Significant reduction in the brittleness of sandy silt/silty sand tailings at high stresses has frequently been observed in laboratory element testing due to curvature of the critical state line and the limiting compression curve. This has led to discussions regarding the range of effective stresses across which such materials can exhibit brittle undrained shearing such that flow liquefaction could occur. However, much testing of such tailings appears to involve saturation of the tailings under relatively low-confining stresses. This differs from the potential in situ loading within a filtered tailings stack, where material placed in a loose, unsaturated state may be subjected to significant overburden pressures prior to potential subsequent saturation. A series of isotropically consolidated triaxial tests were carried out on sandy silt gold tailings to investigate the effects of the saturation process of loose moist-tamped specimens occurring at different confining stresses. The tests indicated much looser states were achievable when saturation occurred at higher confining pressures, with resulting undrained shearing for such specimens being of similar magnitudes of brittleness as observed in flow liquefaction case histories. Consideration of saturation overburden pressure of filtered tailings stacks therefore appears warranted.

中文翻译：

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饱和围压对砂质粉砂尾矿可达密度和剪切行为的影响

由于临界状态线和极限压缩曲线的曲率，在实验室元件测试中经常观察到高应力下砂质粉砂/粉砂尾矿的脆性显着降低。这引发了关于有效应力范围的讨论，在该范围内，此类材料会表现出脆性不排水剪切，从而可能发生流动液化。然而，对此类尾矿的许多测试似乎都涉及尾矿在相对低围压下的饱和。这不同于过滤后的尾矿堆内潜在的原位加载，在这种情况下，处于松散、不饱和状态的材料可能会在潜在的后续饱和之前受到显着的上覆压力。对砂质粉砂金尾矿进行了一系列各向同性固结三轴试验，以研究不同围压下松散湿夯试样饱和过程的影响。测试表明，当在较高围压下发生饱和时，可以实现更松散的状态，导致此类样本的不排水剪切具有与流动液化案例历史中观察到的相似程度的脆性。因此，考虑过滤尾矿堆的饱和覆盖压力似乎是必要的。此类样本的不排水剪切具有与流动液化案例历史中观察到的相似程度的脆性。因此，考虑过滤尾矿堆的饱和覆盖压力似乎是必要的。此类样本的不排水剪切具有与流动液化案例历史中观察到的相似程度的脆性。因此，考虑过滤尾矿堆的饱和覆盖压力似乎是必要的。