考虑黄土结构性的修正邓肯-张模型研究

Study on modified Duncan-Chang model considering loess structural

【目的】对基于重塑土建立的邓肯-张非线性模型进行修正,使其能够应用到具有结构性的天然原状黄土应力应变计算中。【方法】基于综合结构势对结构性的研究和常规三轴试验,分析了原状黄土的力学特性和应力比结构性参数与应变的关系,利用应力比结构性参数对原状黄土的应力应变曲线进行校正。将应力比结构性参数引入邓肯-张模型中对其进行修正,使其能够满足原状结构性黄土的应力应变计算。【结果】应力比结构性参数具有较好的变化规律,经过应力比结构性参数校正后的天然原状黄土应力应变曲线由软化或弱软化型曲线变成硬化型曲线。【结论】修正后的原状黄土应力应变曲线完全可以应用邓肯-张模型进行计算,模型参数合理有效,为邓肯-张模型在原状结构性黄土中的应用提供了一种新的方法和途径。

【Objective】 Duncan-Chang nonlinear model was modified so as to be applied to the nature structural loess calculation of stress-strain.【Method】 Based on comprehensive structure potential（CSP） and structural studies and conventional triaxial test,this paper analyzed the mechanical properties of loess and the relationship between the stress ratio structural parameters and the strain.On this basis,the stress-strain curve of intact loess was corrected by the use of the stress ratio structural parameters.The introduction of the stress ratio structural parameters to Duncan-Chang model to modify it was done,so that it can meet the stress and strain calculation of original structural of loess.【Result】 The stress ratio structural parameter had good change rule.The stress-strain curves of loess became hardened by the softening or weak softening curves after the stress ratio structural parameters were corrected.【Conclusion】 The results show that the modified stress-strain curves of intact loess can apply Duncan-Chang to calculate and the model parameters are reasonable and effective.It provides Duncan-Chang nonlinear model which can be widely used in engineering with a new method and means in the application in intact structural loess.