尾矿渗透破坏及其导波监测试验研究

Experimental research on seepage failure of tailings and its monitoring using guided waves

采用自主设计的尾矿渗透破坏仪,模拟上游水位不断升高,水力梯度持续增加的情况下尾矿发生渗透破坏的全过程。总结了尾矿渗透破坏现象和演化过程,分析了尾矿中的孔隙水压力和弯曲导波参数随时间的变化规律,研究了尾矿渗透破坏过程中弯曲导波信号b值和分形维数的演化规律。根据孔隙水压力和弯曲导波特征参数的变化特征,提出尾矿渗透破坏等级的评价标准。结果表明:(1)在尾矿渗透破坏过程中,孔隙水压力随着水力梯度的增加而增加,但当水力梯度增加到一定程度时,孔隙水压力会出现突降现象。(2)尾矿渗透破坏是一个循序渐进的过程,在这一过程中的弯曲导波参数表现为基本无信号、微弱信号、强信号和剧烈信号,分别对应尾矿正常运行阶段、发展阶段、破坏前期和最终渗透破坏阶段。(3)导波的b值和分形维数在尾矿最终渗透破坏前一直处于低水平状态,在临近渗透破坏时剧烈震荡。(4)通过对弯曲导波参数分析,提出了尾矿渗透破坏程度的量化指标,将尾矿渗透破坏分为4个预警级别,并用蓝、黄、橙、红4种警报颜色对应相应级别的预警。

A tailing seepage failure testing instrument designed by the authors was used to simulate the whole process of tailing seepage failure under the condition of increasing upstream water level and continuous increase of hydraulic gradient.The evolution of the pore water pressure and flexural guided wave parameters,as well as the flexural guided wave signals’b-value and fractal dimension during the experiments,were analyzed.The evaluation criteria of tailing seepage failure level were proposed based on the change characteristics of pore water pressure and flexural guided wave characteristic parameters.The results show that:(1)During the tailing seepage failure process,the pore water pressure increases with the increase of hydraulic gradient,but when the hydraulic gradient increases to a certain degree,the pore water pressure will show a sudden drop.(2)Tailing seepage failure is a gradual process,and the flexural guided wave parameters in this process can be classified into four types:no signal,weak signals,strong signals,and violent signals.The four types of signals correspond to the ordinary operation stage,development stage,pre-damage and final seepage failure stage of tailings,respectively.(3)The b-value and fractal dimension of the guided waves are at a low level before the final seepage failure stage of the tailings and violently oscillate when the final seepage failure is approaching.(4)Through the analysis of the flexural guided wave parameters,the quantitative indices of the tailing seepage failure degree are proposed,and the tailing seepage failure is divided into four warning levels.The four warning colors of blue,yellow,orange and red represent the corresponding warning level.