TUNNEL ASIA 2013 THE CHALLENGES OF TUNNELLING IN KARSTIC LIMESTONE AND THE KLANG VALLEY MRT (KVMRT) SOLUTION Marcus Karakashian

19th March 2013 THE KLANG VALLEY MRT

3 PROCUREMENT BREAKDOWN

Total Length Length (km) Total Station Stations (nos) (km) (nos) Elevated Underground Elevated Underground SBK Line 51 41.5 9.5 31 24 7

MRT Works

Civil & Infrastructure Underground Works Non-Civil Works 27 PACKAGES (BUILD ONLY) 1 PACKAGE (DESIGN & BUILD) 12 PACKAGES (DESIGN & BUILD) •Tunneling & Underground Stations (including tunneling & stations M&E) TNB Incoming Power Supply 2 Packages

Systems Works

Elevated Civil Works / Guide Depots Stations Multi-storey P&R 10 Packages ways 2 Packages 8 Packages 9 Packages • Electric Trains 8 Packages • Power Supply and Distribution System • Signaling & Train 1. RRI Depot • 24 stations Control System (incl. Stabling • Yard) • Depot Equipment & 2. Kajang Depot Maintenance Vehicles (incl. Stabling • Track Works + Power Yard) Rail Nominated Sub-contracts • Telecommunication to Elevated Civil Works • Facility SCADA & BMS • Automatic Fare Collection • Electronic Access Control

4 GEOLOGY- UNDERGROUND SECTION

5 SCOPE OF UNDERGROUND WORKS

3.9 km Karstic Limestone Formation Length 9.5 km Bukit Bintang Station 7 Stations Pasar Rakyat Station

5.4 km Kenny Hills Formation

Pasar Seni Station Cochrane Station Merdeka Station North Portal

Maluri Station

KL Sentral Station

South Portal

6 KENNY HILL FORMATION

Sequence of interbedded sandstones, siltstones and shale/mudstones which have been regionally metamorphosed to form metasediments.

Generally weathered to significant depths and highly variable.

Weathered material generally very stiff and hard or very dense – SPT > 50.

At boundary between Kenny Hill and Limestone weathering of Kenny Hill may be soft or firm – SPT <30.

7 SEMANTAN NORTH PORTAL – KENNY HILL FORMATION

8 LIMESTONE

The stratum termed Kuala Lumpur limestone in an unweathered state is a cream to pale grey crystaline marble.

Limestone holds a vast array of Karstic features where rock has been dissolved by ground water over the geological timeframe.

Rock head can drop 40 metres. Voids can be water bearing.

9 10 27th – 28th January 2015, Singapore COCHRANE LAUNCH SHAFT/STATION

SECANT PILE PROFILE – COCHRANE STATION SECANT PILE PROFILE – COCHRANE STATION 11 COCHRANE TUNNEL EYE

12 TUNNELLING IN KARSTIC LIMESTONE . Karstic Limestone has a highly variable profile caused by weathering which creates pinnacles, troughs, overhangs, floaters and caverns. In KL these are filled with water and very weak soil.

. Experience needed to select tunnel machines and methods that can achieve progress through a wide variety of conditions from hard rock to water filled caverns.

. If tunnelling disturbs the equilibrium of water pressure in channel and caverns it can create large sinkholes in the ground surface (not necessarily directly over the tunnel)

13 EARTH PRESSURE BALANCE (EPB) TUNNEL BORING MACHINE (TBM)

. Face support is provided by the excavated ground that is kept under pressure inside the excavation chamber by balancing the volume of the extracted and excavated material and by the thrust jacks on the shield. Extracted ground is removed from the excavation chamber by a screw conveyor that allows the pressure control by variation of its rotation speed.

14 15 TUNNELLING IN KARSTIC LIMESTONE-BEST REFERENCE

16 NOT EVERYTHING WENT WELL

17 Sinkhole caused by the pressurised bentonite slurry leaking to the surface. The sinkhole destroyed the fuel station of the bus depot on Jalan Chon Sow Lin.

