Study On Characteristics Of Guided Waves Generated During Tailings Seepage Failure Process

Tailings pond is an artificial structure used to store tailings in mine production.If the tailings failure accident occurs,it will inevitably impact the local people,property,and environment.More than half of the tailings failure accidents in China are caused by seepage failure.Therefore,it is of great significance to monitor and predict the seepage failure of a tailings pond.Guided wave monitoring technology uses waveguides to obtain elastic waves inside and deep in rock and soil.Since its inception,the technology has achieved many gratifying results in practical application.However,there are still many problems in applying this technology to the monitoring and early warning of a tailings pond's seepage failure.Among them,the characteristic of guided wave(elastic wave propagating in a finite-size medium is called guided wave)signals in the process of tailings seepage failure is a problem worthy of study.In this paper,the tailings seepage failure test is carried out to collect the guided wave signals in the process of tailings seepage failure.Firstly,the evolution characteristics of the strength and activity of the guided wave in the process of tailings seepage failure are analyzed.Secondly,the time-frequency characteristics and distribution characteristics of the guided wave signals' frequency-band energy are analyzed using the time-frequency analysis method.Secondly,the evolution laws of the correlation dimension and b value of the guided wave signals are analyzed.Then,the variation coefficient and information entropy are introduced to reflect the waveform shape of guided wave signals,and the evolution law of the waveform shape of guided wave signal is analyzed.The results show that:(1)The seepage failure of tailings is a gradual and slow process.The tailings seepage failure process can be divided into three stages: the early stage of tailings seepage failure,the development stage of tailings seepage failure,and the tailings seepage failure stage.The strength index and a cumulative number of guided waves have different responses to each stage of the tailings seepage failure process,which are as follows: keep relatively stable,slow growth,accelerate growth and reach the peak in the tailings seepage failure stage.(2)The energy of guided wave signals is mainly concentrated in 0-120 k Hz.There is a significant difference in the proportion of energy in each frequency band of the guided wave signals.The difference of energy distribution in the tailings seepage failure stage is further aggravated,and the energy is concentrated in 1-2 frequency bands.This phenomenon is the precursor of tailings seepage failure and can be used as the monitoring and early warning index of tailings seepage failure.(3)In each stage of the tailings seepage failure process,the changing trend of correlation dimension and b value is roughly the same,and the change is synchronous,and its evolution law can be summarized as relatively stable,slowly increasing,and accelerating increasing.The accelerated increase of correlation dimension and b value only appears in the tailings seepage failure stage.This phenomenon is the precursor of tailings seepage failure and can be used as the monitoring and early warning index of tailings seepage failure.(4)In the process of tailings seepage failure,the waveform shape of guided wave signals gradually changes from sudden type to continuous type;the waveform shape of the guided wave is determined by the guided wave event rate,while the variation coefficient and information entropy are determined by the waveform shape of guided wave signals.(5)The rapid increase of "weak dispersion" and "large information entropy" guided wave cumulative events is the precursor of tailings seepage failure,which can be used as the monitoring and early warning index of tailings seepage failure.