Page 267 - Engineering Rock Mass Classification_ Tunnelling, Foundations and Landslides
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Chapter 17 Types of Failures of Rock and Soil Slopes 227
and gives examples of typical materials in which failures occurs (Goodman & Kieffer,
2000). Adversely oriented (key) blocks move out first followed by other wedges or
blocks. When sliding opportunities are inhibited, rotation of blocks may take place, caus-
ing toppling, buckling, block slumping, or torsional failures.
It is important to realize that theoretically all that is needed to stabilize a rock slope is to
anchor the “key” or worst oriented wedge or block of the rock mass. Seepage erosion is also
frequent enough to collapse the toe of slopes gradually in soils or soluble rock slopes. Top-
pling failures can be deep, large, and potentially rapid. Spillways can cause a large amount
of erosion of valley slopes and slope failure (see also Figures 17.13 through 17.16).
FIGURE 17.13 (a–e) Rock slumping and (f–h) toppling (use TOPPLE, UDEC, 3DEC). (From
Goodman and Kieffer, 2000)
