Chapter - 7 Construction Program, Manpower and Plant...

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Chapter - 7

Construction Program, Manpower

and Plant Planning

7.0 General

The construction methodology and equipment planning for

construction of various components of the project are described in this

chapter. The construction methodology for each type of structure, type and

sizes of the equipments to be used for the construction has been described

under the relevant sub sections of this chapter. The construction/

deployment schedule for various components of the project has been

prepared and based on this, the number of machines/equipments and total

requirement for each type and size of the major equipments required for

construction of each component of the project has been worked out.

However, if, the work is executed through award of contract, the

contractors may execute the work based on the equipments actually

available with them thereby suitably adopting the related construction

techniques. The tentative requirement of machines/equipments worked out

herein will help in analysis of rates of works, cost estimation and in

evaluating the viability of construction techniques and equipment, within

overall construction schedule and cost estimate.

7.1 Main Project Components

Damanganga – Pinjal link project has been planned as drinking water

supply project to augment the domestic water supply of Mumbai city. The

surplus water of Damanganga basin available at proposed Bhugad and

Khargihill dam is proposed to be transferred to Pinjal dam (proposed by

Govt. of Maharashtra across river Pinjal, a tributary of Vaitarna river) from

where the combined water of Damanganga and Pinjal rivers will be taken to

Mumbai city to augment its domestic water supply. The project envisages

construction of the following components:

i A 851.50 m long composite embankment (concrete faced rock fill) -

cum - concrete dam across river Damanganga near village Bhugad

with FRL 163.87 m and corresponding gross storage capacity of

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427.070 Mm3. The length of concrete faced rockfill portion of the

dam is 527.50 m and the length of concrete non overflow section and

spillway is 324 m;

ii A Power house at the toe of Bhugad dam with 2 units each of 1.0

MW installed capacity each;

iii A 618.20 m long composite embankment (concrete faced rock fill) -

cum - concrete dam at Khargihill across river Vagh (a tributary of

Damanganga river) near village Behadpada with FRL 154.52 m and

corresponding gross storage capacity of 460.896 Mm3. The length of

concrete faced rockfill portion of the dam is 341.0 m and the length of

concrete non overflow section and spillway is 277.20 m. A saddle

dam of 400 m length and 25.92 m height with FRL 154.52 m is

proposed on the left flank of the reservoir;

iv A Power house at the toe of Khargihill dam with 2 units each of 1.5

MW installed capacity;

v A 17.488 km long D shape tunnel with 3.20 m diameter and bed slope

of 1:1342 connecting Bhugad reservoir with Khargihill reservoir;

vi A 25.224 km long D shape tunnel with 4.00 m diameter and bed slope

of 1:1717 connecting Khargihill reservoir with Pinjal reservoir;

vii A 545 m long Roller Compact Concrete Gravity dam across river

Pinjal (a tributary of Vaitarna river) proposed by Government of

Maharashtra and MCGM near village Khidse with FRL of 145.0 m

and corresponding gross storage capacity of 483.0 Mm3 and a saddle

dam of about 190 m long and 11.4 m high on the right flank.

viii Conveyance system beyond Pinjal dam to carry water upto Mumbai

city to be planned by MCGM.

The Pinjal dam and the conveyance system beyond Pinjal dam to carry

water upto Mumbai city has been planned by Water Resource Department,

Government of Maharashtra and Municipal Corporation of Greater Mumbai

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(MCGM), as such, the construction scheduling & equipment planning for

these components has not been considered in this report.

7.1.1 Salient Features of main Components of the Project

The salient features of the main components of the project are indicated in

Table – 7.1

Table - 7.1

Salient Features of Main Components of the Project

S. No. Project Component Details

1 Bhugad Dam

i Concrete Faced Rockfill Dam

a Height 68.63 m

b Length at Top 527.50 m

ii Concrete Dam (Over Flow and Non

Over flow)

a Length 324.0 m

b Height (from deepest foundation

(level)

69.42 m

iii Spillway

a Type Ogee

b Gates 9 radial gates of

13.5 m X 11.51 m

2 Khargihill Dam

i Concrete Faced Rockfill Dam

a Height 72.92 m

b Length at Top 341.00 m

ii Concrete Dam (Over Flow and Non

Over flow)

a Length 277.20 m

b Height (from deepest foundation

(level)

77.92 m

iii Spillway

a Type Ogee

b Gates 6 radial gates of 14

m X 16 m

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3 Bhugad Dam Power house

i Penstock

a Length 176 m

b diameter 1.5 m/ 1.0 m

c Shape Circular

II Power House

a Type Surface Power House

b Installed Capacity 2 X 1.0 MW

4 Khargihill Dam Power house

i Penstock

a Length 215 m

b diameter 1.5 m/ 1.0 m

c Shape Circular

II Power House

a Type Surface Power House

b Installed Capacity 2 X 1.5 MW

5 Bhugad - Khargihill Tunnel

a Length 17488 m

b Shape D Shape

c Diameter 3.2 m

d Type of lining Cement Concrete

lining

5 Khargihill – Pinjal Tunnel

a Length 25224 m

b Shape D Shape

c Diameter 4.0 m

d Type of lining Cement Concrete

lining

7.2 Basis for Study

7.2.1 General

Methodology for construction of Damanganga – Pinjal Link Project

has been adopted with due consideration of the construction schedule, the

compatibility of the construction equipment to site conditions, the

quantities and utilization factor of the equipment within the scheduled

construction period. Number of machines required for construction of each

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component of the project has been worked out and the total requirement for

each type and size of machine for the project as a whole has been arrived at

after drawing up the construction/deployment schedule for the main

components of the project.

Mechanized construction has been planned for almost all types of

construction jobs so as to achieve consistent quality at a faster rate and also

to minimize the requirement of skilled manpower. Moreover, very high

degree of quality standards are required to be maintained as underground

works are normally not available for regular maintenance after the

completion of construction.

Sequencing of construction activities, wherever possible, has been

attempted in such a way that equipment from one activity, on its

completion can be moved to the other. Thus, the total requirement of

equipment at a time would be reduced and also, sufficient utilization of

equipment on the project would be ensured.

7.2.2 Construction Material Sources

Locations of different borrow areas and quarries for construction

material with respect to the dam location have been described in the chapter

- 2 “Survey & Investigations”.

Suitable fill material for the concrete face rock fill dam has been

found in the borrow area upstream of the proposed Bhugad and Khargihill

dam. Borrow areas with minimum lead have been proposed for utilisation

during dam construction. In case of Bhugad Dam, borrow areas with an

average distance of 2.0 km from dam axis have been considered for the

purpose of equipment planning. Similarly, borrow areas with an average

distance of 4.0 km from dam axis have been considered for the purpose of

equipment planning for Khargihill dam. However, during construction,

appropriate decision may be taken to select the borrow areas which meet

the requisite specifications.

Construction material for concrete, viz. sand/fine aggregate,

rock/coarse aggregate, for both non-wearing and wearing surfaces are also

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located in the vicinity of dam site. The Bila quarry (U/s of Bhugad Dam) at

a distance of 2.0 km and Dadri quarry (U/s of Khargihill Dam) at a distance

of 6.0 km have been identified for meeting the requirement of Rock.

For the construction material for concrete lining of Bhugad-

Khargihill link tunnel, the Baphanvihir quarry and Ojharkhed Quarry have

been identified and for the construction material for concrete lining of

Khargihill-Pinjal link tunnel, Dadri and Mehandhipada quarries have been

identified.

Total concrete requirement of different grades for the main

components of the project has been estimated to be approximately 20 lakh

m3.

The area for disposal of excavated material has been considered at an

average distance of 2.0 km from the dam site for equipment planning

purpose.

7.2.3 Basic Considerations

Based on past experience, about 8 working months in a year are

available in the area where the project is situated. Other projects in the

region have also been planned with this consideration. However, all under

ground works like tunnels can be constructed through out the year.

All the surface works are proposed to be executed in two shifts and

during 8 working months. The Tunnelling works are proposed to be

executed in three-shift operation throughout the year.

7.2.3.1 Scheduled Working Hours

Equipment planning for calculating requirement of equipment is

carried out based on the number of working days available, which further

depends upon climatic conditions of the project area. In the present

scenario, the monsoon sets in during June and continues till October in the

project area. For equipment planning purpose the monsoon season has

been considered from 15th June to 15

th October. Thus, for surface/ over

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ground works i.e. dam and appurtenant works a working season of eight

months would be available. The tunnelling works are generally not

affected by the vagaries of weather and thus, the work has been planned to

continue throughout the year. However, since the production capability

would be affected during monsoon months especially for the supplies/

services and muck disposal, etc., suitable reduction in the progress has been

taken into account for the year as a whole. The scheduled working hours

considering 25 working days per month are given in Table - 7.2.

