摘要
渗透破坏对大坝长效安全运行构成严重威胁,时常导致大坝险情发生乃至溃决。针对土石坝多孔介质自相似特点,开展了典型级配下的砂性土、粉质黏土等主要筑坝材料的渗透破坏分形试验,提出了可作为划分渗透变形判别标准的质量分维数。在分形理论基础上,探讨了质量分维数与颗粒级配、密实度、渗透系数等物理力学参数的关系,重点研究土体渗透破坏的分形特征。研究结果表明,土体质量分维数D<2.35时,渗透破坏为流土;当2.35≤D≤2.65时,渗透破坏为管涌或流土;当D>2.65时,土体渗透破坏为管涌。结论认为可通过渗透变形后质量分维数下降的趋势,来预测渗透变形的发生和发展情况,从而减少堤坝因渗透破坏而引起的致灾隐患。
Seepage failure poses a serious threat to dam safety and long-term operation,which leads to severe dangers and even dam collapses.Based on self-similar characteristics of porous media in earth-rock dams,mass-dimensional fractal is introduced as the standard to distinguish the seepage deformation by seepage failure fractal test.The relationship between mass-dimensional fractal and grain size,compactness,and permeability are discussed,and the fractal characteristics of seepage failure are focused on.The results show that flow soil happens when D〈2.35,and piping comes out when D〉2.65,between which both of them are possible to occur.The initiation and development of seepage deformation can be predicted,and hidden danger would be reduced by analyzing the decreasing mass-dimensional fractal.
出处
《中国农村水利水电》
北大核心
2016年第3期80-83,87,共5页
China Rural Water and Hydropower
基金
水利部公益性行业科研专项“土石坝长效安全运行重大关键技术研究”(201501033)
国家国际科技合作专项“大坝原体溃决试验信息获取与挖掘技术合作研究”(2011DFA72810)
关键词
分形理论
多孔介质
渗透破坏
质量分维数
fractal theory
porous media
seepage failure
mass-dimensional fractal
