土的负蠕变特性及其本构模型

姚仰平; 方雨菲

doi:10.11779/CJGE201810001

土的负蠕变特性及其本构模型 English Version

北京航空航天大学交通科学与工程学院,北京 100191

基金项目: 国家自然科学基金项目（11672015,51579005）; 国家重点基础研究发展计划（“973”计划）项目（2014CB047006）

详细信息

作者简介:
姚仰平(1960- ),男,教授,博士生导师,主要从事土的本构关系和机场高填方研究。E-mail：ypyao@buaa.edu.cn。

中图分类号: TU43
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出版历程
- 收稿日期: 2017-07-13
- 发布日期: 2018-10-24

Properties of negative creep and its constitutive model for soils

School of Transportation Science and Engineering, Beihang University, Beijing 100191, China

摘要

摘要: 蠕变是指有效应力不变的情况下,变形随时间的发展。土力学中,蠕变往往指压缩蠕变,如山区机场高填方工程中填方区的工后沉降。然而,高填方工程中有时还需要对山体进行大体积深开挖,以得到大面积的平整场地。开挖后,土体的膨胀变形不能在短时间内稳定,而是随时间继续发展。将这种随时间发展的膨胀变形定义为负蠕变,相对应地,将压缩蠕变定义为正蠕变。试验表明,正、负蠕变都有趋于稳定的趋势。因此可以假设,在e-lnp空间中,当时间足够长时,不论发生正蠕变还是负蠕变,土体都稳定在一条平行于正常压缩线的直线上,这条线为稳定线。在上述概念的基础上,提出了一个可以合理地描述土的负蠕变效应的一维计算公式,结合UH模型,建立了考虑负蠕变效应的UH模型。最后,将模型预测结果与三轴不排水剪切正负蠕变试验结果进行了对比,验证了模型的正确性。
- 饱和黏土 /
- 本构模型 /
- 弹黏塑性 /
- 正蠕变 /
- 负蠕变
Abstract: The deformation over time under a constant pressure is creep. In general, the creep refers to compressive deformation, for example, the post-construction settlements after filling valleys in high-fill engineering. However, in order to get a high-fill ground, sometimes soils are excavated from high places. The expansion of soils after unloading cannot be stable in a short time, but continues to develop. This time-dependent expansion is defined as the “negative creep”, while the traditional compressive creep is named as the “positive creep” in this paper. Moreover, the test results show that as time is prolonged, both the positive and negative creep tend to be stable. Therefore, we can assume that in e-lnp space, when the time for the positive or the negative creeps is long enough, the state point will reach a straight line, which is parallel to the normal compression line. This line is named as the normal stable line. Based on the above concepts, a new one-dimensional formula, which can reasonably describe the negative creep effect of soils, is proposed. By combining the formula with the unified hardening (UH) model, a new UH model considering negative creep is established. Finally, the predictions of the new model are compared with the experimental results of triaxial undrained positive and negative creep tests to validate the new model.
- saturated clay /
- constitutive model /
- elastoviscoplasticity /
- positive creep /
- negative creep

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参考文献(20)

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土的负蠕变特性及其本构模型 English Version

作者简介: 姚仰平(1960- ),男,教授,博士生导师,主要从事土的本构关系和机场高填方研究。E-mail：ypyao@buaa.edu.cn。

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Properties of negative creep and its constitutive model for soils

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作者简介:
姚仰平(1960- ),男,教授,博士生导师,主要从事土的本构关系和机场高填方研究。E-mail：ypyao@buaa.edu.cn。