Bangladesh | Nuclear Power Plant – DSM

Project Overview

In December 2015, Bangladesh signed an agreement to build two nuclear power plants as part of an 11.6 billion euro investment to support the country’s growing energy needs. The project focuses on the Ruppur Nuclear Power Plant (RNPP), situated approximately 160km northwest of Dhaka, the capital.

Ground Condition

The soil conditions at the Ruppur site consist mainly of silty sand, along with layers of loam and clay. These varying layers present challenges related to soil stability, especially considering the region’s susceptibility to seismic activity.

Menard's Ground Improvement Solution

To address concerns about soil liquefaction—which could be triggered by seismic events—and to enhance the deformation properties of the soil, Menard Bangladesh implemented Deep Soil Mixing (DSM). The goal was to solidify and strengthen the soil to ensure the plant's long-term stability.

Deep Soil Mixing (DSM) technique will improve the strength properties of the soil by mixing it with the binder (cement slurry). As a result, a solidified mixture of soil and cement is created with considerably higher strength and mechanical parameters.

For this project, 2-meter diameter Deep Soil Mixing (DSM) columns were installed using a single auger with a wet mixing method.

• Mixing Depth: Between 3 to 15 meters
• Column Overlap: Each column was overlapped six times, ensuring 100% incorporation for better stability.

Menard had to meet several critical performance targets to ensure the project’s success:

• Unconfined Compressive Strength (UCS): Exceeding 2 MPa after 28 days
• No more than 5% of non-mixed zones
• EV2 Modulus: Greater than 100 MPa
• Shear Wave Velocity (S-Waves): Exceeding 1100 m/s
• Friction Angle: Over 35°

The project required extensive resources to meet the tight deadlines and high standards of the nuclear power plant construction. To perform the jobsite, Menard mobilized 6 drilling rigs, 5 mixing plant and 180 workers on site to ensure works during 24 hours a day, 7 days a week.

Project Completion

After 10 months of production, the Deep Soil Mixing (DSM) installation for the project was successfully completed within the dedicated time and budget. This ground improvement solution has greatly enhanced the site's structural integrity and ensure the long-term safety for the nuclear power plant's foundation.