饱和尾矿粉土动力特性试验研究

Experimental Study of the Dynamic Characteristics of Tailings Silts

摘要:

通过动三轴试验研究某尾矿粉土的动强度特性与孔压特性,试验在围压100、200和300 kPa与固结比1.0和2.0条件下进行。结果表明:(1)在循环荷载作用下,等压固结时饱和尾矿粉土全部液化;偏压固结时饱和尾矿粉土未发生液化;(2)各向等压固结时,选取双幅动应变达到5%作为破坏标准;偏压固结时,选取总应变达到5%作为破坏标准;(3)围压越大,τ_d/σ₀'-N_f曲线越高,动剪应力比τ_d/σ₀'与破坏振次N_f在对数坐标图上表现出良好的线性关系,可以采用对数函数来拟合τ_d/σ₀'-N_f关系曲线;(4)固结应力条件相同时,动应力σ_d变化对尾中砂的孔压增长u_d/σ₀-N/N_f关系曲线基本上没有影响;固结应力比K_c一定时,固结围压σ₃越大,u_d/σ₀'-N/N_f关系曲线越高;(5)尾矿粉土孔压发展模式在等压固结和偏压固结时不同,固结比K_c=1.0时,可采用幂函数表达式来描述尾粉土孔压发展;固结比K_c=2.0时,可用对数函数来模拟其发展。

Abstract:

Based on dynamic triaxial tests conducted on tailings silts under different consolidation conditions, the dynamic strength, and developing characteristics of dynamic pore water pressure of tailings silts were studied. The cell pressures used were 100, 200, and 300 kPa, and the consolidation ratios were 1.0 and 2.0. The results indicated that saturated tailings silts underwent liquefaction under isotropic consolidation conditions and did not experience liquefaction under anisotropic consolidation conditions. The failure criterion under the isotropic consolidation condition was the 5% double amplitude strain condition, and the criterion under the anisotropic consolidation condition was the 5% total strain condition. Under the same consolidation ratio, the relationship of τ_d/σ_d and N_f of different cell pressures could not be normalized. The relationship of τ_d/σ_d and N_f could be described by a logarithmic function. Under the same consolidation condition, the relationship of u_d/σ_d-N/N_f was the same. Under the same consolidation ratio, the cell pressures had a certain influence on the relationship of u_d/σ_d-N/N_f.When the consolidation ratio was K_c=1.0, the pore pressure developed characteristics that could be described by a power function, and the pore pressure developed characteristics under K_c=2.0 that could be described by a logarithmic function.