Page 71 - Trenchless Technology Piping Installation and Inspection

New Pipeline Installations 41

• Lack of proper work gear [personal protection equipment
(PPE)], such as lack of insulated boots and gloves (in HDD)
and eye protection glasses.
• Use of machine power to change back-reamers, cutterhead or
other tools.
• Eye injuries from high-pressure drilling, other fluids, or fly-
ing objects.
• Caught-in/crushed-by accidents from rotating/moving
components.
• Fire and/or explosion from breached gas lines.
• Lack of safety training of crew and/or lack of “tool box” or
safety meetings.
• Improperly cutting unrestrained or spooled plastic pipe.
• Lack of good communication (hand signals, two-way radios,
etc.) among machine operators and crew members.
• Lack of good planning and job site organization, such as
assigning responsibilities and tasks to subcontractors, parties,
or organizations that do not have the type of expertise and
authority required to conduct those tasks.

Loose, cohesionless, and granular soils are more susceptible to
borehole collapse if a casing or a pipe is not advanced properly
while the soil is being excavated. Pipe-jacking and horizontal auger-
boring are most affected by this type of soil with respect to tunnel
or borehole collapse or ground subsidence.
The main concern with pipe bursting (see also Chap. 6) is sur-
face heaving which potentially can cause outward ground displace-
ment along the pipe alignment. The displacement is typically local-
ized, and their effects dissipate rapidly from the bursting operation.
Some causes for displacement or upheaval during pipe bursting
include

• Shallow depth of the existing pipe
• The ground displacement is directed upward
• The new pipe diameter is significantly larger than that of the
existing pipe
Ground displacements in pipe bursting can cause damage to nearby
utilities if they are within 2 to 3 times the diameter of the new pipe.
Ground vibrations can affect the surrounding soil and adjacent utili-
ties and structures within a few feet of pipe alignment. This can be
caused by pneumatic pipe bursting, as well as pipe ramming.
As a final word, a safe and productive construction project starts
with a good plan and follows with implementing that plan (like the