CHALLENGES IN CONSTRUCTION OF URBAN

ROAD TUNNELS, THE CASE HISTORY OF TOHID

EXPRESSWAY TUNNELS IN CENTRAL TEHRAN Jamal Rostami Mohsen Kashi

Penn State University, SRS Engineering,

University Park, PA Tehran, Iran

OUTLINE

Introduction

Tunnel Alignment and Profile

Site Development

Portals and Construction Shafts

Tunneling Operation

Crossing an active Subway Station

Conclusions

South Portal

BACKGROUND

Tehran & Suburbs is the home for over 10 million people

City is spread over an area of around 50 km in the E-W and 30 km in

N-S direction

Tehran has experienced a rapid growth in past 3 decades,

The original fabric is old and does not have sufficient ratio of traffic

space to residential space to accommodate the flow

Streets are congested, slow traffic

2 subway lines are operational, 5 under construction

A network of highways has been constructed around the town

A series of road tunnels are planned to connect the highways

First highway tunnel (Resalat) was completed in 2004 (6 lanes)

2nd one is Towheed, Inaugurated in Feb 2010, 3rd is under

construction for 9 km + a 2000 car capacity underground parking

پروژه تونل توحيد

Project Map

Tunnel

The Least Neighborhood Interference

Fuel Cost

Traffic Congestion

Travel Time

ALIGNMENT & PORTALS

VERTICAL ALIGNMENT

Project North

End Point

Toeheed Shaft North

Portal Jomhoury Shaft

Azadi Shaft South

Portal Project

South End

Point

557-m 310-m 2136-m

Metro Line No. 4

Metro Line No.2

557-m 677-m 496-m 406-m

Work Sites Site Name

1 The North Portal

2 Toeheed Shaft

3 Azadi Shaft

4 Jomhouri Shaft

5 The South Portal

Longitudinal Profile North Ramp Slope 6%

Tunnel Overall Slope 4%

South Ramp Slope 4.29%

TUNNEL PROFILE

GENERAL INFORMATION

Tunnel Height : 8.5-m

Tunnel Width: 13.5-m Each

Overall Project length: 3003-m

The Tunnel Length: 2136-m

Tunnel Cross Section Area: 305-m2

Approach Half-Tunnels North 577-m

South 310-m

Start Date: June 10, 2007

Quantity Unit Activity

750000

m3

Open Excavation

660000 m3 Tunnel Excavation

26000 m Pile Construction

56000 m2 Formwork

25000 Ton Steel Reinforcement

200000 m3 Concrete Placement

450000 m2 Shotcrete Application

250000 m2 Wire Mesh

50000 m2 Precast Concrete Elements

Bill of Quantities

Project Budget ~$400M

INTERFACES WITH OTHER UNDERGROUND STRUCTURES

Subway Line No. 2 (Existing). The longitudinal profile of the tunnel is designed to go under the Subway Station Line No. 2 located around station 2+392 of this tunnel.

Subway Line No. 4 (under construction). The Toeheed tunnel passes beneath the Subway Line No. 4 currently under construction.

Subway Line No. 7 (future construction). The tunnel will essentially run parallel to the No. 7 Subway Line and provisions shall be made in the design and construction of this subway line to assure constructability and other operational issues involved.

Urban Utilities. Several underground utilities including water, gas, electric and telephone lines did interfere with the tunnel and other auxiliary structures such as the shafts, galleries, and the access ramps.

GROUND CONDITION

Mainly course grained soils, gravel/sand

Primarily dry except for certain sections

Intersecting old water works (qanats) Table 1. Borehole/Test Pit Soil Classifications

Borehole Station

(km)

Depths at Tunnel

Section(m) USCS Soil Symbols

BH-1 0+360 5-15 SC/GC-GM/GC

BH-2 0+850 9-18 SC-SM/GC-GM

BH-3 1+070 12-21 GM/GC-GM/SC-SM

BH-7 1+810 20-30 SC

BH-8 1+920 21-30 GC-GM/GM/SC-SM

BH-9 2+150 22-31 SC-SM

Test Pits

TP-1 0+270 0-5 GW/SW/GP

TP-2 0+400 0-10 GP/GP-GM/GW/GP

TP-3 0+520 4-13 GW-GM/GM/GP/GM

TP-4 1+200 15-22 GW/GC/GW

Embedded U-Turn Lane

UNIQUE PORTAL ENTRY DESIGN

HALF ARCH U-TURN LANE

Provides additional traffic lane for U-turn

Allows for easier transition to daylight

MOBILIZATION, SITE PREPARATION

Power House, bar Bending & Batching

Plant

Power House

Equipment

10,000 Ton Cement Silos

Staging Area, Equipment Shops

NORTH RAMP

SITE PREPARATION

Traffic Diversion & Preparatory Work Relocating 600-mm Water main Pipe Traffic Diversion Barriers Road Widening

