What is SMART?

SMART is an acronym for Stormwater Management and Road Tunnel, a project under the Federal Government initiated to alleviate the flooding problem in the city centre of Kuala Lumpur. The project is implemented through a joint venture pact between MMC Berhad and Gamuda Berhad with the Department of Irrigation And Drainage Malaysia and the Malaysian Highway Authority as the executing government agencies.

HOW DOES SMART HELP?

Studies had indicated that the critical stretch of Sungai Klang between Sg Klang /Sg Ampang confluence and Sg Gombak/ Sg Klang confluence to be flood prone areas and the fact that the river is further constrained by the Jalan Tun Perak Bridge (near Masjid Jamek) which is low, has resulted in the surrounding areas to experience flash floods.

The SMART system will be able to divert large volumes of flood water from entering this critical stretch via a holding pond, bypass tunnel and storage reservoir. This will reduce the flood water level at the Jalan Tun Perak Bridge, preventing spillover.

Other benefits of SMART

The Motorway to Ease Congestion
The motorway tunnel will provide an alternative route for motorists from the Southern Gateway, i.e. KL-Seremban Highway, Federal Highway, Besraya and East-West Link entering and exiting the city centre. This will reduce traffic congestion at the Southern Gateway leading to the city centre. The travel time will be reduced
significantly. For example from the Jalan Istana Interchange-Kampung Pandan the expected travel time is a mere four minutes compared to ten to fifteen minutes using the existing roads.

CONSTRUCTION METHOD
Kuala Lumpur city is sitting on Karstic limestone geology with high ground water table. The Special Features of Karstic limestone include cliffs, pinnacles, cavities, collapsed cavities and sinkholes. Overlying these Karstic limestones is loose alluvium from previous tin mining activities.

Due to the nature of the soil condition, much thought and planning was channeled towards the selection of a construction method that would have minimal negative impact on the geological condition of the soil.

It is known that the tunnel boring machine is the most advanced and cost effective method used in the construction of tunnel in Europe. However, TBMs come in a variety of shapes, sizes, using a variety of technology according to need. For SMART, after much research, study and survey, the Slurry Shield TBM was opted for. This machine is designed to overcome problems of groundwater drawdown which has been identified as the root cause of incidences of sinkhole appearance.

In terms of cost, the slurry shield machine is not different from any other type of TBM but unlike other types, the slurry shield machine is designed to create a pressured shield made up of bentonite and air pressure.

This pressured shield is able to counter balance the pressures of the groundwater and loose soil acting on the face of the boring machine.

TUNNELING

The slurry shield tunnel boring machine consists of four main parts.

The first is the Rotary Cutter Head with tungsten pick bits used for excavation of soil and disc cutters used for the excavation of rock.

The second part of the machine is the Bulkhead located immediately behind the Rotary Cutter Head. This is where the pressured bentonite slurry shield is formed to provide stability during the tunnel excavation.

The third part of this machine consists of hydraulic rams, which are used to propel the machine forward and to keep the tunnel in its right alignment.

The fourth and the last main part of the machine is the tunnel lining erector used to install the pre-cast concrete lining of the tunnel.Other parts complementing the main Special Features are two boogies on rails that house electrical, slurry pumping, ventilation equipment and cable and pipes.

The pre-cast concrete linings for the tunnel are transported continuously to the erector by boogies on rails. These linings are then hoisted and placed in the correct position in the tunnel with the help of vacuum pads attached to hydraulics arms. The arms are ex tended to keep the linings in place while the linings are bolted together.

The void between the excavated ground surface and the linings is immediately filled with cement mortar grout under pressurized conditions to ensure all the voids are fully filled.

For SMART, two Slurry Shield machines are used, both starting from the JKR field area in Jalan Chan Sow Lin. The first machine will head North under Jalan Tun Razak and Jalan Desa Pandan before terminating at the pond at Ampang behind
Gleneagles Hospital.

The second machine will head south under the Jalan Chan Sow Lin and the KL-Seremban Highway next to the Sg Besi airfield before terminating at the existing pond in Taman Desa.

The unique feature of this project is the 3 km double-deck motorway within the stormwater tunnel. The operation of the SMART system works on the three- principle mode of operation based on the flood discharge at the Klang River/ Ampang River confluence and the operation status of the motorway.

When the second mode is activated, flood water is diverted into the bypass tunnel in the lower channel of the motorway tunnel and it is important to note, that, up to this stage, the motorway section is still open to traffic.

At the third mode of operation the motorway will be closed to traffic. With extensive and effective monitoring stations, when the third mode of operation is needed, the motorway will be closed to traffic. Sufficient time will be allocated to allow the last vehicle to exit the motorway before the automated water-tight gates are opened to allow flood water to pass through. The motorway will be reopened to traffic within 48 hours after the closure.

Tunnel Safety
Ventilation/ escape shafts at 1km intervals: these powerful air ventilators will constantly renew the air and maintain the air quality within the motorway. To protect the ventilation system during the flooding, the systems consist of a series of shafts each containing an exhaust and fresh air injector. This design enables the fans to be situated outside the SMART tunnel to create a longitudinal flow in the tunnel between the shafts that permits the air in the tunnel to be continuously renewed and to enable extraction of the exhaust fumes. The feature also allows for smoke control in the event of a fire.

Equipped with fire fighting, telecommunication and surveillance equipment at 1 km interval.