CRITICAL PROBLEMS AND THEIR SOLUTION FOR HILLY ROAD PAVEMENT WITH

PARTICULAR REFERENCE TO NH-52(A) – A NEW AVENUE

GOKUL K BAYAN

Applied Civil Engineering, Principal Scientist, CSIR-North East Institute of Science & Technology,

NEIST-Branch, Itanagar, Arunachal Pradesh, India

ABSTRACT

Construction of road pavement by cutting or filling in hilly terrains generates instability to the naturally standing

hillock system for some sections of any hilly road. For withstanding under prevailing local atmospheric condition such

pavements need engineering cares. In consistence to such aspects, particularly a hilly road abundantly built in Himalayan

subsoil encounters numerous engineering problems. Out of those engineering problems, geotechnical problems are the

highest in tune, which demand unique care besides the conventional on going practices of engineering cares. Present study

conducted to emphasis such problems that encounter in a national highway NH-52(A) within hilly terrains of Himalayan

subsoil origin since its inception. Efforts have been made to emphasis the problems through detail geotechnical studies

carriedout on the road all along its alignment. Study proclaims recommendations regarding absolute solution against those

prevailing problems. Such recommendations are made based on the out comes of a new innovative R&D activity carried

out recently, which generates a system comprising road foundation concept. Such type of solution prepared for hilly roads

of Arunachal Himalaya which is also suitable for the whole zone of South East Asian hilly roads may deem fit to bring full

success for achieving everlasting pavement section against their prevailing critical problem generating section of any hill

road.

KEYWORDS: Hill, Pavement, Himalayan Subsoil, Problem, Road Foundation, Engineering Cares, Solution

INTRODUCTION

Introduction in General

A very good surface communication under road network is one of the major key to overall progress of a country.

Construction of conventional road network with ongoing practices follow the trend of making pavement by uncontrolled

cutting of open virgin ground as well as refilling the depression carelessly which are co-existing all along the proposed

road alignment which expose to local atmospheric condition. However, under such situation for more durable sustenance,

pavements need different forms of engineering cares. Out of many, geotechnical engineering cares bags top priority. Such

engineering cares are normally provided based on the geotechnical soundness of the subsoil beneath the pavement as well

subgrade layer located all along the formation level of the road pavement.

Those critical sections of the road pavements normally fail to sustain under more traffic loads which bear weak

subsoil layers and have no extra hard material inclusions provided as engineering cares besides some other prevailing

engineering properties. Hence, to achieve more durability with heavy traffic loads, modern process of making pavements

comprise of hard inclusions namely geofabrics, geosynthetics, honeycomb cell (HC-C) (Bayan, 2013.a,&b and 2012.a&b),

etc together with specially derived suitable protection measures need for implementation according to the engineering

problems so encountered. In consistence to such aspect, the concept of road foundation is added to appear as a special care

within the prevailing practices. The concept of road foundation is found after Bayan (2012.a). To achieve the best

International Journal of Civil, Structural,

Environmental and Infrastructure Engineering

Research and Development (IJCSEIERD)

ISSN 2249-6866

Vol. 3, Issue 4, Oct 2013, 47-58

© TJPRC Pvt. Ltd.

48 Gokul K Bayan

performance out of the critically facing problems of road section most particularly the instability problem, introduction of

road foundation is essential, because it offers very high quality production of subgrade soil layer at any places (Bayan,

2013.b). This paper is dealing with such matter which will help in road practicing engineers to achieve their engineering

dreams for having an everlasting pavement section by liminating the problem generating section.

National Highway NH-52(A) in Particular

Construction of road surface implies towards the development of the proposed road pavement. In hilly terrains

such pavement generates instability to the naturally standing hillock system because of either cutting or of fillings.

Consequently, a small disturbance quite often generates multifaceted geotechnical problems under prevailing situation. In

general, geotechnical problems are directly related to the ground properties and parameters comprising subgrade and

subsoil. In concern to such aspects, a hilly road particularly in Himalayan subsoil experiences numerous geotechnical

problems as described in later pages which demand appropriate engineering cares.

