Short notes on engineering geology

1. UNIT-V
GEOLOGICAL INVESTIGATIONS IN CIVIL
ENGINEERING

2. Remote sensing in civil engineering applications
• Remote sensing is the observation and measurement of objects
from a distance, i.e. instruments or recorders are not in direct
contact with objects under investigation.
• Remote sensing depends upon measuring some kind of energy
that is emitted, transmitted, or reflected from an object in order
to determine certain physical properties of the object.

3. Energy for Remote Sensing
* The sunlight falling on the terrestrial surface is reflected
back to satellite
* Green, red and infra - red component of reflected energy
is captured by the multispectral cameras filtered in satellite
* Quantum and type of reflected light will depend upon the
type of the objects.

5.  Aerial photography is the taking of photographs of the ground from an
elevated position.
 The term usually refers to images in which the camera is not supported by
a ground-based structure. Cameras may be hand held or mounted, and
photographs may be taken by a photographer, triggered remotely or
triggered automatically.
 Platforms for aerial photography include fixed-wing aircraft, helicopters,
balloons, blimps and dirigibles, rockets, kites, poles,parachutes,vehicle
mounted poles .

6. Aerial photography is the taking of photographs of the ground from an elevated position.

7. Oblique photograph
Oblique photographs
Photographs taken at an angle are called oblique photographs. If they are taken
almost straight down are sometimes called low oblique and photographs taken
from a shallow angle are called high oblique

8. vertical photograph
Vertical photographs
Vertical photographs are taken straight down. They are mainly used in photogrammetry
and image interpretation. Pictures that will be used in photogrammetry was traditionally
taken with special large format cameras with calibrated and documented geometric
properties

9. Satellite images have many applications in agriculture, geology,
forestry, biodiversity conservation, regional planning, education,
intelligence and warfare. Images can be in visible colours and in other
spectra. There are also elevation maps, usually made by radar
imaging. Interpretation and analysis of satellite imagery is conducted
using software packages like ERDAS Imagine or ENVI.

10. Satellite images

11. Satellite image of india

12. Satellite image of
Tamilnadu

13. What is Remote Sensing?
"Remote sensing is the science of acquiring
information about the Earth's surface without actually
being in contact with it. This is done by sensing and
recording reflected or emitted energy and processing,
analyzing, and applying that information."

14. Basic principle of remote
sensing
• Most remote sensing system utilizes the suns energy
which travel through the atmosphere are selectively
scattered observed depending upon the composition of
the atmosphere and wavelength involved.
• These radiations reaching earth interacts with the
objects. Some of these radiations are absorbed ,
reflected or emitted back to the sensors and that
recorded and processed in the form of image which is
then analyzed to extract the information about the
objects
• Finally information extracted are applied In decision
making and solving particular problem.

15. Solar Energy
Absorption
Scattering
Reflected energy
Incident Radiation
Thermal emission
Transmission
Platforms
& Sensors
Ground Borne
Air Borne
Antenna
Data Processing
Data Products Soft Copy
Data Products Hard Copy
Visual Interpretation
Digital Interpretation
Outputs Hard Copy
Outputs Softcopy
Space Borne
Decision Making

17. Remote Sensing through instrument
Various
Platforms

18. SIX STAGES IN REMOTE SENSING
Stage-1. Source of energy
Stage-2. Transmission of EMR towards the Object
Stage-3. Interaction of EMR with the Object
Stage-4. Transmission of Interacted EMR towards the
Sensor
Stage-5. Recording of the Image by the Detector
Stage-6. Analysis of the Imagery
1
2
3
4
5 (Film)
6
3
3
4

19. Types of remote sensing
• Passive: source of
energy is either the Sun
or Earth/atmosphere
– Sun
- wavelengths: 0.4-5 µm
– Earth or its atmosphere
-wavelengths: 3 µm -30
cm
• Active: source of energy
is part of the remote
sensor system
– Radar
- wavelengths: mm-m
– Lidar
-wavelengths: UV,
Visible, and near infrared
Camera takes photo as example, no flash and flash

20. Active detection
1.Active Sensors provide their own energy source for illumination of the
target by directing a burst of radiation at the target and use sensors to
measure how the target interacts with the energy.
2.Most often the sensor detects the reflection of the energy, measuring
the angle of reflection or the amount of time it took for the energy to
return.
3.Active sensors provide the capability to obtain measurements anytime,
regardless of the time of day or season.
4.They can be used for examining energy types that are not sufficiently
provided by the sun, such as microwaves, or to better control the way a
target is illuminated. However, active systems require the generation of a
fairly large amount of energy to adequately illuminate targets.
Doppler radar is an example of an active remote sensing technology.

