Acknowledgement

This report on “ Detailed estimate and design of Bagarkot –Bhargeswar Road” is the result of the study carried by the students of IOE, pulchowk campus. This report is the outcome of the combine efforts put together by group members as well as those performing directly or indirectly. Hence, the report would be incomplete without giving credit to those who have helped-out us in preparing this report.

First of all we would like to thank Institute of Engineering, Pulchowk Campus for organizing the

project on Green Road.

We  are highly obliged  to our respected teacher Mr. Padma Bahadur Khadka for his effort and invaluable suggestions in making the project successful.

We would like to express our gratitude to GTZ office for having faith in us in carrying out the project.

We would like to thank Bijay Karmacharya, GTZ official for organizing our project.

We would also like to thank GTZ officials for their kind cooperation. In this regard, We would like to extend our warm acknowledgement to  Mr. Shailendra Kumar Jha , The regional coordinator GTZ , Mr. Pasupati Kumar Jha, The District coordinator GTZ office, Dadeldhura, and Mr. Prafulla Pokhrel, Engineer GTZ office, kathmandu. for providing us ample  information of our site prior to our survey works and also for their kind suggestion and  cooperation.

We are also highly greatful to Mr. Laxmi Gautam and Mr.Ashok Silwal, Overseers GTZ office, Dadeldhura, for their support through out the survey works at site. We would also like to extend our thanks to our coworkers who had helped us in carrying out survey works in the field.

We highly appreciate the help we received from Mr. Bhojraj pant, in preparation of this report.

Lastly without missing any one, we would like to extend our thanks to our dear friends and to those who has helped us in carrying out the project works directly or indirectly.

Green Road

Dadeldhura Group

Members

Bhim Kumar Dahal

Dawang Sherpa

Krishna Prasad Rijal

Sachin Man shrestha

Yogesh Lama Pakhrin

Salient Features of the Project:

1. Name of the Project                                               :           Detailed Engineering Survey and

                                                                                    Design of Bagarkot –Bhageswar road.

2. Description of Proposed Road:

2.1 Location

2.1.1 Region                                         :           Far-Western Development Region

2.1.2 Zone                                           :           Mahakali

2.1.3 District                                        :           Dadeldhura

2.1.4 VDC                                           :           Bagarkot VDC, Bhageswar VDC

2.1.5 Latitude                                       :           28°12’––29°26’

2.1.6 Longitude                                    :           80°12’––80°47’

2.1.7 Starting point                               :           Parchetta Khola

2.1.8 Ending point                                :           Bhageshower VDC

2.2 Geographical Features:

2.1.1 Terrain                                        :           Hilly, rolling, and Mountainous

2.1.2 Climate                                        :           Sub-tropical, Mid/Cold Temperate

2.1.3 Geology                                      :           Gneiss, Phyllite, Dolomites, Sand stone.

2.3 Hydrology                                                              :           Rain fed Catchments

3 Classification of Road:

3.1 Classification                                                          :           Rural road Class “A” (District Road)

3.2 Surface                                                                   :           Earthen

4. Length of Road:                

4.1 Length                                                                    :           5.3 Km                       

5. Cross––Section:

5.1 Right of way                                                           :           15m on either side of the road

5.2 Formation width                                                     :           4.5m

5.3 Carriage way width                                     :           3.0m

5.4 Shoulder width                                                      :           0.75m on either side of the road

5.5 Side drain                                                               :           0.50m (Trapezoidal Type)

5.6 Cross slope in carriage way                                    :           5%

5.7 Cross slope in soulder                                             :           5%

5.8 Maximum average gradient                         :           7%

5.9 Maximum gradient                                      :           12%

5.10Minimum gradient                                      :           0.5%

5.11Minimum radius in Horz. Curve                              :           10.0 m.

5.12Average external inclination

                        a. Dry wall                                            :           1H:4V

                        b. Gabion wall                                      :           1H:4V

                        c. Earth Embankment                            :           1:1

                        d. Size of Gabion Box                           :           2*1*1

5.13Hair pin bends                                                       :           Symmetrical or asymmetrical as per

requirement

6. Cross Drainage structure:

6.1 Dry stone Causeway                                               :           1 Nos

6.2 Flood Way                                                             :           2 Nos

6.3 Bridges                                                                   :           Nil

6.4 Hume Pipe Culverts                                                :           Nil       

6.5 Supper Culvert                                                       :           10 Nos

7.0 Retaining structures

                        7.3.1 Dry stonewall                              :           2234.81 m³

7.3.2 Gabion walls                                :           947.00 m³

8. Construction:

            8.1 Earth work

                        8.1.1 Cut Volume                                 :           72730.14m³

                                8.1.2 Fill Volume                                  :           6370.24 m³

            8.2 Dry stone soling                                          :           429.58 m³

9. Project Cost:

9.1 Cost:

9.1.1 Total Cost of Project                   :           Rs.10436865.43

9.1.2 Cost per Km.                              :           Rs.1969219.89

ACRONYMS

HMG/N           =          His Majesty Government of Nepal

MLD                =          Ministry of Local Development

VDC                =          Village Development Committee

DDC                =          District Development Committee

Km                  =          Kilometer        

Kg                   =          Kilogram

OS                   =          Ordinary soil

HS                   =          Boulder mix soil

HR                   =          Hard Rock

MR                  =          Medium Rock

OR                   =          Ordinary Rock

m                     =          meter

No.                  =          Number

Rs.                   =          Rupees

MD                  =          Man Days

GI                    =          Galvanized

VPD                =          Vehicle Per Day

T.U                  =          Transportation Unit

Ch.                   =          Chainage

BM                  =          Bench Mark

E/W                 =          Earthwork

IP                     =          Intersection Point

NRS                =          Nepal Road Standard

NRRS               =          Nepal Rural Road Standart

ACKNOWLEDGEMENT

SALIENT FEATURES

ACRONYMS

S.No.                                        Contents                                                         Page No.

