Modified UH Model: Constitutive Modeling of Overconsolidated Clays Based on a Parabolic Hvorslev Envelope
Modified UH Model: Constitutive Modeling of Overconsolidated Clays Based on a Parabolic Hvorslev Envelope
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DOI：
10.1061/(asce)gt.1943-5606.0000649
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发表时间：
2012-07-01
影响因子：
3.9
通讯作者：
Wan, Zheng
中科院分区：
文献类型：
--
作者：
Yao, Yangping;Gao, Zhiwei;Wan, Zheng
大多数粘土，无论是自然沉积的还是人造的，都具有一定程度的超固结性，这是由于扰动、循环荷载、侵蚀、挖掘和/或地下水位的变化。一个简单易行的超固结粘土本构模型对相关工程应用具有重要意义。基于统一硬化（UH）模型，提出了一种适用于超固结粘土的简化模型。为了评估超固结粘土的潜在峰值应力比，采用抛物线Hvorslev包络线而不是直线包络线（在原始UH模型中使用）。建议的抛物线Hvorslev包络线通过平均应力偏应力平面的原点。当超固结比（OCR）接近无穷大时，它的斜率为3，当OCR达到1时，它与临界州线相交。这种修改导致更切合实际的预测高度超固结粘土比原来的UH模型与直Hvorslev信封，是一致的临界状态土力学中，在超固结粘土中的较高的峰值应力比是联锁（或粘性），而不是凝聚力的结果。修正后的UH模型保留了修正后的剑桥模型的参数。模型预测与试验数据之间的合理协议表明，修改后的模型是能够解决的基本行为的超固结粘土。本模型是针对具有各向同性组构的重塑粘土而建立的。考虑到各向异性和结构效应，该模型的潜在改进进行了讨论。DOI：10.1061/（ASCE）GT.1943-5606.0000649。(C)2012年美国土木工程师学会。
Most clays, either naturally deposited or man-made, possess a certain degree of overconsolidation owing to tamping, cyclic loading, erosion, excavation, and/or changes in groundwater tables. An easy-to-use constitutive model for overconsolidated clays is useful for relevant engineering applications. In this paper, a simple model is proposed for overconsolidated clays based on the unified-hardening (UH) model. To evaluate the potential peak stress ratio of overconsolidated clays, a parabolic Hvorslev envelope rather than a straight envelope (used in the original UH model) is adopted. The proposed parabolic Hvorslev envelope passes through the origin of the mean stress-deviatoric stress plane. It has a slope of 3 as the overconsolidation ratio (OCR) approaches infinity and intersects with the critical state line as the OCR reaches unity. This modification leads to more realistic predictions for highly overconsolidated clays than does the original UH model with a straight Hvorslev envelope and is consistent with the critical state soil mechanics in which the higher peak stress ratio in overconsolidated clays is a result of interlocking (or dilatancy) rather than cohesion. The modified UH model retains the same parameters as those in the modified Cam-clay model. Reasonable agreement between the model predictions and experimental data demonstrates that the modified model is capable of addressing the fundamental behavior of overconsolidated clays. The present model is developed for reconstituted clays with an isotropic fabric. The potential improvement of the model, taking into account anisotropy and structural effects, is discussed. DOI: 10.1061/(ASCE)GT.1943-5606.0000649. (C) 2012 American Society of Civil Engineers.