Geotechnical Instrumentation & Monitoring - Services and Types

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Geotechnical Instrumentation Monitoring
Services Types
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GEOTECHNICAL INSTRUMENTATION AND MONITORING
COMPANIES
INTRODUCTION
TABLE OF CONTENT
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WHAT IS GEOTECHNICAL INSTRUMENTATION?
DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
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WHAT IS GEOTECHNICAL MONITORING?
DIFFERENT TYPES OF GEOTECHNICAL INSTRUMENTATION
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INTRODUCTION
Geotechnical Instrumentation and Monitoring are a
sub-branch of Geotechnical Engineering.
Geotechnical Instrumentation refers to the
various sophisticated instruments that are used
to monitor geotechnical structures, sites, and
the environment. Geotechnical Instrumentation
and monitoring play a significant role in the
success of any construction project. The
geotechnical monitoring can be done for both the
short-term as well as the long-term safety of
the structures. Geotechnical Monitoring is
essential pre-construction, construction stage,
post-construction as well as in the dilapidation
stage.
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WHAT IS GEOTECHNICAL INSTRUMENTATION?
The word Geotechnical is made up of geo-and
technical which means anything specifically
related to the earth. Hence, geotechnical
instrumentation refers to all the different
sorts of instruments that are used to monitor the
earth, structures constructed over it, beneath
it, and on it.
The geotechnical instruments include
inclinometers, piezometers, tilt meters, beam
sensors, joint meters, crack meters, strain
gauges, pressure cells, load cells, plumb lines,
borehole extensometer, magnetic extensometers,
seepage measurement, reservoir level meter,
seismographs, portable readout units, an
automatic data acquisition system etc.
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WHAT IS GEOTECHNICAL MONITORING?
Geotechnical Monitoring goes hand-in-hand with
geotechnical instrumentation. For instance,
whenever a structure is planned, a proper
surveying of the construction site as well as
the nearby site is carried out.
g/a-guide-on-structural-health-monitoring-shm/
Once the construction work begins, continuous
real-time monitoring is carried out so that the
structure is made as per the expectations. Even
after the completion of the project, constant
monitoring is being done to check for the
structural changes.
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GEOTECHNICAL INSTRUMENTATION AND MONITORING
COMPANIES
There are several companies around the world that
deal with the Geotechnical Instrumentation and
Monitoring. One such company is the
Encardio-Rite Group. Established in Lucknow,
India in the year 1966, Encardio-rite Group is a
World leader in safety monitoring providing
geotechnical instrumentation, structural
environmental monitoring along with geodetic
surveying solutions. Over the years,
Encardio-rite has become an established brand for
its specialized services with high-quality
products and innovative online solutions. Encardio
-Rite provides the most comprehensive range of
services and products including data collection,
database management, complex monitoring,
surveying, installation, supply and calibration
of geotechnical and geodetic instrumentation
with in-house developed advanced software.
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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
The Geotechnical Monitoring services is a huge
umbrella that includes all sorts of monitoring
carried out at pre-construction, during
construction, and post-construction stages The
construction phase must have negligible risks
which is why a wide range of sensors with
advanced database management is required. The
monitoring system promotes the monitoring of
sub-surface and surface parameters like water
level, stress, strain, piezometric pressure,
load, lateral deformation, joint openings,
cracks, settlement, convergence, tilt etc.
manually and automatically. The monitored data
is constantly provided either online or through
evaluation reports to the construction
contractor and consultants. This facilitates work
in the safe zones and takes corrective actions
where there is a possibility of any risks.
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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Structural Monitoring The online web-based
structural monitoring services include

Safety of buildings, monuments and structures
during nearby construction activity (like
underground tunnelling, deep excavation for high
rise buildings etc.). Safety of existing multiple
storey buildings, hotel complexes, corporate
offices and buildings of critical
importance. Safety of old and depleted buildings
and structures subject to long-term movement or
degradation of materials. Safety of monuments and
structures of historical importance. Safety of
buildings and structures in landslide-prone areas.