1. INTRODUCTION                                                                                        1-5

             1.1 Introduction                                                                                    1

             1.2 Introduction to Green Road                                                            2

                         1.2.1 Characteristics of Green Road                                        

                         1.2.2 Objectives of Green Road                                              

             1.3 Green Road in context of Nepal                                                      4

2. Project Area and its Scope                                                                            6-11

2.1 Scope of work                                                                               6

2.2 Objectives of Project work                                                 6

2.3 Location of work                                                                            7                                                          2.4 Socio-economic overview                                                                      8

2.5 Geo-morphology                                                                            8

2.6 Hydrology and meteorology                                                            9

2.7Construction Material Survey                                                           9                     

2.8 Land use pattern                                                                             10

2.9 Education                                                                                       10

2.10 Market                                                                                         11

2.  IMPORTANCE OF THE PROJECT                                                          12

4. ADOPTED DESIGN STANDARDS                                                           13-28

4.1 Road Classification, traffic and tonnage                                           13

4.2 Design speed                                                                                  13

4.3 Horizontal Curve                                                                            14-17

4.3.1 Minimum Radius of Curvature                                          14

4.3.2 Super elevation                                                                15

4.3.3 Extra widening                                                                 16

4.3.4 Sight distance                                                                  17

4.4 Vertical curve                                                                                 17-20

4.4.1 Minimum radius of curve                                      18

4.4.2 Length and ordinate of  curve                                           19

4.5 Hairpin bends                                                                                 20

4.6 Vertical clearance                                                                           21

4.7 Lateral clearance                                                                            21

4.8 Right of way                                                                                   22

4.9 By passes                                                                                       22

4.10 Formation width                                                                           22

4.11 Camber                                                                                        22

4.12 Carriage way width                                                                       23       

4.13 Cross section                                                                                23

4.14 Longitudinal gradient                                                                     23

4.15 Drainage                                                                                       24

4.16 Retaining Structures                                                                      24

4.18 Design standards in Green Road (tabular forma)                26

4.19 Design aspects for the vegetative engineering standards      28

5 METHODOLOGY

5.1 ALIGNMENT SURVEY                                                               29-30

                        5.1.1 Desk Study                                                                     29

                        5.1.2 Field Study                                                                      29-30

                                    5.1.2.1 Reconnaissance                                                29

                                    5.1.2.2 Detailed Survey                                                29

6 ALIGNMENT DESCRIPTION                                                                    31-32

            6.1 Description of Alignment                                                                 31

            6.2 Bench marks                                                                                  32

7 ENVIRONMENTAL ASPECTS AND MEASURES                                   33-36

            7.1 Introduction                                                                                    33

            7.2 Measure for Environmental Protection                                             33

            7.3 Road side Plantation for Ecological Balance                                    34

            7.4 Road side Plantation for slope stabilization (Bio-engineering)            34

8 BILL OF QUANTITIES                                                                              

9 SUMMARY OF QUANTITIES

10 CONCLUSION, LIMITATION AND RECOMMENDATION                37-39

            10.1Conclusion                                                                                    37

            10.2 Limitation                                                                         37

10.3 Recommendation                                                              38

12 SAMPLE CALCULATIONS

13 TECHINICAL DRAWINGS

ANNEX

A. Calculation Tables

B. Detailed Estimate of Quantities

1. Detailed estimate of site clearance

2. Detailed estimate of tree cutting and root excavation

3. Detailed estimate of earthwork calculation

4. Detailed estimate of Retaining structures (Dry stone wall & Gabion wall)

5. Detailed estimate of Cross drainage structures (Flood way, Causeway, Scupper Culvert)

6. Detailed estimate of Drain soling

7. Detailed estimate of Spot Gravelling

8. Detailed estimate of Bio-engineering

C. Rate analysis

BIBLIOGRAPHY     

1.0 Introduction

1.1 Overall Scenario of Road Development in Nepal.

Variation in the productivity, culture is among different factors that necessitate the transportation network in Nepal. Although transportation network has become the prime factor for national development of Nepal, many constraints have to be overcome due to hilly and rugged topography. That is why although major part of the national budget goes to transportation section; it always seems to be deficient.

Road construction is very important task for the development but it is capital intensive. To construct the new road especially in hilly area is very difficult so careful planning and prioritization for the road construction is most essential based on which realistic decision can be made. Therefore to find out most efficient alignment, joining different obligatory points, series of studies considering various aspects have to be carried out.

The overall area of Nepal is about 147,181 sq. Km., with length of about 900Km and width of 180km. The reason for the slow development of the rural sector is the Poor transportation system. In context of Nepal, accessibility of rural communities is concentrated on foot tracks, suspension bridges, etc. However, in long term, it is necessary to construct both motorable roads and roadways there is no any standard methodology and approach to planning, design, construction, operation, repair and maintenance of rural roads. Many agencies have developed some approaches. Green Road Concept is one of such approaches. His Majesty’s Government of Nepal has established Department of Rural infrastructure Development and agriculture roads under the ministry of local development and it has proposed an approach similar to Green Road Concept.

The overall Nepal Road Network can be presented in the tabular form as:

Source: Nepal Road Statistics 2000 (HMIS news)

Note:   BT        = Bituminous Road

            GR       = Gravel Road

            ER       = Earthen Road

            NH      = National Highway

            FRN    = Feeder Road Network

            DR       = District Road

            UR       = Urban Road

1.2 Introduction to Green Road:

Green road is a low-cost, low volume, fair weather earthen road. It is environmental friendly, labour-based road constructed with the view to conserve the delicate mountain ecology and to protect and strengthen vegetation preventing the excessive soil erosion. The road is technically viable as well as cost effective. The construction of Green Road being labour-based, the local rural population directly benefits from the approach. In the short term, they gain off-farm employment opportunities during construction. In the mid term, the community obtains better access to the outside world and enjoys reduced transport costs for goods and people. In the long term, Green Roads provide improved public and private service and economic development because the community is less “cut off”.

Characteristics of green road:

·              Road suitable to mountain terrain

·              Fair weather road that means the road is opened to the traffic for 8-9 months and remains closed during the monsoon season.

·              Road with fixed centre line.

·              Pavement surface is earthen with spot gravelling at places wherever required

·              Road can be upgraded to gravel road when AADT increases

·              Short drains are provided only n those places where surplus accumulated run-off floes into the road from the mountain side viz. at paddy fields and slopes with springs as well as in cases where the longitudinal gradient of the road is more than 7% such drains would discharge into the nearest causeways, pipe culverts or cross drains.

The following are the objectives of Green Roads:

• Development of rural road and trail network designed to meet the minimum traffic requirements for districts, in order to reduce transportation costs
• Involvement of local authorities and stakeholder communities from the preparation phase on wards, thus supporting HMG/N’s decentralization efforts in the road sector while promoting a sense of local-level road ownership in view of main
• Use of an environment-friendly road construction and maintenance technology that provides the natural environment, its agricultural potential and its natural resource against excessive erosion

• Optimum use of locally available resource in terms of labour, material and finance
• Generation of short term, off-farm employment opportunities using labour-based road construction and maintenance techniques.
• Phased Construction. They are

·        Phase I: a trail along the future road alignment.

·        Phase II: a track created by the gradual widening of the trail.

·        Phase III: a road including retaining structures, water management structures and bioengineering.

·        Phase IV: Road surface compaction and construction of road surface draining system including bioengineering.

