不同围压条件下淤泥质黏土蠕变力学特性试验及模拟

淤泥质黏土是码头工程常见地基土,其蠕变特性与码头地基稳定性紧密关联。为研究不同围压条件下的淤泥质黏土蠕变力学特性,对其开展固结排水三轴压缩蠕变试验。基于蠕变试验结果,引入Mesri和Log-Modified模型模拟淤泥质黏土的蠕变力学行为,得到蠕变经验模型,并对比两个模型的辨识效果。结果表明,同一围压下,随着轴压的提升,轴向应变逐渐递增,初始和稳态蠕变速率均呈线性递增趋势;同一加载等级下,围压和轴压的升高促进轴向应变的增长,较高轴压和围压条件下初始、稳态蠕变速率均始终大于较低轴压和围压条件;淤泥质黏土等时轴压-轴向应变曲线近似双曲线,具有明显的非线性特征;Mesri蠕变经验模型辨识效果优于Log-Modified蠕变经验模型。

Test and simulation of creep mechanical properties of muddy clay under different confining pressures

Muddy clay is common foundation soil in wharf engineering,and its creep properties are closely related to the stability of wharf foundations.To study the creep mechanical properties of muddy clay under different confining pressures,we carry out consolidated drained triaxial compression creep tests.On this basis,we introduce the Mesri and Log-Modified models to simulate the creep mechanical behavior of muddy clay,obtain the empirical creep models,and compare the identification effects of the two models.The results show that with the increase in axial pressure under the same confining pressure,the axial strain increases gradually,and the initial and steady creep rates show a linearly rising trend.With the same loading level,the increase in confining and axial pressure promotes the growth of axial strain,and the initial and steady creep rates under high axial and confining pressure are always greater than those under low axial and confining pressure.The isochronous axial pressure-strain curve of muddy clay is approximately hyperbolic and has prominent nonlinear characteristics.Moreover,the identification effect of the empirical Mesri creep model is better than that of the empirical Log-Modified creep model.