A number of recent tailings storage facility (TSF) failures has been indicated through post-failure investigations to have been triggered in tailings that were under drained conditions up to the initiation of instability. Such field-scale behaviour is consistent with many laboratory element studies on drained triggering of instability. However, essentially all available data on the drained initiation of instability has been carried out under conditions where the principal stress angle (α) is zero. This is despite the principal stress angle in zones of TSFs where instability is likely to be triggered being below-slope, where α is higher than zero. To assess the implications of anisotropy on the drained initiation of instability, the limited data available that enables assessment of the effects of α on instability in undrained testing is referenced. These data suggest that the likely range of principal stress angles below-slope areas of TSFs are such that anisotropy should be considered in estimating relevant triggering stress ratios. The need for more experimental data of drained triggering of instability at principal stress angles relevant to below-slope conditions is outlined.

中文翻译：

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各向异性对排水静态液化触发的影响

通过故障后调查表明，最近有许多尾矿存储设施（TSF）发生故障，这些情况是在排干条件下直至引发不稳定的尾矿中触发的。这种现场规模的行为与许多关于排水引发不稳定性的实验室元素研究一致。但是，基本上所有有关失稳引发的可用数据都是在主应力角（α）为零的条件下进行的。尽管在TSF区域中的主应力角是可能会引发失稳的TSF区域，但低于坡度，其中α大于零。为了评估各向异性对排水失稳引发的影响，参考了可用于评估不排水测试中α对不稳定性影响的有限数据。这些数据表明，在TSFs坡度以下的主应力角的可能范围是，在估计相关的触发应力比时应考虑各向异性。概述了需要更多的实验数据，以在与斜坡以下条件相关的主应力角下排水引发失稳。