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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
The monitoring of new construction
includes Verification of the hypothesis and the
assumption of design parameters. Monitoring
safety during construction Measuring the change
in parameters during construction Ensuring that
interface of construction with adjacent
structures and foundation is sound. Certifying
the performance of the new construction/excavation
.


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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Rail/Road, Metro Sewer Tunnels Monitoring

During the design stage, instrumentation
installed in the exploratory tunnels and
boreholes gives information regarding the
existing ground conditions which in turn helps
in optimizing the design. During the construction
stage, instrumentation gives information on how
the design is actually performing during
execution. Long term monitoring during the
operational stages of the tunnel, ensures its
safety, determining the effects of any natural
calamity (like an earthquake) on its structural
integrity. It also helps in planning and
optimizing the maintenance schedules.


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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Landslides/Slope Stabilisation Monitoring In
general, the following steps can be adopted in
landslide-prone areas

Monitoring slope to detect any sign of
instability. Remedial measures can then be
instituted before alarm conditions are
generated. Stabilizing slopes that need
corrective action using appropriate slope
stabilization technique(s). Devising an online
(near real-time) monitoring program to verify
that stability of the slope is achieved. A good
prediction and forewarning system, when
implemented with effective efforts to control
and mitigate landslides, can drastically reduce
the destruction caused by landslides. Advances
in geotechnical instrumentation, surveying
technologies and data transmission systems now
make it possible to monitor these slopes
conveniently and economically.




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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Groundwater Level Monitoring

For any program of efficient water management to
be successful, continuous monitoring of water
level in the groundwater is necessary. Reliable
and accurate groundwater data is required, well
in time, to assess groundwater conditions such
that adverse situations like drought and loss of
pumpage in agriculture and domestic water supply
can be efficiently handled. Automated monitoring
systems are the best solution that provide data
from different parts of Country at a remote
central location in near real time. The primary
objective of groundwater monitoring on such large
scale is to record the response of the ground
regime to the natural and anthropogenic stresses
of recharge and discharge parameters with
reference to geology, climate, land use pattern
and hydrologic characteristics.



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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Diaphragm Wall Displacement Associated Ground
Movement Monitoring

Deep excavation is carried out before the
construction of structures like high rise
buildings, underground garages, and underground
mass transport systems operating at several
levels. In many such cases, a diaphragm wall is
one of the best solutions. Excavation in soft
ground induces ground movement. This may damage
the adjacent existing sensitive
structures. Deformation must be limited to
acceptable levels in a deep excavation.
Monitoring of the zone of influence is crucial
for the safety of the construction work.


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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Bridge Monitoring

For bridges, it is recommended that structural
health be continuously monitored to ensure
proper maintenance and safety of man and
material. The collapse of a bridge is often
preceded by a change in the tilt of affected
areas. The comprehensive instrumentation is
effectively used to online monitor the different
type of structures to give timely warning on
impending danger. The purpose is to assist and
inform the owner/designer/contractor/architect
about the continued performance of structures
under gradual or sudden changes to their state.


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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Consolidation Of Soft Soil Monitoring

Considerable settlement may occur when
constructing projects such as highway
embankments, bridge approaches, dykes, dams,
large storage areas, tanks, airport runways or
buildings on soft compressible soil, due to the
consolidation of soil under the superimposed
load. To avoid serious and potentially expensive
problems due to such settlement, it is desirable
to cause the consolidation to occur at the outset
of the project, and in the shortest possible
time during the construction period. Construction
of a facility on top of a soft soil foundation
will normally be delayed until there is an
assurance that it will not be damaged by the
settlement that occurs during subsequent
consolidation. If the predicted delay is not
acceptable, the time required for consolidation
can be reduced by surcharging and/or by the
installation of vertical drains.


