Case story

Mirafi® HPa – Subgrade Stabilization and Load Transfer Platform for Stormwater Management System

Malaysia, Kuala Lumpur, Segambut

Project Data

Project	Subgrade Stabilization and Load Transfer Platform for Stormwater Management System
Location	Segambut, Malaysia
Client	Fixus Construction Sdn Bhd
Products used	Mirafi® HPa

introduction

Climate changes and human mismanagement on water resources such as river channel and floodplain increase flooding and erosion problems. Poor urbanization restricts flood water flow and eventually leads to destructive flooding hazard. To improve this, detention and retention systems are commonly adopted in urbanization planning and development to prevent flooding.

project description

This project site is located at Taman SPPK, Segambut in Malaysia. Insufficient drainage and sewerage capacity in the residential area raised the alarm of flood risk due to high intensity thunderstorms. An underground stormwater detention system (StormTrap® Double Trap) was then introduced to store water runoff in the underground chamber for some time before releasing it back to the drain. StormTrap® is one of the global pioneer providers of stormwater management system who provides cost effective solution to engineers, owners and municipalities. The land above the underground system will be utilized for playground and car parking lots. However, the construction at site was constrained by soft subgrade.

A 7.0m depth soft soil was spotted at the project area, with ground water table nearly at the same level. The soft soil comprised of 3.0m marine soft clay at the top, followed by 4.0m very soft sandy silt at the bottom before firm ground. Due to very soft subgrade problem, a stable load transferring platform was needed to support the underground stormwater detention system.

installation

The construction began with installation of sheet piles over the entire project perimeter, followed by excavation to the designed depth for load transferring platform. Bakau pile was installed at 500mm c/c spacing. A thin soil layer was then backfilled to create flat surface for laying geotextile. Next, Mirafi® HP380a geotextile was laid throughout the platform area. Lastly, a 500mm thick aggregate fill was placed and compacted over the Mirafi® HP380a geotextile to complete the construction of the stabilized load transferring platform. The subsequent construction was completed with installation of StormTrap® system and finally a backfilling of soil on top.

conclusion

Geosynthetic has been proved to be useful and effective in improving the performance of roads and load support structures. The combination functions of Mirafi® HP380a geotextile included separation, reinforcement, lateral confinement and permeability helps to stabilize the soft subgrade and transfer loading from the stormwater detention system to the piles. We acknowledged ‘Fixus Solutions Sdn Bhd’ for trusting our Mirafi® HPa and this project is a well done job.