(Note: A trail is a way with a defined alignment, sometimes within a corridor, and mostly used by pedestrians. Mule trails are used by mule caravans and have slightly higher width requirement compared with pedestrian trails. A track is a way with a defined alignment, sometimes   within a corridor that may change seasonally. It   may be used by various types of standard four-wheel-drive vehicles or agricultural equipment (animal cart, tractor, trailer, etc); generally only during fair weather conditions. )

1.3 Green road in context of Nepal:

For a country of about 147,000 sq. km, with dimensions of 900 km by 160 km, and estimated population about 23 million, Nepal’s road density is quite small, only about 9 Km per 1200 sq. km. with a coverage of about 6km per 10,000 people. Nepal is hence one of the least accessible countries in South-Asia.

Despite much progress in the road construction works, Nepal remains one of the least accessible countries in South Asia with a total recorded road network of less than 16,000 kms. Alternatively, 10km of roads per 100 sq. km.

In 80’s new concept of road building technology developed that was appropriate for Nepal. It was more conservation-oriented construction and the concept being building a new type of rural low-cost, low volume roads using participatory and labour-based methods Its main goal being the conservation of the delicate mountain ecology, and in particular, to protect vegetation as a mean to prevent excessive soil erosion. The road building approach being so simple that even the local community could easily understand it. Besides, regular trainings are carried out to develop the local manpower; so that they can resolve any difficult situation in the road; usually during the maintenance.

More than 75% of the people in Nepal are engaged in agriculture with most of its parts being inaccessible. With the view of getting maximum benefit Green Road concept has emerged. Green road construction is conducted only in the off-farm season, so that the community can utilize their time and get the benefit for themselves. In addition, the Green Road approach arouses kind of self-ownership and hence the people have to construct and maintain it by themselves.

2.0 Area and Scope of Work

2.1 Scope of Work:

1. To conduct detail survey, design and cost estimation in 10 Km of the alignment
2. To access the remaining work on 5 Km of existing track.

2.2 Objectives of Project work:

1. Coordinate with the GTZ-TA team  in the distinct in selection of alignment in view of starting point, control points and ultimate destination,
2. Carry out field survey of the project area setting out alignment in consultation with the beneficiaries of the project and the TA-Team in a completely participatory manner.

The survey work consisted of :

Ø      Alignment survey with levelling instrument/Theodolite

Ø      Centerline pegs at an interval of 25m. Cross-slopes at these intervals

Ø      Benchmark at an interval of 500m, reference points at the rate of 4 per km

Ø      Detailed survey at the critical sections, hairpin bends/loop etc. where necessary.

Ø      Plant community survey at various chainages and elevations consulting local people.

Assessment of the remaining works:

Ø      Assess the progress achieved until now

Ø      Estimate remaining works that is to be done in order to complete the road to full width.

Ø      Design structures, curves, loops etc where required and suggest grade improvement if required.

3. To develop basic concept for using vegetation and the small scale civil engineer structures in the compatible form in the most effective way at the site.

4.   Produce estimates of the structural works specifying, type of structures, chainages,

required quantity of material and requirements by year in tabular form

5.   Produce detailed survey report of whole 10 Km alignment and assessment of existing 5 Km alignment including the following:

Ø      Longitudinal profile

Ø      Horizontal plan

Ø      Cross-sections at given intervals/typical cross-sections for various slopes.

Ø      Type design of structural works such as hairpin bends/loops.

Ø      Detailed design at critical sections such as hairpin bends/loops

Ø      Quantity and cost estimates for road sections of each VDC specifying required mandays of skilled, unskilled labours, materials, VDC cash contribution in the standard formats of RCIW

Ø      Breakdown the cost estimates for each phase of road construction in standard format.

2.3 Location of work

The proposed road starts at Parchheta of Bagarkot VDC and ends at Bhageswar VDC. The proposed alignment encompasses many highly fertile land having existing surface irrigation facilities as well as rain fed arable land.

The proposed alignment will be spinal chord for the transportation of human and good of various important VDCs of Dadeldhura. There is one important Indian boarder called Gairibagad which is about 10 Km far from Rupal through Mahakali River. If this stretch can be opened, it might be one of the important point and this road might be one of the main roads for neighboring districts like Doti, Dadeldhura, Baitadi, Acham and Bhajang etc., which will help in boosting the economic value of the area.

Besides, the presence of arable land suitable for different kinds of food, vegetables and fruits along the alignment may open door for the farmers to timely sell out the products in the market. In addition there is potentiality of dairy development and establishing milk collection center but road network is lacking to transport to the market centers.

At the confluence of the Budhi Gardh and Nani Gardh in the parchheta there is possibility of establishment of micro hydropower development that may benefit the people residing in these areas.

2.4 Socio-economic overview:

Demographic characteristic of the project:

The pertinent data of the project VDCs and population data of the area have been analyzed and reproduced from the population census of 2058 B.S is presented below.

2.5 Geo-morphology:

syncline structure. . The portion of the road between khal-Bogata passes parallel to the thrust line with the same rock type of melmura formation.

2.6 Hydrology and Meteorology

The climate of the district varies in accordance to the altitude. Since the alignment lies in the Far Western region where the monsoon reaches later. The monsoon usually starts in the middle of May and ends in the start of the September. There is tropical hot climate in the riverbank and cold climate in high hill areas and sub tropical climate at hill areas. In the vicinity of the project area the climate is sub-tropical. The rainfall is mainly due to monsoon. About 80 percent of the monsoon precipitation is concentrated to 4 months of the year.

Rainfall is steady rainfall. During monsoon rainfall, high surface runoff and some places flood discharge takes place due to the high cross slope of the ground. At winter the Kholsi are normally dry. The major Kholsis along the alignment are Dainshila khola and Ghatte Gad.

Maximum rainfall= 506.5 mm

Minimum rainfall= 7.2 mm

2.7 Construction Material Survey:

 During the Survey works, information regarding the availability of the construction materials to be used in the project was also investigated.

Naturally available materials like block stone, boulder, timber etc are easily available at every spot and the quality is suitable for gravelling. In case of sand and other stones required can be brought from the Daishila khola etc. the maximum lead is 7 Km. Water is easily available at most reaches.

Materials, which are to be, imported either from Dhangadi or through MRM to Dadeldhura are cement, steel, nails, gabions wires etc.

For the stabilization of road works bio-engineering works are to be done. For this purpose bio-engineering survey has been done.

2.8 Land use pattern

General observation of the area during the feasibility study reveals that most of the people living in these areas are agriculture based. More than 90 percent of the total area is under cultivation. Houses, forests, trails occupy the remaining; cliffs barren land and pasture land along the alignment corridor. The farming of Maize.paddy, Millet, Barley, Wheat etc are very common. Beside these vegetables and fruits farming like mango, oranges etc are very common.

