ROLL NO: 11EDGCE027
DEEPSHIKHA KALA SANSTHAN
GROUP OF INSTITUTIONS
PROF. JAMBU JAIN (HOD)
CIVIL ENGINEERING DEPARTMENT
What Is Trenchless Technology?
Need Of Trenchless ?
Rehabilitation and Renovation
Techniques of Trenchless Technology
Trenchless Technology In India
What is Trenchless?
A family of methods, materials, and equipment capable of being
used for the installation of new or replacement or rehabilitation of
existing underground infrastructure with minimal disruption to
surface traffic, business, and other activities.
Trenchless technology is basically making tunnel below the
surface and installing service lines like gas pipes or
telecommunication cables without disruption to flow and
minimum damage to the environment.
Trenchless technology has been around for many decades
Auger or Jack and Bore in use for 40-50 years
Impact moles were populars for street crossings and to go under
Horizontal Directional Drilling (HDD) started to gain popularity
in late 80`s
Address at 1991 ‘ NO DIG’
Need Of Trenchless ?
Minimal disturbance to traffic
Year around construction
Reduced landscape damage
Minimal disturbance to local business
Improved construction productivity
Can access otherwise inaccessible areas
The disadvantages and difficulties encountered in conventional
trenching methods have resulted in thinking of the need for
The advantages of the trenchless technology are also responsible
for the need of this technology to be adopted in mainly urban
TWO TYPES OF TRENCHLESS TECHNOLOGY
Methods for the installation of a new pipeline or duct, including
dealing with service connections are :
Horizontal Directional Drilling
To excavate the soil, which is
transported by augur flights
operating in a casing the drive
Range 100 to 1000 mm diaUsed
for installation of steel pipes
and casings, especially under
railways & road embankments
It reduces damage to pavements
and disruption to traffic, hence
reduces social costs associated
with pipeline installations
Impact moling is a technique in which a percussive mole (soil
displacement hammer) is launched from an excavation to displace
the soil and form a bore.
This method is restricted to relatively small diameter lines in
compressible soil conditions.
The method which forms the bore hole by compressing the earth
that immediately surrounds the compacting device.
The micro tunneling boring machine is remote controlled, a laser
guided system is employed, a jacking system is used to thrust, and
continuous pressure is provided to the face of the excavation to
balance groundwater and earth pressures.
Used to describe remotely
controlled mechanical tunneling
Used extensively for sewage
work where surface disruption
has to be minimized
Noise levels and traffic
disruptions are minimized
Used for installing pressure pipes under major obstacles such as
airport runways, rivers, railway tracks and roads.
These are nowadays widely used for installing pressure pipes
under major obstacles such a motor way intersections, large rivers
and airports runways.
The first stage consists of drilling a small diameter pilot hole along
the desired centre line of a proposed line.
In the second stage, the pilot hole is enlarged to the desired
diameter to accommodate the utility line and to pull the utility line
through the enlarged hole.
As the pilot hole is being drilled, bentonite-drilling mud is pumped
down the center of the drill rods. The drill head consists of either
a jetting head or drill bit.
Before the start of back reaming the pipeline has to be positioned
on rollers in line with the hole to minimize any axial load on the
Rehabilitation and Renovation
Methods including are:
i. Pipe bursting
ii. Pipe eating
iii. Relining the existing pipes
iv. Localized repair
In this method an existing
pipe can be replaced with a
pipeline of the same or
larger dimension without
opening up the ground.
It used where the load on
the system is more than the
existing pipe can handle and
replacement is required.
Pipe eating is an online micro tunneled replacement technique.
The existing defective pipeline is crushed and removed through
the new pipeline.
Based on micro tunneling.
Defective pipe excavated together with surrounding ground.
Consists of micro tunneling shield.
Shield has larger diameter than existing pipe.
Pipe fragment can be removed by 2 methods
Relining the Existing Pipes
This method require access, usually by manholes, at both end
of the pipes.
Pipe is relined at the places where the joints have moved or
sections are missing ,but the passage should be available.
Local defects may be found in pipes are due to cracking
or joint failures.
Chemical grouting with urethane and similar materials
are used in sewer rehabilitation.
Techniques of Trenchless Technology
A. Augur boring
D. Directional drilling
Auger boring is a technique for forming a horizontal bore hole
through the ground, from a drive shaft to a reception shaft, by
means of a rotating cutting head.
The cutting head is attached to the leading end of an auger string.
Spoil is transported back to the drive shaft by the rotation of
helical-wound auger flights within the steel casing pipe. Vertical
control, using a water level, is typical.
The major advantage is that the casing is installed at the same
time as the borehole excavation takes place.
This method can be used wide variety of soil types.
