SPEL Vortceptor, Руководство по установке

Страница: 6 / 14

6 Installation Manual
Vortceptor
D. BED AND
BACKFILL
Proper backfill selection and compaction is required for
a proper installation. The allowed backfills are shown
in Table D-1 along with the degree of compaction
required.
TABLE D-1
BED AND BACKFILL COMPACTION
Soil type-pipe bedding
material (Unified Soil
Classification System -
see Table D-2)
Minimum Degree of
Compaction Required*
Fine - grained soils
(Liquid Limit < 50) with
medium to no plasticity
with less than 25% coarse
grained particles.
CL, ML, ML - CL
High
Fine grained soils (Liquid
Limit < 50) with medium
to no plasticity with more
than 25% coarse grained
particles.
CL, ML, ML - CL
Moderate
Coarse grained soils
containing more than 12%
fines.
GM, GC, SM, SC
Moderate
Coarse grained soils with
less than 12% fines.
GW, GP, SW, SP
Slight
Coarse grained soils with
less than 12% fines.
GW, GP, SW, SP
Dumped
* Degree of compaction:
• Dumped - No compaction effort.
• Slight - Some compactive effort. In-place density
<85% standard compaction. Or < 40% modified
compaction.
• Moderate - Intermediate level of compactive
effort, In-place density >/=85% and < 95% standard
compaction, or >/=40% and <70% modified
compaction.
• High - Considerable compactive effort. In-place
density >/= 95% standard compaction, or >/= 70%
modified compaction
• The difference in the “dumped” and “slight” degree
of compaction values are significant and are based
on the method of construction, not the measured
densities.
• “Dumped” means that there is absolutely no
compaction of the embedment soil.“Slight” means
there was something done that increased the soil
density, even if minor, such as water settling, jet-
ting, flooding, equipment travel, and in some cases,
foot traffic.
• For stable soils (cohesion ≥ 36 kpa and / or a
bearing capacity ≥ 170 kpa a minimum 300mm of
backfill must be placed around the wetwell.
• For unstable soils (cohesion ≤ 36kpa and ultimate
bearing capacity ≤ 170 kpa).
• Wetwells 1200mm diameter or smaller require
a minimum 600mm of backfill around the entire
circumference of the wetwell.
• Wetwells larger than 1200mm diameter require
a minimum backfill of ½ the wetwell diameter
around the entire circumference of the wetwell.
• If muck, bog or peat are present, consult with a
Geotechnical Engineer for backfill and excavation
requirements.
• For permafrost conditions, consult with a Geotech-
nical Engineer for backfill and excavation require-
ments.
Keep backfill dry and free of ice in freezing conditions.
Ensure that no foreign objects such as large stones,
concrete clumps, tree roots/limbs, or debris is in the
backfill surrounding the wetwell.
Prevent large surges of backfill from displacing the
wetwell.
TABLE D-2
LETTER AND
DEFINITION SECOND LETTER
AND DEFINITION
G Gravel
S Sand
M Silt
C Clay
O Organic P Poorly Graded
(uniform particle sizes)
W Well Graded
(diversified particle sizes)
H High Plasticity
L Low Plasticity