According to land holding pattern, about 4% households are reported to be land less. They have only a small piece of land for erecting thatches and growing kitchen garden vegetables.

Their main source of livelihood is to rent in land for sharecropping, livestock raising and wage labour. The average land holding size of the VDCs household is about 0.2 hectare.

In recent years the crop yield is observed to have decreasing, the main cause behind this is the high rate of migration of the skilled manpower to India and other countries.

January, February, March, April, September and October are the agriculture slack months. During these months the migration to India in search of works among the villagers are common.

2.9 Education:

Bagarkot VDC:

Lower Secondary school and primary schools in this VDC are 1 and 9 respectively. There are altogether 40 teachers in total with 900 boys and 300 girls.

Bhageswar VDC:

Total schools in this VDC are 5 Nos and 24 teachers, 1200 boys and 300 girls students.

2.10 Market

The major agricultural production in the area is paddy, maize, wheat, Millet etc and cash crops like millet, peanut, pulses, beans etc. Many fruit species like oranges, mousam, lemon, Banana, Mango, Naspati are produced. Also the local vegetables like potato, cauliflower, brinjal, vegetable chilly, pumpkin, beans, mustard etc are produced according to the need of the farmers and condition of the monsoon rain.

There are no farmers having surplus food production in this area. However a few farmers earn cash out of selling fruits and vegetables in near market at Khalanga. The main market for Doti Ghatal, Bagarkot and Bhageswar VDC where the people from the southern Baitadi districts also come to trade the products like rice, wheat, millet etc. The total number of people transiting through the existing trail from Bagarkot BDC and Bhageswar VDC are 350 and 300 persons respectively.

3.0 IMPORTANCE OF THE PROJECT

The proposed road project passes through mainly two VDCs; Bagarkot VDC and Bhageswar VDC.

The 4.5 m width road has extended to the Parchetta khola of Bagarkot VDC. Beyond Parchetta is the mule track. The primary means of transportation in this area is mainly mule and porters form the secondary means of the goods transportation. The VDC’s, which lie in the project area, confirm the arable land used for the production of the paddy, vegetables and fruit like mango. Similarly, milk and milk products like; ghee etc, are produced by the farmers in mass scale. But due to lack of fast transportation, the products as vegetables and fruits tend to perish or rot and get wasted Due to this reason the farmers are not motivated to make optimum production.

The construction of this road will affect the people living in these areas directly and indirectly. The road will provide income generation activities for the people for the people of this area. The direct benefit to the villagers from the road will create off farm employment opportunities in road construction works during agricultural slack season. Because road is stopped during farming season as the result there will be no affect in production of farmers. The most evident fact is that road functions as a transportation and communication from the centre to the peripheral community and vice versa. The road can assure the villagers the market place for their products and can influence more interest in optimum utilization of their cultivable lands.

4.0 GEOMETRIC DESIGN AND STANDARDS

4.1 Road Classifications, Traffic and loading:

According to Nepal Rural road Standard (2055) the road is classified as Rural Road class “A” (district road). The road gives access from one or more villages to the nearest market or to higher type of roads. District Roads are important roads within a district serving areas of production and markets and connecting people with each other and the main highways.

Since this is a link road within the district, traffic may or may not be substantial on many years to come. There will not be less than 30 vehicles per day (VPD). This road designed for low traffic single lane is enough and hence it has been recommended to make the road width of 4.5 meters with adequate bypasses at an average of 3-4 bypasses per kilometer.

The maximum vehicle loading capacity for district roads under the Green Road is 8 tonnes, The designed vehicles are light bus, light truck and tractor-trailer for this type of road.

4.2 Design

4.2.1 Designed Speed:

The designed speed is the main factor on which geometric design elements depend. The sight distance, radius of horizontal curve super elevation extra widening of road and the length of summit and valley curves all depends on design speed.

The design speed of road depends on (I) class of the road (II) terrain.

In general terrain                       -           30Kmph

In steep terrain                          -           20Kmph

As the road falls in the category of District road the designed speed has been adopted as 30 Kmph.

4.3 Horizontal Curves:

4.3.1 Minimum radius of Horizontal curve:

A horizontal highway curve is a curve in plan to provide change in direction to the central line of a road. When a vehicle traverses a horizontal curve, the centrifugal force acts horizontally outwards through the center of gravity of the vehicle.

The centrifugal force developed depends on the radius of the horizontal curve and the speed of the vehicle negotiating the curve.

For smooth vehicles like minibus etc., the minimum radius required is 5m. Sometimes 12 m radius has also been practiced, But in case of sharp bends in hilly areas like in our case, minimum of 10m radius has been adopted. Such sharp bends are somehow similar to Hairpin bends.

Generally, following types of horizontal curves are used in the alignment of Green Roads:

a) Simple curve

b) Compound curve

c) Reverse curve

d) Transition curve

a. General formula for the design of horizontal curve (simple Curve),

     First assumption of radius (R) =

     Tangent length =

     Length of curve =

    Apex distance =

   Where,

            R = radius of curve

           = deflection angle in degree

b. Transition curve:

The transition curve has a radius, which decreases from infinity at the tangent point to a designed radius of the circular curve.

The functions of the transition curves in the horizontal alignment of highway are summarized as below;

·                    To introduce gradually the centrifugal force between the tangent  point and the

   beginning of the circular curve avoiding a sudden jerk on the vehicle.

·  To enable the driver to turn the steering gradually for his own comfort and security.

·  To enable gradual introduction of the designed super elevation and extra widening of road at the start of the circular curve.

·  To improve the aesthetic appearance of the road.

 The primary purpose of transitional curve is to enable vehicles moving at high speed to make the change from the tangent section to the curved section and again to the tangent section of a road in a safe and comfortable fashion. This minimizes the intrusion of vehicles on to the wrong lanes, tends to encourage uniformity in speed and increases vehicle safety.

In our case, as the designed speed is adopted to be 30 Kmph and also the road is designed for low traffic, no transition curve has been provided.

4.3.2 Super elevation:

In order to counteract the effect of centrifugal force and to reduce the tendency of the vehicle to overturn or skid of a curved section of a highway, it is customary to raise the outer edge of the road above the inner edge, which we call as super elevation. It is also called cant or banking. Where the super elevation is insufficient to balance the outwards force, it is necessary for some frictional force to be developed between the tyres and the road surface in order to prevent the vehicle from sliding laterally.

Expression for super elevation as per NRS 2045 is given by,

    Where,

               e = super elevation

               f = lateral coefficient of friction between the road surface and tyres

              V = speed of vehicles in Kmph

              R = radius of curves

In our case super elevation of 5% has been adopted.

