TRAINING REPORT OF

SIX WEEK INDUSTRIAL TRAINING, UNDERTAKEN

AT

“DELHI METRO RAIL CORPORATION LTD”

ON

“UNDERGROUND STATION AT AZADPURAND CONSTRUCTION OF TUNNEL

BY SHIELD TBM AND RAMPS AT MUKUNDPUR”

SUBMITTED IN PARTIAL FULFILLMENT OF THE DEGREE

OF

BACHELOR OF TECHNOLOGY

IN

DEPARTMENT OF “CIVIL ENGINEERING”

LIST of Content

1. COMPANY PROFILE2. INTRODUCTION TO ASSINGNED JOB3. DETAILED ANALYSIS OF INDIVIDUAL

MODULE4. MODULAR DISCRIPTION OF JOB5. PROJECT UNDERTAKEN6. CONCLUSION7. REFERENCES

I COMPANY PROFILE : II.1.Delhi Metro Rail Corporation Ltd.

Delhi Metro is a metro system serving Delhi metropolitan area and its satellite cities

of Gurgaon, Noida, Faridabad and Ghaziabad in the National Capital Region of India. Delhi Metro has been ranked second among 18 international Metro systems in terms of overall customer satisfaction in an online customer survey.

According to a DMRC official, in the survey conducted among the commuters of those Metro systems by Global Metro Benchmarking Groups NOVA and CoMET, Delhi Metro along with London DLR and Bangkok were the best three performers in the Net Promoters Score (NPS) category. Delhi Metro is also the world's 13th largest metro system in terms of length and 12th largest in terms of number of stations. It is a member of Nova Group of Metros. Delhi Metro is India's third urban mass rapid transport system (after the Kolkata Metro and Chennai MRTS) and first modern rapid transit system.

As of June 2015, the network consists of five colour-coded regular lines (Red, Blue, Green, Yellow, Violet), and a sixth express line, the Airport Express, with a total length of 194

kilometres (121 mi), serving 142 stations (with 6 more Airport Express stations), of which 38 are underground, five are at-grade, and the rest are elevated. All stations have escalators, elevators, and tactile tiles to guide the visually impaired from station entrances to trains.

It has a combination of elevated, at-grade, and underground lines, and uses both broad gauge and standard gauge rolling stock. Four types of rolling stock are

used: Mitsubishi Rotem broad gauge, Bombardier Movia, Mitsubishi Rotem standard gauge, and CAF Beasain standard gauge.

Delhi Metro Rail Corporation Limited (DMRC), a state-owned company with equal equity participation from Government of India and Government of National Capital Territory of Delhi built and operates the Delhi Metro. However, the organisation is under administrative control of Ministry of Urban Development, Government of India. Besides construction and operation of Delhi Metro, DMRC is also involved in the planning and implementation of metro rail, monorail and high-speed rail projects in India and providing consultancy services to other metro projects in the country as well as abroad.

I.1.1History: DMRC

Planning for the metro started in 1984, when the Delhi Development Authority and the Urban Arts Commission came up with a proposal for developing a multi-modal transport system for the city. The Government of India and the Government of Delhi jointly set up the Delhi Metro Rail Corporation (DMRC) registered on 3 May 1995 under The Companies Act, 1956. Construction started in 1998, and the first section, on the Red Line, opened in 2002, followed by the Yellow Line in 2004, the Blue Line in 2005, its branch line in 2009,the Green and Violet Lines in 2010, and the Delhi Airport Metro Express in 2011.

The concept of a mass rapid transit for New Delhi first emerged from a traffic and travel characteristics study which was carried out in the city in 1969. Over the next several years, many official committees by a variety of government departments were commissioned to examine issues related to technology, route alignment, and governmental jurisdiction. In 1984, the Delhi Development Authority and the Urban Arts Commission came up with a proposal for developing a multi-modal transport system, which would consist of constructing three underground mass rapid transit corridors as well augmenting the city'sexisting suburban railway and road transport networks.

While extensive technical studies and the raising of finance for the project were in progress, the city expanded significantly resulting in a twofold rise in population and a fivefold rise in the number of vehicles between 1981 and 1998. Consequently, traffic congestion and pollution soared, as an increasing number of commuters took to private vehicles with the existing bus

system unable to bear the load.[20] An attempt at privatising the bus transport system in 1992 merely compounded the problem, with inexperienced operators plying poorly maintained, noisy and polluting buses on lengthy routes, resulting in long waiting times, unreliable service, extreme overcrowding, unqualified drivers, speeding and reckless driving. To rectify the situation, the Government of India and the Government of Delhi jointly set up a company called the Delhi Metro Rail Corporation (DMRC) on 3 May 1995, with E. Sreedharan as the managing director. Dr. E. Sreedharan handed over the charge as MD, DMRC to ShriMangu Singh on 31 December 2011.

