软黏土速率势固结蠕变模型及其温度效应修正

沿海公路和港口堤坝等工程的长期沉降与软黏土的固结蠕变特性密切相关. 速率势模型是软黏土固结蠕变特性研究的重要组成部分. 在梳理Mesri团队和Leroueil团队研究成果的基础上, 从弹性应变、微观结构和温度3方面探讨了速率势模型的适用性. 考虑到温度对软黏土固结蠕变特性的影响, 提出了耦合温度的软黏土速率势模型. 主要结论有: 速率势模型中的速率指不可恢复的塑性应变而不是总应变; 在以极低的应变速率进行加载时, 软黏土微观结构的恢复会对速率势模型的合理性产生影响; 速率势模型对于常温条件下的软土工程问题分析基本适用; 由于温度对软黏土固结蠕变特性产生较明显影响, 考虑温度的速率势模型具有更广泛的适用性.

Study on consolidation creep model of soft clay considering strain rate and temperature effect

The long-term settlement of coastal highway and harbor dams are closely related to the consolidation creep characteristics of soft clay. The isotache rheological model is very important for the analysis of creep effect of soft clay or soft foundation. This paper summarizes the research results of Mesri and Leroueil’s team and discusses the applicability of the isotache rheological model from three aspects, i.e., elastic strain, microstructure and temperature. Considering the effect of temperature on the creep behavior of soft clay, the thermal isotache rheological model is proposed. The main conclusions include: the rate in the model refers to the irreversible plastic strain rather than the total strain; the recovery of the microstructure of the soft clay has effect on the rationality of the model when loading at very low strain rates; the isotache rheological model is suitable for the analysis of soft soil engineering problems under normal temperature conditions; the temperature load has a significant effect on the creep behavior of soft clay, and therefore the thermal isotache rheological model has wider applicability.