冯燕博,刘东燕,杨超*,陈远川.考虑混合赤泥强度增长特性的修正邓肯-张模型[J].实验力学,2018,33(4):610~620 |
考虑混合赤泥强度增长特性的修正邓肯-张模型 |
On the Modified Duncan-Chang constitutive model of mixed red mud by taking account of strength growth characteristic |
投稿时间:2017-09-25 修订日期:2018-01-20 |
DOI:10.7520/1001-4888-17-194 |
中文关键词: 混合赤泥 强度增长 结构性 邓肯-张模型 |
英文关键词:mixed red mud strength growth structural constitute Duncan-Chang constitutive model |
基金项目:国家自然科学基金(41602301);重庆市教委科学技术研究项目(KJ1601130);重庆文理学院人才引进项目(R2015JJ07);重庆市科委项目(cstc2014jcyjA30019) |
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中文摘要: |
混合赤泥在堆存过程中,随着脱水、滤水龄期的延长,其强度有明显增长,由初始的流塑状态转变为具有较高强度的硬塑状态。为研究混合赤泥的这种胶结硬化特性,对不同自然脱水龄期和浸水浸泡龄期下的混合赤泥开展了无侧限抗压强度试验和固结排水三轴剪切试验。试验结果表明:① 混合赤泥的胶结特性主要体现在粘聚力的增长方面;② 混合赤泥的胶结强度形成主要集中在赤泥堆存龄期前70天内。基于混合赤泥强度变化规律,提出了反映混合赤泥胶结硬化特性的结构性定量化参数mc,将原有不稳定的呈软化型的应力-应变曲线修正为表现出双曲线特征的硬化型曲线,并根据试验结果拟合得到初始切线模量Eci,结构性强度参数cc和φc随龄期t的变化公式,从而建立了考虑混合赤泥强度增长特性的修正邓肯-张模型。对比验证表明,所建立的模型可以较好地反映混合赤泥随时间的强度增长特性。 |
英文摘要: |
During the storage of mixed red mud, its strength increases obviously with the prolongation of water filtration age and dehydration, resulting it transformed from initial fluid-plastic state to hard-plastic state with high strength. In order to study the cementing hardening characteristics of mixed red mud, unconfined compressive strength experiment and consolidation drainage tri-axial shear experiment were carried out for mixed red mud at different ages of natural dehydration and immersion in water. Experimental results show that ①the cementation characteristics of mixed red mud is mainly embodied in the growth of cohesion; ②The formation of bonding strength of mixed red mud mainly concentrated in the early 70 days of storage age. Based on the change characteristics of mixed red mud strength, the structural parameter mc that reflects the cementation hardening characteristics of mixed red mud was put forward. By using mc, the original unstable softening stress-strain curves can modified to the hardening curve with hyperbolic characteristic. Then the fitting formula for initial tangent modulus Eci, structural strength parameters cc and φc change with age t were established. Thus, the modified Duncan-Chang constitutive model considering the strength growth characteristics of mixed red mud was constructed. Comparison results show that the model can better reflects the strength growth characteristic of mixed red mud. |
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