The DMRC opened its first corridor between Shahdara and Tis Hazari on 25th December, 2002. Subsequently, the first phase of construction worth 65 kilometres of Metro lines was finished two years and nine months ahead of schedule in 2005. Since then the DMRC has also completed the construction of another 125 kilometres of Metro corridors under the second phase in only four and a half years.

DMRC Project Update

Phase I Project: CompletedLength (Kms): 65.00

No. of Stations: 58

Phase II Project: CompletedLength (Kms): 124.63

No. of Stations: 85

Phase III Project: Completion by 2016

Mukundpur - Shiv Vihar : Inner Ring Road Line (Line 7) Length (Kms): 58.40

No. of Stations: 37

Janakpuri West - Botanical Garden : Outer Ring Road Line (Line 8) Length (Kms): 37.25

No. of Stations: 26

Central secretariat - Kashmere Gate : Violet Line Extension Length (Kms): 9.36

No. of Stations: 7

Jahangirpuri - Badli : Yellow Line extension Length (Kms): 4.48

No. of Stations: 3

Badarpur - YMCA Chowk (Faridabad) Length (Kms): 13.875

No. of Stations: 11

Dwarka - Najafgarh : Blue Line branch Length (Kms): 5.5

No. of Stations: 4

Mundka - Bahadurgarh : Green Line Extension Length (Kms): 11.182

No. of Stations: 6

1.2CEC CICI JV

As per rules of DMRC (Delhi Metro Rail Corporation) the contractor should be a joint venture. So CEC CICI JV is joint venture between Continental Engineering Corporation(CEC) Taiwan And CEC International Corporation India Pvt. Ltd (CICI) subsidiary ofCEC & Member of Continental Holdings for the ‘Design and Construction of underground works in DELHI METRO. CEC is a TAIWANIAN Company having head office in TAIPEI CITY, TAIWAN and CICI is a wholly-owned subsidiary of CHC's ContinentalEngineering Corp. (CEC) having head office in GURGAON.

Continental Engineering Corp. (CEC), headquartered in

Taiwan, is CHC’s flagship company and a leading construction and engineering contractor widely recognized for having completed over the last five decades a wide range of public infrastructure and private-sector construction projects across the whole of Taiwan. CEC has also extended its operations into the overseas markets of theRyukus, Singapore, Malaysia, Saudi Arabia and India, where the infrastructure market is growing rapidly.

CEC International Corporation (INDIA) Private Limited (CICI), a wholly-owned subsidiary of CHC's Continental Engineering Corp. (CEC) established in December 2005, is a civil engineering and construction company based in Delhi. CICI commenced its operation in April 2006 when it started undertaking works to help CHC’s flagship company

Continental Engineering Corp execute its many projects in India. CICI has also established a significant and growing participation in the building of India’s transportation infrastructure, drawing on the vast experience and expertise of CEC.

Location of Project

The Pink Line is one of the under construction lines of the Delhi Metro, a rapid transit system in Delhi, India. It consists of 38 metro stations from Mukundpur in Delhi to Shiv vihar . On completion the Pink line with a length of 58.59 kilometres (36.41 mi) will be the longest line in Delhi Metro. It will be mostly elevated and will be covering Delhi in 'U' shape.

The Pink line has planned interchanges with the Yellow, Red, Blue, Green, Airport Express Line and Violet lines of the Delhi Metro, as well as with the HazratNizamuddin and AnandVihar Terminal (Indian Railways) and AnandVihar ISBT and Sarai Kale Khan Inter State Bus Terminal. The Pink line will have highest point of Delhi Metro at DhaulaKuan with a height of 23.6 metres passing over the DhaulaKuan grade separator flyovers and Delhi Metro Airport Express line.

1. Underground Station at Azadpur

2. Tunnel to Shalimar bagh

3. Tunnel and ramp at Mukundpur

These all metro stations are almost on one side of inner Ring road inDelhi.

The work tunnelling in line- 7 of DMRC Phase-3 under contract CC-04 is done between Shalimar Bagh Station and Mukundpur Station on Pink line along the inner Ring road in Delhi. The underground method of transportation is adopted because of restriction of space and traffic condition.

II. INTRODUCTION TO ASSINGED JOB

Personal Protective Equipment

Personal protective equipment (PPE) is anything used or worn by a person to minimise a risk to the person's health or safety.

PPE includes:

eye protection, like goggles, glasses and face shields

hearing protection, like ear plugs and ear muffs

respiratory protection, like filter respirators, air line respirators and self-contained breathing apparatus (SCBA)

foot protection, like safety shoes and boots, spats and rubber gum boots

head protection, like hard hats, helmets and broad brimmed hats

body protection, like aprons, overalls, gloves and high visibility clothing

any substance used to protect health, like sunscreen

When selecting PPE to minimise a risk to health and safety, the business or employer must make sure the PPE is:

suitable for the nature of the work and any hazard associated

a suitable size and fit and reasonably comfortable for the person to wear

maintained, repaired or replaced so it continues to minimise the risk to the worker

Used or worn by the worker, so far as is reasonably practicable.