4.3.3 Extra widening on curves:

It has been found that the drivers on curves have difficulty in steering their vehicles to keep to the center line of the road , and are not able to keep to the outer edge of the road as they are able to on the straight. Also, there is psychological tendency to drive at greater clearances, when passing vehicles on curves than on the straights. Hence , there is dire necessity for widening the carriageway on curves.

        Total widening =

     where, L = length of wheel base

                V = design speed (kmph)

                n = number of lanes

                = design radius in meters

As evident from the above equation the amount of extra widening depends upon the following parameters:

·                    Radius of Curve

·                    Distance of front wheel and back wheel of the vehicle

·                    Design speed

A minimum of 2 m extra widening on the curve towards inner side has been provided, Thus the total width of the road on the curve will be 6.5 m.

4.3.4 Sight Distance:

Sight distance is the length of highway ahead visible to driver. It is the element, which has the most important influence on the rural road safety and efficient operation. This must be provided on straight lengths as well as on horizontal and vertical curves. These can be classified as:

a. Stopping sight distance

b. Passing sight distance

c. Meeting sight distance

d. Heading sight distance

As per NRS 2045 Sight distance of 30 m has been adopted for designed speed of 30 Kmph.

4.4 Vertical Curves:

Vertical curves are provided in elevation at change of gradients. These curves are generally parabolic primarily because of the ease with which it can be laid out as well as enabling the comfortable transition from one grade to another. Generally, we do carry out the design of summit curves and valley curves.

In general vertical curves have been designed to ensure the following criteria:

i)                                             To provide sufficient sight distance in the summit curves and to develop additional stress to

balance the centrifugal force in valley curves.

ii) To obtain better drainage of the carriage way.

iii) To select the grade line in order to balance the cuts and fills on the profile so that an

optimization in the cost of earthwork is achieved.

iv) To allow safe design speed and hence to ensure safe and smooth movement of the vehicles.

v) To avoid sudden, hidden and unexpected dips unstable areas.

The vertical curves used in highways may be classified into two categories.        

a.       Summit Curves

b.      Valley Curves

4.4.1 Minimum Radius:

a)                  For Valley curves

The cubic parabola is generally preferred in valley curve. The minimum radius of the curve for cubic parabola is given by

            R₂ = L × 100/2N

Where,   L =  Length of the valley curve

              N = Deviation angle (g₁-g₂) in %

              g₁= 1^st  gradient

              g₂= 2^nd  gradient

a)                  For Summit Curve:

Since the parabolic curve is considered for summit, the minimum radius of the parabolic summit curve may be calculated as

R₁= L × 100/N

Thus the minimum radius in both cases is governed by the length of the curve and the deviation angle. Since, the minimum radius for summit curves is 269m. Whereas, in case of valley curve it is 178 m.

4.4.2 Length and the ordinates of vertical curves:

a)                  Summit curves or crest curves with convexity Upwards:

When, L>S, L=

When, L<S, L=

But L_min= 2.7 N

Y_min=

b)                  Valley or Sag curves with concavity upwards for this, length of curve is designed as

below:

When, L>S, L=

When, L<S, L=

When, L_min= 3.63 N

       Y_min=

S= Minimum sight distance (30m assumed)

N=g1-g2

g1=first gradient

g2=second gradient

L=Length of the vertical curve

Y_max=Maximum ordinate distance

T= Tangent length (L/2)

L_min= Minimum length of the vertical curve

Note: Design of the vertical curve is not necessary if the value of N<3%

4.5 Hairpin bends or Reverse loop curves:

When developing a route in mountainous hills, it is frequently necessary to insert sharp turning angles, within whose limits it is very difficult, and sometimes even impossible, to lay out curves following normal geometric standards of design.

When inscribing a curve inside a turning angle the length of the route will be substantially reduced, which will result in steep longitudinal gradients. Easing out of the latter will entail excessive and expensive earthworks. In such circumstances, it is preferable to round off the route not by inscribing, but by circumscribing the curve around the turning point, called Reverse loop or hairpin bends.

It should be located on a hillside having the minimum slope and the maximum stability . It must also be safe from the point of view of landslide and g round water. The selection of a gently sloping hillside leads to an appreciable reduction in the quantity of construction work.

The following relationships are used for designing such curves:

Whence, the angle can be determined.

 r = radius of reverse loop curves

= deflection angle , degrees

m = length of straight reach in between

Hence, the total length of reverse loop is

Where,  is the length of reverse curve, m.

Note: The minimum horizontal curve radius in bends radius is adopted as 8 m.

4.6 Vertical clearances:

It is the vertical height above vehicle within where any structures , extension lines or pipe lines are not expected. It is generally kept 4.75 m but if high voltage line is being extended there, it should never be less than 7m.

4.7 Lateral Clearance

In horizontal curves especially in mountain roads, steep cut slopes and dense vegetation mostly obstruct visibility in the lateral direction. In order to have good visibility, a minimum set back distance is derived using following equations.

SD =   

Where,

SD = Set back distance in meters. (From the centerline of the road to the site of the ovstruction at the middle of the curve)

R    = Radius of the curvature in meter.

A    = S/2R in radians

S    = Stopping Sight Distance

4.8 Right of Way

Right of Way may be used for the following purposes

i)                                            To develop road side arboriculture.

ii)                                           To improve visibility in curves.

iii)                                         To accommodate various road ancillaries.

iv)                                         To widen the road where required in future. Etc.

Right of Way is considered 15m on either side from the centre line of road alignment that makes total of 30m. In actual practice specially in district road this guideline of right of way has not been successfully implemented.  Encroachment of the right of way through the construction of houses has been seen in man district/rural roads.

4.9 Bypass:

The space provided for vehicles to cross the vehicle coming from other side and is generally needed at frequent interval in the case of green roads as we know that green roads are generally single lane roads. However, they should not be sited on curves and near the bridge or other structures. Bypass is usually provided at an interval of 200m to 300m but it also depends on site condition. The length is about 25 to 30m and the additional width is about 2m.

4.10 Formation width

It is the total width of the road including both the shoulders too. Generally, it is taken as 4.5 m in case of green roads. Same has been adopted in our case.

4.11 Camber slope or Cross-slope or Cross-fall:

Camber is the slope provided to the road surface in the transverse direction and is dependent upon the type of road and amount of rainfall expected. One- sided outward camber of 5% is usually provided in green roads. The objective behind the provision of the camber is draining of the surface water quickly preventing infiltration of water into the road subgrade..

4.12 Carriage way width

The carriage way width of 3m has been adopted.

4.13 Cross section

In general, the cross-sections are designed at interval of 25 m depending upon the topography. However, some flexibility has been adopted to choose the cross profile where there is a sudden change in topography. In such cases the sections are taken at lesser intervals.