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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Seepage Monitoring In An Open Channel The
quantity of seepage is important for the
following reasons

A large quantity of seepage around a dam (through
the abutments), under a dam (through the
foundation) and in some cases, through the dam
itself, may dissolve some of the chemical
constituents of the rock or soil material present
at those locations. Larger the seepage, greater
is the dissolution. This, in turn, provides an
enlarged seepage path which results in even
greater seepage. Dams founded on certain
evaporites like gypsum are especially affected by
this problem. A large quantity of water moving
through, around or under a dam result in
completely saturated soils and rock in the
seepage areas, excessive hydrostatic uplift
pressure, as well as softening and weakening of
the soil and rock. An excessive quantity of
seepage may in extreme cases, compromise the
storage capability of the reservoir



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SERVICES
The location of the seepage paths is of concern
because

If the majority of the seepage water is confined
to only a few discrete seepage paths and the
velocity of the seepage is sufficiently high,
then progressive erosion of particles of soil
may occur resulting in a piping type failure of
the dam. Seepage water in sufficient quantity in
a few paths may result in concentrated
dissolution in those areas.

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SERVICES
Monitoring Of Dams

Instrumentation plays a key role in safety
monitoring for dam and people, providing
necessary information on performance of the dam
and detecting problems at an early and
preventable stage. The extent and nature of
instrumentation depend not only on the complexity
of the dam and size of the reservoir but also on
the potential for loss of life and property
downstream. This information is critical for the
dam owner who is directly responsible for any
consequences of a dam failure. Safe operations of
the dam is an important matter of economic
benefit and public safety. Catastrophic dam
failure can threaten life and property downstream.


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DIFFERENT TYPES OF GEOTECHNICAL MONITORING
SERVICES
Monitoring Of Nuclear Power Plants For Nuclear
Power Plants, it is strongly recommended that
structural health is con- tinuously monitored to
ensure the following
Safety of personnel, material, nearby communities
and the environment. Compilation of long-term
and reliable data on the various elements of the
plant especially foundations, anchoring systems
and containment structures. Data to determine the
effects of natural calamities such as earthquake,
cyclone, flooding etc. on the structure. Data to
plan and schedule predictive and preventive
maintenance programs for the plant.



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DIFFERENT TYPES OF GEOTECHNICAL INSTRUMENTATION
A wide variety of instruments are used to carry
out the geotechnical monitoring, geodetic
surveys, structural monitoring, as well as,
environmental monitoring. The most common
geotechnical instrumentation provided by
Encardio-Rite are mentioned in the upcoming
slides.
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DIFFERENT TYPES OF GEOTECHNICAL INSTRUMENTATION
Web Data Monitoring Service (WDMS)

WDMS is a web-based data management and
presentation tool for data collected by Model
ESDL-30 range of data loggers. Encardio-rite
Model ESDL-30 data logger is designed to log data
from sensors with SDI-12 interface. Any sensor
with an SDI-12 signal interface can be connected
to the data logger Thus, this single data logger
is suitable for monitoring the groundwater level,
piezometric pressure, stresses in soil/concrete,
strain or displacement, load, temperature, tilt
in structures, lateral displacement in boreholes
using in-place inclinometers, etc.


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WDMS consists of software such as a data
collection agent, a database server and a web
server hosted on a high-reliability server
computer. The host computer periodically collects
data from remote data loggers, which can be
geographically spread over a large area, over
cell phone networks. Users interact with the
software using their web-browser, when connected
to the Internet, from any location in the
world. The only requirement is that each
individual data logger site is covered by a
cellphone service provider who can provide
reliable GSM/GPRS enabled cellular data
connection locally.



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Tilt Meters

To online monitor tilt of buildings that may be
caused due to the differential ground
settlement, a suitable sensor is the Model
EAN92-M bi-axial tilt meter with the SDI-12
interface. The tilt meter should ideally be
installed at an indoor location or in shade to
prevent the effect of large temperature
fluctuations on the monitored results. Users may
use two or more of tilt meters to monitor tilt
of buildings with time. For safety monitoring of
existing structures two or more such systems may
be mounted at proper locations, data being
available online with alarms through
Encardio-rite Web Monitoring Services.


