometer condition
Long-term Non-linear creep and swelling behavior of Hong Kong marine deposits in oedometer condition
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DOI：
10.1016/j.compgeo.2016.11.009
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发表时间：
2017-04
影响因子：
5.3
通讯作者：
W. Feng;Borana Lalit;Z. Yin;Jianhua Yin
中科院分区：
文献类型：
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作者：
W. Feng;Borana Lalit;Z. Yin;Jianhua Yin
粘土随时间变化的应力应变行为是预测长期沉降的一个重要问题，特别是对于大型土地复垦项目。本文通过多阶段加载里程计试验研究了香港海洋沉积物（HKMD）在加载阶段和卸载阶段的长期随时间变化的行为。特别强调研究蠕变和膨胀行为。研究发现，粘土在加载阶段表现出蠕变行为，而在卸载阶段表现出膨胀行为。蠕变行为分析表明，一定时期内蠕变应变与时间（对数尺度）之间存在线性趋势，而长期来看则呈现非线性关系。对于膨胀行为也发现了类似的结果。发现非线性函数适合预测长期蠕变和膨胀行为。采用非线性函数对实验数据进行拟合，即可得到蠕变应变极限和膨胀应变极限。此外，提出并提出了一种新的考虑膨胀的改进弹性粘塑性模型（EVPS模型），该模型考虑了非线性蠕变和膨胀行为。在该修正的EVPS模型中，当时间无穷大时，也可以获得最终的蠕变和膨胀平衡应力应变状态。
The time-dependent stress-strain behavior of clayey soil is a great concern for predicting long-term settlement especially for large-scale land reclamation projects. In this paper, long-term time-dependent behavior of Hong Kong Marine Deposits (HKMD) under the loading stage and unloading stage is investigated by multi-staged loading oedometer test. Special emphasis has been given to study creep and swelling behavior. It is found that the clayey soil demonstrates the creep behavior during the loading stage, whereas it shows the swelling behavior during the unloading stage. The analysis of the creep behavior shows that there exists a linear trend between creep strain and time (in log-scale) within a certain period, whereas a nonlinear relationship in a long term view. Similar result is found for the swelling behavior. A nonlinear function is found to be suitable to predict the long-term creep and swelling behavior. The creep strain limit and swelling strain limit can be obtained if the nonlinear function is adopted to fit the experimental data. In addition, a new modified Elastic Visco-Plastic model considering Swelling (EVPS model) is proposed and presented, which considers the nonlinear creep and swelling behavior. In this modified EVPS model, the final creep and swelling equilibrium stress-strain state can also be obtained when the time is infinite.