The project consists of ground improvement works to accelerate the filling of a valley for the construction of an industrial complex to manufacture the fan cover of an aeroplane engine. The facility is to be built across an existing valley at a general level of RL+65.00 m, where the existing valley has its lowest point right in the middle of the future built up area, at level of RL+41.00 m, with stagnant water at level of RL+45.00 m approximately. The surrounding hills are having peak level at RL+80.00 m and above.
A factory is to be built on a piece of land that geographically is a valley with lowest point at RL+41.00 m and highest point in excess of RL+80.00 m. The land needs to be cut and filled to establish a final platform level at RL+65.00 m. In the initial design, filling of the valley is to be done using conventional layer by layer compaction method. Nonetheless, an innovative solution combining Dynamic Compaction (DC) and Dynamic Replacement (DR) is eventually adopted to accelerate the filling of the valley. The following design criteria shall be respected at level RL+65.00 m after the ground improvement works using DC and DR at the fill area:
- The total post construction settlement shall not exceed 15 cm under the maximum load of 50 kPa (due to the dead and live loads of future structures)
- The maximum differential settlement shall not be more than 1:500
Menard has implemented Dynamic Compaction (DC) and Dynamic Replacement (DR) method to reduce the filing duration from 4 months to 2 months and also to meet the post construction settlement criteria of 15 cm. DC and DR are the ground improvement methods carried out on site to compact the fill material with thickness of about 5 m. DC is the primary method to compact the fill material while DR is adopted at the first layer to compact and reinforce the existing soil that is ponded with water.
DC/DR treatment is carried out in 5 layers i.e. at RL+45.00 m, RL+50.15 m, RL+54.90 m, RL+59.65 m and RL+64.40 m. The total treatment area combining all 5 layers is approximately 82,650 m². The works is competed ahead of time within 2 months period.