Environmental Engineering Reference
In-Depth Information
FIGURE 6.37
Parallel ridges in sedimentary rocks
foldedinto a monocline in an arid
climate (hogbacks). Mesas are
formed where beds are horizontal.
FIGURE 6.38
SLAR image of Harrisburg and the Appalachian Mountains of central Pennsylvania. (Courtesy of USGS, 1984.)
By Spacing
The rock mass is designated according to spacing between joints as solid (
10 ft),
massive (1-3 m)(3-10 ft), blocky or seamy (30 cm-1 m)(1-3 ft), fractured (5-30 cm)(2-12
in.), and crushed (
3 m)(
5 cm)(
2 in.), as given in
Table 5.23.
Characteristics
Physical
Joints are characterized by spacing as defined above, width of opening, continuity or length,
and surface roughness or configuration. They can be clean or can contain filling material. All
