Preparation of trenches
Page 104 OmniTrax Product Guide
1. For each trench, make two parallel cuts through the hard surface, 15 cm (6 in.) away from the
cable path (i.e., two cuts 30 cm (12 in.) apart, centered on the sensor cable route).
2. Remove the cut sections of asphalt and dig two 30 cm (12 in.) wide by 30 cm deep trenches.
OR for hard surfaces with a crushed stone layer extending to the depth of the sensor cables:
2. Dig the trenches 30 cm wide by 38 cm (15 in.) deep to accommodate a protective stone dust
or sand buffer.
3. Pour a 7.5 cm (3 in.) stone dust or sand layer in the trench so that the trench is 30 cm (12 in.)
deep (from surface level).
4. Lay the cable in the trenches.
5. Pull the cable taut and partially backfill the trench with 7.5 cm (3 in.) of stone dust, sand, or soil
as you go to hold the sensor cable in place.
6. Place cable marker tape on the stone dust, sand, or soil 7.5 cm (3 in.) above the sensor cable
(optional).
7. Backfill the trench with native soil and compact the soil.
8. Restore the cut section of asphalt.
Figure 67: Trench dimensions under a thin strip of asphalt
Note For dual trench installation keep the cable spacing to within ±5 cm
(2 in.).
For single trench installation with narrow cable spacing, keep the cable
spacing to within +2.5 cm (1 in.) (no minus tolerance).
Note Do not cover the ends of the sensor cables as ferrite beads,
connectors, and decouplers must be installed first.
Note Before backfilling the trench to ground level, install the ferrite beads and
connectors, but do not seal the heatshrink at this time (see Installing
cable fittings on page 121). Next, do the cable tests (see Cable tests on
page 146) and then do a sensitivity profile to verify the installation (see
OmniTrax calibration - Sensitivity Profile and Transmitter Power
on
page 197).
asphalt
trench
trench
38 cm
(15 in.)
30 cm
(12 in.)
stone dust or sand
30 cm
(12 in.)
7.5 cm
(3 in.)
asphalt
30 cm
(12 in.)
30 cm
(12 in.)
soil from
trench
soil from
trench
crushed stone
crushed stone
soil
To Next Page
Loading...