Table - 7.2

Schedule Working Hours

Type of Work/

Shift

Surface/Over

Ground Works

(hour)

Tunnelling/Underground

Works (Hour)

Single shift work/ day 8x25x6 = 1200

12x25x20= 6000 Two shifts work/ day 8x25x11= 2200

Three shifts work/ day 8x25x15 = 3000

Two shifts working of equipment is normally considered most

economical in view of the high cost of three shifts working on account of

low availability of equipment and higher stand-by equipment requirement.

Thus planning for all surface/over ground works has been carried out based

on two shifts per day working. Tunneling/ underground works are planned

for three shifts working as these involve cyclic operations, which do not

follow normal shift operation. Provision of standby equipment has been

considered as follows:

i. Single shift working 10%

ii. Two shifts working 20%

iii. Three shifts working 30%

7.2.3.2 Construction Period

A total period of seven years has been considered for completion of

the project. The infra-structural development, pre-construction surveys and

investigations, preparation of design/ specifications and tender documents

are proposed to be taken up during the first two years. In case the works are

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to be executed through award of contract, it is planned to award contracts

for all major works by the 3rd

quarter of year 2. However, some of the

works like stripping, River diversion and portal formation & slope

stabilization for tunnels may have to be undertaken from the 1st quarter of

the 2nd

year itself and therefore award of work for these works may be

planned accordingly. The work on infrastructure facilities like project

colonies, approach roads, workshop, haul roads, stores, office buildings etc.

will also start in the second year itself. Some of these activities will

continue for some time during the third year also. The construction of all

civil structures is proposed to be completed within 3rd quarter of year 7.

The erection, commissioning and testing of units would be required to be

planned so that full benefits could be accrued at the end of the proposed

construction period. Though, presently construction period of Damanganga

– Pinjal link project is kept 7 years, but by using advance construction

technology/ equipments and tunnel boring Machines (TBM) in tunnel

excavation, the construction period can be reduce to 6 years.

7.3 Construction Methodology and Equipment

The construction methodology and equipment planning along with

construction programme for different components of the project have been

described in the succeeding sub-sections:

7.3.1 River Diversion Works

No formal diversion arrangement has been provided for the

construction of both the dams (Bhugad and Khargihill Dams). The

diversion arrangement during project construction will be evolved

depending upon the requirement. As sufficient width is available, the flow

only needs to be channelized through diversion channels which can be

decided at construction stage. Also the sluices proposed can be used for

diversion during construction stage. The following construction methods

have been considered for river diversion works:

Excavation and loading of the material by 2.0 m3 hydraulic

excavator.

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Transport to the disposal area by means of 18/20t rear

dumpers.

The rock excavation to be undertaken by drilling & blasting.

Jack hammers and wagon/crawler drill with hole patterns of

1m and 2.75 m c/c respectively to be deployed for drilling of

charge holes.

Separate provision of the equipment for this activity has not been kept

as some of the equipments to be deployed for earth dam can be utilized on

this activity.

7.3.2 Concrete Face Rock-Fill Dam (Bhugad Dam)

The construction of the dam involves surface excavation, placement of fill

materials, spreading & wetting and compaction of the fill materials. Total

quantity of Bhugad dam excavation including OF and NOF section is about

11,90,100 m3. The excavation of 6,93,200 m

3 quantity which does not

involve blasting operation is considered as common excavation and

remaining 4,96,900 m3 which requires blasting is considered as rock

excavation. Following assumptions have been made while working out the

quantities of different activities for the construction of dam. The details are

in Table – 7.3.

i. Total river bed excavation quantity has been divided in a ratio of 6:4

for the estimation of excavation quantity for CFRD portion and

Concrete portion of Dam.

ii. While working out the quantity for common excavation and rock

excavation of each portion of dam, same ratio i.e. 6:4 has been used

over the total excavation quantities of each type.

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Table - 7.3

Quantities of Different Activities for Construction of

CFRD Portion of Bhugad Dam

Description of

Work

Type / Material Quantity,

in-situ

Unit

Stripping - 60,000 m3

Excavation

Common 4,15,920 m3

Rock 2,98,140 m3

Fill placement

Impervious material 3,06,000 m3

Filter, Fine (2B Zone+3A

Zone)

2,77,700 m3

Filter, Coarse(Zone 3B) 9,69,000 m3

Filter, Coarse(Zone 3C) 6,52,800 m3

Rock toe 2,800 m3

Total Quantity 22,08,300 m3

7.3.2.1 Surface Excavation

The surface excavation for main dam involves both common and rock

excavations. The volume of required excavation is given in Table – 7.4:

Table – 7.4

Volume of Surface Excavation

Type

Description

Common

excavation (m3)

Rock

excavation (m3)

Stripping 60,000 Nil

River Bed Excavation 4,15,920 2,98,140

Total 4,75,920 2,98,140

One working season has been earmarked for undertaking surface

excavation pertaining to main dam. Although work in the river bed can be

undertaken only after completion of river diversion work, the work of

stripping can be taken up earlier. The requirement for which provision of

equipment for the surface excavation is to be made is estimated and given in

Table – 7.5:

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Table – 7.5

Estimation of Hourly Quantity of Excavation

Type

Description

Common

Excavation

Rock

Excavation

Total volume (cum) 4,75,920 2,98,140

Time period (months) 8 8

Shift proposed 2 2

Total operational hours (hour) 2200 2200

Volume to be handled in-situ (cum/hr) 216 136

Volume to be handled loose (cum/hr) 270 217

Total quantity 270+217 = 487 m3/hour

Peak quantity 487 m3/hour

Following construction methods are proposed for surface excavations:

Stripping and excavation for trenching & preparation of base of dam and

loading of the soft material (earth and alluvium) by 2.0 m3 hydraulic

excavators assisted by 180 HP crawler dozer

Transportation to the disposal area by 18/20t capacity rear dumper

A 180 HP bulldozer is also considered to stay in the disposal area for

spreading of the unloaded materials

The rock excavation to be undertaken by drilling & blasting. Jack

hammers and wagon/crawler drill with hole patterns of 1m c/c and 2.75

m c/c respectively to be deployed for drilling of charge holes.

7.3.2.2 Fill Placement

The construction of concrete faced rockfill portion of Bhugad dam

involves placement of 22,08,300 m3 of fill materials. As per construction

schedule the fill placement is to be undertaken in period of three working

season. The break-up of total quantity into different types of fill material to

be placed in different zones and their expected source of supply is given in

Table – 7.6:

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Table – 7.6

Quantities and Source of Fill Material

S.

No.

Fill Material Quantity

(compacted)

(m3)

Average distance of

borrow

area/quarry (km)

1 Impervious material 3,06,000 2.0

2 Filter, Fine (2B Zone+3A

Zone)

2,77,700 1.5

3 Filter, Coarse(Zone 3B) 9,69,000 1.5

4 Filter, Coarse(Zone 3C) 6,52,800 1.5

5 Rock toe 2,800 1.5

Total 22,08,300

The fill placement will require excavation and loading of material at

the borrow areas/quarries, transportation of the material to the placement

site and unloading. It is necessary that various alternative methods and

equipment are evaluated and appropriate construction methods and suitable

construction equipment are selected.

Hydraulic excavator-rear dumper combination is the most commonly

used method of material transportation in a river valley project. The

selection of hydraulic excavators depends on the quantities to be handled,

limitations of space at the site and the availability of standard equipment.

Matching rear dumpers are estimated taking into account the distance to be

traveled, the load ratings of haul roads and traffic intensity. This method is

considered quite flexible as this allows introduction of additional equipment

to supplement the capacity, if required. These equipments are available as

standard items and most of the sizes which may be required on river valley

projects are manufactured indigenously.

Belt conveyor system is considered a good alternative for

transportation of material over long distances. In this method the capital

cost of equipment is high, but the disadvantage is offset by the low running

and maintenance costs. However, some limitations are posed by the

maximum lump size, which can be transported through these belt

conveyors.

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In the present case, since fill material is available within a distance of

2 kilometer and borrow areas are scattered over different locations, the

conventional method of material transportation, i.e., hydraulic excavator-

dumper combination has been considered for material transportation.