4.13 Longitudinal Gradient

Gradient is the rate of rise or fall along the length of highway. It depends upon the nature of traffic and nature of surfacing material. It can be classified into the following categories:

a. Ruling gradient

b. Limiting gradient

c. Exceptional gradient

The gradient is the main factor to be considered while designing the green road. Higher gradient results in higher vehicle operation cost, lower safety and discomfort to the passengers. It represents the quality of the road. According to the Nepal Rural Road Standard(2055) following types of grades are provided as per topography.

i)                                            Maximum average gradient=7%

ii)                                           Maximum gradient=12%

iii)                                         Easing of gradient for every 500m increment in altitude (rate of easing)=0.5%

iv)                                         Minimum gradient on hill roads (for better drainage) =5%

In our case maximum gradient of 12% and minimum gradient of 0.5% has been adopted.

4.15  Drainage:

Water management is important for hill roads. Side drains are provided where gradient is more than 7%. In the settlement and paddy field areas where water movement is frequent on roadside, drains are provided. To provide side drain, in such places it is not necessary for road gradient to be more than 7%.

As an alteration and low cost solution 5% outward cross slope as a camber is provided on the road surface, in the curve 5% slope has been provided inward as a super-elevation. The natural drainage system is fully utilized to discharge the drain water. The side drain of trapezoidal section type has been chosen. According to NRS (2055), a 50cm. wide trapezoidal side drain is provided all along the alignment, which ultimately crosses the road through cross drains. Side drain may be earthen, dry-stone. The drain slope follows more or less the alignment grade but not less than 0.6%.

Cross drainage structures has also been provided at required places to pass the side drain water and other water from natural courses, Cross drainage structures adopted in our case are in the form of dry stone soling causeway, Scupper culvert, Flood way.

4.16 Retaining structures:

Retaining structures are required to support the soil laterally, so that soil can be retained at different levels. Retaining walls are the most important structures for hill roads to provide adequate stability to the roadway and to the slope.

Retaining walls are constructed on the valley side of the road and on the cut hillside as well to prevent landslide towards the roadway.

While designing the retaining structure, it is assumed that the soil is granular, i.e. the angle of internal friction is the dominating factor, homogenous, isotropic and follows Coulomb’s law of stability. No laboratory tests are carried out to determine the soil parameters.Detailed design of structures are made on the basis of soil types and corresponding site condition.

Following structures can be used as retaining structures as below

a)            Rip rap stone pitching:

Stone Rip Rap soling can be provided for the height up to 1.5.

b)            Dry stone wall:

Dry stone wall can be provided up to the height of 3m. The  foundation for the construction of dry wall is prepared at a slope of 3:1 that is why the outer face of wall would be at a slope of 1:3.

i)                      Retaining Wall:

The function of the retaining wall is to retain the back filling. It is provided for the following cases.

v     Where the hill section is partly in the cutting and partly in back filling

v     At all re-entering curves

v     Where a road crosses a drainage

ii)                                           Breast Wall

The purpose of breast wall is to prevent the cut hill from sliding

v     Weep holes are provided in case of cement masonary breast wall.

v     Sometimes vertical gutters connecting weep holes to side drain are provided.

iii)                                         Gabion stone wall

v     For more than height of 3m, gabion wall is designed.

v     A composite wall of dry stone and gabion wall is designed for the effective estimate.

v     The foundation for the construction of gabion wall is prepared at a slope of 4:1 (However) that is why the outer face wall would be at a slope of 1:4.

As for our case Retaining structures in the form of the Dry stone wall and Gabion wall has been adopted.

4.18 Design Standards for "Green Roads" (Tabular format)

5.0 METHODOLOGY

5.1 Alignment Survey

The methodology for alignment Survey adopted for the completion of the project includes the following steps

5.1.1 Desk study

The study of the area was carried out at our college in Kathmandu.

• Study of TOR provided by the GTZ office Kathmandu.
• Review of all available information, reports and documents pertaining to proposed alignment.
• Careful study of the topographical map and its interpretation.
• Locating the contours and the alignment for the project.

5.1.2 Field Survey

The field study comprises following survey techniques:

5.1.2.1 Reconnaissance Survey

Walk over survey of the proposed alignment was carried out to determine different distinctive features of the site such as; the soil type, location of active and potential landslides, erosion, creep etc, the topography, road geometry, environmental aspects

5.1.2.2 Detailed Survey

This is the most important aspect. For carrying out the survey works our team was divided into four groups. The first group was assigned for the alignment i.e., fixing IPs and with suitable grade not exceeding 7% as far as possible and also noting down the type of soil and its percentage presence along the alignment. The second group comprised of team with thedolite, they had to take the deflection angles at each IPs and subsequent staff readings for determining the R.L and distances tallying with the measurement of the tape. The third group was assigned for bio-engineering part, they had to consider the type of vegetation, species of plants, land use pattern and the availability of the construction materials in the vicinity, the total no. of trees to be cut down along the alignment for construction, also they had to measure the distances between IPs,. The fourth group comprised the group that had to sketches of cross sections at every 25 meters interval.

The centre line of the road was pegged within 25 m distance. In case of sudden change

of topography, the center line was pegged at even lesser distances and where the topography remains same, pegging interval was more than 25 m. The cross sections was taken by the abney level for sloping area, tape and surveying Rods for stepping ground.

To minimize the cutting heights as well as the cost, longitudinal gradient was fixed in line with formation level of the road. Reference points of each IPs were marked in the field with respect to the rigid boundaries as trees and boulders. In addition to it, the benchmarks were fixed at regular intervals and marked with paints. At each IPs the radius of curvature was first assumed on the basis of deflection angle measured and by subsequent hit and trial method radius was fixed. Thereafter the tangent length, apex distance and the length of curve was computed.

During the detail survey following studies were also carried out; socio-economic survey, soil/rock survey, geological survey, Hydrology and meteorology survey etc.

6.0 Alignment Description

 6.1 Description of the alignment

The starting point of the alignment surveyed is Parchheta Khola suspended bridge. The elevation of zero chainage is 800m from the mean sea level. In Bagarkot area the alignment passes with cultivated land on the valley side, the soil here is more fertile and the topography here in more or less flat.

From the starting point the alignment ascends till the dhittadi khola is reached at chainage 2700m, where there is abrupt fall in height. The river has the longitudinal slope of 1:30 and requires flood way at the present moment, which later might be developed to a bridge. The river has medium rock bank and the bed is boulder. After crossing Dittadi khola the alignment  again ascends following cultivable land on its either sides. The land in this area is more fertile. The alignment then passes through the jungle area until it reaches Dainshila village area.

