面板裂缝对积石峡水电站大坝渗流场影响的数值模拟

基于面板等宽缝隙稳定流的运动规律,采用裂缝面单元法建立了混凝土面板裂缝的渗流计算模型,实现了渗流全场和裂缝渗流分析的统一。在此基础上编制了含裂缝面单元的三维渗流场有限元计算软件GWSS,利用该软件对积石峡水电站大坝正常运行和发生竖向裂缝的工况进行渗流场分析,获得了大坝面板产生裂缝后的渗流场分布规律。计算结果表明,不同位置、长度和宽度的面板裂缝对大坝渗流场、渗流量和渗透比降影响不同,上部裂缝对大坝渗流场的影响较小,下部和中部裂缝的影响较大。一旦面板发生裂缝,面板附近、垫层和过渡区出现较大渗透比降,且随着与裂缝距离的增大而快速衰减。

Numerical simulation of influences of cracks on seepage fields of Jishixia Hydropower Station

Based on the motion law of the steady flows in aequilate cracks,a numerical model for the cracks in concrete face rockfill dams was established by use of the interface element method.The unification of the seepage analysis in cracks and other sections was achieved.Accordingly,a finite element analysis software—ground water simulation system(GWSS) for 3D seepage fields of concrete face rockfill dams with crack elements was compiled.By means of the GWSS,the seepage fields of Jishixia Concrete Face Rockfill Dam under two working conditions without cracks and with vertical cracks were analyzed.The distribution laws of the seepage fields were obtained after the occurrence of cracks in the face.The numerical results show that the cracks at different locations with different depths and widths have different influences on the seepage fields of the dam,seepage discharge and permeability gradient.The cracks appeared at the upper part of the dam exert less influences on the seepage fields than those at the lower and middle parts.Once cracks appear in the face,large permeability gradient will be aroused in the surrounding areas of the face and transition materials in the cushion layer and it rapidly decays with the increase of the distance from the cracks.