(i) Impervious Material: As mentioned above, the fill quantities are to be

placed in three working seasons. As the quantity of this type material is

comparatively less, single shift work/day is proposed for the placement. The

hourly placement quantities for hearting material have been worked out and

indicated in Table – 7.7:

Table – 7.7

Estimation of Hourly Quantity of Hearting Material Placement

S.No. Description Quantity Unit

1 Total volume 3,06,000 m3

2 Time period 24 month

3 Shift proposed 1 -

4 Operational hours/month 150 hour

5 Total operational hours 3,600 hour

6 Volume to be handled (in-situ) 85 m3/hour

7 Volume to be handled (loose) 106 m3/hour

8 Peak quantity 133 m3/hour

The following construction methods have been considered for hearting fill:

Excavation and loading by means of 2.0 m3 hydraulic excavator

Transport to the embankment by means of 18/20t capacity rear end

dumpers.

Spreading in layers up to 30 cm thick by 180 HP bulldoze.

Moisture adjustment by 8000 L water sprinklers.

Compaction by 8 passes of 10t pad foot vibrating roller.

An average distance of 2.0 km from dam site has been considered for

the borrow areas for impervious material.

(ii) Filter, fine (2B Zone+3A Zone): The fine filter will have a total

volume of 2,77,700 m3. The fine filter material is used to fill 2B zone and

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3A zone of CFRD Dam. This quantity will be brought from quarries located

at an average distance of 1.5 km from dam site. The material will be

processed in a processing plant located suitably near the quarry itself. The

fine filter material will be processed and brought to the dam site for

placement.

As the quantity of filter material is comparatively less, single shift

work/day is proposed for filter placement. The hourly rate at which

placement of filter is to be carried out has been estimated in Table – 7.8:

Table – 7.8

Estimation of Hourly Quantity of 2B Zone Material Placement

Description Quantity Unit

Total volume 2,77,700 m3

Time period 24 month

Shift proposed 1 -

Operational hours/ month 150 hour

Total Operational hours 3,600 hour

Volume to be handled (in situ) 77 m3/hour

Volume to be handled (loose) 122 m3/hour


The following construction methods have been considered for the

placement of fine filter:

Loading at the quarry by 2.0 m3 hydraulic excavator and transportation

up to filter processing plant by 18/20t capacity rear dumper

Processing at the filter processing plant of capacity, 300 tph installed

near the quarry

Loading by 1.5 cum loader and transport to the dam site by 18/20t

capacity rear dumper

Spreading on the embankment in layers up to 30 cm thick by bulldozer

with flywheel power of 180 HP

Compaction with 6 passes of 10t smooth drum vibratory roller.

(iii) Filter, Coarse (Zone 3B): The requirements of coarse filter which is

going to be used in zone 3B filling is approximately 9,69,000 m3. The same

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will be met from rock quarries. The rock will be transported to the

placement site. The Table – 7.9 indicates the estimation of hourly quantities

involved.

Table – 7.9

Estimation of Hourly Quantity of

Coarse Filter and Rock-Toe Material Placement



Time period 24 Month

Shift proposed 2 -

Operational hours/month 275 hour

Total operational hours 6,600 Hour

Volume to be handled/hr (in situ) 146 m3/hour

Volume to be handled/hr (loose) 235 m3/hour


The following construction methods and equipment are considered

suitable for rockfill placement:

Drilling of charge holes at the quarry by means of jack hammers and

crawler drills with hole patterns of 1-2.75 m c/c

Blasting by means of electric detonators connected to proper wire

circuits




near the quarry

Loading at the filter processing plant by 2.5 cum loader and transport to

the dam site by 18/20t capacity rear dumper

Spreading of the unloaded material on the embankment to about 50 cm

to 70cm layer thickness, by means of 180 HP flywheel power bulldoze.

Compaction by 6 pass of 10t smooth drum vibrating rollers.

(iv) Filter, Coarse (Zone 3C) and Rock toe: The requirements of coarse

filter which is going to be used in zone 3C filling and rock- toe is

approximately 6,55,800 m3. The same will be met from rock quarries. The

Table – 7.10 indicates the estimation of hourly quantities involved.

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Table – 7.10






Shift proposed 2 -











circuits

Loading at the quarry by 2.0 cum hydraulic excavator and transportation



near the quarry

Loading at the filter processing plant by 2.5 cum loader and transport to



to 150cm layer thickness, by means of 180 HP flywheel power bulldozer


7.3.2.3 Major Construction Plant and Equipment for Bhugad

CFRD Dam

Based on above methodology and equipment planning the list of

equipment required for construction of Concrete Face Rock Fill Dam

(Bhugad) is given in Table – 7.11:

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Table – 7.11:

Major Construction Plant and Equipment for

Bhugad CFRD Dam

S. No. Description Size/capacity Quantity

1 Hydraulic excavator 2.0 m3 6

2 Crawler/wagon drill 600 cfm 4

3 Jack hammer 120 cfm 16

4 Front end loader 2.5 m3 5


6 Rear end dumper 18/20t 31

7 Crawler dozer 180 HP 10

8 Vibratory compactor (pad foot) 10t 1

9 Vibratory compactor (smooth

drum)

10t 3

10 Water sprinklers 8000 L 8

11 Air requirement cfm 3500

12 Filter processing plant 500 tph 2


14 Truck 8/10 ton 8

7.3.2.4 Construction Programme

The excavations for the dam will start from the abutments above river

bed level in the 2nd

quarter of year 2 and will be completed within three

months working period. Excavations in the river bed will start as soon as the

work area in the river bed becomes dry. The dam foundation treatment,

which includes consolidation grouting and curtain grouting, will start locally

as the excavation is completed in that area.

Embankment construction will start by 3rd

quarter of year 3, once the

excavation and foundation preparation works in the river bed are

sufficiently advanced. The period before the beginning of the embankment

construction shall be devoted to the preparation of the haul roads and

development of the borrow area.

A total period of 24 months, excluding the monsoon period has been

allowed for the completion of the dam embankment with the aim to reach

crest elevation by the end of 3rd

quarter of year 6.

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7.3.3 Concrete Dam (Bhugad)

Main activities to be undertaken for construction of Bhugad concrete

dam (over flow & non-over flow sections) are surface excavations and

concreting. Surface excavations will comprise of common excavation in

overburden and rock excavation. The total quantity of concrete dam

excavation is about 4,76,040 m3, and total quantity of concreting is about

7,69,900 m3. Details are indicated in Table – 7.12:

Table – 7.12:

Quantities Involved in Construction of Concrete Dam

(Over Flow & Non-Over Flow)

Description of Work Type / Material Quantity,

in-situ

Unit

Stripping - - m3

Excavation

Common 2,77,280 m3

Rock 1,98,760 m3

Total excavation 4,76,040 m3

Concreting 7,69,900 m3


The surface excavations have been planned to be completed within 1

working season (8 months). The surface excavation for main dam involves

both common and rock excavations. The excavated material will be

transported to the disposal area using conventional excavator and rear

dumper combination. The provision of equipment for the surface

excavation to be made is estimated in Table – 7.13:

Table – 7.13


Type

Description

Common

Excavation

Rock

Excavation

Total volume (m3) 2,77,280 1,98,760


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Shift proposed 2 2

Total operational hours (hour) 2,200 2,200

Volume to be handled in-situ

(m3/hour)

126 90

Volume to be handled loose

(m3/hour)

157 144

Total quantity 157 + 144 ~ 301 m3/hour

The construction equipment for surface excavations is as under:

Excavation and loading of the soft material (common excavation) by 2.0

m3 hydraulic excavators assisted by 180 HP bulldozers

For rock excavations requiring drilling & blasting, drilling the very steep

areas by hand-held rigs (jack hammer) of 38 mm diameter with hole

patterns of about 2.75 m2 and drilling the accessible areas by crawler

drill

Loading of blasted rock by 2.0 m3 hydraulic excavator, shovel

attachment and assisted by 180 HP dozers

Transportation to the disposal areas/main dam by 18/20 t rear dumpers

Crawler dozer, 180 HP to be deployed at the disposal area to spread the

material.

7.3.3.2 Concreting

For concreting of main dam and appurtenant structures, total quantity

of the order of 7,69,900 m3, will have to be placed. A period of 3 working

seasons has been planned for the placement. The rate of placement works

out to 70 m3/hour approximately. The concrete required for main dam is

proposed to be produced in a centralized Batching and Mixing Plant of

capacity 90 m3/hour. The plant shall be located in the vicinity of the dam. In

addition, two numbers mobile batching & mixing plant each of capacity 18

m3/ hour will be provided. The concrete from the plant will be transported

with the help of transit mixers of 4.5 m3 capacity.

