不同模型参数对面板堆石坝应力变形的影响研究

Study on influences from different model parameters on stress and deformation of concrete face rockfill dam

为探讨室内三轴压缩试验及大型现场压缩模量试验在研究面板堆石坝坝筑坝材料实际力学特性的科学合理性,结合某100 m级混凝土面板堆石坝工程,分别对各区筑坝材料进行上述两种试验研究,其中对现场压缩试验成果采用基于免疫遗传算法的反演方法计算得到材料的邓肯E-B模型参数,同时整理室内压缩试验成果得到另一组参数。基于以上两组参数,运用三维非线性有限元法进行数值计算。计算结果显示,室内三轴试验过程因为缩尺试验料与实际筑坝料之间较大的颗粒粒径差异,计算得到的坝体及面板变形协调性较差,试验成果难以客观反映材料实际的力学性质,建议加强对缩尺效应及颗粒破碎机理的进一步研究以及直接对原级配筑坝材料试验方法的探索。

In order to discuss the scientific reasonability of the indoor triaxial compression experiment and the large-scale on-site compressive modulus experiment in the aspect of the study made on the actual mechanical properties of the dam construction materials for concrete face rockfill dam, both the experimental studies mentioned above are respectively made on the dam construction materials for all the construction zones in combination with a 100 m-grade concrete face rockfill dam project, in which the Duncan E-B model parameters of the materials are obtained from the calculation with the immune genetic algorithm-based inversion method for the result from the indoor triaxial compression experiment, while another set of parameters is obtained through sorting out the results from the indoor compression experiment. Based on both sets of the parameters, the 3-D nonlinear finite element method is used for the relevant numerical calculation. The calculation result shows that due to the larger difference between the particle sizes of both the scaled experiment materials and the actual dam construction materials, the coordination between the deformations of both the dam body and the dam face obtained from the calculation during the indoor triaxial experiment is poor, and then the experiment result is difficult to objectively reflect the actual mechanical properties of the materials, thus it is suggested that the further study on the scale effect and the mechanism of particle breakage as well as the direct exploration on the experiment method for dam construction materials of the original gradation are necessary to be strengthened.