Present study conducted on a National Highway, NH-52(A) in hilly terrain forming a part of the lower Himalayan

belt made for a new state capital complex, Itanagar, Arunachal Pradesh (AP), India during 1987-92. Geographically the

study area covers a global space inscribed by latitude 26.8880N to 27.131

0N and longitude 93.593

0E to 93.824

0E. Figure 1

depicting satellite imaginary picture of present NH-52(A).

Figure 1: Demonstrating a Few Parts Location of NH-52 and Total Length of the NH-52(A)

Through Satellite Imaginary Map Made Based on Google Map 2012 and Present Status,

Standard & Perfection of Engineering Cares

NH-52(A) is a spur route of NH-52 (Figure 1) 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. As a whole, the NH-52(A) starts at Bandardowa (27.1090N, 93.824

0E & 110 m) as 0 km

Critical Problems and their Solution for Hilly Road Pavement with 49

Particular Reference to NH-52(A) – A New Avenue

point, in Assam and passing through Karshingsa (27.1220N, 93.762

0E & 145 m), Nirjuli (27.131

0N, 93.752

0E & 185 m),

Naharlagun (27.1000N, 93.688

0E & 210 m), Itanagar (27.075

0N, 93.593

0E & 750 m) and ends at Gohpur (26.888

0N,

93.6320E & 85 m) in Assam. The alignment of NH-52(A) follows the path of Dikrong river valley upto Itanagar.

Accordingly, 11 numbers of major tributaries and Nallah of the river Dikrong crosses the NH-52(A) within its first 23 km.

In this regards, Table 1 gives an account of such account of major Nallah.

It is found after many years observations over such road crossing natural drainage system, since 1992 onwards,

that it poses various kinds of problems over the NH-52(A) pavement. Of the many problems, it generates geotechnical as

well as hydrological problems during monsoon period. To raise the counted present status of some problems Figure 2(a) &

(b); Figure 3(a) & (b) and Figure 4 (a) & (b) are incorporated in body of this paper. 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 (Bayan,

2010.a&b, 2008, and 2004.a) which is geologically termed as sinking zone. The Karshingsa section of about 1 km length

generates severe flow type landslides (Figure 2(a)) almost every year and experiences of instability problems as shown in

Figure 2(A&B). Similarly, the other nature of problems like geotechnical and hydrological problems comprising the

sections of NH-52(A) as shown in Figure 2(A&B), Figure 3 (a&b) and Figure 4 (a&b).

(a) Chronic Problems of Landslide of NH-52 (b) Recent Problems in Filling of NH-52 (A) at

(A) at Karshingsa Near 7.05 to 8.05 Km Point Karshingsa Developed during 2012 on 6.95

Km Point Near 7.0 Km Point

Figure 2A: Depicting a Few Scenarios of Present NH-52(A) Experiencing Severe Engineering Problems

GEOLOGY OF THE HILLY TERRAINS HOLDING NH-52(A)

Geology of the subsoil forming the base of the pavements of NH-52(A) is that of the geology of a portion of the

Arunachal Himalayan belt comprising Itanagar complex (Bayan, 2012.b, 2010.a&b). It consist mainly two kinds of rock

group formations. They are Quaternary group and Siwalik group of formation.

The part of NH-52(A) from Bandardowa upto 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 (Figure 2(a),(b) and Figure 3 (a)&(b)). On the

other hand, the rest part upto Gohpur area is composed of siwalik group of formation exposed at surface. Hence, it reveals

better geotechnical properties and generates fewer problems.

