-
8/9/2019 Geotechnical Instruments
1/5
SETTLEMENT MARKERS
The settlement marker is used to measure a localised settlement or heave of roads, slopes,
embankments, utility pipes and cables.
INSTALLATION AND MONITORING
Concrete Nail
Concrete Nail
Painting
Concrete Structure
5 0 m m
Schematic diagram of installed settlement marker in soil
Schematic diagram of installed settlement
marker on concrete
Cross‐section of
Utilities/Services 10 cms
Backfill soil
75 mm dia Heavy duty
PVC pipe with Cap
16 mm dia mild steel rod
50x50x4mm steel plate
V a r i e d L e n g t h
Backfill
soil
Schematic diagram of installed settlement marker on utility
Settlement Marker on Concrete
Installed
on
a
Pavement
Settlement Marker for Utility
services Settlement Marker in Ground
The monitoring of settlement marker is carried out by leveling survey and readings are taken at regular intervals to
check any settlement or heave.
8 0 0 m i n i m u m
100Ф PVC or
Steel Tube
Convex End
Sand Fill
75 mm Ф hole filled with
cement grout after
placing‐in the steel rod.
25Ф Steel rod
Concrete to be
painted in yellow
Concrete
-
8/9/2019 Geotechnical Instruments
2/5
GROUNDWATER STANDPIPE
Measures fluctuation of ground water level. It is used as part of a system for early detection
of water loss that could cause ground settlement.
INSTALLATION
MONITORING
Schematic
diagram
of
ground
water
stand
pipe
Bottom Cap
Ground
Level
Protective
Cover
Coarse Grain Sand
Bentonite Pellets
Perforated PVC Pipe
Water level indicator
A cap and protective box is placed
over
the
water
standpipe
tube
opening to prevent disturbance.
Ground
water
level
is
measured
by
using
water
level
indicator.
The
probe
of
water
level
indicator
is
lowered
down
into
the water standpipe until light or buzzer indicates contact with the water. Depth to water level is measured from the
measuring tape attached to the indicator.
-
8/9/2019 Geotechnical Instruments
3/5
-
8/9/2019 Geotechnical Instruments
4/5
INCLINOMETER
Measures lateral movements of the ground, retaining walls and piles for early detection of
any disturbance or effect to structures and property due to construction activity.
INSTALLATION
MONITORING
The inclinometer probe is lowered down in to the casing and at every 0.5 m intervals it records the lateral movement. The
raw data obtained is transmitted from the inclinometer probe to a read out or a PDA by Bluetooth technology.
After the installation of
inclinometer casing in the
hole, the casing top is
capped to prevent the
entry of foreign particles.
Metal protective boxes
are used to prevent the
instruments from being
disturbed. Instrument
identification is affixed
on to the box.
Schematic diagram of inclinometer casing
Grout
Protective
cover
Ground Level
Bottom
Inclinometer
casing
Inclinometer probe
Cross
section
view
of
inclinometer
probe
inside
the
casing
during
monitoring
works
-
8/9/2019 Geotechnical Instruments
5/5
MAGNETIC EXTENSOMETER
Measures settlement of the ground at various depths for early detection of any disturbance
or effect due to construction activity.
INSTALLATION
MONITORING
The
magnetic
extensometer
probe
is
lowered
down
into
the
casing
untill
light
or
buzzer
indicates
the
contact
with
the
spider
magnet. Depth of the magnet is measured from the measuring tape attached to the probe.
Installed casing is capped and kept in a protective
metal box to prevent damage & disturbance
Schematic diagram of magnetic extensometer
Magnetic extensometer probe & spider magnet
