尾矿坝边坡土石混合体强度遇水软化的规律研究

为了揭示露天矿土石边坡的稳定性影响因素,开展土石混合体强度遇水软化的试验研究。首先介绍了制作该试样的方法和试样微观结构特点,然后分别对天然和饱和状态的试样开展三轴压缩试验,得到了3种围压的应力-应变曲线,最后分析了试样强度软化的规律和机制。结果表明:由SEM图像显示土石混合体的微观裂隙发育;三轴应力应变曲线经历了线弹性变形、塑性变形和破坏软化3个阶段;饱和试样的峰值强度大幅低于天然状态下的试样,且软化系数随围压增加而减小;土石混合体的强度软化主要是因为试样经过水的入渗后孔隙结构出现不均匀应力,这也是其强度软化的本质原因。

Study on the Strength Softening of Soil-Rock Mixture in Tailings Dam Slope

In order to reveal the influencing factors of the stability of soil-rock slope in tailings dam slope, an experimental study on the strength of soil-rock mixture by water is carried out. Firstly, the method of preparing specimens and the microstructure characteristics of the specimen are introduced. Then triaxial compression tests are carried out on the natural and saturated specimens, and the stress-strain curves under three confining pressures are obtained. Finally, the law and mechanism of strength softening of the specimen are analyzed. The results show that the micro-cracks of soil-rock mixtures are common by SEM images;the triaxial stress-strain curves have undergone three stages:linear elastic deformation, elastic-plastic deformation and failure softening;the peak strength of saturated specimens is much lower than that of natural specimens, and the softening coefficient decreases with the increase of confining pressure;the strength softening is mainly due to the heterogeneous stress in the pore structure after water infiltration, which is the essential reason for strength softening of soil-rock mixture.