堆石料变形参数的粒径尺寸相关性研究

Particle size correlation of deformation parameters for rockfill materials

堆石料变形参数的尺寸效应直接影响土石坝的变形预测,关系土石坝防渗体的变形协调,也是当前高土石坝的关键技术难题。基于前人的研究成果,根据不同尺寸试样之间的应力应变转换关系,推导了邓肯–张E–B模型各个参数与粒径的相关性。结果表明堆石料这类易破碎材料可以根据颗粒强度的粒径相关性和缩尺样的应力–应变曲线预测大尺寸试样的应力–应变关系。在邓肯–张模型中,尺寸效应较为明显的参数有φ0,K和Kb,参数Rf,n和mb是无粒径尺寸效应或尺寸效应不明显的参数。通过对比不同尺寸试样的邓肯–张模型参数的试验结果,进一步验证了该规律的合理性。

The size effect on the deformation parameters directly affects the deformation prediction of earth-rockfill dams and the deformation coordination of their seepage body. It is a key technical problem for high earth-rockfill dams. Based on the existing researches, the stress-strain relationship considering the size effect is demonstrated, and the particle size correlations for parameters of the Duncan-Chang model are deduced. The results show that the stress-strain relationship of samples with larger particles for crushable rockfill materials can be predicted based on the size-related strength of single particle and stress-strain curves of samples with smaller particles. In the Duncan-Chang model, the parameters with obvious size effect are φ0, K and Kb. The remaining parameters, such as Rf, n and mb, are invariant parameters or have no significant size effect. The rationality of this rule is further verified by comparing the predicted Duncan-Chang model parameters with the test results for samples with different particle sizes.