50 Gokul K Bayan

Table 1: Geotechnical Properties of Subgrade Soil Forming Bridge Approaches under Phase-I Construction

of the NH-52(A) from Bandardowa (0.0 km pt) to Itanagar (for Total length = 31.5 km) S

eri

al

No

. Identity of soil sample

marked as per name of Nallah

i.e. major tributary/ River of

main river Dikrong at

respective closer point in

kilometer (km)

Grain size as %

passing the sieve

size in (mm)

Geotechnical parameters

from Triaxial ‘qC –test’ on

undisturbed samples

Result of

Proctor’s

density test

Result of

laboratory

CBR-Test

4.7

5 (

IS:4

00)

0.4

25 (

IS:4

0)

0.0

75 (

IS:8

)

Fie

ld d

en

sity

in g

m/c

c

Mo

istu

re

co

nte

nt

in %

‘c’

in k

g/c

m2

‘’

in d

eg

ree

OM

C i

n %

Max

DD

in

gm

/cc

Un

soak

ed

CB

R-

Valu

e

4 d

ay

s-S

oak

ed

CB

R-

Valu

e

1 Sukha Nallah (1.0 km) 94 78 29 - - - - 13 1.77 28 7

2 Nowbhanga river (2.3 km) 93 82 28 1.95 28 0.02 26034' 17 1.66 21 5

3 Khunda Khowa river (3.9 km) 100 94 33 1.81 33 0.04 24026' 13 1.78 26 7

4 Karshingsa river (4.7 km) 96 71 35 1.95 27 0.06 34042' 12 1.87 31 7

5 Karmajuli river (8.55 km) 92 70 40 - - - - 11 1.87 32 8

6 Nirjuli river (10.45 km) 86 53 15 - - - - 22 1.58 18 3

7 Kankan Nallah river (14.65 km) 100 95 48 1.79 27 0.08 31035' 18 1.56 17 4

8 Lagun river (17.70 km) 91 72 31 1.80 29 0.05 30053' 13 1.77 25 7

9 Pachim/Barpani river (18.5 km) 96 80 24 - - - - 16 1.67 23 5

10 Papu Nallah river (20.5 km) 88 63 19 1.98 32 0.04 28022' 21 1.61 21 4

11 Shiva-Mandir Nallah (22.45) 91 69 29 1.78 33 0.06 29050' 14 1.74 27 6

(a) Recent Problems of Landslide & Breaching (b) Problem of Landslide Adjacent to NH-52(A)

at Karshingsa Starting during at Karshingsa Developed during 2012

2011 on 6.75 Km Point on 6.70 Km Point

Figure 2B: Depicting a Very Critical Section of NH-52(A) Experiencing Severe Geotechnical Engineering Problem

As per Bayan (2013.c; 2010.a&b) the geology of the region may be described as: 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.

However, stratiographical points of view some subsoil bends of stratifications so exposed in various locations are

identified as Kimin formation under upper Siwalik group. It is obvious from the field study that the particular subsoil so far

known as colluvial subsoil (Bayan, 2010.b; 2004.a&b) is fallen under Quaternary group only. An active fault is found

associated with the slide prone zone of Karshingsa (Figure. 2 a&b). The geological map of the capital complex bearing

NH-52(A) is given in Figure 5.

Critical Problems and their Solution for Hilly Road Pavement with 51

Particular Reference to NH-52(A) – A New Avenue

(a) Present Hydrological Problems of NH-52(A) (b) Common Feature of Landslide/ Side Falling

at Naharlagun Near 15.7 Km Point Problems of NH-52(A) at Itanagar

Developed during 2011 Near 24.3 Km Point

Figure 3: Depicting a Few Scenarios of Present NH-52(A) Experiencing Severe Geotechnical Engineering Problems

(a) Failure of Lagun Bridge during 1995 at Naharlagun (b) Failure of Khunda-Khowa Bridge during

Near 17.7 Km Point – Hydrological Problem 1995 at Closer to Bandardowa on 3.9 Km Point

Figure 4: Failure of Bridges on NH-52(A) during 1995 – Inadequate Design Concept and Practices

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 (Figure 5). These rocks have been deposited during Mid-Miocene to Lower-Pleistocene period. The

Formation consist mainly of alternations of conglomerates known as pseudo-conglomerate (geotechnical name of this layer

of soil is colluvium), soft and massive sand rock/ sandstone, and silty clay beds (geotechnical name is Soft Rock-Hard

soil). 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.

