In 2021, the construction of CBL Biomass Boiler Plant in Phnom Penh, Cambodia, marked a significant milestone in sustainable energy development. Menard Asia, a renowned geotechnical engineering company, played a crucial role in the project by implementing an advanced ground improvement technique using Controlled Modulus Column (CMC) technology as an alternative to traditional piling system.
The CBL Biomass Boiler Plant project in Phnom Penh, Cambodia, witnessed the implementation of ground improvement technique as an alternative to traditional deep piling system, aiming to optimize the project schedule and costs. The Controlled Modulus Column (CMC) technique was chosen as the primary method for ground improvement, expertly executed by Menard Asia. By installing CMCs, the soil’s stability was enhanced, its load-bearing capacity increased, and settlement issues were mitigated. This alternative approach, offering cost-effective and time-efficient benefits, was proven to be the favourable choice for the CBL Biomass Boiler Plant project.
The subsoil conditions at the CBL Biomass Boiler Plant site posed significant challenges for the construction of the project. The ground consisted of several layers:
- Layer 1: Soft clay extended to 10 meters below the ground surface.
- Layer 2: Loose sand and silt mixtures continued from 10 to 13 meters deep.
- Layer 3: Medium dense sand and silt mixtures persisted from 13 to 19 meters deep.
- Layer 4: Dense sands were encountered beyond the depth of the previous layers.
Furthermore, to reach the final project elevation, the existing ground level required backfilling of approximately 1 meter.
Menard Asia’s team began the ground improvement process by conducting detailed geotechnical investigation to assess the soil conditions and determine the appropriate design parameters. This is followed by installation of 250 CMCs within a month.
The redesigned building structure involved the following modifications:
- CMC Installation: The initially driven piles were replaced with Controlled Modulus Columns. The CMCs had a diameter of 320 millimetres and varied in length from 17 to 19 meters based on the specific subsoil conditions.
- Columns on Shallow Foundations: Instead of being installed on pile caps, the columns were placed on shallow foundations. The design considered a reinforced bearing capacity of 3 bars at the Serviceability Limit State (SLS), ensuring the stability and performance of the structure.
- Slab on Grade: A 20-centimeter-thick slab on grade was installed on a 50-centimeter sandy load transfer platform. This design provided a stable and level surface for the plant’s operations.
By adopting the Controlled Modulus Column technique, the project aimed to optimize the construction schedule and reduce costs while still ensuring the necessary stability and load-bearing capacity. These design modifications demonstrated the construction process’s adaptability and flexibility in response to the ground conditions and project requirements.
The ground improvement works performed by Menard Asia contributed significantly to the overall success of the CBL Biomass Boiler Plant project. The stable foundation provided by the CMCs ensures the plant’s long-term performance, even in challenging soil conditions. The completed biomass plant also reinforced Cambodia’s commitment to sustainable energy development and reducing its carbon footprint.