Page 63 - Trenchless Technology Piping Installation and Inspection
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PR (ft) 2 3 4
4 ft of cover or 3 times outside diameter whichever is more
PTMT
6 ft of cover or 3 times outside diameter whichever is more
MT
HDD (ft) 4 8 25 a Among other factors, minimum depth depends primarily on the type of soil and diameter of the pipe. Unstable soil conditions (such as running sand) require deeper installations, while more stable soils such as hard clays would allow for shallower installations. Also,
HAB (ft) 4 4 6 6 6 8 12 20 10 14 20 25 Minimum Depth Guidelines Based on Soil Conditions and Diameters for Trenchless Installation Methods a
PJ/UT 6 ft of cover or 3 times outside diameter whichever is more
Conditions Gravely Gravely Gravely
Soil Clayey Silty Sandy Clayey Silty Sandy Clayey Silty Sandy would allow for shallower installations.
Pipe Diameters (in.) Small (<12) Medium (12~24) Large (>24) TABLE 1.7
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