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DIFFERENT TYPES OF GEOTECHNICAL INSTRUMENTATION
Crack Meters/Crack Gauges/Displacement
Meters/Joint Meters

With time cracks develop in buildings, structures
and monuments. Monitoring change in its width
provides important information. To online monitor
changes in crack width, a suitable sensor is the
Model EDJ-40V vibrating wire crack meter. For
online monitoring, EDJ40V with SDI-12 signal
interface is used with Model ESDL-30 datalogger
for logging in data. The data is transmitted to a
central server through GSM/GPRS for Web Data
Monitoring Service by Encardio-rite.


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Inclinometers

In-place inclinometers (IPI) are used for
continuous monitoring of lateral movement of the
ground at construction sites involving deep
excavation. Such lateral movement of the ground
may affect the safety of adjoining
structures. For online monitoring of lateral
movement in boreholes, Encardio-rite offers Model
EAN-52MV Vertical In-place Inclinometer System
with SDI-12 interface sensors. The digital
inclinometer consists of a traversing type
digital tilt sensing probe that is connected to
a reel unit kept at borehole top. The reel
consists of a winding reel that holds the cable
and a wireless Bluetooth relay unit that sends
the digital probe data to the mobile phone.


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DIFFERENT TYPES OF GEOTECHNICAL INSTRUMENTATION
Borehole Extensometer Encardio-rite Models
EDS-71V single channel and EDS-70V 2-6 channel
borehole extensometer (BHE) is extensively used
for online monitoring of sub-surface ground
settlement during construction activity. In case
the BHE is mounted in a horizontal borehole, it
gives important information on lateral movement.
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Piezometers

Encardio-rite Model EPP-30V piezometer is
recommended for online monitoring of groundwater
pressure/level near the construction site,
between building and excavation and underground
works. An online piezometric pressure monitoring
system provides very important information on
safety, especially during the rainy season for
any structure built on a hill. For online
monitoring, vibrating wire piezometers are used
with SDI-12 signal interface and connected to
model ESDL-30 data logger for logging in data.
The data is transmitted to a central server
through GSM/GPRS for WDMS by Encardio-rite.


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Strain Gauges and Load Cells Construction of deep
foundations may result in lateral movement and
settlement of the surrounding structures in case
the latter fall in the zone of influence of the
construction activity. This may necessitate the
construction of a diaphragm wall or sheet piles
around the area to be excavated. During
excavation, struts or anchors may be used to
contain the lateral movement. For monitoring of
struts or anchors, the following sensors are
available from Encardio-rite
EDS-20V-AW arc weldable strain gage for
monitoring stress in struts ELC-32V centre hole
anchor bolt load cell

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Geodetic Targets And Survey Markers Geodetic
Targets are designed to measure deformation in
dams, roads, tunnels, bridges and overpasses,
multi-storey and historical buildings,
foundations, mining exploitation, landslides
and sloping and in earthquake-prone
regions. Survey Markers are placed to mark
significant survey point on the earths surface
during geodetic and land surveying.
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DIFFERENT TYPES OF GEOTECHNICAL INSTRUMENTATION
Seismograph And Accelerometer Seismometers are
designed to measure ground movements/vibrations
caused by earthquakes, excavations, boring,
drilling, etc. They record these movements as
graphs often known as seismographs.
Accelerometers, on the other hand, are used to
measure static or dynamic accelerating
forces. Encardio-Rites Model EADA-350F
Accelerometer with digital output is the first
ever accelerometer to be manufactured in India
under the Make In India initiative.
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Model EADA-350F Accelerometer with digital output
Model ESDA-120S Broadband Seismometer with
digital output
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