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邓肯张模型应用于钙质结核土三轴试验的分析时,发现部分应力应变曲线不能有效地被预测。文章基于本构模型所具有的特性,结合土的结构性及应力应变曲线的特性,分析本构方程参量的作用并引进能有效描述S型应力-应变曲线的参量(密实点D为切线弹性模量为最大值时对应的应力应变点)。通过推广邓肯张模型、建立和修正反正切模型,结合钙质结核土应力应变曲线类型,探究本构模型各自的实用性与适应范围。结果表明:应用于应变硬化的反正切修正模型与邓肯张修正模型,由于变量的增加,而使得对应力-应变曲线的拟合度有所增加;邓肯张修正模型适应于反映应变软化岩土的性质,但其表现岩土物理性质的形式随着参量增加而更加复杂;反正切修正模型能较为简单地体现S型应力应变曲线的性质,表达密实点D的位置。
When Duncan’s model was applied to the triaxial test of calcareous soil, it was found that some of the stress-strain curves could not be effectively predicted. Based on the characteristics of the constitutive model and the characteristics of soil structure and stress-strain curve, the paper analyzes the role of constitutive equation parameters and introduces parameters that can effectively describe the S-stress-strain curve (D is the tangent elastic modulus Corresponding to the amount of stress-strain point). By promoting the Duncan model, establishing and correcting the arc tangent model, combined with the type of stress-strain curves of calcareous nodules, we explore the practicality and adaptability range of the constitutive model. The results show that the modified model of anti-tangent applied to strain hardening and Duncan Zhang’s modified model make the fitting degree of stress-strain curve increase due to the increase of variables. The modified model of Duncan Zhang is suitable to reflect strain softening rock However, the form of physical properties of rock and soil is more complicated with the increase of parameters. The arc tangent correction model can more simply reflect the nature of S-stress-strain curve and express the position of compact point D.