Using PPE PPE is one of the least effective ways of controlling risks to health and safety and should only be used:

when there are no other practical control measures available

as an interim measure until a more effective way of controlling the risk can be used

to supplement higher level control measures

Choosing PPEWhen choosing PPE, businesses must consult with workers and must also:

evaluate the risk and performance requirements for the PPE

review the compatibility of the equipment where more than one type of PPE is required

consult with the supplier to make sure PPE is suitable for the work and workplace conditions

Make sure that the PPE complies with the relevant Australian Standard or equivalent standard.

We do not sell safety equipment.

Fire Protection

Introduction

This is The Fire Triangle. Actually, it's a tetrahedron, because there are four elements that must be present for a fire to exist. There must be oxygen to sustain combustion, heat to raise the material to its ignition

temperature, fuel to support the combustion and a chemicalreaction between the other three elements.

Remove any one of the four elements to extinguish the fire.

The concept of Fire Protection is based upon keeping these four elements separate.

Types of Fires

Not all fires are the same. Different fuels create different fires and require different types of fire extinguishing agents.

Class A

Class A fires are fires in ordinary combustibles such as wood,paper, cloth, trash, and plastics.

Class B

Class B fires are fires in flammable liquids such as gasoline,petroleum oil and paint. Class B fires also include flammable gases such as propane and butane. Class B fires do not includefires involving cooking oils and grease.

Class C

Class C fires are fires involving energized electricalequipment such as motors, transformers, and appliances.Remove the power and the Class C fire becomes one of the other classes of fire.

Class D

Class D fires are fires in combustible metals suchaspotassium, sodium, aluminium, and magnesium.

Class K

Class K fires are fires in cooking oils and greases such as animals fats and vegetable fats.

Types of Fire Extinguishers

Water and Foam

Water and Foam fire extinguishers extinguish the fire by taking away the heat element of the fire triangle. Foam agents also separate the oxygen element from the other elements.

Water extinguishers are for Class A fires only - they should not be used on Class B or C fires. The discharge stream could spread the flammable liquid in a Class B fire or could create a shock hazard on a Class C fire.

Carbon Dioxide

Carbon Dioxide fire extinguishers extinguish fire by taking away the oxygen element of the fire triangle and also are removing the heat with a very cold discharge.

Carbon dioxide can be used on Class B & C fires. They are usually ineffective on Class A fires.

Dry Chemical

Dry Chemical fire extinguishers extinguish the fire primarily by interrupting the chemical reaction of the fire triangle.

Today's most widely used type of fire extinguisher is the multipurpose dry chemical that is effective on Class A, B, and C fires. This agent also works by creating a barrier between the oxygen element and the fuel element on Class A fires.

Ordinary dry chemical is for Class B & C fires only. It is important to use the correct extinguisher for the type of fuel! Using the incorrect agent can allow the fire to re-ignite after apparently being extinguished successfully.

Wet Chemical

Wet Chemical is a new agent that extinguishes the fire by removing the heat of the fire triangle and prevents re-ignition by creating a barrier between the oxygen and fuel elements.

Wet chemical of Class K extinguishers were developed for modern, high efficiency deep fat fryers in commercial cooking operations. Some may also be used on Class A fires in commercial kitchens.

Clean Agent

Halogenated or Clean Agent extinguishers include the halongen agents as well as the newer and less ozone depleting halocarbon agents. They extinguish the fire by interrupting the chemical reaction of the fire triangle.

Clean agent extinguishers are primarily for Class B & C fires. Some larger clean agent extinguishers can be used on Class A, B, and C fires.

Dry Powder

Dry Powder extinguishers are similar to dry chemical except that they extinguish the fire by separating the fuel from the oxygen element or by removing the heat element of the fire triangle.

However, dry powder extinguishers are for Class D or combustible metal fires, only. They are ineffective on all other classes of fires.

Water Mist

Water Mist extinguishers are a recent development that extinguish the fire by taking away the heat element of the fire triangle. They are an alternative to the clean agent extinguishers where contamination is a concern.

Water mist extinguishers are primarily for Class A fires, although they are safe for use on Class C fires as well.

Cartridge Operated Dry Chemical

Cartridge Operated Dry Chemical fire extinguishers extinguish the fire primarily by interrupting the chemical reaction of the fire triangle.

Like the stored pressure dry chemical extinguishers, the multipurpose dry chemical is effective on Class A, B, and C fires. This agent also works by creating a barrier between the oxygen element and the fuel element on Class A fires.

Ordinary dry chemical is for Class B & C fires only. It is important to use the correct extinguisher for the type of fuel! Using the incorrect agent can allow the fire to re-ignite after apparently being extinguished successfully.

