堆石料的湿化变形模型

Slaking deformation model for rockfill materials

堆石料的湿化变形严重影响心墙堆石坝初蓄水时的安全。通过分析堆石料单线法湿化试验数据发现,堆石料的湿化应力水平与湿化轴向应变成双曲线关系,但也有学者认为是指数函数关系,通过比较发现双曲线关系表述更佳。分析大量单线法试验数据发现,湿化过程中体积应变增量与轴向应变增量的比值保持不变。由此并根据非线性弹性理论,提出了一个堆石料的湿化本构模型,给出了湿化割线模量与湿化泊松比的表达式。与改进的沈珠江湿化模型比较,该湿化模型与试验数据拟合的更好。研究显示,采用传统Prandtl-Reuss流动法则计算得到的湿化应变在高湿化应力水平下偏小。

The safety of core wall type rockfill dams during reservoir impounding is greatly affected by the slaking deformation of upstream shell materials. The slaking deformation of the rockfill materials is analyzed using the triaxial slaking tests, in which the specimens with natural water content are compressed to various deviatoric stress levels, and then saturated by water flow fi＇om the bottom while the stress condition remains unchanged. The results show that there is a hyperbolic relationship between the slaking axial strain and the stress level before slaking for rockfill materials. Compared with the exponential function expression for the relationship between the slaking axial strain and the stress level, the hyperbolic expression is more suitable. Plenty of test data show that the ratio between the volumetric strain increment and the axial strain increment remains constant during sample saturating. Based on the above experimental findings, a simple model is proposed for predicting the deformation of rockfill materials induced by slaking, in which, the slaking secant modulus and the slaking Poisson＇s ratio are expressed. Comparied with the modified Shen Zbu-jiang＇s slaking deformation model, the curves calculated by the proposed model are more in good agreement with the experimental data. And the research shows that the slaking deformation calculated by traditional Prandtl-Reuss flow rule is smaller than the model numerical value under the high slaking stress level.