We have briefly listed out the impact of highway construction and the challenges faced .

1. Geological
Challenges &
Ecological Effects
of Highway
Construction
PREPARED BY GROUP -1
MEMBERS :
ABHINAV ANAND [120104001]
ABHISHEK ARORA [120104002]
AJAY SINGH MEENA [120104003]
AKASH YADAV [120104004]
AKSHAY JAIN [120104005]

2. Introduction
 India has a road network of over 42,36,000
km, the third largest road network in the
world. However qualitatively India’s roads
are a mix of modern highways and narrow ,
unpaved roads.
 Major modern highways that connect cities
in populous developed and developing
countries usually incorporate features
intended to enhance the road's capacity,
efficiency, and safety to various degrees.

3. Engineering Geology of rock
slopes in Highway Construction
 Rock slopes form part of the components in many
highway or roadway construction in hilly terrain.
The key question with regard to rock slope can
have serious consequences. The stability of a
particular rock slope is governed by three main
engineering geologic factors namely-
 Lithology
 Structure
 Weathering Grade

4. Slope failure

5. Lithology
 Refers to rock type.
 Different rock types have different material
properties and behaviour. For example, granitic
rocks differ from shales and schist.
 In case of granitic rocks joints control the stability
of rock slope at a particular location. On the
other hand bedding planes control the stability of
cut slopes in case of shales and sandstones.
 Similarly, in phyllites and schist which are foliated,
the foliations would be the controlling features.

6. Structures
 Geological Structures include a host of features
such as joints, faults ,bedding planes ,foliations
,folds ,etc.
 They represent breaks/discontinuities or
weaknesses in the rock mass.
 Detailed mapping of various major joint sets in cut
slopes is required for slope stability assessments
and follow-up stabilization measures.

7. Weathering Grade
 Intense chemical weathering reduces rocks into much
weaker soil like material, resulting in thick soil mantles over
bedrock formations.
 Superimposed on the lithology and structures, the
weathering effects can be predominant in controlling the
behaviour of resultant rock mass. For example-
In a typical granitic weathering profile, while the grades I
to II zones generally have tight joints, the grade III zone just
below the rockhead or soil-rock interface often has wide,
open sheet/exfoliation joints which are prone to sliding.
These sheet joints are formed by stress relief during the
weathering process, and tend to run sub parallel to the
rockhead, with great tendency to daylight in the cut
slope.

8. Survey of rock slopes
 In the construction of rock slopes along a
highway, an initial survey along the highway
alignment would be necessary to determine the
rock types that would be traversed by the
highway.
 The use of geological maps coupled with surface
geologic mapping and site investigation data
would be useful.
 During the construction stage, close monitoring of
the rocks excavated and especially mapping of
geological structures would be needed for every
cut slope for the assessment and identification of
potential instability problems.
 Post-failure investigation of rock slopes is also
necessary.

9. Case Study: NH-52(A)
 NH-52(A) is a spur route of NH-52 connecting the
Itanagar with Brahmaputra valley in Assam, India.
It is the principal road communication to the hilly
state capital complex, Itanagar.
 Presently, the NH-52(A) is a 2-lane width Indian
national highway traverses a total distance of 57.7
km out of which 15 km is in plains of Assam near
Gohpur and rest 42.7 km is in hilly terrains of AP,
built in two phases. Phase-I comprises the part
from Bandardowa to Itanagar(31.2 km) which
was planned and built during 1988-90. Phase-II
which was built during 1992-94 (11.5 km) consist of
the rest part from Itanagar to Gohpur.

10. Case Study: NH-52(A)
 Of the many critical sections
of NH-52(A) pavement, the
highest grade of critically
suffering pavement section
of NH-52(A) is the Karshingsa
area which is geologically
termed as sinking zone. The
Karshingsa section of about 1
km length generates severe
flow type landslides almost
every year and experiences
of instability.

11. Geology of Hilly Terrains of NH-
52(A)
 The part of NH-52(A) from Bandardowa up to Itanagar-
Chimpu area (except Mowb-II hillock area in Itanagar)
via Naharlagun-Papu Nallah area along Pachim river is
composed of quaternary formation bearing weak
subsoil and soft rock layers (Bayan, 2004.b), for which it
generates more engineering problems. On the other
hand, the rest part up to Gohpur area is composed of
siwalik group of formation exposed at surface. Hence,
it reveals better geotechnical properties and
generates fewer problems.

12. Geology of Hilly Terrains of NH-
52(A)
 From geological point of view in general, the NH-
52(A) as a whole passes over those areas which
are situated within the main plate boundary fault
between Eurasian and Indian plates and the main
thrust fault of Himalayan hill ranges. As a whole
the base rock formation of the area principally
falls under Quaternary group of rock formation.
 Geologically, the selected corridor of the NH-
52(A) where Karshingsa is one of the critically
important parts between Bandardowa and
Itanagar runs almost entirely through the
Quaternary Formation/ upper Siwalik, locally
known as the Kimin Formation. These rocks have
been deposited during Mid-Miocene to Lower-
Pleistocene period.

