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Laying Conditions
Trench Type 2: Embedment with very light compaction, greater than 75% standard Proctor density.
Trench Type 3: Embedment with light compaction, greater than 80% standard Proctor density.
Trench Type 4: Embedment with medium compaction, greater than 85% standard Proctor density.
Trench Type 5: Embedment with high compaction, greater than 90% standard Proctor density.
Notes:
A layer of loose soil at least 100mm deep should be used as lower bedding for all trench conditions.
INT Laying Conditions
Soil
Designation |
Soil
Description |
(o) |
 |
Cs
(kg/m2) |
fC |
(kg/m3) |
Kn |
| Laying Condition |
| 2 |
3 |
4&5 |
| CLAY 1 D |
CLAY OF MEDIUM TO LOW
PLASTICITY, LL<50,
<25% COARSE PARTICLES
[CL & CL-ML] |
0 |
0 |
1465 |
.80 |
1440 |
.40 |
.60 |
.85 |
| SILT 1 D |
SILT OF MEDIUM TO LOW
PLASTICITY, LL<50,
<25% COARSE PARTICLES
[ML & ML-CL] |
29 |
.75 |
0 |
0 |
1440 |
.40 |
.60 |
.85 |
| CLAY 2 C |
CLAY OF MEDIUM TO LOW
PLASTICITY WITH SAND
OR GRAVEL, LL<50,
25-50% COARSE PARTICLES
[CL] |
0 |
0 |
1465 |
.80 |
1440 |
.60 |
.85 |
1.0 |
| SILT 2 C |
SILT OF MEDIUM TO LOW
PLASTICITY WITH SAND
OR GRAVEL, LL<50,
25-50% COARSE PARTICLES
[ML] |
29 |
.75 |
0 |
0 |
1440 |
.60 |
.85 |
1.0 |
| GOOD SAND A & B |
CLEAN SAND,
>95% COARSE PARTICLES
[SW & SP] |
36 |
.80 |
0 |
0 |
1600 |
.60 |
.85 |
1.0 |
Table 3. Suggested values for soil parameters and reduction constant, Kn. Definition "course particles" - held on No. 200 sieve. See Table 4 for more detailed soil descriptions.
Notes:
For conservatism, values for  shown in Table 3 and used in this procedure are lower than the soil weight values used to calculate earth loads in ANSI/AWWA C150/A21.50. All other values in Table 3 assume saturated soil conditions and were also selected as such for conservatism. |
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