离子吸附型稀土矿剪切力学特性及微震信号特征

为了研究稀土矿滑坡发生剪切破坏时的力学性质，以赣南离子吸附型稀土矿为研究对象，运用微震监测技术在室内环境下对重塑土试样开展了直接剪切试验，利用微震监测记录设备同步采集稀土试样试验过程中的微震信号，对以含水率表征的不同浸渗状态下试样的力学特性和微震信号特征进行了研究。结果表明：（1）随着试样含水率的增大，黏聚力显著下降，趋于饱和阶段时黏聚力下降速率减缓，由应变软化型转变为应变硬化型。（2）剪切过程波形幅值短时大幅提升，时频和波形图像对比分析表明存在微震信号且其主频率为10~20 Hz，含水率变化并不会影响信号主频；随着含水率的增加，剪切过程信号具有更高峰值振幅，整体释放能量增加，由主震型向群震型演变。研究结果可作为稀土矿发生滑坡破坏时微震信号的判别依据。

Shear Mechanical Properties and Microseismic Signal Characteristics of Ionadsorption Rare Earth Ore

The in-situ leaching process is used to mine ion-adsorption rare earth ore.Due to the infiltration and seepage of leaching solution，it is easy to induce landslide instability，and shear failure is considered to be the main failure mode.In order to study the mechanical properties of shear failure of the orebody landslide，the ion adsorption type rare earth ore was taken as the research object，and the microseismic monitoring technology was used to carry out the direct shear test of the remolded soil sample in the indoor environment.The mechanical properties and microseismic signal characteristics of the specimens under different impregnation state were studied，and the influence of water content on the shear strength of the samples and the change process of shear stress-displacement under different normal stress conditions during the shear failure process were obtained.At the same time，microseismic monitoring and recording equipment was used to collect microseismic signals in the test process of rare earth samples simultaneously.The frequency domain characteristics of the test microseismic data were obtained by fast Fourier transform of the signal based on Python open source software Scipy.The corresponding waveform，time-frequency and spectral images were analyzed to obtain the spectral characteristics of the microseismic signals and the energy distribution characteristics in the frequency domain during the shear process of samples with different water content.The results show that：（1）With the increase of water content，the cohesion of rare earth samples decreases，and the failure characteristics change from plastic failure to viscous failure，and the failure behavior changes from strain softening to strain hardening.For the samples with the same water content，the strain softening characteristics of the samples are more significant with the increase of the consolidation normal stress，and there is an obvious peak strength when the water content is low.（2）The background noise does not affect the results，and the amplitude of the microseismic signal jumped significantly in a short time during the shear process.The comparative analysis of time-frequency and waveform images show that the microseismic signal existes and the main frequency is 10~20 Hz，and the change of water content does not affect the signal main frequency.With the increase of water content，the shear signal has a higher peak amplitude，the overall released energy increases，and the main shock type changes to the group shock type.（3） The signal waveform and spectrum image reflects the rare earth sample shear energy evolution characteristics of upper and lower when the soil relative sliding，including extrusion，rupture，friction，collision between particles and the formation of crack behavior such as the release of the micro size of the strength of the shock wave energy and frequency distribution，microtremor signals as rare earth soil internal activities forward the external manifestations of form.The results can be used as the discriminative basis for the microseismic signal of landslide in ion-adsorption rare earth ore.