21. GROUND PENETRATING RADAR (GPR)

22. Sensor Detection
1.Passive Detection
• sensors measure levels of energy that are
naturally emitted, reflected, or transmitted by the
target object.
• Passive sensors are those which detects naturally
occurring energy. Most often, the source of radioactive
energy is the sun.
• Detection of reflected solar energy, for example, can only
proceed when the target is illuminated by the sun, thus
limiting visible light sensors on satellites from being used
during a nighttime pass.
• The Thematic Mapper, the primary sensor on the Landsat
satellites, is a good example of a passive sensor.

24. Active and Passive Remote Sensing

25. Application of Remote Sensing in civil Engineering
• Various civil engineering application areas include
1. Urban/ Regional planning
2. site investigation
3. terrain mapping and analysis
4. water resources engineering
5. town planning and urban infrastructure development,
6. transportation network analysis
7. landslide analysis.
• Regional Planning and Site Investigations: Site investigations in general
require topographic and geologic considerations. Remote sensing data permits
such an assessment.
• In case of dam site investigation, information on topography is essential.
Geological consideration involves the different soil and rock types and physical
properties
e sourc

26. • In selecting river-crossing sites for bridges and pipelines, an
important consideration is the stability of slopes leading down to
and up from the water crossing. Such slopes include riverbanks,
terrace faces and valley wall. History of river erosion and
sedimentation would give clues needed for locating the sites where
scour is likely to occur. High spatial resolution satellite data with
stereo vision capability can facilitate depth perception in the above
said investigations and also for regional planning of large
commercial airports, harbors, industrial towns and recreational
sites.
• The hydro geological and geomorphologic information along with
geological structures derived from satellite data are very useful in
sitting the ground – water bore holes.
• Terrain Mapping and Analysis Assessment of the performance of
the terrain for specific developmental activities can be made
through terrain evaluation. For this, terrain information can be
acquired from RS data and by generating the Digital Terrain Model

27. • In engineering construction like dam, the knowledge of material
comprising the terrain is essential for proper planning, location,
construction and maintenance of engineering facilities.
• For computation of hydrograph parameters like peak runoff rate,
time of concentration and time to peak, the height and slope
information derived from Digital Elevation Model (DEM) are useful.
• In large area reconnaissance studies, various technically feasible and
economically viable alternatives in locating surplus flow diversion
routes to water deficient basins can be arrived at.
• projects of large dimensions require considerations of land use /
land cover, soil and geological mapping, terrain evaluation,
construction material inventory etc. the latter are derived from
satellite remote sensing data of particular resolution depending
upon the scale on which such information is required

28. Advantages of Remote Sensing
• Provides a view for the large region
• Offers Geo-referenced information and digital
information
• Most of the remote sensors operate in every
season, every day, every time and even in real
tough weather
• Easy acquisition of data over inaccessible
areas
• Asingle data can be used for different uses

31. SATELLITE REMOTE SENSING APPLICATIONS
Natural Resources
AGRICULTURE
•CROP PRODUCTION ESTIMATION
SOILRESOURCES
• SOIL MAPPING
• LAND CAPABILITY, LAND IRRIGABILITY
• SOILMOISTURE ESTIMATION
• MAPPING W
ATER-LOGGED AREAS
•SALT-AFFECTED SOILS, ERODED LANDS, SHIFTING CULTIVATION
LANDUSE/LAND COVER
• LAND USE/LAND COVER MAPPING
• WASTELAND MAPPING
GEOSCIENCES
• GROUND W
ATER POTENTIALZONE MAPPING
•MINERALTARGETTING
FORESTRYAND ENVIRONMENT
• FOREST COVER MAPPING
• FOREST MANAGEMENT PLAN - RS INPUTS
• BIODIVERSITY CONSERVATION
• ENVIRONMENTALIMPACTASSESSMENT
• GRASSLAND MAPPING