Following construction equipments have been considered for

concreting of main dam and appurtenant structures:

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Placing of concrete with the help of 4 Nos. tower cranes, 6 ton @ 40

metre radius are proposed to be deployed at suitable locations. In

addition, 3 Nos. 38 m3/hr concrete pumps with 25 m boom will be used

for concrete placement

Concrete transportation by transit mixers of 4.5 m3 capacity

Batching and mixing plant of capacity 90 m3/hr to be located preferably

within a radius of 2 km from the concrete dam

The aggregate crushing and screening plant of 250 tph for preparation of

coarse and fine aggregates.


Concrete Dam

Based on above construction methodology, major construction plant

and equipment required for construction of concrete dam are listed in Table

– 7.14:

Table – 7.14:

Major Construction Plant and Equipment for Bhugad Concrete Dam

S. N0. Equipments Size/capacity Quantity



3 Front End Loader 2.5 m3 2



6 Rear dumper 18/20 t 15

7 Tippers 4.5 m3 3

8 Tower Crane, traveling type 6t@40 m 4

9 Aggregate processing plant 250 tph 1

10 Batching & mixing plant 90 m3/hour 1

11 Mobile Batching & mixing plant 18 m3/hour 2

12 Transit mixers 4.5 m3 12

13 Concrete pump with 25 m boom 38 m3/hour 3

14 Concrete Vibrator (electrical/

pneumatic)

8

15 Compressed air cfm 1600

16 Grout pump 20 kg/m2 4

17 Trucks 8/10 ton 4

18 Mobile Crane 16t 2

403


The sequence of construction of concrete dam takes into account the

following aspects:

Surface excavation of concrete dam to start during the 3rd

quarter of Year

2

The total quantity of excavation to be completed in a period of 1 working

season. The activity to be completed by the end of 1st quarter of year 3

Concreting to start in the 3rd

quarter of Year 3 and will continue for 3

working seasons and to be completed by the end of the 2nd

quarter of

year 6

Since a part of over-flow section (two blocks) is to be used for diversion

of river during construction of earth dam, the phasing of concreting is to

be planned in such a way that the work of these two blocks is completed

during lean season

Gate installation work to start in the beginning of 4th quarter of year 5

and will be completed by the end of 3rd

quarter of Year 7.

7.3.4 Bhugad Dam Power House

7.3.4.1 Excavation and Concreting

Main activities to be undertaken for construction of power house are

surface excavations and concreting along with erection of electro-

mechanical equipment. The quantities involved in the dam power house

complex are indicated in Table – 7.15:

Table – 7.15

Quantities Involved in Bhugad Dam Power House Complex

S. No. Description Quantity (m3)

1 Surface excavations

Common Excavation 8,300

Rock excavation 20,700

2 Concreting 4,240

The sequence of operations for power house complex is based on the

following construction methods and equipment:

404

Excavation and loading of the soft material by 2.0 m3 hydraulic

excavators assisted by 180 HP dozer

For rock excavations requiring drilling and blasting, drilling the very

steep areas by hand-held rigs with 38 mm diameter with hole patterns of

about 1-2.5 m2 and drilling the accessible areas by crawler rigs with 76

mm bits and hole patterns ranging from 7.5 to 9.0 m2

Loading of the blasted rock by 2.0 cum hydraulic excavator bucket

shovel attachment and assisted by 180 HP dozers

Transportation to the disposal areas by 18/20t rear end dumpers

Placing of concrete with 20 m3/hr concrete pumps with 25 m boom

Concrete transportation by 4.5 m3 transit mixers

Concrete production in a Batching and mixing plant of capacity 90 m3/hr


coarse and fine aggregates

Mobile crane of 16t is to be utilized for handling of construction

material, shutter forms etc.


Power House

No separate equipment for construction of Bhugad powerhouse

complex has been provided as equipment deployed for concrete dam shall

be utilized for construction of power house.


As the excavation quantities are not much, a period of 3 months has

been planned beginning in the 3rd

quarter of year 6. The construction of the

concrete structures will begin by the 4th

quarter of Year 6 starting from the

structures of the erection area. Almost 15 months have been considered

necessary to complete the powerhouse.

All works including electro-mechanical works will be essentially

completed by 3rd

quarter of year 7.

405

7.3.5 Concrete Face Rock-Fill Dam (Khargihill Dam)

Total quantity of Khargihill dam excavation including OF and NOF section

is about 21,35,500 m3 in which 8,93,200 m

3 quantity is considered as

common excavation and remaining 4,96,900 m3 is considered as rock

excavation. Following assumptions have been made while working out the

quantities of different activities for the construction of dam. Details are in

Table – 7.16.

i. Total river bed excavation quantity has been divided in a ratio of 1:1

for the estimation of excavation quantity for CFRD portion and

Concrete portion of dam.

ii. While working out the quantity for common excavation and rock

excavation of each portion of dam, same ratio i.e. 1:1 has been used

over the total excavation quantities of each type.

Table – 7.16

Quantities of Different Activities for

Construction of CFRD Portion of Khargihill Dam

Description of

Work


In-situ

Unit

Stripping - 57,500 m3

Excavation

Common 4,29,050 m3

Rock 6,55,200 m3

Fill placement

Impervious material 2,81,100

Filter, Fine (2B Zone+3A Zone) 2,29,200

Filter, Coarse(Zone 3B) 12,05,600

Filter, Coarse(Zone 3C)Rock toe 7,16,900

Total Quantity 24,32,800 m3


The surface excavation for main dam involves both common and rock

excavations. The volume of required excavation is given in Table – 7.17:

406

Table – 7.17

Volume of Surface Excavation

Type

Description

Common

excavation (m3)

Rock excavation

(m3)


River Bed Excavation 4,29,050 6,55,200

Total 4,86,550 6,55,200

Two working seasons have been earmarked for undertaking surface

excavation pertaining to main dam. Although work in the river bed can be



equipment for the surface excavation to be made is estimated in Table –

7.18:

Table – 7.18


Type

Description

Common

Excavation

Rock Excavation

Total volume (m3) 4,85,550 6,55,200


Shift proposed 2 2

Total operational hours (hour) 4400 4400


(m3/hr)

110 149

Volume to be handled loose (m3/hr) 138 238

Peak Volume to be handled(m3/hr) 173 297

Total quantity 173+297 = 470 m3/hour

Peak quantity 470 cum/hour



loading of the soft material (earth and alluvium) by 2.0 m3 hydraulic

excavators assisted by 180 HP crawler dozer

Transportation to the disposal area by 18/20t capacity rear dumper.

407


spreading of the unloaded materials


hammers and wagon/crawler drill with hole patterns of 1m c/c and 2.75

m c/c respectively to be deployed for drilling of charge holes.


The construction of concrete faced rockfill dam involves placement

of 24,32,800 m3 of fill materials. As per construction schedule the fill

placement is to be undertaken in period of three working seasons. The

break-up of total quantity into different types of fill material to be placed in

different zones and their expected source of supply is given in Table – 7.19:

Table – 7.19

Quantities and Source of Fill Material

S.

N

o.

Fill Material Quantity

(compacted)

(m3)

Average distance

of borrow area/

quarry (km)

1 Impervious material 2,81,100 4.0

2 Filter, Fine (2B Zone+3A Zone) 2,29,200 6.0

3 Filter, Coarse(Zone 3B) 12,05,600 6.0

4 Filter, Coarse(Zone 3C) 7,16,900 6.0

Total = 24,32,800 m3

In the present case, since fill material is available within a distance of

6.0 kilometer and borrow areas are scattered over different locations, the

conventional method of material transportation, i.e., hydraulic excavator-

dumper combination has been considered for material transportation.

(i) Impervious Material: As mentioned above, the fill quantities are to be

placed in three working seasons. As the quantity of this type material is

comparatively less, single shift work/day is proposed for the placement. The

hourly placement quantities for hearting material have been worked out and

indicated in Table – 7.20:

408

Table – 7.20

Estimation of Hourly Quantity of Impervious Material Placement

S. No. Description Quantity Unit

1 Total volume 2,81,100 m3

2 Time period 24 month

3 Shift proposed 1 -

4 Operational hours/month 150 hour

5 Total operational hours 3,600 hour

6 Volume to be handled (in-situ) 78 m3/hour

7 Volume to be handled (loose) 98 m3/hour

8 Peak quantity 122 m3/hour

The following construction methods have been considered for hearting fill:

Excavation and loading by means of 2.0 m3 hydraulic excavator

Transport to the embankment by means of 18/20t capacity rear end

dumpers

Spreading in layers up to 30 cm thick by 180 HP bulldoze

Moisture adjustment by 8000 L water sprinklers

Compaction by 8 passes of 10t pad foot vibrating roller

An average distance of 4.0 km from dam site has been considered for the

borrow areas for impervious material.

