Stability of Colluvial Slopes

该研究计划解决了建立在崩积层上的天然和人工边坡的不稳定性。 （崩积层由残积土和搬运土的混合物组成。） 当这种材料是斜坡的一部分时，由于重力引起的持续下坡运动，混合物持续处于接近破坏的状态。 由于崩积层是一种非常常见的表层存款，这种故障模式有重要的影响，创造，运作，这种不稳定性的例子包括1996年3月俄亥俄州一个135英亩的垃圾填埋场的边坡破坏--这是城市固体废物填埋场有史以来最大的边坡破坏--以及1981年9月圣路易斯大坝的上游边坡破坏。根据这些和其他最近的案例历史，似乎可以在天然和人工边坡下的粘性崩积物中调动排水剩余剪切强度，其不利影响是需要更平坦的边坡来设计以防止破坏。 这导致自然斜坡的开发面积缩小，填埋场的空间或容量减少，要么限制扩张，要么需要从扩张区域和/或现有废物下挖掘崩积层，成本高昂。该项目包括实地案例历史研究以及分析和实验技术的结合。 本项目的目标之一是为建立在崩积层上的天然和人造斜坡的建造/扩建提出设计建议。

This research program addresses the instability of natural and man-made slopes founded on colluvium. (Colluvium consists of a mixture of residual and transported soils.) When this material is part of a slope, the mixture is continually in a near-failure state because of constant downslope movement caused by gravity. Since colluvium is a very common surficial deposit, this failure mode has important implications for the creation, operation, and/or expansion of the large number of natural and man-made slopes that are founded on this material.Examples of such instability include the March 1996 slope failure of a 135-acre landfill in Ohio -- the largest slope failure ever in a municipal solid waste landfill -- and the upstream slope failure of the San Luis Dam in September 1981.Based on these and other recent case histories, it appears that a drained residual shear strength can be mobilized in cohesive colluvial materials underlying natural and man-made slopes, with the adverse effect that a much flatter slope is required to design against failure. This results in a smaller area for development in natural slopes and reduced airspace or capacity in landfills, either by limiting the expansion or requiring the expensive excavation of colluvium from the expansion area and/or from under the existing waste.The project includes a study of field case histories and a combination of analytical and experimental techniques. A goal of this project is to develop design recommendations for the construction/expansion of natural and man-made slopes founded on colluvium.