高压下尾矿材料幂函数型摩尔强度特性研究

Study of characteristics of power function Mohr strength criterion for tailings material under high pressures

高压下尾矿材料的强度特性是高尾矿坝稳定性分析的基础。理论推导了幂函数型摩尔(Mohr)强度通式S(σ)=aσn+b须满足的条件为a≥0,b≥0,1/2≤n≤1;基于高压三轴试验研究了尾矿材料的强度特征,研究表明:幂函数型摩尔强度包络线能较好地反应尾矿材料在高压下的强度特征;尾矿材料在高压作用下试验前、后的颗粒分析结果表明:当围压达到某一阈值时,尾矿材料在剪切过程中将发生颗粒破碎,对于德兴铜矿尾粉砂,阈值为1 200 kPa;对于德兴铜矿尾亚砂,阈值为1 600 kPa。研究成果可为高尾矿坝坝体稳定性评价提供理论依据。

It is necessary for stability analysis of high tailings dams to grasp the strength property of tailings material under high pressures.The theoretical derivation of a general power function based on the Mohr criterion must satisfy restrictions {,,}.The high stress traixial test results indicate that the power function of Mohr criterion reflects the strength characteristics of tailings material well under high pressures.The grain-size distribution curves of the pre-and post-test show that tailings material particles will crush in the cutting process when the confining pressure reaches or exceeds the threshold value.The threshold value for tailings silt of copper mine in Dexing is 1 200 kPa,and for tailings sub-silt of copper mine in Dexing is 1 600 kPa.Research results can provide the theoretical basis for the stability analysis of high tailings dams.