Supporting 1000-mm Water main Pipe Relocating the military base walls

REDIRECTING

TRAFFIC

CONTINUED HEAVY TRAFFIC

TOEHEED SHAFT SITE

Toeheed Shaft

Chain Bucket

Vertical Conveyor

Lowering the Road Header

Inside the shaft

Towheed Shaft

Side Gallery

Middle Gallery

Inside Towheed Shaft

AZADI SHAFT SITE

AZADI

SHAFT

METRO

Station

Azadi

Shaft Site

AZADI SHAFT 677-M TO TOEHEED SHAFT

496-M TO JOMHOORI SHAFT

AZADI

SHAFT

METRO

LINE

كارگاه شفت

آزادي

Galleries Excavated in the Access Tunnel

from Azadi Shaft

JOMHOORI SHAFT SITE

JOMHOORI

SHAFT

METRO

LINE

Jomhoori

Shaft Site

JOMHOORI SHAFT

496-M TO AZADI SHAFT 406-M TO THE SOUTHERN

PORTAL

Middle Galleries inside the Jomhoori Shaft

گالری های کناری شفت گالری میانی شفت جمهوری

Installing the Pre-cast Lining and Concreting جمهوری

SITE PREPARATION FOR

SOUTHERN RAMP / PORTAL

U Turn

South Portal

Face

km 2.600

South Ramp

28(m)

28(m)

South Ramp Portal Access

گالری میانی فوقانی و تونلهای دسترسی شرقی و غربی

A view of South Ramp at Night

TUNNEL EXCAVATION METHOD

Sequential Excavation Method (SEM)

Excavation of the upper part of the middle gallery

1

Excavation of the Bench, or lower part of the middle gallery

1

2

Excavation of the side galleries

2

1

3 3

Construction of cast in placement of concrete piles Installation of a portion of final lining in the side galleries

3 3 2

1

4

Excavation of the crown region of the tunnels

2

1

3 3

4

5 5

Removing the temporary supports, benching, and completion of crown lining

2

1

3 3

4

5 5

6 6

Excavation of the lower portion of the tunnels

2

1

3 3

4

5 5

6 6

7 7

Completing excavation of the lower parts of the tunnels

2

1

3 3

4

5 5

6 6

7 7 8 8

Installation of Permanent Concrete Forms

and concreting

2

1

3 3

4

5 5

6 6

7 7 8 8 9 9

Drainage Ditch and Base Slab Construction

2

1

3 3

4

5 5

6 6

7 7 8 8 9 9

10 10

Completed Tunnel Profile

Using Conveyor Belt for Soil Removal

Excavation using Roadheader

Excavation using Roadheader

Shotcrete Application

Reinforcing Cages For the Piles

عملیات الینینگ دیواره های کناری عملیات بتن پاشی برای تثبیت دیواره گالری

Installation of Precast Elements

Permanent Linings عملیات بتن پاشی برای تثبیت دیواره گالری

CHALLANGES

CHALLENGES

Crossing the active subway line, under the station

Small footprint for work

Redirecting of traffic

Restriction in access, muck haulage

Fast -Track project, accelerated schedule

Maintaining existing utilities, (i.e. a1.8 m water main)

Dealing with historical waterworks (qanats)

Causing water leakage into the tunnel

Subsidence - sinkhole

CROSSING OF THE ACTIVE SUBWAY

STATION

PROFILE

CROSSING OF SUBWAY STATION

Intersecting Station in

North

Middle

South

ADDITIONAL PROVISIONS FOR STATION

CROSSING

Installation of Invert

beam in the middle

gallery

Heavy grouting of the

lining under the station

MODELING AND ANALYSIS

Numerical Modeling of Sequential Excavation

under the station

GROUND REACTION MODELING

RESULTS

Max measured settlement at the station was:

COMPLETION OF THE WORK

CONSTRUCTION PROGRESS

FINISHING TOUCHES

VENTILATION AND CONTROL STRUCTURE

UTILITIES & FIT OUTS

Ventilation

Fire protection

Lighting

Communication

Traffic Control

CCTV

Art Works!

UTILITIES & FIT OUTS

70 jet fans, each powered at 30 KW.

North fan combined ventilation equipment: 3 axial fans, powered at 600 KW.

Niyayesh fan combined ventilation equipment: 2 axial fans (to let in fresh air into Tunnel) powered at 410 KW. 4 axial fans (to let out exhaust air from Tunnel) powered at 500 KW.

South portal fan combined ventilation equipment: 3 axial fans powered at 990 KW.

Air purification system at the air entering Niyayesh fans.

Lghts in the Tunnel: 1,064 lights powered at 550 KW.

Length of cables for the utilities: 220 km.

Special and standby power generators

Air pollution monitoring sensors

Smart firefighting system.

Traffic alarms.

Intercom telephones.

Closed-Circuit TV.

Vehicles counter.

Road closure system.

Traffic signs.

Thermal sensors.

FINISHED TUNNEL

FINISHED TUNNEL

INAUGURATION CEREMONEY, FEB 2010

Opening of the project by Citizens / Veterans

Questions ?????

Thank You