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膨胀土是岩土工程中常见的一类特殊土,具有失水收缩和吸水膨胀的变形特征,如何量化收缩变形及其与干缩裂缝之间的关系是土工建筑物稳定性和安全性评估的基本问题。本文利用Bishop有效应力原理和广义胡克定律证明了采用含水率或基质吸力为基本变量的两种分析方法的等价性。把岩土工程中常用的原状土收缩实验中测量的收缩系数与收缩应变关联,得到了土体两端存在和没有位移约束时的总水平应力及其与含水率分布之间的关系。结果表明,无边界位移约束时,收缩变形的不均匀性小,应力水平低,且含水率对应力分布的影响小;存在约束时,收缩变形将受到限制,易诱发干缩裂缝,其深度受土体弹性模量和收缩系数的影响。
Expansive soil is a kind of special soil which is common in geotechnical engineering. It has deformation characteristics of water loss and water absorption and expansion. How to quantify shrinkage deformation and its relationship with shrinkage cracking is the evaluation of stability and safety of geotechnical structures fundamental issue. In this paper, Bishop’s principle of effective stress and generalized Hooke’s law are used to prove the equivalence of the two analytical methods using water content or substrate suction as the basic variables. In this paper, the shrinkage coefficient and the shrinkage strain measured in the shrinkage experiment of undisturbed soil commonly used in geotechnical engineering are correlated. The total horizontal stress and the relationship between the horizontal stress and the moisture content distribution are obtained when the soil is restrained with and without displacement at both ends. The results show that the non-uniformity of shrinkage deformation is low and the stress level is low, and the influence of moisture content on the stress distribution is small when there is no boundary displacement constraint. When the constraint exists, the shrinkage deformation will be restricted and the shrinkage crack will easily be induced. Influence of Soil Elastic Modulus and Shrinkage Coefficient.