13. Geology of Hilly Terrains of NH-
52(A)
 The Formation consist mainly of alternations of
conglomerates known as pseudo-conglomerate,
soft and massive sand rock/ sandstone, and silty
clay beds.
 The beds strike NW - SE and gently dip towards NE.
Three sets of joints exist in these rocks. Besides the
Upper Siwalik rocks, Quaternary deposits and
terraces also occur at some places. The Main
Boundary Thrust passes on its north and in the
south is the Plate boundary fault (i.e. the
Himalayan Foothill Thrust) between Indian Plate
and Eurasian Plate.

14. Geology of Hilly Areas of NH-
52(A)
 Pseudo-Conglomerates are
the prominent rock unit
exposed along the national
highway. These rocks are
easily erasable because of
poor cementation and
pronounced weathering.
The thickness of pseudo-
conglomeritic bends varies
from 1.2 – 15 m and that of
sandstones is 0.6 – 10 m on
the uphill side above road
level. However, it is seen
that the waste materials
reveals out of various
pattern of landslides are
comprises of Colluvium
subsoil layers only. The
figure shows geological
map of Capital Complex
Covering the Study Area
NH-52(A)

15. Solutions
 The concept of skirted retaining wall together with road
foundation system for hilly roads is targeted to hold
structural soil by confining them within a hard thin circular
structural layer made of concrete or PVC materials, and
place them in a pattern of honey comb cell.
 For drainage outlet section of hilly road, the skirted wall in
the toe side is normally extended down to the required
design depth below road level, such that it can rest on an
almost flat ground in such structure the other three side of
the skirted wall provides excessive retaining as well as
lateral strength.

16. Impacts of Highway
Construction on Soil & Geology
 The construction and operation of the trunk road
network can also have an impact on the function
of soil and geological properties of an area.
 These impacts may arise through the physical
removal or importation of soils and rocks or the
compaction and sealing of the ground during
construction. Impacts may also be caused during
the operation of the road by the effects of air-
borne pollution and spray.

17. Environmental Impacts of Highways
 Air Quality
 Water Pollution
 Noise
 Habitat Fragmentation

18. Air Quality
 Negative Impacts
 Air pollution from fossil (and some biofuel) powered
vehicles can occur wherever vehicles are used and
are of particular concern in congested city street
conditions. Emissions include particulate emissions like
NOx,volatile organic compounds, Carbon monoxide
etc.
 Road dust kicked up by vehicles may trigger allergic
reactions. Carbon dioxide is a major greenhouse gas
and motor vehicle emissions are an important
contributor to the growth of CO2 concentrations in
the atmosphere and therefore to global warming.

20. Air Quality
 Positive Impacts
 The construction of new roads which divert traffic from built-
up areas can deliver improved air quality to the areas
relieved of a significant amount of traffic. The Environmental
and Social Impact Assessment Study carried out for the
development of the Tirana Outer Ring Road estimated that it
would result in improved air quality in Tirana city centre.
 For Example :
A new section of road being built near Hindhead, UK, to
replace a four-mile section of the A3 road is expected by the
government to deliver huge environmental benefits to the area
including the removal of daily congestion, the elimination of air
pollution in Hindhead caused by the congestion, and the
removal of an existing road which crosses the environmentally
sensitive Devil's Punchbowl area of outstanding natural beauty.

21. Water Pollution
 Urban runoff from roads and other impervious surfaces is a major
source of water pollution. Rainwater and snowmelt running off
of roads tends to pick up gasoline, motor oil, heavy metals, trash
and other pollutants. Road runoff is a major source of nickel,
copper, zinc, cadmium, lead and polycyclic aromatic
hydrocarbons (PAHs), which are created as combustion
byproducts of gasoline and other fossil fuels.
 De-icing chemicals and sand can run off into roadsides,
contaminate groundwater and pollute surface waters. Road
salts (primarily chlorides of sodium, calcium or magnesium) can
be toxic to sensitive plants and animals.Sand can alter stream
bed environments, causing stress for the plants and animals that
live there.

22. Noise
 Road noise can be a nuisance if it impinges
on population centres, especially for roads
at higher operating speeds, near
intersections and on uphill sections. Noise
health effects can be expected in such
locations from road systems used by large
numbers of motor vehicles.
 Speed bumps, which are usually deployed
in built-up areas, can increase noise
pollution. Especially if large vehicles use the
road and particularly at night.

