Design situations and limit states

Limit states for slopes and embankments typically involve loss of overall stability of the ground and associated structures, excessive movement, loss of serviceability, or disruption of drains in an embankment dam.

Section 12 includes an extensive list of additional limit states for embankments, including: internal erosion; surface erosion or scour; deformations leading to loss of serviceability; damage to adjacent structures; problems with transition zones; effects of freezing and thawing; degradation of base course materials; deformations due to hydraulic actions; and changes in environmental conditions.

Examples of situations where slope stability is a concern are shown in Figure 9.2.1 From left to right, these include: (top) translational slab sheet slide and block slide on a weak stratum; (middle) circular and non-circular slides; and (bottom) a large slide encompassing an otherwise adequate structure.

Each design situation must consider the construction process; previous or continuing ground movements; the effects of the slope or embankment on existing structures or slopes; vibrations; climatic variations; vegetation and its removal; human or animal activity; variations in water content or pore-water pressure; and wave action. [en 1997-1 ยง11.2(2)P]

Figure 9.2. Examples of ultimate limit states for slopes
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