(ii) Filter, fine (2B Zone+3A Zone): The fine filter will have a total

volume of 2,29,200 m3. The fine filter material is used to fill 2B zone and

3A zone of CFRD Dam. This quantity will be brought from quarries located

at an average distance of 6.0 km from dam site. The material will be

processed in a processing plant located suitably near the quarry itself. The

fine filter material will be processed and brought to the dam site for

placement.

As the quantity of filter material is comparatively less, single shift

work/day is proposed for filter placement. The hourly rate at which

placement of filter is to be carried out has been estimated in Table – 7.21:

409

Table – 7.21

Estimation of Hourly Quantity of 2B Zone Material Placement



Time period 24 month

Shift proposed 1 -

Operational hours/ month 150 hour

Total Operational hours 3,600 hour

Volume to be handled (in situ) 64 m3/hour

Volume to be handled (loose) 102 m3/hour


The following construction methods have been considered for the placement

of fine filter:


up to filter processing plant by 18/20t capacity rear dumper.


near the quarry.

Loading by 1.5 cum loader and transport to the dam site by 18/20t

capacity rear dumper.

Spreading on the embankment in layers up to 30 cm thick by bulldozer

with flywheel power of 180 HP.

Compaction with 6 passes of 10t smooth drum vibratory roller.

(iii) Filter, Coarse (Zone 3B): The requirements of coarse filter which is

going to be used in zone 3B filling is approximately 12,05,600 m3. The

same will be met from rock quarries. The rock will be transported to the

placement site. The Table – 7.22 indicates the estimation of hourly

quantities involved.

410

Table – 7.22






Shift proposed 2 -






The following construction methods and equipment are considered suitable

for rockfill placement:




circuits




near the quarry

Loading at the filter processing plant by 2.5 m3 loader and transport to



to 70 cm layer thickness, by means of 180 HP flywheel power bulldozer


(iv) Filter, Coarse (Zone 3C) and Rock toe: The requirements of coarse

filter which is going to be used in zone 3C filling and rock- toe is

approximately 7,16,900 cum. The same will be met from rock quarries. The

Table – 7.23 indicates the estimation of hourly quantities involved.

411

Table – 7.23






Shift proposed 2 -











circuits




near the quarry

Loading at the filter processing plant by 2.5 m3 loader and transport to



to 150 cm layer thickness, by means of 180 HP flywheel power

bulldozer


7.3.5.3 Major Construction Plant and Equipment for Khargihill

Concrete Faced Rockfill Dam


equipment required for construction of Khargihill Concrete Face Rock Fill

Dam (CFRD) is in Table – 7.24.

412

Table – 7.24

Major Construction Plant and Equipment for

Khargihill Concrete Faced Rockfill Dam

S.

No.

Description Size/

capacity

Quantity









9 Vibratory compactor (smooth drum) 10t 3





14 Filter processing plant 250tph 1

15 Truck 8/10 ton 8


The excavations for the Khargihill dam will start from the abutments

above river bed level in the 2nd

quarter of year 2 and will be completed

within three months. Excavations in the river bed will start as soon as the

work area in the river bed becomes dry. The dam foundation treatment,

which includes consolidation grouting and curtain grouting, will start locally

as the excavation is completed in that area.

Embankment construction will start by 3rd

quarter of year 4, once the





413

A total period of 24 months, excluding the monsoon period has been


crest elevation by the end of 1st quarter of year 7.

7.3.6 Khargihill Concrete Dam

Main activities to be undertaken for construction of Khargihill

concrete dam (over flow & non-over flow sections) are surface excavations

and concreting. Surface excavations will comprise of common excavation in

overburden and rock excavation. The total quantity of concrete dam

excavation is about 10,84,250 m3, and total quantity of concreting is about

9,58,970 m3. Details are in Table – 7.25:

Table – 7.25

Quantities Involved in Construction of Concrete Dam

(Over Flow & Non-Over Flow)

Description of

Work


in-situ

Unit

Stripping - - m3

Excavation

Common 4,29,050 m3

Rock 6,55,200 m3

Total excavation 10,84,250 m3

Concreting 9,58,970 m3


The surface excavations have been planned to be completed within 2

working seasons (16 months). The surface excavation for main dam

involves both common and rock excavations. The excavated material will be

transported to the disposal area using conventional excavator and rear

dumper combination. The provision of equipment for the surface

excavation to be made is estimated in Table – 7.26:

414

Table – 7.26


Type

Description

Common

Excavation

Rock

Excavation

Total volume (m3) 4,29,050 6,55,200


Shift proposed 2 2



(m3/hour)

98 149


(m3/hour)

122 239

Peak Volume To be

Handled(m3/hour)

153 297

Total quantity 153 + 297 = 450 m3/hour

The construction equipment for surface excavations is as under:

Excavation and loading of the soft material (common excavation) by 2.0

m3 hydraulic excavators assisted by 180 HP bulldozers

For rock excavations requiring drilling & blasting, drilling the very steep

areas by hand-held rigs (jack hammer) of 38 mm diameter with hole

patterns of about 2.75 m2 and drilling the accessible areas by crawler

drill

Loading of blasted rock by 2.0 m3 hydraulic excavator, shovel

attachment and assisted by 180 hp dozers

Transportation to the disposal areas/main dam by 18/20t rear dumpers

Crawler dozer, 180 HP to be deployed at the disposal area to spread the

material.

7.3.6.2 Concreting

For concreting of main dam and appurtenant structures, total quantity

of the order of 9,58,970 m3, will have to be placed. A period of 3 working

seasons has been planned for the placement. The rate of placement works

out to 90 m3/ hour approximately. The concrete required for main dam is

proposed to be produced in a centralized Batching and Mixing Plant of

415

capacity 120 m3/hour. The plant shall be located in the vicinity of the dam.

In addition, two numbers mobile batching & mixing plant each of capacity,

18 m3/hour will be provided. The concrete from the plant will be transported

with the help of transit mixers of 4.5 m3 capacity.

Following construction equipments have been considered for

concreting of main dam and appurtenant structures:

Placing of concrete with the help of 3 Nos. tower cranes, 10 ton @ 50

metre radius are proposed to be deployed at suitable locations. In

addition, 3 Nos. 38 m3/hr concrete pumps with 25 m boom will be used

for concrete placement

Concrete transportation by transit mixers of 4.5 m3 capacity

Batching and mixing plant of capacity 120 m3/hr to be located preferably

within a radius of 2 km from the concrete dam


coarse and fine aggregates.


Concrete Dam

Based on above construction methodology, major construction plant

and equipment required for construction of concrete dam are listed in Table

– 7.27:

Table – 7.27

Major Construction Plant and Equipment for Khargihill Concrete Dam

S. No. Equipments Size/capacity Quantity



3 Front End Loader 2.5 m3 2



6 Rear dumper 18/20t 15

7 Tippers 4.5 m3 3

8 Tower Crane, traveling type 10t@50m 3

9 Aggregate processing plant 300 tph 1

416

10 Batching & mixing plant 120 m3/hour 1

11 Mobile Batching & mixing plant 18 m3/hour 2

12 Transit mixers 4.5 m3 16

13 Concrete pump with 25m boom 38 m3/hour 3

14 Concrete Vibrator (electrical/

pneumatic)

9

15 Compressed air cfm 1600

16 Grout pump 20 kg/m2 4

17 Trucks 8/10 ton 4

18 Mobile Crane 16t 2


The sequence of construction of Khargihill concrete dam takes into

account the following aspects:

Surface excavation of concrete dam to start during the 3rd

quarter of Year

2.

The total quantity of excavation to be completed in a period of 2 working

seasons. The activity to be completed by the end of 1st quarter of year 4.

Concreting to start in the 3rd

quarter of Year 3 and will continue for 3

working seasons and to be completed by the end of the 2nd

quarter of

year 6.

Since a part of over-flow section (two blocks) is to be used for diversion

of river during construction of earth dam, the phasing of concreting is to

be planned in such a way that the work of these two blocks is completed

during lean season.

Gate installation work to start in the beginning of 4th quarter of year 5

and will be completed by the end of 3rd

quarter of Year 7.