Starting at the recommended distance, Sweep the nozzle or hose from side to side until the fire is out. Move forward or around the fire area as the fire diminishes. Watch the area in case of re-ignition

DETAILED ANALYSIS OF INDIVIDUAL MODULE

Tunnel Boring Machine (TBM)

Earth pressure balance shields originated in Japan in the 1970s. The first reported use of an EPB tunnel boring machine was in 1974 for driving an 11-foot (3.35-m) diameter, 1.2-mile (1.9 km) long aqueduct tunnel. In the U.S., the first time an EPB machine was deployed was in the excavation of a 3,002-foot (915-m) long tunnel in 1981 as part of the San Francisco Clean Water Program.

A Tunnel Boring Machine (TBM) is a complex system with a main body and other supporting elements to be made up of mechanisms for cutting, shoving, steering, gripping, shielding, exploratory drilling, ground control and support, lining erection, spoil (muck) removal, ventilation and power supply.

In this project DMRC CC-04 an Earth Pressure Balance Type TBM or also known as Shield TBM is being used which is designed and built by Herrenkneacht AG.

Chart showing different type of TBM’s

Details of EPB TBM

Earth balance pressure (EPB) tunnel shields or tunnel boring machines (TBMs) are usedin excavating and advancing tunnels through any type of soft ground or soil condition, particularly below the water table. Used in North America in only in the last three decades, the earth balance pressure method has actually revolutionized soft-ground tunnelling as the technique has become widely applied in constructing shallow, soft-ground, close-to-the-surface tunnels in heavily congested urban areas. Today, earth balance pressure machines are commonly used in the excavation and driving of rail and highway tunnels, metropolitansubway systems, and other civil works projects that require tunneling in a soft soil, below the water table.

Depending on the geological parameter and construction programme tunnel boring machines of M/s Herenknecht, Mitsubishi, Kawasaki and OMC etc. are selected for the project

Earth Pressure Balance Type TBM

Working procedure of TBM

The underlying principle of the EPB method is that the excavated soil or muck itself is used to provide continuous support to the tunnel face by balancing earth pressure against the forward pressure of the machine.

As the shield advances at the face, the cutterhead on the TBM rotates through the earth. The excavated soil is then mixed together with a special foam material that actually alters its viscosity or thickness and transforms it into a flowing material. The use of a foaming agent to break down muck into a liquefied form provides some obvious benefits. This muck is then stored and controlled in a pressurized chamber located inside the cutterhead, and is used to apply support and balance pressure to the tunnel face during the excavation process. The foam acts as a lubricant that conditions the soil to a suitable fluidity, in effect reducing the risk of clogging in the pressurized chamber head or muck storage area.

A screw conveyor then removes excess fluidized muck in controlled volumes from behind the cutterhead and in front of the “pressure bulkhead”. Synchronizing the screw conveyor with the actual speed of the tunnel boring machine, and equalizing the actual volume of soil traveling into and out of the machine establishes earth pressure balance during excavation, thereby also reducing the risk of surface or ground settlement. The performance of the EPB machine, however, largely depends on the actual properties of the excavated muck. The soil may range from coarse sands, to types of gravel, to stiff clays.

The EPB TBM also has the unique capability of placing a continuous ring of segmented liners from within the tail shield of the machine inside the tunnel as it advances. These concrete segments provide critical additional reinforcement and support and accomplish all tunnel construction in one-pass.

INSIDE VIEW OF TBM

Stages of tunnel construction by EPB TBM

Stage 1. Mining stage:-

In this stage cutter head is operated from the operator’s room and mining of soil is started.

Cutter head consists of 16 scrapper and 252 knifes which cut the soil in proper 0 shape without creating problem on the ground. During mining stage tunnel boring machine moves in forward direction with the help of thrust jacks which are 16 in nos. The net stroke and monitor stroke distance is taken for knowing how much mining is done. The net stroke and monitor stroke readings are seen in monitors in TBM operator’s room.

Stage 2. Ring Selection:-

Ring is known as assembly of 5 segments and 1 key. The positioning these segments and a key are done in this stage. A segment is supported over 3 jacks and a key is supported over1 jack. So, the positioning of key is known by the jack’s number.Two adjacent Rings should not have Key at same location/ same jack.

Stage 3. Ring Built Up:-

As we know that a ring is consists of 5 segments and a key. During this phase segments are carried to the Segment Erector by the help of Gantry Crane provided in the TBM and from there Segment Erector lift each segment and place it to their proper location.

Segment: - Segments are made up concrete of grade M45.

Stage 4. Grouting:-

In any project where excavation is carried out in the ground, not only is there a duty of care on the construction team whilst the permanent structure is completed but there is professional and moral responsibility to ensure that the completed structure is fit for the purpose intended.

Backfill grouting is the construction method to fill up the gap between TBM excavation and segmental lining, which called “Tail Void”.

Grouting is done in two stages first is called Primary Grouting and second is called Secondary Grouting.