23. Habitat Fragmentation
 Roads can act as barriers or filters to animal movement and
lead to habitat fragmentation.Many species will not cross the
open space created by a road due to the threat of predation
and roads also cause increased animal mortality from traffic.This
barrier effect can prevent species from migrating and
recolonising areas where the species has gone locally extinct as
well as restricting access to seasonally available or widely
scattered resources.
 Habitat fragmentation may also divide large continuous
populations into smaller more isolated populations.These smaller
populations are more vulnerable to genetic drift, inbreeding
depression and an increased risk of population decline and
extinction.

24. Habitat Fragmentation

25. Need of Green Highways for Sustainable
Development
 Development of road infrastructure is currently being given high
priority by the government of India to meet the requirement of
growing travel demand and to help the faster growth of
economic activity. Most of these roads have bituminous surface
at the top constructed using naturally available road
aggregates and bitumen, a petroleum product, which being
mixed at high temperature to produce hot mix asphalt (HMA).
 By this process there has been a faster depletion of road
aggregates and also increase in emission of gases in to the
atmosphere causing environmental pollution. Use of low
emission bitumen (green bitumen materials) and milling and re-
use of material collected from old existing pavement, recycled
asphalt pavement (RAP), to build green highways will be the
most promising alternative to the current practice to achieve
sustainability in road construction.

26. Benefits of Concrete Pavements over
Asphalt pavements
 Reduced Lighting
Requirement
because of the more
reflective nature of
concrete pavements, a
specified luminance level
can be achieved with
fewer high-output lighting
fixtures and standards.
Ultimately, this translates to
lower costs and lower
energy consumption over
time.

27. Benefits of Concrete Pavements over
Asphalt pavements
 Reduced Vehicle Fuel Consumption and Emissions

28. Benefits of Concrete Pavements over
Asphalt pavements
 Heat Island Mitigation
The energy of sunlight that
is not reflected off pavement
surfaces is converted into
thermal energy that
increases the pavement’s
temperature. This, in
turn,increase the
temperature of the air
around the pavement. In
urban areas, the higher air
temperature occurs as a
result of pavements and
other surfaces absorbing the
sun’s heat.

29. Key Areas for the Development
of a Green Highway
Watershed Driven
Storm Water
Management
Recycle,
Reuse
and Renewable
Conservation
and Ecosystem
Management
Lifecycle
Energy and
Emissions
Reduction
Overall
Societal
Benefits
Watershed Driven
Storm Water
Management
Recycle,
Reuse
and Renewable
Conservation
and Ecosystem
Management
Lifecycle
Energy and
Emissions
Reduction
Overall
Societal
Benefits

30. Watershed Driven Storm Water
Management
 Stormwater is rainwater and melted snow that runs off
streets, lawns, and other sites. When stormwater is
absorbed into the ground, it is filtered and ultimately
replenishes aquifers or flows into streams and rivers. In
developed areas, however, impervious surfaces such as
pavement and roofs prevent precipitation from naturally
soaking into the ground. Instead, the water runs rapidly
into storm drains, sewer systems, and drainage ditches
and can cause:
 Downstream flooding
 Stream bank erosion

31. Watershed Driven Storm Water
Management
 Increased turbidity (muddiness created by stirred
up sediment) from erosion
 Habitat destruction
 Changes in the stream flow hydrograph (a graph
that displays the flow rate of a stream over a
period of time)
 Contaminated streams, rivers, and coastal water.
 Technologies used are bioretaintion, pervious
pavement shoulders, environmentally friendly
concrete, forest buffers, wildlife crossings, restored
and storm water wetlands, etc.

32. Watershed Driven Storm Water
Management
 Pervious concrete has the
potential to provide an
environmentally sensitive
product for specific
applications. Currently, the
most common uses of
pervious concrete are
parking lots, low traffic
pavements, and pedestrian
walkways.

33. Energy & Emissions Reduction
 Given projected cement production, using 50% fly
ash can save the equivalent energy in 6.4 billion
gallons of gas annually.
 2.9 billion gallons of gas was wasted due to
vehicles in congestion in 2007.

34. Recycle, Reuse and Use
Renewable
 Conservation of natural minerals and reduction of
waste during construction and maintenance of
highways.
 Recycle is a process and Reuse is practice.
 Industrial By-products can be recycled and used
as highway construction materials like fly ash,
blast furnace slag, foundry sand, etc.

35. Conservation and Ecosystem
Management
 The impacts of highway construction are division
and displacement of natural habitat.
 Solutions
 Provide animal crossing structures.
 Maintaining natural flows of streams, rivers.

36. Overall Societal Benefits
 Highways are tied to the quality of life in a
particular area.
 Highways have an important economic role.

37. A Future for the Nations
Infrastructure
 Green construction has been implemented in the
structural market successfully.
 We need innovative ways to solve environmental
issues while maintaining a strong infrastructure

38. THANK
YOU