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.

52 Gokul K Bayan

Figure 5: Geology of the Capital Complex Covering the Study Area NH-52(A)

PROBLEMS ENCOUNTERING NH-52(A)

As per Bayan (1994.(a&b); 1995.a; 1996; 2003; 2008 and 2010.(a&b)), there are numerous prevailing problems

associated with smooth running of the NH-52(A) since inception. Of course, all problems generate out of natural situation

as well as of the prevailing unskilled engineering practices i.e. thumb rule nature of layman’s practices (Figure 2(b); Figure

3(a&b) and Figure 4(a&b). However, studies made continuously since 1992 onwards based together on geotechnical

investigations and direct observations over NH-52(A) road performance reveal the following principal categories of

problems:

Geotechnical problems comprising -

o Unsound subsoil condition including uniquely reveal weak CBR-values (Bayan, 2010.b, 2004.(a&b), 1994

and 1992).

o Landslides due to static liquefaction and toe erosion of hill flanges (Bayan, 2013..c, 2010.(a&b), 2008 and

2004.a)

o Revealing poor geotechnical parameters due to nature of origin of the subsoil arising out of immature

geological formation (Bayan, 2013.c, 2010.b, 2004.b, 1994 and 1992).

Hydrological problems associated with heavy rainfall and very poor system of drainage outlets (Bayan, 2010.b,

2004.a, 1996, 1994 and 1992).

Topographical problems associated with narrowing of pavement’s width because of unprotected side falling of

some critical pavement sections (Bayan, 2010.b, 1996, 1994 and 1992) and

Inadequate suitable engineering knowledge for design and execution of any form of engineering measures to take

care of the road pavement (Bayan, 2004.a 1996, 1994 and 1992 and Nani, 1995.b).

Most of the even nature of geotechnical problems are depicting in Figure 2(A&B), Figure 3(a&b), the detail

description of which are found in relevant published papers given under references. However, for comprehensive

Critical Problems and their Solution for Hilly Road Pavement with 53

Particular Reference to NH-52(A) – A New Avenue

understanding of the problems, some of them which are describing all about the unsoundness properties of the subsoil are

given in relevant tables of this publication and also depicted in some photographs.

At the initial stage of construction, authority of the NH-52(A) was state government. Subsequently, upto 1997 it

was found that the bridge structures so erected over the major Nallah & rivers (Table 1) were washed out 2-3 times (for

instance Figure 4(a&b)). The reasons are lack of basic practical engineering knowledge on:

Geotechnical behaviours of the subsoil forming the road pavements and its bases upto certain depth.

Effect of hydraulic energy on substructures as well as hydrological behaviour of hilly rivers (Bayan, 2010.b,

2004.a, 1996, 1994.a&b and 1992) on its subsoil forming its banks powered by heavy rainfall.

Good management of efficient drainage outlet system including perfectly designed and executed storm water

drainages system needed at road side all along the total length of NH-52(A).

Updating engineering technical knowhow for implementations.

However, during 1998-2009 bridge structures on the rivers turns to a preferable and durable phase of concrete

structures under the engineering care of 1353 GE, BRTF, C/O 99APO. On the other hand, the present overall status of the

NH-52(A) road pavement is witnessing by the photographs given in Figure 1, 2 and 3 effectively.

GEOTECHNICAL PROPERTIES AND ITS EFFECTS

Geotechnical Properties

In total 65 disturbed soil samples were collected all along the NH-52(A) @ about 0.50 km interval from road

formation level which were analyzed by covering series of laboratory tests. Most of them are routine tests like

classification test, moisture and density tests, Proctor’s compaction test and CBR-value tests. Consolidated quick triaxial

shear test (qc) were also performed.

Similarly, field investigation mostly covers advancement of 150 mm boreholes with SPT. There were 11

number of boreholes upto depth of 10-12 m were carried out to ascertain soundness of the in-situ status of the road

subgrade in some critical sections like Karshingsa landslide zone. Thus, some of the evaluated geotechnical properties of

the subsoil of NH-52(A) are given in Table 1 and Table 2.

