碾压混凝土重力坝层间应力地震响应分析

Analysis on interlaminar stresses of RCC dams under seismic load

强震作用下碾压混凝土重力坝的动力响应特征和破坏与碾压层的层状性态密切相关。基于碾压混凝土中碾压层与本体混凝土力学参数关系,以及横观各向同性本构模型,利用宏观等效单元建立了地震动作用下含碾压层影响的重力坝等效模型。利用此模型进行了地震作用下的计算,将常态混凝土坝坝体应力与碾压混凝土坝各碾压层间应力进行比较。结果表明,文中的等效单元方法能够反映出强震作用下碾压层特征对结构的动力响应特性的显著影响,并且能够大幅度提高计算效率,节约计算时间和成本。对不同碾压层等效厚度的比较可以看出,当软弱夹层厚度较大时,它对坝体层间应力的影响更为明显。

Dynamic response characteristics and destruction of RCC dams under strong earthquake are closely related to physical properties of the compacted layers. In this paper, a gravity dam equivalent model considering the impact of compaction layer under ground motion is established by using the macro equivalent unit, based on mechanical parameters relationship between the roller compacted concrete layers and the concrete bodies, and based on transversely isotropic constitutive model. A comparison between stresses of normal concrete dam and the interlaminar stresses of RCC dam is conducted based on this model. The results show that the equivalent unit method in this paper can well reflect the characteristics of compacted layers impacting on dynamic response of the structure under strong earthquakes, and can improve the computational efficiency. It can conclude that thicker weak interlayer has more effect on interlaminar stresses.