Why Backfill Grouting required?

Prevent the ground movement and surface settlement due to the volume loss at the tail void.

Stabilize the segmental lining in the ground.

Improve water tightness of the segmental lining.

Material used for Backfill Grouting:-

Cement

Bentonite

TAC RE

Water

Sodium Silicate

Grout Basic Ratio

Name Proportion 1m3Quantity

Curing Material Cement 3.15 230 Kg

Note Material Bentonite 2.79 30 KgA

Stabilizer TAC-RE 1.28 3 Kg

Water WATER 1 850 Kg

B Condensation Material Silicate 1.39 91 Kg

Mixing Ratio A:B =15:1

Stage 5. Ring Checking

The place of joint between two adjacent segments is known as LIPS. The place of joint between two adjacent rings is known as STEP.

After the ring build-up and grouting stage over we need to check the LIPS and STEP. In this process we need to find out how much lips and step are there in the ring.

According to the specification, In a ring there should no amount of LIPS and only 5mm of step is adopted if it is more then further treatment is done to minimize it.

Cracks in Concrete Segments

Improper ring built up create more steps and when the pressure from thrust jack is applied on segments it will create cracks.

The cracks which are larger than 1mm in size are noted down and their locations are also noted so that their treatment is done properly and timely.

These cracks are noted minor cracks from 1mm to 3mm and major cracks from 3mm to more.

Stage 6. Repair Work

After knowing the different type of cracks the repair work is being started and also water*proofing work is done.

An assortment of common damages on segments and repair measures is discussed:

Voids: The porosity of the surface is conditioned by number and size of voids perrated surface area. By adherence to defined maximum values no repair is required. Measure: closure of voids by stopping with cement-bound mortar and final surface smoothing.

Cracks: Distinction between micro-cracks or damage-cracks. Dominant characteristicis the measured crack width. Micro-cracks (in general smaller 0, 2 mm) within the groove need no repair since being filled by glue. Damage cracks within the groove may be penetrated with epoxy resin of low viscosity.

Spalling: Spallings within the edges of the groove are conditioned by depth anddefined maximum length respective. Repair of spalling segment edges is necessary when > 5 mm depth and/or > 20 mm length. When the bottom of the groove is intact the edges can be post formed by stopping with cement-bound mortar and final forming. Spalling greater 3cm needs repair with epoxy resin reconstructing the original geometry.

Breakage: Breakages are to be distinguished as within the groove or within thecontact area or within the erector cones and bolting gaps. Limitation of repair to size of depth (8, 7, 6, 5 mm) and corresponding length (50, 60, 70, 80 mm). Repair measure by stopping with cement bound mortar and final forming. Smaller breakage (< 5 mm) and those which are outside areas with defined special requirements need no repair.

LEAKAGE IN RINGS

Grouting of Segment

This method statement details the various aspects relating to the annular grouting of the segmental tunnel lining.The procedure for annular grouting according to DMRC is given below:-

All TBMs are being provided with single component grouting system.

Grout availability will be ensured on site before shoving of TBM commences.

Grout is provided from a grout plant set up adjacent to the working shaft or from a local batching facility where working space at the shaft may be at a premium. It includes silos for storage of cement/ fly ash and bunker for sand.

The mix is discharged into a grout car in the shaft bottom and transported along the tunnel to the TBM by locomotive.

The mix will be discharged into a holding tank on the TBM where it is kept agitated until required.

The grout is injected direct through a series of pipes built into the tail skin of the TBM shield by pumps.

Grout Mixing Plant

The grout mixing plant is normally set up at the working site, adjacent to the shaft and in such position as to give safe access for delivery and sufficient space for stockpiling of mix materials. Particularly for the short drives plant should be nearly available. The set up for grout mixing plant is given below:-

Stock pile area for sand including provision of wheeled loader for transferring to sand hopper. The stock pile area will have concrete base and steel wall to prevent contamination.

Mechanical bucket lift for transferring sand from storage hopper to mixer with weigh batcher facility.

60 tonne silo for storage of cement: bagged cement will be delivered to site and housed in separate cement shed. The bagged cement will be fed into screw conveyor facility feeding the silo. Adequate ventilation will be provided in the cement shed and flooring arrangement such as to prevent dampness permeating the bagged cement.

60 tonne silo for fly ash is also provided.

Electronic weigh batcher for all grout components provided on the mixer with automatic data print out facility

Water tank with clean water supply and measurement control.

Transfer hopper with pump for mixed grout.

Grout transfer to TBM

Transfer of each approx. 0.5 cubic meter mixer is made from the mixer drum either directly into grout car in the shaft bottom or via a grout holding take sited on the surface. The mix is kept agitated in the grout car prior to being transported along the tunnel to the

TBM as a part of train set.

Tail skin Injection

Grout will be supplied at the TBM commensurate with TBM advance.