Overall, there are three types of subsoil layers identified in the area traversing by the NH-52(A), namely –

Colluvium layer (i.e. Pseudo-conglomerate in origin), Hardsoil–Softrock of Upper Siwalic sandstone and shalestone layer

and Gravelly sand i.e. Conglomerate layer found after Bayan (2010.a&b, 2004.b and 1992). These three layers in alternate

bends constituted the whole hillock land masses. Out of these, only colluvium layer normally generates flow type landslide

(Figure 2(A&B)) during heavy rainfall under such a condition when its underlained layer is impervious (Figure 2.B(b)).

Obviously, a conclusion was drawn in this regard (Bayan, 2010.a&b) is that, every year as and when consecutive

3-month rainfall precipitation within peak monsoon period exceeds about 2,300 mm, then there is a flow type landslide

happens to occur all along the lower Himalayan region particularly in the critical road sections of NH-52(A) route or more

particularly in Karshingsa sinking zone.

Moreover, it is found that as and when such colluvial soil layer comes into continuous contamination of runoff

water, its soil grains disintegrate quickly and generates blocks of slum soil falling which may also be called as landslides

(Figure. 2(A&B)). In this regard, it is also ascertained that the subsoil strata beneath the road pavements alignment are not

very dense in present state as it is revealed by N-values.

54 Gokul K Bayan

Table 2: Geotechnical Properties of Subgrade Soil for Pavement of NH-52(A) at Formation Level

Ser

ial

No

. Identification

of soil sample

marked as

kilometer point

of formation

level

Grain size as % passing

the sieve size in (mm)

Atterberg’s

limits

Ty

pe

of

So

il i

n

Sy

mb

ol

as i

n B

IS Result of

Proctor’s test

Result of laboratory

CBR-Test

20

.000

10

.000

4.7

50

0.6

00

0.0

75

WL PL PI

OM

C i

n %

Max

DD

in

gm

/cc

Un

soak

ed

CB

R-

Val

ue 4 days-Soaked

CBR- Value

CBR-

value

Moisture

as tested

A. Under Phase-I: From Bandardowa to Itanagar (Total length 31.2 km)

1 CH-17.00 99 98 96 77 29 - NP - GP 12 1.83 33 9 14.5

2 QBH-18.68 100 100 100 94 58 32 18 14 CL 14 1.75 26 6 16.1

3 CH-18.50 100 98 98 92 53 28 17 11 GP 12 1.87 35 12 13.8

4 QDH-20.83 100 100 100 92 50 32 22 10 CL 16 1.64 19 5 18.4

5 CH-21.50 93 86 79 62 35 - NP - GP 13 1.78 26 8 15.5

6 CH-22.00 100 100 99 96 57 31 19 12 CL 13 1.79 29 8 14.9

7 CH-23.50 100 100 100 94 47 - NP - SC 12 1.81 31 9 14.1

8 CH-29.50 87 84 81 66 50 30 19 11 CL 20 1.56 15 3 23.1

9 CH-30.00 99 95 93 74 46 - NP - SC 19 1.57 17 4 21.9

10 CH-31.20 97 90 89 83 31 - NP - SM 14 1.74 23 6 16.5

B. Under Phase-II: From Itanagar to Gohpur (Total length 11.5 km)

1 8.00 Km pt 100 99 97 84 30 - NP - SM 11.0 1.94 34 14 13.3

2 8.50 Km pt 100 100 99 85 32 - NP - SM 11.6 1.92 22 8 13.5

3 10.50 Km pt 100 100 100 93 57 - NP - SC 12.3 1.90 24 9 14.3

4 10.9 Km pt 100 100 100 99 37 - NP - SC 12.6 1.87 30 10 15.1

SOLUTIONS AGAINST ENCOUNTERED PROBLEMS

Conventional Measures Proved Unsuitable

It is found that, all form of conventional remedial measures comprising mainly retaining structures. Such