7.3.7 Khargihill Dam Power House

7.3.7.1 Excavation and Concreting

Main activities to be undertaken for construction of Khargihill power

house are surface excavations and concreting along with erection of electro-

mechanical equipment. The quantities involved in the Khargihill dam power

house complex are indicated in Table – 7.28:

417

Table – 7.28

Quantities Involved in Khargihill Dam Power House Complex

S. No. Description Quantity (m3)

1 Surface excavations

Common Excavation 5,382

Rock excavation 11,810

2 Concreting 4,364

The sequence of operations for Khargihill power house complex is based on

the following construction methods and equipment:







Loading of the blasted rock by 2.0 m3 hydraulic excavator bucket shovel



Placing of concrete with 20 cum/hr concrete pumps with 25 m boom

Concrete transportation by 4.5 cum transit mixers

Concrete production in a Batching and mixing plant of capacity 120

m3/hr


coarse and fine aggregates

Mobile crane of 16t is to be utilized for handling of construction

material, shutter forms etc.


Power House

No separate equipment for construction of powerhouse has been

provided as equipment deployed for concrete dam shall be utilized for

construction of power house.

418


As the excavation quantities are not much, a period of 3 months has

been planned beginning in the 4th

quarter of year 6. The construction of the

concrete structures will begin by the 1st

quarter of Year 7 starting from the

structures of the erection area. Almost 12 months have been considered

necessary to complete the powerhouse.

All works including electro-mechanical works will be essentially

completed before one month of completion of the project.

7.3.8 Khargihill Saddle Dam

The construction of the dam involves surface excavation, placement

of fill material, spreading & wetting and compaction of the fill material.

The quantities involved in construction of the Khargihill Saddle dam are

given in Table – 7.29:

Table – 7.29

Quantities Involved in Construction of Khargihill Saddle Dam

Description of

Work

Type /

Material

Quantity,

in-situ

Unit

Stripping 18,900 m3

Excavation

Common 34,600 m3

Rock 3,100 m3

Fill placement

Hearting

material

42,200 m3

Casing material 2,24,900 m3

Filter, Fine 31,590 m3

Filter, Coarse 33,440 m3

Rock toe 16,200 m3

Total 3,48,330 cum

419


The surface excavation for main dam as well as for cofferdams

involves both common and rock excavations. The volume of required

excavation is given in Table – 7.30:

Table – 7.30:

Volume of Surface Excavation for Khargihill Saddle Dam

Type

Description

Common

Excavation (m3)

Rock Excavation

(m3)


Excavation for trenching

and preparation of base

34,600

3,100

Total 53,500 3,100

Four month has been earmarked for undertaking surface excavation

pertaining to Khargihill saddle dam. Although work in the river bed can be



equipment for the surface excavation is to be made is inTable – 7.31:

Table – 7.31: Estimation of hourly quantity of excavation

Type

Description

Common

Excavation

Rock

Excavation

Total volume (cum) 53,500 3,100


Shift proposed 2 2



(cum/hr)

48 3


(cum/hr)

60 4

Total quantity = 60+4 = 64 m3/hour

Peak quantity = 64 m3/hour


420


loading of the soft material (earth and alluvium) by 2.0 cum hydraulic

excavators assisted by 180 HP crawler dozer.

Transportation to the disposal area by 18/20 t capacity rear dumper.


spreading of the unloaded materials.


hammers and wagon/crawler drill with hole patterns of 1m and 2.75 m

c/c respectively to be deployed for drilling of charge holes.


The construction of earth fill dam involves placement of 3,48,330 m3 of fill

materials. As per construction schedule the fill placement is to be

undertaken in a period of 5 working months (Table – 7.32):

Table – 7.32:

Estimation of Hourly Quantity of Excavation for

Khargihill Saddle Dam

Type

Description

Hearting

Material

Casing

Material

Fine

Filter

Coarse

Filter

Total volume (m3) 42,200 2,24,900 31,590 49,640

Time period (months) 5 5 5 5

Shift proposed 2 2 2 2

Total operational

hours (hour)

1375 1375 1375 1375

Volume to be handled

in-situ ( m3/hr)

31 163 23 36

Volume to be handled

loose ( m3/hr)

39 205 37 58

Total quantity = 39+205+37+58 = 339 m3/hour

Peak quantity = 339 m3/hour

The Following construction methods have been considered for fill:

Excavation and loading by means of 2.0 m3 hydraulic excavator.

Transport to the embankment by means of 18/20 t capacity rear end

dumpers.

421


crawler drills with hole patterns of 1-2.75 m c/c.


circuits.

Loading at the quarry by 1.5 cum hydraulic excavator and transportation

up to filter processing plant by 18/20t capacity rear dumper.

Processing at the filter processing plant of installed near the quarry.

Spreading by 180 HP bulldoze.

Moisture adjustment by 8000 L water sprinklers.

In case of Hearting and casing material, compaction by 8 passes of 10t

pad foot vibrating roller and in case of fine and coarse filter 6 passes of

10t smooth drum vibrating roller.


Saddle Dam


equipment required for construction of Khargihill saddle dam is given in

Table – 7.33:

Table – 7.33

List of Equipment Required for Construction of Khargihill Saddle Dam

S. No. Description Size/capacity Quantity









9 Vibratory compactor (smooth drum) 10t 1




13 Truck 8/10 ton 4

422


The excavations for the saddle dam will start from the abutments

above river bed level in the 3rd

quarter of year 6 and will be completed

within 4 months. Excavations in the river bed including cut-off trench will

start as soon as the work area in the river bed becomes dry. The dam

foundation treatment, which includes consolidation grouting and curtain

grouting, will start locally as the excavation is completed in that area. The

timely completion of the surface treatments for the core foundation in the

river bed is essential in order to allow the beginning of the clay placement.

Thereafter, this work will proceed slightly in advance of the raising of the

core where it is required.

Embankment construction will start by 4th quarter of year 6, once the





A total period of 15 months, including the monsoon period has been


crest elevation by the end of 3rd

quarter of year 7.

7.3.9 Bhugad-Khargihill Tunnel

The Bhugad-Khargihill Tunnel having 3.2 m diameter (finish) is of

17488 m length. Two construction adits have been proposed for

construction of Bhugad-Khargihill tunnel. The provision of two adits

provides opportunity to excavate tunnel from 6 faces simultaneously;

provided deployment of equipment sets is feasible at all the faces at a time.

The RD of each adits and distance between them is in Table – 7.34:

423

Table – 7.34

Bhugad – Khargihill Tunnel Adits – RD and Distance between Adits

Adit Adit Length

(m)

RD from

Inlet Portal

(m)

Tunnel Length (m) Distance

b/w Adits

(m) Face

Number

Length Served

Through Face

Inlet

Portal

- 0.00 F1 3350

6500

Adit-1 205 6498 F2

F3

3150

3125 6250

Adit-2 154 12750 F4

F5

3125

2422 4738

Outlet

Portal

- 17488 F6 2316

Total 17488 17488

7.3.9.1 Excavation of Tunnel

Before taking up actual tunnel excavation, portal construction and

slope stabilization would be required for which following construction

sequence is suggested:










Slope Stablization using shotcrete machine and anchoring by jack

hammer/hydraulic drilling rig

Portal concreting by using portable concrete mixer with weigh batches.

The portal excavation and slope stabilization will be completed

within three month from start of work. Once the same is completed, the

excavation of adits and tunnel (from inlet and outlet faces) will start. In

view of its size, both adits and tunnel are proposed to be excavated by full

face drill and blast method. For a finish diameter of 3.2 m, the minimum

424

excavated diameter of the tunnel shall be 4.2m to account for 500 mm thick

concrete lining and shotcrete. Following construction method for the

excavation of tunnel and adits may be adopted.

Drilling of charge holes by means of single boom hydraulic drill jumbo

Driving of each round variable according to the Class of rock

(approximate 3.5 m for the Class I & II, 3.0 m for the Class III and 2.5

m for the rock Class IV and V)

Number of holes per round (including those necessary for carrying out

the smooth blasting along the peripheral surface) approximately 30-40

Charging operations of explosive to be executed by means of man basket

and firing of the rounds using nonel detonators

Loading of the muck resulting from blasting, by Railway Hydraulic

mucker/rock loader (40 m3/hr output capacity)

Transport of the muck to the spoil area by Granby-type Side dump cars

(6 to 9 m3 capacity) mounted on rail system

Shotcrete with the help of 4-6 m3/hr capacity wet shotcrete machine

Rock bolting using mechanized rock bolting rig.