The tail skin arrangement for grout injection and location of ports for primary grouting is shown in

figure below. Twin injection ports of 50mm diameter are provided at the quadrant around the tail

skin. They are built into the tail skin wall thickness in a cluster with smaller grease pipe.

Grouting through Segment

To facilitate this method of grouting the lifting hole in the segments, which extends part way through the segment, are drilled out to full thickness. Expanding rubber sleeved grout guns will be provided each with a manual shut valve. Grout is injected at the lower segments first and pumped until it reaches the next grout hole. The valve is then closed and the grout nozzle moved up to the next injection point using a new grout gun, the grout gun being retained in the first hole until the grout has set. The grout gun valve assembly is then removed, dismantled and cleaned ready for reuse.

Grouting through the segmental lining is carried out under in the following situations:-

For secondary or proof grouting

For topping up locations where over break has been identified.

During initial stages of TBM launch .

Cross PassageCross passage is the structure which is constructed to provide a passage between two tunnels. In this methodology we study about the different stages of construction of cross passages with or without sump.

This Procedure shall cover the sequence of excavation, temporary support & permanent lining of the cross passages

Cross Passage

Scope of work

The cross passage shall be constructed between the two bored tunnels.

No. of Cross passage towards Shalimar bagh: 6

No. of Cross passage towards Mukundpur: 5

The detailed sequence of construction of cross passage is as follows:-

1. Surveying and Setting Out

Survey marking for cross passages opening shall be made as per drawing and instrumentation for settlement monitoring shall also be installed.

2. Fixing of temporary Steel Structure in main Tunnel

Temporary steel supporting frames will be transported to location by forklift. The gap between the segmental lining and the support frame will be packed with wooden wedges.

.

3. Core Cutting on Top & Bottom

Prior to core cutting at least 2 meter long probe drill or as directed by DMRC shall be done

to ensure that rings are sufficient grouted and also to determine whether any water is present behind the segment.

4 .Removal of Segment

Demolition of the Tunnel ring segments for the breakouts shall be carried out in a controlled manner so as to ensure the safety of the operation and the structural integrity of the tunnel wall.

5.Excavation and Construction

The initial excavation from the face will be done manually, assisted by the back hoe loader or mini excavator. The work will be carried out in two halves. First the excavation for top heading will be carried out as per construction sequence, and then the invert will be excavated and supported. After completion of 50% cross passage excavation from one side install the second temporary frame in other tunnel.

following excavation stages will be repeated till completion of the cross passage:

6. Installation of permanent steel frame

After completion of the primary lining, fabricated structural steel permanent support as per attached drawing shall be installed behind both openings of the cross passages from lower portion to top.

7.Crown portion concreting

M35 grade concrete shall be used.The concrete shall be pumped through the concrete windows provided in the gantry

MODULAR DISCRIPTION OF JOBBasic Layout of Typical Underground Station

The typical underground station is a two-level station with platforms at the lower level and concourse on the upper level. Concourses are provided at the two ends only in such a manner that the total height of underground station and hence the cost is kept to the minimum. The upper level has - in addition to the concourse - all the passenger amenities, ECS plant rooms, electrical and S&T equipment rooms, station operation areas such as Station Control Room, Station Master's Office, Waiting Room, Meeting Room, UPS & Battery Room, Signalling& Train Crew Room, Train Crew Supervisor's Office, Security & Station Store Room, Staff Toilets, etc. Lower level has platforms, tracks, seepage sump, pump room and similar ancillary spaces beyond the platforms on either side.

Utility DiversionsFor underground construction utility diversion in itself is a great challenge as Large number of sub-surface, surface and overhead utility services viz. sewers, water mains, storm water drains, telephone cables, OH electrical transmission lines, electric poles, traffic signals, etc. generally exists along the alignment. These utility services are essential and have to be main diversions or by supporting in position. Since these may affect construction and project implementation time schedule/costs, for which necessary planning/action need to be initiated in advance.ained in working order during different stages of construction, by temporary/permanent.

DIVERSIONS OF STATION BY CONCRETE BLOCKS

Layout of Azadpur Underground Metro Station

Cut and Cover Construction Methods

Cut-and-cover tunnellingis a simple tunnelling construction method used to build shallowtunnels such as those commonly used by subways, railways, and metro systems.

Bottom -up Method

In the cut-and-cover bottom-up or caisson wall method, a drilling rig is used to install caisson walls down to the existing bedrock. Once the caisson walls are in place, soil between the walls is excavated to a depth below the tunnel floor. The tunnel floor, a slab, is poured, followed by the sidewalls of the tunnel from the bottom-up. After the walls of the tunnel are completed, the roof is constructed and the roadway or ground on top of the tunnel restored. Materials used to provide the structure and support in the construction of the tunnel may include concrete, pre-cast concrete, pre-cast arches, or corrugated steel arches.

Conventional bottom-up sequence construction.