Before reaching Dainshila village the alignment crosses Bagarkot VDC and enters Bhageswar VDC at chainage 3087m.

The Dainshila khola is reached at the chainage of 4390m. The riverbank is formed with medium rock and the bed is formed with boulder. The river has the longitudinal slope of about 1:15.

After crossing  Dainshila khola, the alignment climbs up the hill with an average slope of about 11% until it reaches khal at the chainage of 5015m. Following a loop at khal, the alignment escapes the thrust boundary at chainage 5190m before reaching Borigyan village. Climbing up and down, the alignment reaches Bogata village and ends at Bhageswor VDC office at chainage 8822m..

6.1 Bench Marks:

The Bench mark details along with their chainage, elevation are tabulated as follows.

Bio-engineering is not a substitution of civil engineering. It offers only a new set of tools for the engineers so that incorporation of bio-engineering with civil engineering leads us to the effective solution of the problems as it serves two distinct roles-provides additional techniques for stabilizing shallow seated failures and controlling erosion; enhancing civil engineering structures by protecting them and maximizing their effectiveness.

Its ancillary benefits could be listed as follows;

a.       Environment friendly

b.      Socially beneficial

c.       Aesthetic value

d.      Low cost

e.       Versatile in use

f.        Flexibility in choice

g.       In some cases, only the solution to slope stability might be the use of bio-engineering

h.       Increased factor of safety of the slope

However, it is not like that we have stick only with its advantages and its limitations should also be strictly adhered to at the same time for attaining the effective solution.

The use of bio-engineering in “Green road” approach for rural road construction should never be under-estimated. The name “Green road” itself reveals for the preservation of greenery-grass, shrub and trees; protection of forests and vegetative covers, in totality. As such, the role of bio-engineering becomes crucial as preventive measure rather than curative one, with the help of which it would never have been possible to achieve.

The species may comprise the shrubs, herbs or the trees. The Bio-engineering technique is integrated with different civil engineering structures to be built along the roadside. It becomes more effective, economical, local skill requirement in the long run. Thus, minimizing the environmental disturbances. This system of environmental measures helps the alignment to have stabilization in cut slopes, the influence area of road and a failure zone by dealing with following stability problem bio-technically.

The bio-engineering system mainly performs 5 main functions:

i.   Catch

ii . Armour

iii. Support

iv. Reinforce

iv. Drain

Thereby preventing

• Soil erosion
• Increasing the soil shear strength
• And Reduction of Ground water table or moisture content reduction

Sample Calculation:

1. Super Elevation:

    Where,

               e = super elevation

               f = lateral Coefficient of friction between the road surface and tyres=0.4

              V = speed of vehicles in Kmph= 30 Kmph

              R = radius of curves = 12 (min)

 Or,  

t = 0.19 m

 2. Extra widening on curves:

Total widening =

Where,

L = length of wheel base =6.0 m

V = design speed (kmph) = 30 Kmph

n = number of lanes =1

= design radius in meters

 W       =

t W    = 2.02 m                         (Note: Adopted 2m according to NRS2045)

4. Stopping sight distance:

        S = Reaction distance + Braking distance

=

Where

V = Design speed in Kmph = 30 Kmph

T = Reaction time of driver in sec.

Note: As per IRC recommendation:

For design speed ≤ 50 Kmph, T= 3.0 Sec

f = Coefficient of friction between tyre and road surface

   = 0.4

G= Gradient expressed as a fraction

For plane road stretch

S          =

S          = 30.88 m

For 5% descending gradient,

S          =

 t S    = 31.14 m

(Adopted S = 30 m from NRS 2045)

5. Stability of the Retaining Structure

For X-section, Chainage 2+885

Data Available:

Soil type                                   = Coarse to medium sand

Internal angle of friction,         = 35° to 45°

Unit Weight,                          = 1700 to 2100 Kg/m³

Bearing capacity                       = 2.80 ton/m2

Height of Retaining wall =  2.0 m

Depth of foundation provided    = 1.351 m

a. Check for the depth of the foundation:

D_f

D_f

D_f  1.235m ,   Since we have provided the depth of 1.35. The value is okay.

b. Check for safety against Sliding:

Active earth pressure, P_A          = 

                                                =

                                                = 9.92 KN/m

Weight of the wall, W   =

                                                = 50 KN/m

Factor of safety against sliding=

                                                =

                                                =

                                                =3.798 (>1.50, hence safe)

c. Check for safety against overturning:

Overturning moment     = 

                                    =    

                                    =      6.61 KNm

Stabilizing moment        =

                                    = 43.33 KNm

Factor of Safety against Overturning      =

                                                            =

                                                            = 6.55 (> 1.5, Hence safe)

Thus,

The wall is safe against sliding and overturning.

6. Horizontal Curve

At chainage 3+222.81,

= 82.020°   

 First assumption of radius (R) = 12 m

a)Tangent length           =

                                    =

                                    = 10.44 m

 b) Length of curve       =

                                    =

                                    = 17.18 m

 c) Apex distance          =

                                    =

                                    = 3.9 m

   Where,

            R = radius of curve

           = deflection angle in degree

7. Vertical Curve:

a.Summit Curve:

At Chainage 2923.20

With R.L= 853.352 m

              N₁= 1^st  gradient = 9.84 %

              N₂= 2^nd  gradient = 3.55 %

Now,      N       = Deviation angle (N1-N2) in %

                        = 9.84 % - 3.55 %

                        = 6.29 %

Since,    (N₁-N₂)>0, It is a summit Curve

Adopt, S= 30m

When, L>S, L  =

                        =

Adopt L=30 m

Now,

Chainage of BVC         = Chainage of PVI – L/2

                                    = 2923.20 – 30/23      

                                    = 2908.2 m

Chainage of EVC         = Chainage of PVI + L/2

7.0 Environmental Aspects and Measures

7.1 Introduction

Road construction activity starts with land acquisition, removal of vegetation, cutting and filling of hill slopes, establishment of settlements of labours, construction of site offices etc. These activities will disturb the ecological balance of the area, which in term accelerate the degradation of the environment. Moreover as the road will make the area accessible, settlement, market place will develop in different places along the road, which will change the present land-use pattern and have negative impact on the natural resources in the influence area. However, the construction of road will have positive impact on the socio-economic condition of the influence area as well.

Traditional way of highway planning, design, construction and maintenance mainly accounts for economical and operational aspects only. But these days efforts have been made to include the biological system under the influence of road project area to maintain and enhance the balance of existing environmental conditions along the proposed road alignment. Among such various efforts roadside plantation is also the latest techniques in this aspect.

The roadside plantation has been felt very useful for the development of the project area for the following reasons:

a)      As a slope stabilization technique

b)      As a contributor to the ecological needs of the area.