18 LESSONS LEARNT FROM SMART . Dewatering can cause sinkholes far away from the excavation site . EPB machines are inappropriate . Slurry type TBMs are inadequate . Can manage the third party impact of sinkholes but they cause delay

19 A revolutionary new design of TBM based on SMART experience

. The first of its kind in the world

. Able to excavate in both Kenny Hill and Limestone

. Easily convertible from Slurry to EPB mode

. Greater efficiency in dealing with Karstic Limestone

. Reduction in settlement/ sinkholes

. Reduction in surface grouting

20 TBM INNOVATION FOR KVMRT

21 VARIABLE DENSITY TBM AND ITS VARIOUS MODES

Mode 1: Earth Pressure Balance (EPB) – Closed mode

• Used in soft ground with high water table • Gives pre-calculated face support • Ideal for KL Kenny Hill Formation • Addition of foam to make impermeable paste

Mode 2 : EPB – Closed mode with bentonite support

• Used in soft ground • Excavated material has low fines content • Addition of foam not enough to make impermeable paste • Bentonite added along with foam to make paste

Mode 3: Mixshield mode with Low Density Slurry Machine (bentonite slurry)

• Used in hard rock conditions and mixed face • Slurry used to maintain face pressure and stop ground water drawdown • Same principle as SMART TBM • Specific Gravity : 1.2

Mode 4: High Density Slurry Machine (HDSM) mode • Used in Karstic Limestone • Technological advance on Mode 4 • Efficient in stopping sinkholes • Specific Gravity : 1.6 – 1.8

22 HERRENKNECHT AG- VARIABLE DENSITY TBM

23 TUNNEL BORING MACHINES

. A total of 10 TBMs will be used.

. Kenny Hills Formation - 4 EPB TBMs o 2 Herrenknecht AG (China) • Open Ratio >40% • 40 17” discs & 52 scrapers • Vacuum erector for SFRC segmental lining

o 2 China Railway Tunnelling Equipment Co. Ltd. (China) • Open Ratio 32 to 40% • 36 discs and 114 scrapers

. Karstic Limestone Formation – 6 Variable Density TBMs o 6 Herrenknecht AG (2 Schwanau; Germany, 4 China) • Open Ratio ~30% • 40 17” discs & 54 scrapers

24 EARTH PRESSURE BALANCE TBM (EPBM)

2.4 km (100% Kenny Hill) 1.39 km (100% Kenny Hill)

NORTH KL SENTRAL PASAR SENI MERDEKA PUDU PORTAL STATION STATION STATION LAUNCH

2 nos EPB 2 nos EPB

25 VARIABLE DENSITY TBM (VD SLURRY)

1.75 km (50% Kenny Hill) (50% Limestone) 1.05 km (100% Limestone) 1.31 km (100% Limestone)

PUDU BUKIT JLN PASAR COCHRANE SOUTH RETRIEVAL BINTANG INAI RAKYAT STATION STATION PORTAL STATION LAU. STATION

2 nos VD Slurry 2 nos VD Slurry 2 nos VD Slurry

26 LAUNCH SHAFT PROVISIONS

Suitable TBM Launch Sites

Launching and supporting a major TBM drive requires a significant worksite area. An area of two acres is commonly accepted as the minimum needed. Whilst TBMs can be launched and serviced from smaller sites, this will inevitably result in compromise and reduced advance rates.

Ideally the site should be away from adjacent property to avoid impacting on residential or commercial neighbours and have good access to the main highway network.

Study of the alignment identified that locations which met these requirements were the areas adjacent to the North Portal (Semantan), Cochrane Station, a small site at the junction of Jalan Bukit Bintang and Jalan Pudu and an area of land next to Pasar Rakyat Station.

27 SEMANTAN NORTH PORTAL SITE PUDU SITE

28 ARIEL VIEW OF COCHRANE LAUNCH JALAN INAI SITE STATION SITE

29 EPB TBM- CHINA RAILWAY

30 VD TBM - GERMANY VD TBM – SLURRY/DILUTION BOX

31 Extended grading curve

32 THANK YOU

33 27th – 28th January 2015, Singapore