32. SATELLITE REMOTE SENSING APPLICATIONS
WATER RESOURCES
• SNOWMELT RUNOFF FORECASTING
•RESERVOIR SEDIMENTATION
OCEANAPPLICATIONS
• COASTALZONE MAPPING
• POTENTIALFISHING ZONE (PFZ) MAPPING
•CORALREEF MAPPING
DISASTERASSESSMENT
• FLOOD / CYCLONE DAMAGEASSESSMENT
• AGRICULTURAL DROUGHTASSESSMENT
• VOLCANIC ERUPTION, UNDERGROUND COAL
FIRE
• LANDSLIDE HAZARD ZONATION
• FOREST FIREAND RISK MAPPING
INTEGRATED MISSION FOR SUSTAINABLE
DEVELOPMENT
•SUSTAINABLE WATERSHED DEVELOPMENT
URBAN APPLICATION
ENGINEERINGAPPLICATIONS
Infrastructure

33. Flood due to cyclone (29th October 1999) off
Orissa coast
IRSLISSIII
Pre-cyclone(1
1.10.99)
IRSLISSIII
Post-cyclone(05.1
1.99)
RADARSAT
DATA of 2nd NOV

35. Snow and Glacier Monitoring

36. 45
Vegetation/Forests/Agriculture
Kharif-1999 (Sep-Oct) Rabi-2000 (Feb-Mar)

37. 46
Mapping and monitoring mangroves, coastal
wetlands
P
P
P
KRISHNA R.
IRS-1B LISS-I
IMAGE, 1992
KRISHNA R.
P = Prawn cultivation
IRS-1C LISS-III
IMAGE, 2000

38. • ROCK TYPES
• GEOLOGICAL STRUCTURES (LINEAMENT /FAULT/DYKE)
• VALLEY FILL WITH VEGETATION
• BLACK SOIL COVER
• SALT AFFECTED LAND
WHAT CAN BE SEEN FROM SATELLITE IMAGES?

39. • HILLY TERRAIN WITH FOREST
• AGRICULTURAL LANDS - DELTA
• RIVER COURSES
• COASTLINE
WHAT CAN BE SEEN FROM SATELLITE IMAGES?
• MANGROVE FOREST
• WET LANDS
• WATER TURBIDITY

40. Land Use
Land cover means any surface cover on the ground
which can include vegetation, urban infrastructure,
water, lake, mountain, transportation networks,
buildings or any other. The attributes measured by
remote sensing techniques relate to land cover,
from which land use can be inferred, particularly
with ancillary data or a priori cognition.
Application of Remote Sensing

42. Mapping
Generating different maps from
remotely sensed data can be so
effective ad valuable. A classification
of sensing elements and methodologies
to generate theses remotely sensed
models are essential for mapping. Two
primary methods of generating
elevation data are:
1.Stereogrammetry techniques by air
photos
2. Radar interferometry
 Wageningen UR 2002

43. Tunnels

44. • WHA
TIS TUNNEL?
• It is an underground or underwater passageway, dug
through the surrounding soil/earth/rock.
• They could be used for carrying freights and
passengers, water, sewage, etc.
• Atunnel may be for foot or vehicular road traffic,for rail
traffic, or for a canal.
• Secret tunnels are built for military purposes.
• Special tunnels, such as wildlife crossings, are built to allow
wildlife to cross human- made barriers safely.
• The methods involved are underground operations
known as tunnel driving and the surface is not
disturbed.

45. • REASONS TO BUILD A
TUNNEL
•
When the lane encounters an obstacle such as a
mountain to avoid bypassing the obstacle.
Built sometimes to overcome a water obstacle as a
replacement for building a bridge above it.
•
•
Built to connect between military posts so the
movement between them will not be visible for the
enemy.
Sometimes built for infrastructure like electricity cables,
water, communication and sewerage to avoid damage
and disruption above ground.
•

46. • HISTORY
• the first tunneling was done by prehistoric people
seeking to enlarge their caves.
• First tunnel in Babylonia was a brick-lined pedestrian
passage some 3,000 feet (900 meters) long was built about
2180 to 2160 B.C. under the Euphrates River to connect the
royal palace with the temple.
• The largest tunnel in ancient times was a 4,800-foot- long,
25-foot-wide, 30-foot-high road tunnel (the Pausilippo)
between Naples and Pozzuoli, executed in 36 B.C.
• In 1681 gunpowder was first used for blasting the
tunnels. First time the ventilation system for tunnel was
developed in 1927 in Holland tunnel.

