CASE STUDY
Flood Mitigation at Admiralty Rd West
SINGAPORE, SINGAPORE
The Challenge
Climate change has brought about extreme weather events, bringing unpredictable rainfall and rising sea levels resulting in flash floods occuring around Singapore over the years. There have been several flash flooding incidents occuring along Admiralty Road west causing inconvenience to the motorist along the area.
Figure 1: Underground Live services identified.
Figure 2: Temporary structure steel support for the live services
The Solution
To prevent further occurrence of flash floods along admiralty road west, Hocklim Engineering was tasked with widening the existing box cover by building a drainage across Admiralty road west. This will help to increase the volume of water flow into the drainage system, thus alleviating the flash flooding occurrence around the area.
Utilities management
Before excavation begin, it was necessary to investigate the presence for any existing live underground services. Using the trial trench and probing with a plastic drill bit, various live services were identified underground. The live services identified were old British army fuel pipes (on the surface), Singtel cables, 66KV, HT cables, LV cables, 300mm dimeter water mains and 1800mm water main, which were found to be 1-5 meters deep underground. To ensure no damages to the live services occur during the entire project, they were protected using temporary structural steel support which was specifically designed by Hocklim Engineering's professional engineer.
Deep excavation
Due to the presence of the existing live services, the excavation process became tedious as additional protection work was needed to ensure that the live services were not damage during the excavation process. In order to do so, the setting up of ERSS (Earth Retaining Stabilising Structure) by sections parallelly aligned to support the live services and retain the surrounding soil during the deep excavation. This results in a more time consuming and labor intensive job.
Figure 3: Setting up the ERSS
Tidal water management
As Admiralty Rd West is close to the sea, the need to control the tidal water and rain water flowing to and fro through the outlet drain during the entire process was necessary.
In order to do so, Hocklim deployed, 2 automated tidal gates to control the flow of sea water. The automated tidal gate operates with a sensor that activates based on the water level. This ensures that Hocklim is able to control the water flow during the entire project, thus prolonging the working hours by creating a conducive work environment.
Figure 4: Tidal gate to control the flow of sea water
Using natural energy for site power supply
Hocklim firmly believes in reducing carbon emission and protecting the environment. One example is to use solar panels to replace some of the diesel empowered generators for power onsite.
These include the CCTV system onsite, the electricity at the temporary bus stop and the automated tidal gates. The reliance on natural power allows Hocklim to be more environmental friendly while lowering its cost simultaneously.
Figure 5: Utilising natural power such as solar panels to drive operations
Traffic diversion
During the tender stage, the notional design of the traffic diversion was a six-phase diversion scheme. Hocklim optimise the six-phases into a two-phrase diversion scheme. This greatly reduces the impact to the existing traffic while improving the work continuity.
This project showcases Hocklim's ability in handling the challenges during the deep excavation while controlling external elements such as tidal water movement during the entire process.
