考虑固结压力和加热温度影响的软土次固结系数

目前常用的软土次固结变形计算方法视次固结系数为常数,但研究表明,固结压力和温度对软土次固结都有着重要影响。本文在梳理已有研究成果的基础上,对原状软土次固结系数C_α随固结压力p和温度T变化的规律进行了研究,提出了考虑两者耦合作用的数学表达式,并进行了验证。结果发现:软土的结构性对C_α-p变化曲线有显著影响,当固结压力很小时,土体结构还未破坏,次固结曲线变化较小,当固结压力接近或超过结构屈服强度时,次固结曲线出现明显上升或者下降,随着固结压力的进一步增大,软土的结构性消失,次固结曲线变化趋势减小;随着温度升高,软土次固结性状增强,次固结系数增大。此外,还讨论了土样类型、取样深度等因素对软土次固结系数的影响,研究成果可供涉热岩土工程问题分析时参考。

Influence of consolidation pressure and heating temperature on secondary consolidation coefficient of soft clay

The commonly used calculation method for secondary consolidation deformation of soft soil regards the secondary consolidation coefficient as a constant. However, studies have shown that consolidation pressure and temperature have important effects on secondary consolidation of soft soils. In this paper,combing the existing research on the basis of the results,the law of the secondary consolidation coefficient C_α of the intact soft clay with the consolidation pressure p and temperature T is studied,and the mathematical expression considering the coupling effect of the two factors is proposed and the verification is carried out. It is found that the structure of soft clay has a significant effect on the C_α-p change curves.When the consolidation pressure is very small,the clay structure has not been destroyed,and the secondary consolidation curve changes little. When the pressure approaches or exceeds the structural yield strength,the secondary consolidation curve appears to rise or fall significantly. As the consolidation pressure further increases,the structure of the soft clay disappears and the secondary consoidation curve change decreases. With the temperature increases,the secondary consolidation properties of soft clay increase and the secondary consolidation coefficient increases. In addition,the clay types,the depth of sampling and other factors affecting the coefficient of secondary consolidation of soft soils are discussed.The study results could be used for the reference in the analysis of thermal geotechnical issues.