47. • In 1952 James . S. Robbins comes up with a good
idea and designs the modern tunnel- boring
machine.
• In 1988 Japan's 33-mile-long Seikan Tunnel, the
world's longest and deepest railway tunnel (787
feet below sea level), connects the islands of
Honshu and Hokkaido.
• In 1994 after 192 years of planning and six
years of building, the Channel Tunnel runs
under the English Channel.

48. A tunnel is an underground passageway,
completely enclosed except for openings for
egress, commonly at each end.
A tunnel may be for
foot or vehicular road traffic,
for rail traffic, or for a canal.
Some tunnels are aqueducts to supply water
for consumption or for hydroelectric stations
or are sewers.
Other uses include routing power or
telecommunication cables, some are to permit
wildlife such as European badgers to cross
highways.
Secret tunnels have given entrance to or escape
from an area, such as the Cu Chi Tunnels or the
smuggling tunnels in the Gaza Strip which
connect it to Egypt.
.
Tunnel

50. Selection of tunnel route:
Selection of excavation method
Selection of design for the tunnel-
D-shaped, rectangular, square, oval, and circular
shaped
Assessment of cost and stability
Assessment of environmental hazards

54. GEOLOGICAL PROBLEMS
•Direction of Tunnel excavation with reference to
the direction of fold axis.
TUNNELING ALONG FOLD AXIS (STRIKE
DIRECTION)
•Tunnel passes through the same bed / beds
throughout
oNo series tunnel problem if THICK,
•PROBLEM CROPS UP in the case of MULTIPLE
AND INTERBEDDED FORMATION.
TUNNELING ALONG ANTICLINAL AXIS
WEDGE SHAPED ---- Arch
LIMBS dip away from each other.
ROCK LOAD – limited / directed from the roof to
the limbs by arch action.
•ROOF & SIDES SAFE
oOpen fold (wider inter limb angles)
oConverging joints (Groundwater
problems)
•TIGHT FOLDS
oSteeply dipping beds with very small
inter limb angles - Fully loaded.
oSerious rock falls due to intense
fracturing along with groundwater inflow.
Tunnel passage

55. TUNNELING ALONG SYNCLINAL AXIS
•Down folding and limbs dipping into the
tunnel troublesome ARTESIAN
CONDITIONS.
• Heavy surges of groundwater under
HIGH HYDRAULIC PRESSURE.
ANTICLINE
•Sudden rock falls Less Joint blocks in the
shape of NORMAL KEYSTONES unlikely
to fall.
•Water – bearing strata --- water flows
away from it.
FAULT ZONES
•Found associated with a ZONE OF
HIGHLY CRUSHED ROCK OR CLAY
GOUGE.
oWater seeps into the tunnel
oUnstable roof rock.
CLAY GOUGE ---- Plastic and caves into
the tunnel.

56. FAULTS --- a source of major trouble tunneling
•Better to deviate the tunnel ALIGNMENT &
AVOID FAULT ZONES.
•Driven right angles to the fault
To meet the disturbed zone for the
minimum distance.
Strong lining is required.
JOINTED ROCKS
•Helps in excavating the rock.
•Closely spaced + water bearing
Rock fall Groundwater
seepage
•Presence of lake, cave, River --- drains into
Joints and Fissure.
WATERBEARING ROCKS
•Flooding
•Clayey rocks --- strength – affected.
STRATIFIED ROCKS
HORIZONTAL BEDS
•Uniform bed - easy
•Multiple bedding – Roof and Floor
Selection – Hard & sound rocks.
Uniform characters - easy
Soft and hard strata – difficult.
Tunnel passage

57. VERTICAL JOINTS
•Rectangular block – gets as beam
•Joints spacing equal to the tunnel diameters
•Bending - corbel and pins.
THIS LOOSE JOINTING
•Support and back filling – closer over-break.
GEOLOGICAL SURVEY OF TUNNELS
•Location
•Alignment of tunnels
•Size of the bore
Are established prior to the geological survey.
PHOTO-GEOLOGIC INTERPRETATION
•Along tunnel alignment
•Provide information
Topography
Nature and surface material
Broad geologic structures
Water conditions and vegetation

58. TUNNELING METHODS
• depends on
• ground conditions,
• the ground water conditions,
• the length and diameter of the tunnel drive,
• the depth of the tunnel,
• the logistics of supporting the tunnel
excavation,
• the final use and shape of the tunnel and
appropriate risk.

