RELATIVE INSTABILITY OF COLLUVIUM-FILLED BEDROCK DEPRESSIONS
RELATIVE INSTABILITY OF COLLUVIUM-FILLED BEDROCK DEPRESSIONS
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DOI：
10.1002/esp.3290150404
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发表时间：
1990-06-01
影响因子：
3.3
通讯作者：
TIPPETT, JM
中科院分区：
文献类型：
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作者：
CROZIER, MJ;VAUGHAN, EE;TIPPETT, JM
风化层滑坡通常发生在崩积物填充的基岩凹陷处，而不是山脊，马刺或具有平面基岩表面的场地。新西兰惠灵顿基岩洼地崩积层的排水直剪试验表明，所有样品中均存在粘聚力，这表明累积沉积物的厚度可能成为稳定性的限制因素。临界深度的范围内的坡度角进行了计算（假设条件的无限极限平衡），并进行了比较的深度/角度关系的抑郁症和interdepression风化发生在现场。结果表明，在饱和条件下，凹间风化层厚度不足以允许滑坡的发展。另一方面，崩积物填充的基岩洼地通常超过临界深度，在没有任何显著的根凝聚力的情况下，必须被认为是易受滑坡影响的。沉积物的年龄和大量未破坏的崩积物填充的基岩洼地表明，它们在冰后期的大部分时间里都是不活动的。稳定性分析，通过观察滑坡的发生情况进行了验证，表明最近的不稳定是由砍伐森林造成的。
Regolith landslides commonly occur in colluvium‐filled bedrock depressions rather than on ridges, spurs, or sites with planar bedrock surfaces. Drained direct shear tests of colluvium from bedrock depressions in Wellington, New Zealand, indicate the presence of cohesion in all samples, suggesting that thickness of accumulated deposits may become a limiting factor for stability. Critical depths for a range of slope angles were calculated (assuming conditions of infinite limiting equilibrium) and compared to the depth/angle relationships for depression and interdepression regolith occurring in the field. The results indicate that, under saturated conditions, interdepression regolith is not thick enough to permit the development of landslides. Colluvium‐filled bedrock depressions, on the other hand, generally exceed critical depth and must be considered susceptible to landsliding in the absence of any significant root cohesion.The age of deposits and the abundance of unfailed colluvium‐filled bedrock depressions suggest that they have been inactive for most of post glacial time. Stability analysis, verified by observing the occurrence of landslides, indicates that recent instability has been brought about by deforestation.