This method requires different size cutting heads and augur sizes
or each casing diameter, which increases the investment in
The investment in bore, pit construction, and the initial setup is
In case of soils containing large boulders, this method cannot be
Instead pits are excavated at intervals for the mole to be placed.
The mole is then entered into the earth on the horizontal face at
the bottom of the pit. Destination pits of similar proportions are
The mole displaces the soil creating a bore for the new services
to then be pulled through.
It is a rapid, economic, and effective method of installing small
Any type of utility line can be installed using this method.
The stability of the soil around the borehole is increased due to
The investment in equipment is minimum.
Compaction method are limited in their length by reliability because
basic systems are unintelligent, unguided tools that tend to bury
themselves, surface in the middle road or damage exiting utility lines.
Ramming creates very little displacement in the surrounding
The pipe is rammed through the soil by using a device attached
to the end of wide to drive the pipe through the soil.
This method is economical for small dia pipelines.
This method is not suitable where there are solid rock formations
DIRECTIONAL DRILLING (DD)
Directional Drilling makes the impossible possible.
Generally, it is preferred for long line drilling.
Involves steer able for both small and large diameter lines. The
major advantage of directional drilling is the speed of installation
combined with minimum environmental impact. The disadvantage
of directional drilling is that the equipment is of high cost
The major advantage is the speed of installation combined with
the minimum environmental and social impact.
Long and complicated crossings can be accomplished with a
great degree of accuracy.
Sufficient depth can be accomplished to avoid other utilities.
Special equipment and very high degree of operation skill is
As the cost of equipment and the operation are high, bore length
should be sufficient in order for it to be economical.
Mainly steel pipe is being installed by this method.
TRENCHLESS TECHNOLOGY IN INDIA
Brihan Mumbai Municipal Corporation for the construction of
3m dia. Tunnel by micro tunneling.
MTNL in Delhi, kolkata installing large telephone cables by
T.T.in Delhi 185 k.m line is made by this.
Pipe line laying below river bed is impossible by open trench
method, pipe line laying below Hoogly river by this technique
is sufficient to say its importance
In Varanasi(u.p) an urgent repair for brick sewers is
successfully done by this
In kolkata 700m length and .762 dia. Iron pipe was repaired
which started leakage.
Laying of 18’ dia. Pipe of HBJ across yamuna river is
accomplished by this technique
1719m gas pipeline was laid 35m below gautam-godavari river
3 underground crossing of 24’ dia. And 350 long pipes were
completed by Indian
Oil Corporation for panipat refinery.
Advantages Of Trenchless
It reduces damages of valuable surface.
It reduces the danger of improperly compacted excavations.
It saves resources.
It is accident free.
It avoids traffic jam.
It makes the use of the line (track) of the old pipe possible.
It saves underground space (pipe busting).
It reduces the impact on the environment.
It provides the hassle-free road surface.
It is possible to lay service lines across railway track, narrow
lanes etc. When open trenching is impossible.
Presence of a canal, pond, river etc. across the root poses no
problems to the trench less technology systems.
Without disturbing the traffic and life on the surface, the lines can
be laid below ground in a much shorter time by using this
For replacement, repair and rehabilitation of old water and sewer
lines in cities, it is very helpful to use trench less technology without
disturbing the normal life on the surface.
Disadvantage of Trenchless
As the open trench is going to create obstruction roads, busy areas,
diversions have to be provided before start of any digging work.
As the obstruction is created, the traffic has to be rerouted causing
Many a time, while cutting deep trenches in congested areas
appear in the adjacent buildings.
While cutting open trenches, trees, shrubs, gardens etc. may have
to be destroyed damaging the environment.
Excavation is not necessary between access points.
Require less space underground, minimizing chances of
interfering with existing utilities or abandoned pipes are generally
quiet and nondisruptive.
Require less exposed working area & therefore are safer for both
workers & the community 30
Low labor requirements
Little site restoration required
Reduce environment Construction hazards
Reduce noise and air quality impacts
Reduce traffic congestion
Trenchless technology is the new way forward.
Jagadish Chandra, “Trenchless Technology in India: Need of the
Neww Millennium.” Civil Engineering and Construction Review
October 2000- page 48
Maninder Singh, “Techniques of Trenchless Technology In Use In
India.” Civil Engineering and Construction Review October 200-
Dr.Neeraja Lugani Sethi, “Pre- Requisites for Trenchless
Technology.” Civil Engineering and Construction Review October
2000- page 21
Sarkar A.K, “Trenchless Technology and INDSTT In India.” Civil
Engineering and Construction Review October 2000- page 13
Mohammad Najafi, Sanjiv Gokhale, Trenchless Technology, Mc
Graw-Hill Professional Publications.
Steven R Kramer, William Jesse McDonald,James C Thomson,An
intoduction to trenchless technology. 33