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现有的考虑颗粒破碎的本构模型主要是通过引入颗粒破碎率来反映颗粒破碎对材料力学性质的影响,由于颗粒破碎率只是粗颗粒料在受外荷作用下的一种外部表现,在测定的其它参数中实际上已经包含了颗粒破碎的影响,因此为反映颗粒破碎而引入颗粒破碎率的方法是不合适的。基于Ueng和Chen剪胀方程,通过分析三轴剪切试验过程中的能量平衡,提出了考虑颗粒破碎的剪胀方程及其参数确定方法。将Rowe剪胀方程和考虑颗粒破碎的剪胀方程分别引入Duncan E-ν非线性模型和沈珠江“南水”双曲服面模型,通过与三轴CD剪切试验成果的对比分析和工程实例的有限元数值分析,表明所提模型可较好地反映材料的剪胀特性。如采用弹塑性模型尚能反映颗粒破碎在增加变形的同时降低了材料的强度等特性,验证了所提模型的合理性和可靠性。与现有的考虑颗粒破碎的本构模型相比,所提模型具有试验工作量小、参数少和参数物理意义明确等优点,便于在工程中推广使用。
The existing constitutive model which considers particle breakage mainly reflects the effect of particle breakage on the mechanical properties of the material by introducing the particle breakage rate. Since the particle breakage rate is only an external manifestation of the coarse particle material under the action of the external load, Of the other parameters actually include the impact of particle crushing, so to reflect the particle crushing method to introduce particle crushing rate is not appropriate. Based on the Ueng and Chen dilatancy equations, the dilatancy equation considering the particle crushing and the method for determining the parameters are proposed by analyzing the energy balance during the triaxial shear test. The Rowe dilatancy equation and the dilatancy equation considering particle breakage are respectively introduced into the Duncan E-ν nonlinear model and the Shenzhu River “Nanshui ” hyperboloid surface model. By comparison with the triaxial CD shear test results and The finite element numerical analysis of the engineering example shows that the proposed model can better reflect the dilatancy characteristics of the material. Such as the use of elastic-plastic model can still reflect the particle crushing in increasing the deformation while reducing the strength of the material and other characteristics of the proposed model to verify the rationality and reliability. Compared with the existing constitutive model which considers particle breakage, the proposed model has the advantages of small experimental workload, less parameters and clear physical meaning of parameters, which is convenient for popularization and application in engineering.