Step 1: Installation of temporary excavation support walls, such as soldier pile and lagging, sheet piling, slurry walls, tangent or secant pile walls.

Secant Piling and strut Support

Step 2: Dewatering within the trench if required

Step 3: Excavation and installation of temporary wall support elements such as struts or tiebacks.

Step 4: Construction of the structure by constructing the floor;

Step 5: Complete construction of the walls and then the roof, apply waterproofing as required;

Step 6: Backfilling to final grade and restoring the ground surface.

Advantages:

It is a conventional construction method well understood by contractors.

Waterproofing can be applied to the outside surface of the structure.

The inside of the excavation is easily accessible for the construction equipment and the delivery, storage and placement of materials.

Drainage systems can be installed outside the structure to channel water or divert it away from the structure.

Disadvantages;

Somewhat larger footprint required for construction than for top-down construction.

The ground surface cannot be restored to its final condition until construction is complete.

Requires temporary support or relocation of utilities.

May require dewatering that could have adverse effects on surrounding infrastructure.

Slab construction

This method statement describes methodology and sequence of construction of slab. It also describes the main equipment which will be needed to execute the works. The objective of this statement is clearly understand the job and procedures of execution along with safety precautions, which are necessary to avoid any kind of injuries to personnel and maintaining the quality of work.

Scope: The Scope of work includes the various construction activities involved in the construction. This method statement is applicable for both top down as well as bottom up construction and for all station, shafts & cut & cover.

Material:

1 Concrete of grade will be M35 or as per approved drawing conforming to IS 456:2000 shall be used.

2 .Reinforcement bar conforming to IS 1786:2000 shall be used.

3 .Water shall be free from solid suspended matters and organic particles

4.PVC water stop of approved brand will be installed at construction joint of base slab.

PROJECT UNDERTAKEN

Case Study: Repairing Work at G-3/3, Model TownDuring the boring of tunnel towards Mukundpur (Project CC 04 of DMRC) a major settlement was caused by TBM. It was a residential building under which the metro tunnel was passing.

Cracks were developed in all parts of building located at Model Town III, Delhi.

Settlement by TBM

When a load is applied on the ground, it increases the vertical effective stress. This stress increases the vertical strain in the soil. This increase in vertical strain causes the ground to move downward. This downward movement of the ground is called settlement.

A soil shear failure can result in excessive building distortion and even collapse. Excessive settlements can result in structural damage to a building frame nuisances such as sticking doors and windows, cracks in tile and plaster, and excessive wear or equipment failure from misalignment resulting from foundation settlements.

Repair Methodology for Cracks in Building at Model Town, Delhi

Erection of Scaffolding and Installation of working platform:-A proper working platform/ scaffolding to be provided at site of strengthening so as permit ease to the workers carrying out the strengthening work.

Chipping:Chipping of loose Plaster / POP material from slab, beams, columns, wall etc. with light weight chipper.

Walls After Chipping

Slurry: (For 0.5 to 10 mm wide cracks)

Making ‘V’ groove of about 10 to 15 mm wide and about 10 to 15 mm deep along the length of cracks, cleaning the crack using blower and fixing the Teflon nozzles using non-shrink Lime Powder.

Grouting by injecting cement slurry using manual operating grouting machine with the 3 – 5 kg/cm2 pressure.

Cutting and Sealing the Nozzle by cement paste / Lime powder Mortar.

Polymer Modified Mortar

Application of Bond Coat on the chipped Portion so provide as proper bond between old wall and polymer modified mortar.

Providing and applying 6mm to 15 mm thick polymer modified mortar (Product – Monobond) to load carrying R.C.C. member in single layers in proportion as specified by manufacturer.

After Proper Curing of PMM, the surface must be levelled using levelling mortar so that further strengthening can be done.

Ratio for PMM

Monobond: Cement: Quartz Sand: - 1: 5: 15

Strengthening of brick wall / Beams / Columns using specialized carbon fiber wrapping.

Apply the first coat of epoxy R&M Resin Primer 11 due to which the surface becomes smooth and it stops the absorption power of concrete.

Fill up all unevenness & undulations on the surface with R&M Levelling mortar.

Apply R&M Matrix 20 Saturant

Carry out fibre wrapping around the surface as per the design and instruction. While wrapping roller application is must to build a tension in the fibre so that the fibre should get properly embedded in epoxy for superior bonding with concrete which results in developing a better strength.

Fixing Carbon fibre anchor including drilling hole in the base concrete, fixing the anchor using epoxy 50X55 systems, spreading the anchor fibres in star pattern including application of saturant. Strengthening of slab using carbon laminates

Design Specification: 50 mm width / 1.4 mm thick Carbon laminates

Laminates will be placed perpendicular bisector to crack line. Per laminate c/c 500 mm

Marking is carried out as per the provided drawings over the grinned surface. Centre to centre distance between the laminates is also marked accurately.