59. • ADVANTAGES OF TUNNELING
• Tunnels are more economical than open cuts beyond certain
depths
• Tunnels avoid disturbing or interfering with surface life and
traffic during construction
• Tunnels prove to be cheaper than bridges or open cuts
to carry public utility services like water, sewer and gas
• if tunnels are provided with easy gradients, the cost of hauling
is decreased
• In case of aerial warfare and bombing of cities, the tunnels
would grant better protection as compared to bridges.

60. • Parts of Tunnel

61. TUNNEL LININGS
These are the permanent or temporary
support for keeping tunnel from collapse
and provide safe.
• Tunnel linings are grouped into three main
forms some or all of which may be used in
the construction of a tunnel:
• 1. Temporary ground support
• 2. Primary lining
• 3. Secondary lining

65. 4. WIRE MESH:-
• Wire mesh is used to support small pieces
of loose rock or as reinforcement for shot
crete.
• Two types of wire mesh are commonly
used in underground excavations:
• 1. Chain-link mesh:- commonly used for
fencing
• 2. Weld mesh:- commonly used for
reinforcing shotcrete.

66. 5. IN SITU CONCRETING
• The process of placing concrete in situ
was incompatible with timber supports.
• The first uses of concrete were for tunnels in good
rock and it was only with the introduction of steel
supports that concrete became the norm for a tunnel
lining material.
• In-situ forms used for lining tunnels are, with few
exceptions, of the travelling type, constructed of steel.

67. • VENTILATION IN TUNNELS
• Ventilation is required because of
• 1) Dust and gas caused by drilling,
blasting, loading of excavated materials
and Shot creting
• 2) Exhaust gas and smoke discharged
by diesel
• 3) Poison gas made from explosive or
organic solvent
• 4) Poison gas, flammable gas or
oxygen shortage gas in ground
• 5) High temperature and high humidity

68. VENTILATION DURING
CONSTRUCTION
• During construction it is
necessary to ventilate a tunnel for
various reasons:
• T
o furnish fresh air for the workers
• T
oremove the dust caused by
drilling, blasting, mucking, diesel
engines, and other operations
• T
o remove obnoxious
gases and fumes
produced by explosives

69. • SHAPES OF TUNNELS
• (A) CIRCULAR :This type of
section offers greater resistance
to external pressure .
• If ground is highly unstable , such as
soft clay or sand , it is necessary to use
circular section .
• For carrying water and sewerage
circulation shape tunnels are used
.ex.Aqueduct
• Circular tunnel are not prefer as traffic
tunnel.

71. • ELIPTICAL SECTION
• They are used in grounds compare
than rock .
• These tunnels serve as
water sewage condition.
• They are difficult construct .
• They cannot be used as traffic
tunnels because of their narrow
base.

73. • EGG – SHAPED SECTION
• These section have narrow cross
sections at bottom. They are best
suited for carrying sewage. They
maintain self-cleansing velocity of
flow of sewage both in dry and
rainy seasons
.
• They are resist external as
well as internal pressure due
to their circular walls .
• These tunnels are difficult to
construct

75. • HORSE SHOIE SECTION
• This form consists of a semi-
circular roof together with arched
sides and a curved invert.
• They are most popular as
traffic tunnels for road and
railway routes .
• These tunnels are also difficult to
construct.

77. • Geological Survey For Tunneling
• A geological survey is the systematic investigation of the
subsurface and surface of a given piece of ground for the
purpose of creating a geological map ,model and feasibility
studies.
• A geological survey employs techniques from the traditional
walk-over survey, studying outcrops and landforms, to
intrusive methods, such as hand auguring and machine
driven boreholes, use of geophysical techniques and remote
sensing methods, such as aerial photography and satellite
imagery etc.

78. • Types Of Geological Survey
• Mainly geological surveys are classified into two types:
• Surface Geological Survey
• Subsurface Geological Survey
• Surface Geological Survey:
• includes on land geology and geological structures,
landforms, hydrology, outcrop pattern ,engineering
properties etc
• Subsurface Geological Survey:
• includes on underground geology and geological structures,
Geo-hydrogeology, subsurface rock or soil pattern etc.

79. • Surface Geological Survey
• Geological profile is prepared along line of
tunnel.
• Geological observations are done along this profile
like engineering properties of rock/soil, geological
structures like fold, faults, joints, spring, stream, river
alignment and any seepage etc
• Trial boring plan is prepared along the tunnel line.