structures are made of gravity wall constituted by boulders or concrete masses, which were failed repeatedly many times

even in a same location (Figures 1, 2, 3 and 4). Moreover, the present in-growing practice of providing dry stone-crated

wall built in stages (Figure 2 A(b) and Figure 3(a&b)) used to fail severely in the same manner. The simple reason behind

its failure is absence of structural foundation. The foundation, which can hold its structural soilmass in their same position

till life time of the super structure, is void in any locations. So to achieve successful road section in critically weak

pavement zone of hilly road mostly threatened by high speed runoff water along drainage outlet i.e. storm water drainage

path, or stream or river, the ongoing engineering practices must have to adopt a new system of constructing road

foundation which is described below in brief. In this conception, the critically threatened road section must be retained

with such RCC structure which is built on a rigid and stable foundation system. This new system is propounded as road

foundation system (Figure 6).

(a) Surface Foundation System for (b) Pavement in Section Showing its Surface

Pavement in Plan Foundation with Retaining Wall

Figure 6: Shows the Overall Plan for Introduction of a New Structural

System i.e. Road Foundation to Pavements

Critical Problems and their Solution for Hilly Road Pavement with 55

Particular Reference to NH-52(A) – A New Avenue

Skirted Retaining Wall with Road Foundation System – A New Solution

Pertaining to present practices, for achieving an ever lasting nature of critically threatened road pavement section

as described in earlier pages, more particularly in weak subsoil zone, the concept of skirted retaining wall together with

road foundation system for hilly roads shall be adopted. The concept of road foundation is found after Bayan (2012.b).

Such process 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 (HC-C) as shown in Figure 6. 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 (Bayan, 2013.a&b). Hence engineers will possess a permanent road section in

such most critical weak zones of hilly road.

DISCUSSIONS

NH-52(A) is the threshold road communication to the Itanagar, i.e. the capital complex of Arunachal Pradesh.

Hence, it was built over the hilly subsoil irrespective of their geotechnical properties. Further, it is the engineering

challenges to achieve suitable road communication out of adversely pronounced weak subsoil properties, for which

updated engineering science and technology shall be adopted and implemented with skill hands.

In this paper, almost all form of required information regarding geotechnical properties and geological

characteristics and problems of subgrade/ subsoil of the road pavement of NH-52(A) are stated scientifically. Its depicting

present status and standard implies to the poor characteristics of an Indian National Highway (2-lane), which are also well

illustrated with figures and photographs. Hence, it is becoming the sole responsibilities of those organisations which are

fully involved with the engineering development of the NH-52(A). It is obvious that, updated engineering knowledge and

technology can offer suitable solutions towards mitigation of such road problems, which are described briefly herein this

technical paper for the benefit of the state particularly and the nation as a whole.

Suggestions regarding selection of absolutely suitable solution as remedial measures are preferably indicated

within the context of this paper. Therefore, it is proclaimed that – the concerned authority may come forward with broad

intention to provide a smooth NH-52(A) such that the character of the Indian National Highway/ Express way shall

flourish in Arunachal Pradesh also in near future.

CONCLUSIONS

Present study carried out during recent and a few past years for generating in-situ data as well as for

understanding the behaviour of pavement subsoil characteristics etc, which may help in achieving a very smooth surface

and of permanent nature of road communication network for the benefit of the country as a whole. Through the study on

NH-52(A), following opinions may be made in favour of its healthy engineering growth:

Studies carried out to establish the quality, problems, status & standard of Himalayan subsoil along NH-52(A) as

a whole.

Conventional practices for highway development techniques offering stable road surface are failed under such

Himalayan subsoil properties and hilly environments for NH-52(A) because of lack of perfect engineering

knowledge, improper planning, design, implementations etc.