Low viscosity epoxy primer compatible to the substrate is applied with a roller until the substrate is locally saturated.

The surface is well prepared with putty/levelling mortar to fill the undulations /unevenness.

Laminate is applied with adhesive: Immediately after adhesive application, the laminate is placed over the surface prepared. Pressure is applied with the help of rollers so that it should get properly stretched and fixed with surface for effective bonding.

The end Anchor Plates are fixed by drilling the holes and bolted up to tighten-up on both the ends. The anchor plates keep the laminate in position and prevent the peeling off at the loose end.

Pressure with roller is applied throughout the length of the laminate. Adhesive is applied on either side of the laminates to prevent air pockets and get effective bonding with the concrete surface.

Applying second coat of saturant after drying rectify air voids if any, paste the river sand on it to make surface rough to take any further finishes .

Demolition of Paraphet wall and reconstructing structure

Dismantling the existing the damaged parapet wall using chipper machine / chisel and hammer.

Reconstructing the Parapet wall of same thickness and height by brickwork.

Finishing of whole internal and external wall by plaster

Internal / External plastering of whole wall by 12 mm thick plaster in 1:4 CM

Painting the interior and external walls, beam, column, and slab, outer building surface with required Shade and paints with two coats wherever required.

EPIBOND

Epibond can be used to bond fresh concrete to concrete that is fully cured. Epibond will give monolithic bond capable of transmitting high stresses when traditional bonding agents such as cement slurry cannot always be relied upon to provide good adhesion, which is particularly the case when large areas are involved. In addition, Epibond possesses excellent water and alkali resistance.

Typical Applications:

Concrete jointing (cold joints) and for repairs using cement plaster/guniting.

Reinforcing existing concrete structure or elements and also in jacketing of columns.

Waterproof joints.

Unique Advantages:

Excellent bonding agent between New and Old concrete.

Conforms to ASTM-C-882-87 (Arizona Slant Shear Test).

Application Procedure:

1. To obtain good adhesion it is necessary to have a clean and sound substrate, which can be obtained by grinding, wire brushing, chipping, sandblasting, etc.

2. Mix EPIBOND thoroughly in the prescribed proportion and apply on the clean, sound and dry substrate.

3. Apply concrete/cement plaster/gunite on the tacky EPIBOND layer, which would be achieved approximately after 30 minutes of application and under any circumstances within one hour. Best results are obtained when w/c ratio of the new concrete is as low as practicable.

Technical Data:

Base Epoxide Resin (Two Component)Appearance Dark Brown/Black.

Coverage 3 – 5 m2 /lt. On level surface

Mix proportion Base : Curing agent

[By Volume] 1 : 1

Monobond

Monobond is a polymer latex additive for modifying cement concrete / mortar / plaster / grouts. The addition of Monobond improves mechanical properties especially flexure and tension. Due to low permeability of polymer-modified systems, remarkable improvement in prevention of carbonation, chloride ion penetration is observed. Also chemical resistance improves significantly.

The addition of Monobond imparts resilience to the cement matrix. Thereby improving impact resistance. Also the modified cement matrix cures in air, eliminating the necessity of wet curing.

Typical Applications

Excellent Repair Mortar, for strengthening dilapidated RCC structures.

Excellent lining material on concrete surface to protect it against carbonation, chloride

ion penetration, etc. As bond coat.

As an additive to cement grout.

Application Procedure

Mix Monobond® in water first prior to addition in cement mortar/concrete. Dosage 10% to 15% by weight of cement.

Conclusion

Tunnelling under varying geological conditions was carried out successfully without causing any disturbance to the city especially within the tight construction programme. In addition, settlement control and other precautions taken while tunneling under sensitive structure proved successful. Thoughtful planning and effective communication including identifying problems and proposing realistic solutions together proved a positive factor in successful tunneling operation.

During the geological investigation survey at the site, there were no existence of rocks but while tunnelling by TBM the cutter head get damaged due to collision with rock.

Also due to settlement caused by TBM,a residential building at Model town,Delhi get Damaged.Cracks were induced in different parts of building.DMRC is now managing the total repair cost of the building as well the migration of residencies.

Underground station construction is not at all easy task. It takes more effort and accuracy than elevated or at grade stations. There are many challenges like to cope with earth pressure, pore water pressure, sliding of soil, diversion of sewer lines and pipelines.

Bottom up construction methods a conventional construction method well understood by contractors. The inside of the excavation is easily accessible for the construction equipment and the delivery, storage and placement of materials.in this method drainage systems can be installed outside the structure to channel water or divert it away from the structure. But bottom up construction needs very efficient planning and designing and skilled supervision and labour force.

References

http://www.delhimetrorail.com/

http://www.cici.co.in/

DMRC Method Statement notes for works in tunnelling

www.herrenknecht.com

en.wikipedia.org

IS 456 – 2000

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CEC-CICI JV Method statements

TBM Method Statement

Cross Passage MS