Environmental Engineering Reference
In-Depth Information
1000
Soil
Open fracture
Indurated clay and shale
Slope prior to failure
Birmingham sandy shale,
shaly sandstone
carbonaceous silt shale
Approximate shape
of slump
900
Zone 4
Duquesne coal shale
Ames limestone
Pittsburg redbeds
indurated clay
Zone3
Zone 2
Sandstone and shale
800
Clay shale
Zone 5
Zone 1
Failure surface
Zone 1
Indurated clay
200
300
400
500
Offset (ft)
(a)
Approximate limit
of slide
C tracks
N
L
Allegheny
river Blvd.
800
Bridge
825
85 87 900
50 ft
Open joint filled with concrete
(initial tension crack)
925
950
(b)
FIGURE 9.21
Rotational slide in rock at Brilliant Cut (Pittsburgh, Pennsylvania, March 28, 1941). (a) Generalized section
through Brilliant Cut; (b) plan of slide area. (From Hamel, J.V., Proceedings of the ASCE, 13th Symposium on Rock
Mechanics , Urbana, Illinois [1971], 1972, pp. 487-572. With permission.)
Usually, neither the volume of mass involved nor the distance moved is great; therefore, the
consequences are seldom catastrophic although slump slides cause substantial damage to
structures. If their warning signs are recognized they usually can be stabilized or corrected.
Recognition
Occurrence
Slump or rotation slides are characteristic of relatively thick deposits of cohesive soils
without a major weakness plane to cause a planar failure. The depth of the failure surface
varies with geology.
Deep-seated failure surfaces are common in soft to firm clays and glaciolacustrine, and
glaciomarine soils. Deep to shallow failure surfaces are common in residual soils, depending
 
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