Solution regarding deleting the most critically worst section, by introducing combined efforts of skirted retaining

56 Gokul K Bayan

wall with HC-C generated by using outer and inner skirt condition and placement of at least one layer of

honeycomb cell situation (Figure 6) enhances many times the value of untreated pavement properties pertaining to

design parameters like CBR-value, K-value and SBC-value (Bayan, 2013.b, 2012.b).

Complete road foundation system comprising confined situation, definitely increases the overall elasticity of the

engineered pavement even with very weak soil properties and proclaims minimum maintenance job cost of road

surface.

ACKNOWLEDGEMENTS

The author extends his thanks gratefully to the Acting Director, CSIR-North East Institute of Science and

Technology, Jorhat, Assam; India (formerly RRL-J), for his kind permission to publish this paper.

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belt located at Arunachal Pradesh. National Conference (IGC-10), Proc. Vol-1, of IGS & IIT, Bombay, pp 659 -

662.

7. Bayan Gokul K (2010.b): Study of landslide in part of the road NH-52(A) from Bandardowa to Itanagar in

Arunachal Pradesh – A DST sponsored project for “Jai Vigyan Technology mission for Natural Hazard

Assessment in Himalayan – Landslide Components; Final project report, Northeast Institute of Science and

Technology (CSIR), (Formerly RRL) Jorhat Assam; pp 1 - 69.

8. Bayan Gokul K. (2008): Static liquefaction for flow type Landslide at Karshingsa – A case Study. Proc. Vol.

International Conference 12th

IACMAG, Goa; IIT, Mumbai; pp3021 - 3030.

Critical Problems and their Solution for Hilly Road Pavement with 57

Particular Reference to NH-52(A) – A New Avenue

9. Bayan G. Kakati (1996): Basic causes of failure of Hilly roads with particular reference to NH-52(A) and possible

remedies. Arunachal REVIEW, a magazine of Govt. of A.P.; Directorate of Information and Public relationship

(DIPR), Naharlagun, A.P.; Vol-IV, No.13; June; pp 18-26.

10. Bayan Er. G. K (1995.a): Collapse of Lagun Bridge a predicted failure. The Arunachal Front, Weekly magazine

of the State, Arunachal Pradesh; Thursday 6 July.

11. Nani Kojeen (1995.b): Sinking Bridge- The ‘Lagun Bridge’. – An Editorial Note of the Arunachal Front, Weekly

magazine of the State, Arunachal Pradesh; Thursday 29 June.

12. Bayan Gokul K. (2004.a): Erosion Controlling measures in High speed River at Karshingsa in Eastern Himalayas

– A case study. Proc., International Conference on Geosynthetics and Geoenvironmental Engineering, ICGGE-

04, IIT, Bombay; (2004), 395-402.

13. Bayan Gokul K. (2004.b): Engineering behaviour of hard soil-Soft rock of north-eastern region of India and its

problems”. National Conference (IGC-04) Proc. Vol-1, of IGS & NIT, Warangal, pp 90-96.

14. Bayan Gokul K. (2003): Need of Forensic Geotechnical Investigation for construction of Bridge and Culverts in

the Hilly Roads of North eastern Region of India. Proceeding of a national workshop organized by Committee on

professional practice of Indian Geotechnical Society (IGS), Chennai, India, Feb 28- March 1, pp 57-62.

15. Bayan Er. G. K (1994.a): Will the Lagun bridge collapse again? The Arunachal Front - an English weekly

magazine of the State, Arunachal Pradesh, Friday 7 October.

16. Bayan Gokul Kakati (1994.b): Contour surveying and geotechnical investigations for the design of the proposed

Lagun Bridge at Naharlagun on NH-52(A), A.P.; Technical Report; RRL, Naharlagun & Galaxy Engineering,

Itanagar; pp 1-29.

17. Bayan Gokul K. (1992): Evaluation of various geotechnical properties of the road NH-52(A) from Bandardowa to

Gohpur via Itanagar in Arunachal Pradesh. Final project report, Regional Research Laboratory (CSIR), Jorhat

Assam; Branch Laboratory Itanagar (1988-92), pp 1 - 20.