基于屈服接近度概念的尾矿坝静力稳定性分析及其与强度折减系数法的对比

Analysis on the static stability of the tailings dam with the concept of yield approaching degree comparing to strength-reduction method

建立了能考虑塑性变形、温度、饱和度和孔隙比等对材料特性影响、土-水特性曲线并采用扩展的Mo-hr-Coulomb屈服准则、以屈服接近度为安全指标的尾矿坝流固耦合有限元分析模型.分别运用上述方法和强度折减系数法对龙都尾矿坝干滩面为100 m时的饱和-非饱和渗流场和变形场的耦合响应特性进行了模拟,比较表明两者的结论吻合.但本文所采用的方法仅需一次计算就能获得坝体变形、浸润线等重要指标,以及考虑各种影响因素的屈服接近度分布,据此可直观全面地了解不同工况下坝体安全的全场信息,同时大大简化了分析过程和减少了计算工作量和人为因素的影响,有利于对尾矿坝的稳定性进行客观的评价.

Based on the extended Mohr-Coulomb failure criterion and the concept of yield approaching degree,a flow-deformation coupled finite element approach is presented for the analysis of the static stability of a tailings dam.The yield approaching degree is defined as the ratio of the existing equivalent stress to the yield stress,taking into account the effects of plastic deformation,temperature,saturation and void ratio,water and soil interaction,etc.The response of the tailing dam subjected to the coupled saturated/unsaturated seepage and deformation is simulated with the approach and strength-reduction method,respectively,and the results are in reasonable agreement.Compared with the simulation process and the safety information as strength-reduction approach,the present approach is simple and time thrift and can provide the distribution of well as important indexes such as deformation and phreatic surface by a single trial without factitious interference,which implies its availability in the analysis of the stability assessment of tailing dams.