基于PPR无假定建模的水工沥青混凝土偏应力计算模型

Calculation model of deviatoric stress of hydraulic asphalt concrete based on projection pursuit regression non-assumed modeling

为精确描述水工沥青混凝土应力-应变关系,改变了传统的通过构建力学表达式建立本构模型的建模思路,以三轴试验数据为研究对象,提出基于采用投影寻踪回归(projection pursuit regression,PPR)的偏应力计算模型构建方法,通过与双曲线模型进行对比,分析并验证了偏应力PPR模型的有效性。结果表明:1)将PPR无假定建模技术应用于水工沥青混凝土应力-应变关系的构建中,避免了采用传统方法建模时存在的模型假定与水工沥青混凝土力学特性不相符的问题;2)所建立的偏应力PPR模型相较双曲线模型对水工沥青混凝土应力-应变曲线有更高的拟合精度和更强的预测能力,能够有效地反映水工沥青混凝土的应变软化和应变硬化特性,具有一定的工程应用价值。

To describe the stress-strain relationship of hydraulic asphalt concrete precisely,the traditional modeling idea of establishing constitutive model by constructing mechanical expressions is changed.The paper takes the triaxial test data as the research object,proposes a method of establishing the calculation model of deviatoric stress by constructing numerical function using projection pursuit regression(PPR)non-assumed modeling technology,and analyzes and verifies the effectiveness of the calculation model by comparing with the hyperbolic model.The results show that:1)the application of PPR non-assumed modeling technology to the construction of the relationship between stress and strain of hydraulic asphalt concrete avoids the problem that the model assumptions are not consistent with the mechanical properties of hydraulic asphalt concrete of traditional modeling methods.2)Compared with hyperbolic models,the established deviatoric stress PPR calculation model has higher fitting accuracy and stronger prediction ability for the stress-strain curve of hydraulic asphalt concrete,which can effectively reflect the strain softening and hardening characteristics of hydraulic asphalt concrete,and has certain engineering application value.