基于子结构的精细化特高面板坝面板挤压破坏机理研究

Study on Extrusion Damage Mechanism of Concrete Face of Super-high Concrete-Faced Rockfill Dam Based on Substructure

为研究特高面板堆石坝运行期面板挤压破坏发生机理和特征,结合金沙江拉哇特高面板堆石坝工程,采用河海大学统一广义塑性模型,在考虑堆石料流变过程遗传效应下,对坝体进行三维有限元计算.认为堆石体流变和波动水荷载影响下面板接触效应是发生挤压破坏的本质原因.基于有限元分析结果,建立面板-缝子模型结构进行精细化分析,通过整体网格与面板-缝子模型共享节点位移场的回归拟合,对子模型二次建模计算.计算结果表明:处于河床处的面板接缝处表面部位,在坝高上部约1/3处容易发生应力集中,最终导致面板混凝土发生挤压破坏.

In order to study the mechanism and characteristics of super-high concrete-faced rockfill dams(CFRD)under operation period,a unified generalized plastic model of Hohai University was used to perform three-dimensional finite element calculations of the Lawa super-high concrete-faced rockfill dam body in Jinsha river under consideration of the genetic effects of the rockfill material rheological process.It is considered that the mechanism of extrusion contact under the influence of rock pile rheology and fluctuating water load is the essential reason for the occurrence of extrusion damage of concrete slabs.Based on the results of three-dimensional finite element analysis,the structure of the model is established for refinement analysis.By sharing the overall and local displacement fields,the submodel is modeled and calculated again.The calculation results show that the stress concentration is easy to occur at about 1/3 of the upper part of the dam height at the surface of the panel joint at the riverbed,which eventually leads to the extrusion failure of the panel concrete.