With the above construction methods and equipment, it is possible to

complete a cycle of operation within a period of 10.7 hours. Although the

time of each activity within a cycle may vary according to class of rock

encountered, the total cycle time for the pull [planned as indicated above for

different classes of rock will be the same order. A typical cycle for Class III

(pull of 3.00m) is in Table – 7.35:

Table – 7.35

Typical Cycle for Class III (Pull of 3.00 m)

1 Preparation of job 0.5hr

2 Drilling of Charge Holes 2.2hr

3 Charging 1.0hr

4 Removal of Jumbo to safe position 0.5hr

5 Blasting and defuming 1.0hr

6 Mucking 2.0hr

7 Scaling 0.5hr

8 Shotcreting and rock bolting 3.0hr

Total 10.7hr

425

In whole tunnel, 99% tunneling is in rock class of I, II & III (no –rock

support system required) and 1% tunneling is in rock class IV & V(require

rock support system). As per the rock condition of tunnel and with above

cycle time, an average sustainable progress of 140 m/month/face can be

achieved.

Considering 6 face excavation, all the construction activities of

Bhugad – Khargihill tunnel would be planned and staged for optimum

utilization of equipments for planned time period.

7.3.9.2 Concrete Lining

Concrete lining is to be undertaken after the completion of

excavation. Following sequence of operation will be followed for concrete

lining of the head race tunnel:

Concrete to be placed in three stages viz., kerb, overt, invert

Kerb concreting to be placed with the help of 20 m form work

Installation of Rails on kerb for movement of 10 m travelling collapsible

formwork for overt concreting

Pouring of concrete for Overt by 25 m3/hr capacity concrete pump.

Transportation of concrete by 4.5 m3 capacity transit mixers.

Invert concreting with the help of screed board.

Pouring of concrete for invert with similar equipment as deployed for

overt.

Preparation of Concrete in a Batching & Mixing Plant of 30 m3/hr

capacity installed near Portal of each adit and outlet.

An Aggregate Crushing & Screen Plant of 70 tph to be installed near

each adit location for preparation of coarse aggregate. A tertiary crusher

for preparation of crushed fine aggregate is also to be provided as river

sand is to be blended with crushed

Excavated material from tunnel excavation to be utilized as aggregate

after crushing & screening. In case material from quarries is to be

obtained, tipper, 10 T payload capacity to be utilized for transportation

and wheel loader, 1.0 m3 for loading .

A typical cycle time for overt concreting is in Table – 7.36:

426

Table – 7.36

Estimated Cycle Time in Overt Concreting (10 m)

1 Erection time 16.00 hr

2 Pouring time 8.00 hr

3 Setting time 20.00 hr

4 Dismantling of formwork 4.00 hr

Total 48.00 hrs

With 48 hr cycle time and two set of shutter form, a progress of 10 m

per day or an average progress of about 200 m/month/face at each face can

be achieved. Invert concrete to be undertaken simultaneously with overt

concreting with a time lag.

Based on the above methodology, major Construction Plant &

Equipment required for construction of tunnel have been listed out in Table

– 7.37:

Table – 7.37:

Major Construction Plant & Equipment for Construction of

Bhugad – Khargihill Tunnel

S. No. Item Qty./ No.

1 Single Boom hydraulic Drill Jumbo with

working platform

4

2 Rock Bolting Jumbo 4

3 Railway Hydraulic mucker/rock loader 4

4 Wagon Drill 4

5 Heavy Duty Rock Drill, 120 cfm 4

6 Muck cars 6 m3 capacity 24

7 Crawler Dozer, 165 hp 4

8 Loader-cum-Excavator, 1.0 m3/ 0.24 m

3 4

9 Shotcrete m/c, 4-6 m3 4

10 Shotcrete m/c with Robot Arm, 10 cum 4

11 Air Compressor, 500 cfm, Diesel 4

12 Aggregate Crushing & Screening Plant,

70 tph

4

13 Concrete Batching & Mixing Plant, 30

m3/hr

4

427

14 Collapsible Shutter Form with Traveller,

6.8x10 m

6

15 Transit Mixer, 4.5 m3 12

16 Concrete Pump, 25 m3/hr 4

17 Concrete Mixer, 14/10 cft 4

18 Tipper, 10 t 28

19 Wheel loader 1.0 m3 4

20 Grout pump 6

An average distance of 7.0 km from quarry site has been considered

for calculating the number of tippers required.

7.3.9.3 Construction Program

The sequence of Construction of Bhugad – Khargihill tunnel takes

into account the following aspects:

Open excavation for face and portal construction is to be started in the

1st quarter of year 2 and will completed within three months

Adits/Tunnel excavation to start in 2nd

quarter of year 2 and are to be

completed by the end of 1st quarter of year 4

Concrete lining of whole of tunnel to be taken up from all the face

simultaneously. Lining to start in the 4th quarter of year 3 and to be

completed by the end of 1st quarter of year 6

Contact/consolidation grouting of the tunnel to start simultaneously

with the concreting and will finish in three months after concreting

Final cleaning of tunnel and other miscellaneous work will be

completed in two months after consolidation grouting.

7.3.10 Khargihill - Pinjal Tunnel

Khargihill - Pinjal Tunnel having 4.0 m diameter (finish) is of 25224

m length. Four construction adits have been proposed for construction of

Khargihill - Pinjal tunnel. The provision of 4 adits provides opportunity to

excavate tunnel from 10 faces simultaneously; provided deployment of

equipment sets is feasible at all the faces at a time. The RD of each adits and

distance between them is given in Table – 7.38.

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Table – 7.38

Khargihill - Pinjal Tunnel Adits – RD and Distance between Adits

Adit Adit

Length

(m)

RD from

Inlet

Portal

(m)

Tunnel Length (m) Distance

b/w Adits

(m) Face

Number

Length

Served

Through

Face

Inlet

Portal

- 0.00 F 1 3690

5729

Adit-1 1700 5729 F 2

F 3

2039

3216 5983

Adit-2 2283 11712 F 4

F 5

2767

2135 4370

Adit -

3

2050 16082 F6

F 7

2235

2231 5862

Adit -

4

623 21944 F8

F 9

3631

1722 3280

Outlet

Portal

- 25224 F 10 1558

Total 25224 25224

7.3.10.1 Excavation of Tunnel

Before taking up actual tunnel excavation, portal construction and

slope stabilization would be required for which following construction

sequence is suggested:









Transportation to the disposal areas by 18/20 t rear end dumpers

Slope stabilization using shotcrete machine and anchoring by jack

hammer/hydraulic drilling rig

Portal concreting by using potable concrete mixer with weigh batches.

429

The portal excavation and slope stabilization will be completed

within three month from start of work. Once the same is completed, the

excavation of adits and tunnel (from inlet and outlet faces) will start. In

view of its size, both adits and tunnel are proposed to be excavated by full

face drill and blast method. For a finish diameter of 4.0 m, the minimum

excavated diameter of the tunnel shall be 5.0 m to account for 500 mm

thick concrete lining and shotcrete.

Following construction method for the excavation of tunnel and adits

may be adopted:

Drilling of charge holes by means of single boom hydraulic drill jumbo

Driving of each round variable according to the Class of rock (approx.

3.5 m for the Class I & II, 3.0 m for the Class III and 2.5 m for the

rock Class IV and V)

Number of holes per round (including those necessary for carrying out

the smooth blasting along the peripheral surface) approximately 45-55

Charging operations of explosive to be executed by means of man basket

and firing of the rounds using nonel detonators

Loading of the muck resulting from blasting, by Railway Hydraulic

mucker/rock loader (60 m3/hr output capacity)

Transport of the muck to the spoil area by Granby-type Side dump cars

(6 to 9 cum capacity) mounted on rail system

Shotcrete with the help of 4-6 m3/hr capacity wet shotcrete machine

Rock bolting using mechanized rock bolting rig

With the above construction methods and equipment, it is possible to

complete a cycle of operation with in a period of 11.9 hours. Although the

time of each activity within a cycle may vary according to class of rock

encountered, the total cycle time for the pull [planned as indicated above for

different classes of rock will be the same order. A typical cycle for Class III

(pull of 3.00m) is given in Table – 7.39:

430

Table – 7.39

Typical Cycle for Class III (Pull of 3.00m)

1 Preparation of job 0.5 hr

2 Drilling of Charge Holes 3.3 hr

3 Charging 1.0 hr

4 Removal of Jumbo to safe position 0.5 hr

5 Blasting and defuming 1.0 hr

6 Mucking 2.1hr

7 Scaling 0.5 hr

8 Shotcreting and rock bolting 3.0 hr

Total 11.9 hr

In entire tunnel, 99% tunnelling is in rock class of I, II & III (no –

rock support system required) and 1% tunnelling is in rock class IV & V

(require rock support system). As per the rock condition of tunnel and with

above cycle time, an average sustainable progress of 125 m/month/face can

be achieved. Considering 10 face excavation, all the construction activities

of Khargihill - Pinjal tunnel would be planned and staged for optimum

utilization of equipments for planned time period.