7.2 Measures for Environmental Protection

The activities that are likely to affect the environment can be discussed under the following headings:

a)      Natural

b)      Socio-economic

c)      Proposed road construction

d)      Maintenance and operation

The activities as weathering and slides due to rainfall, earthquake, other natural hazards are natural activities which cannot be prevented absolutely. However, some preventive measures such as roadside plantation use of Bio-engineering measures in land erosion area etc. can be done along the road alignment to manage successfully these activities.

After the construction of the road, the people are motivated in using more advanced methods for farming, establishment of the industries etc that disturbs the natural environment. These, relates the socio-economic activities.

Road project being a long term process, it carries activities like acquisition of land, cutting, filling, use of technologies etc, such activities if carried out haphazardly is likely affect the environment by loss of many animals and birds, plus the plants.

Bio-engineering measures has to be adopted in this context from the beginning of construction works. Thus maintaining ecological balance along the alignment, and stabilizing the alignment.

The measures that can be adopted are as follows:

a.       Road side plantation for ecological balance

b.      Road side plantation for slope stabilization or Bio-Engineering

7.3 Road side plantation for ecological balance

During the construction of road, the ecological system along the alignment is disturbed mainly due to clearing of the sites, throwing of the debris haphazardly and cutting down of the trees. To have proper ecological balance the road side plantation does aid to restore, conserver and maintain the ecosystem.

7.4 Road side plantation for slope stabilization (Bio-Engineering)

It refers to Bio-Engineering techniques. Bio-engineering technique utilizes the locally available suitable species of plants for the stabilization of the slopes and erosion prone areas. Bio-engineering refers to the use of living plants either alone or in conjunction with small-scale civil engineering structures. The purpose of which is controlling erosion and reducing shallow seated instability.

                                    = 2923.20 + 30/2

                                    = 2938.2 m

Chainage of MVC        = 2923.20

R.L of BVC                 = R.L of PVI – L* N1/200

                                    = 853.35 – 30 * 9.84/200

                                    = 851.88 m

R.L of EVC                  = R.L of PVI + L* N2/200

                                    = 853.35 + 30 * 3.55/200

                                    = 853.89 m

R.L of MVC                = R.L of PVI + N*L/800

                                    = 853.35 + 6.29 * 30/800

                                    = 853.12 m

b. Valley Curve:

At Chainage 2+574.15  &

R.L 837.296 m

              N₁= 1^st  gradient = -6.18 %

              N₂= 2^nd  gradient = 5.72 %

Now,      N       = Deviation angle (N1-N2) in %

                        = -6.18 % - 5.72 %

                        = 11.9 % (Positive Value is taken)

Since,    (N₁-N₂)<0, It is a Valley Curve

Adopt, S= 30m

When, L>S,     L          =

                                    =     

adopt L = 48 m

Now,

Chainage of BVC         = Chainage of PVI – L/2

                                    = 2574.15 – 48/2        

                                    = 2550.5 m

Chainage of EVC         = Chainage of PVI + L/2

                                    = 2574.15 + 48/2

                                    = 2598.15 m

Chainage of MVC        = 2574.15

R.L of BVC                 = R.L of PVI – L* N1/200

                                    = 838.296 – 48 *(- 6.18)/200

                                    = 838.78 m

R.L of EVC                  = R.L of PVI + L* N1/200

                                    = 838.296 + 48 * 5.72/200

                                    = 838.67 m

R.L of MVC                = R.L of PVI - N*L/800

                                    = 837.296 – 11.9 * 30/800

                                    = 838.01 m

10 CONCLUSION, LIMITATION

AND

RECOMMENDATION

10.1 Conclusion

The alignment was taken avoiding the cultivable land, as far as possible the existing trail has been followed. At places where the longitudinal gradient exceeded 12% different alignment was taken. This alignment is selected with the consideration of gradient and the topographical conditions. Geologically unstable areas are avoided as far as possible.

Nepal Road Standard (2055)/ Green Road standards have been followed as far as possible in the design for safe and smooth traffic movement. In addition the structures; retaining walls have been designed according to Green Road concept and both longitudinally and transversely mass balancing is adopted.

Side drain has also been provided as per requirement and standards. Camber with one-sided slope of 5% is adopted. Cement structures are avoided as far as possible in its place dry stone structures have been proposed.

The environmental considerations have been carefully observed. The provision of roadside development program such as plantation and bio-engineering for slope stabilization has been adopted.

10.2 Limitation

Some of the major limitations of the project are identified in the following headings

1. Time frame
2. Budget constraint
3. Topography
4. Manpower constraint
5. Alignment limitation

The time scheduled for the survey works in the field was only 15 days. Allocating 4 travel days for traveling, the work had to be completed in within 11 days, which was not possible. In addition the computational work had to be completed during the study hours. So, only detail survey, design and cost estimation of 8.822 Km of the alignment was done. 

Due to limitation of the project budget and the time frame the work to be completed in the field was not possible within 15 days without additional manpower.

Due to the steep topography of the project area, it was difficult to work at the site.

In addition due to the limitation to follow the previously laid track as far as possible, we were not free to choose the alignment due to steep topography.

10.3 Recommendation

The proposed alignment passes through the terrain where cut and fill can be balanced partially during the construction. However, at the time of construction following precautions should be taken into consideration:

v     The excess materials obtained from cutting should be dumped at safe place without causing

any damage to the environment.

v     While designing the cross sections, overtaking and by passes are provided at suitable

intervals.

v     Bio-engineering and slope-stabilization works are highly recommended.

v     Stability analysis of steep slopes is recommended.

v     Due to high gradient of the existing road, at some places the alignment has been changed.

Hence care must be taken during the fixation of alignment as well as excavation.

v                 During the construction work strict supervision should be undertaken so that the design

criteria is fulfilled.

v                 The Drainage works should be carried out carefully during the construction phase.

Bibliography:

1.  Nepal Road Standards (NRS-2045)                             – Department of Roads, Kathmandu

2.  Highway Engineering                                                     – Khanna & Justo

3. Work Norms for Labour Based Construction                        – Department of Local Infrastructure

   Development and Agriculture Roads       

   (DOLIDAR)

4. Survey vol.2                                                             – Punmia

5. Green Roads in Nepal                                                          – Meyer, Warner Paul, Acharya B.N.,

   Aryal, R. Karmacharya, D.

6. Design and Selection of retaining walls                                    –ICIMOD

7. Detail design and drawing of Dipayal- Mellekh-patihalne – Q.S. Technical Pvt. Ltd.                                       –

8. Draft Report on feasibility of Baghbazar-Rupal Road – Alphaus Consulting Group

9. Roadside bio-engineering(site handbook and manual