Environmental Engineering Reference
In-Depth Information
Typical permeability values for intact and
in situ
rocks are given in
Table 3.12.
Typical strength values for rock mass discontinuities (joints and shear zones) for use in
preliminary analysis are given in
Table 3.34.
3.6.2
Weathered Rock and Residual Soil
Shear strength parameters for various rock types and in situ conditions are given in
Table
3.35.
Typical engineering properties of residual soils of basalt and gneiss are given in
Table
7.5;
and for the tertiary formations of the Los Angeles area in
Table 7.9.
3.6.3
Cohesionless Soils
Common properties including relative density, dry density, void ratio, and strength as
related to gradation and
N
are given in
Table 3.36.
Relationships between
φ
and
D
R
for var-
ious gradations are given in
Figure 3.93.
Typical values for the permeability of soils are given in
Tables 3.10-
3.14.
3.6.4
Clay Soils
Common properties, including relationships between consistency, strength, saturated
ous plasticities are given in
Figure 3.94.
TABLE 3.34
Typical Strength Values for Rock-Mass Discontinuties for Use in Preliminary Stability Analysis
a,b
Defect
Condition
Strength Parameter
c
Joint surface: smooth,
Hard massive, well-interlocked or
φ
u
30-35°
unweathered rock
d,e
cemented(granite, basalt, gneiss,
sandstone, limestone)
Hard shaley or schistose (hard shale,
φ
u
25-30°
slate, phyllite,mica-schist)
Soft, laminated or schistose
φ
u
20-25°
(clay shale, talc schist,
chlorite schist)
Asperity angle
j
(add to
φ
u
)
e
Very irregular surface
j
30-40°
Average surfaces
j
5-15°
Smooth, planar surface
j
0-2°
Gouge or mylonite from
Sandy material
φ
d
24-32°
fault or shear zones
Intermediate material
φ
d
16-23°
Clayey material
φ
d
8-15°
a
After Deere, D.U.,
Proceedings of ASCE, Rock Engineering for Foundations and Slopes, Speciality Conference
,
Boulder, CO, Vol. II, 1976, pp. 55-85.
b
For FS
1.5 to 2.0,
φ
u
basic friction angle,
φ
d
drained test.
c
Generally assume c
0 for weak zones (weathered, altered, sheared), and in no case
1 tsf even (or hard)
rock surfaces when tested.
d
To
φ
u
add asperity angle j, or for analysis,
φ
φ
u
j. Joint roughness angle j defined in
Figure 3.45
e
Reduce
φ
,
φ
u
j by 5 to 10° for weathered surfaces (Equation 3.59).
f
Values for
φ
r
are generally 5 to 10° or more lower than values for,
φ