7.3.10.2 Concrete Lining

Concrete lining is to be undertaken after the completion of

excavation. Following sequence of operation will be followed for concrete

lining of the head race tunnel:

Concrete to be placed in three stages viz., kerb, overt, invert

Kerb concreting to be placed with the help of 20 m form work

Installation of Rails on kerb for movement of 10 m travelling collapsible

formwork for overt concreting

Pouring of concrete for Overt by 25 m3/hr capacity concrete pump

Transportation of concrete by 4.5 m3 capacity transit mixers

Invert concreting with the help of screed board

Pouring of concrete for invert with similar equipment as deployed for

overt.

Preparation of Concrete in a Batching & Mixing Plant of 30 m3/hr

capacity installed near Portal of each adit and outlet

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An Aggregate Crushing & Screen Plant of 70tph to be installed near each

adit location for preparation of coarse aggregate. A tertiary crusher for

preparation of crushed fine aggregate is also to be provided as river sand

is to be blended with crushed

Excavated material from tunnel excavation to be utilized as aggregate

after crushing & screening. In case material from quarries is to be

obtained, tipper, 10 T payload capacity to be utilized for transportation

and wheel loader, 1.0 cum for loading

A typical cycle time for overt concreting is in Table – 7.40:

Table – 7.40

Estimated Cycle Time in Overt Concreting (10 m)

1 Erection time 16.00 hr

2 Pouring time 8.00 hr

3 Setting time 20.00 hr

4 Dismantling of formwork 4.00 hr

Total 48.00 hrs

With 48 hr cycle time and two set of shutter form, a progress of 10 m

per day or an average progress of about 200 m/month/face at each face can

be achieved. Invert concrete to be undertaken simultaneously with overt

concreting with a time lag.

Based on the above methodology, major Construction Plant &

Equipment required for construction of HRT have been listed out in

following Table – 7.41:

Table – 7.41

Major Construction Plant & Equipment for

Construction of Khargihill – Pinjal Tunnel

S. No. Item Quantity

/ No.

1 Single Boom hydraulic Drill Jumbo with working

platform

6

2 Rock Bolting Jumbo 6

3 Railway Hydraulic mucker/rock loader 6

4 Wagon Drill 6

432

5 Heavy Duty Rock Drill, 120 cfm 6

6 Muck car 9 m3capacity 42

7 Crawler Dozer, 165 hp 6

8 Loader-cum-Excavator, 1.0 cum./ 0.24 m3 6

9 Shotcrete m/c, 4-6 m3 6

10 Shotcrete m/c with Robot Arm, 10 m3 6

11 Air Compressor, 500 cfm, Diesel 6

12 Aggregate Crushing & Screening Plant, 70 tph 6

13 Concrete Batching & Mixing Plant, 30 m3/hr 6

14 Collapsible Shutter Form with Traveller, 6.8x10 m 10

15 Transit Mixer, 4.5 m3 24

16 Concrete Pump, 25 m3/hr 6

17 Concrete Mixer, 14/10 cft 6

18 Tipper, 10 t 48

19 Wheel loader 1.0 m3 6

20 Grout pump 10

An average distance of 10.0 km from quarry site has been considered for

calculating the number of tippers required.

7.3.10.3 Construction Program

The sequence of Construction of HRT takes into account the following

aspects:

Open excavation for face and portal construction is to be started in the 1st

quarter of year 2 and will be completed within three months

Tunnel excavation to start in 2nd

quarter of year 2 and are to be

completed by the end of 2nd

quarter of year 5

Concrete lining of whole of tunnel to be taken up from all the face

simultaneously. Lining to start in the 4th quarter of year 3 and to be

completed by the end of 2nd

quarter of year 7

Contact/consolidation grouting of the tunnel to start simultaneously with

the concreting and will finish in three months after concreting

Final cleaning of tunnel and other miscellaneous work will be completed

in two months after consolidation grouting.

433

7.4 Deployment Schedule

Based on equipment planning and construction programme described

in preceding Sections, a construction schedule for whole of the project has

been prepared in the form of a Bar Chart and is placed at Annexure - 7.1 in

Volume - II. Keeping this construction schedule as one of the major

criteria, a deployment schedule of major construction equipment that would

be required for the project is shown in Annexure - 7.2 in Volume - II. The

number of equipment shown in the list has been arrived at after scheduling

the equipment in such a way that minimum number of equipment, in

general, would be needed. The basis for planning, indicating the type of

equipment to be used, has already been dealt with in the respective sections

and sub-sections corresponding to different items of the structures. As the

deployment schedule may differ depending upon the number of executing

agencies, the total number of equipment required will have to be reviewed at

the time of project execution.

7.5 Total Requirement of Major Construction Equipment

A list of major construction equipment and plants, which would be

required for construction of various components of the project is shown in

Annexure - 7.3 in Volume - II. The latest budgetary prices of the equipment

have been indicated in the list which could be utilized for working out the

analysis of rates as required. The total cost of construction equipment has

been worked out as Rs. 27663 lakh.

The provision on this account will not be included in the sub-head Q -

Special T&P of Cost Estimate when works are to be executed by the

contracting agencies.

7.6 Manpower Planning

7.6.1 Organisation Set Up

The project will be implemented under an organisation set-up headed

by an officer of the rank of General Manager. The works will be executed

under the overall supervision of four Officers of the rank of Chief Engineers

who will report to General Manager. In addition, there will be four officers

434

of the rank of Superintending Engineer to assist General Manager: Director

(Administration), Director (Finance), Director (Technical Coordination) and

Director (Planning) and Public Relation Officer and Labour Welfare

Officer. Each will be assisted by appropriate subordinate officers and staff.

The organisation chart for the project is appended as Annexure - 7.4 in

Volume - II.

There will be four Chief Engineers for the Project to look after the

works, viz., Chief Engineer (Head works), Chief Engineer (Tunnels), Chief

Engineer (Designs) and Chief Engineer (Electrical & Mechanical). Each

Chief Engineer except Chief Engineer (Designs) will be supported by two

officers of the rank of Superintending Engineer who will be heading the

field formations of circles. Each circle will have three to four division

offices which will be headed by the officers of the rank of Executive

Engineers. Executive Engineers in turn will have Assistant Engineers as

their subordinate officers who will man Sub-Divisional offices. The Chief

Engineer (Designs) will be supported by four officers of the rank of

Superintending Engineer: two for design units, one for Quality control and

one SE for EMP and R&R. These SEs will be further supported Executive

Engineers/ Assistant Engineers and other supporting staff.

Chief Engineer (Head Works) will be responsible for execution of

works related to construction of Bhugad and Khargihill dams and Power

Houses. One of the Superintending Engineers under him will be responsible

for construction of Bhugad dam and Power House and another

Superintending Engineer will be responsible for construction of Khargihill

dam and Power House. They will be supported by appropriate subordinate

officers as elaborated under the organisation chart. The designs of various

components of the project will be carried out by the Chief Engineer

(Designs).

Chief Engineer (Tunnels) will be responsible for execution of works

related to construction of both the tunnels: Bhugad - Khargihill tunnel and

Khargihill – Pinjal tunnel. One of the Superintending Engineer under him

will be responsible for construction of Bhugad – Khargihill tunnel and

another Superintending Engineer will look after the construction of

Khargihill – Pinjal tunnel.

435

The civil designs of all the components of the project will be carried

out by the Chief Engineer (Designs). The Chief Engineer (Electrical &

Mechanical) will look after the electro-mechanical works of the two power

houses. His formation will also provide assistance in respect of electrical

and mechanical works for whole of the project.

Detailed manpower requirement has been indicated in Annexures -

7.5 to 7.7 in Volume - II.

7.7 General Purpose Equipment and Inspection Vehicles

In case the works are to be executed through award of contract, the

general purpose equipment for infra-structure works and inspection and

transport vehicles which are required to be procured and used by the project

owners for the project have been estimated and indicated in the Annexure -

7.3 in Volume - II. The total cost of general purpose equipment and

inspection vehicles has been worked out as Rs. 1593 lakh.

7.8 Year Wise Allocation of Cost

The year wise allocation of cost for the project is in Table – 7.42 and

the details are at Annexure - 7.8 in Volume – II.

Yearly phasing of Expenditure

Year Allocation of cost (lakh Rs.)

1st Year 3925

2nd

Year 31835

3rd

Year 68628

4th Year 62240

5th Year 51869

6th Year 38984

7th Year 17180

Total 274661

Chapter - 7 Construction Program, Manpower and Plant...

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