The Adisseo Quanzhou Methionine Project is a 150,000-tonne-per-year powder methionine production facility located in Quanhui Petrochemical Industrial Park, Hui’an County, Quanzhou, Fujian Province, China.

The development comprises multiple buildings and process areas, including offices, warehouses, tank farms, emergency containment basins and chemical processing installations.

Settlement monitoring in the 910D process area identified excessive movement affecting several equipment foundations, including pump foundations P92630, P93020, P93060 and P93070. Monitoring also indicated that settlement beneath most of the affected pump foundations had not yet stabilised.

A targeted foundation strengthening solution was therefore required to transfer the equipment loads to a more competent bearing layer and control further settlement without removing the installed process equipment.

The affected pump foundations were located directly beneath an existing pipe rack, with the process equipment already installed.

The maximum available headroom for piling equipment was less than 6 metres, while the minimum working width was only approximately 2 metres. These constraints prevented the use of conventional piling rigs and made the project an ultra-low-headroom construction operation.

The restricted working area also limited the positioning, assembly and movement of equipment. Pile installation had to be completed between existing foundations, pipelines and process installations without causing damage or disrupting the surrounding structures.

Because the equipment had already been installed, protection of the pumps, pipe rack and adjacent facilities was a critical requirement throughout the strengthening works. The project therefore required a compact construction method offering both reliable load-transfer performance and precise installation control.

Considering the restricted working space, installed equipment and stringent safety requirements, QUAMBO proposed an ultra-low-headroom grouted crushed-stone-filled steel pipe pile system to strengthen the affected pump foundations and control further settlement.

Grouted Steel Pipe Pile Installation

Depending on the dimensions of each pump foundation, two to three steel pipe piles are installed on each side. The steel pipes are filled with crushed stone and grouted to form grouted crushed-stone-filled steel pipe piles.

The preliminary pile length is approximately 12–13 metres. Each pile is designed to terminate in Layer ⑥-2-1, consisting of sandy highly weathered granite. The characteristic axial bearing capacity of each pile is not less than 120 kN.

Ground Beam Connection

Reinforced-concrete ground beams are installed at the pile heads and connected to the existing pump foundations using post-installed reinforcing bars. The steel pipe piles serve as the load-bearing elements, transferring the foundation loads to the underlying bearing stratum and controlling further settlement of the pump foundations.

Construction Under Ultra-Low Headroom

All piling works are carried out within a maximum available height of 6 metres and a minimum working width of approximately 2 metres. Ultra-low-headroom construction methods are therefore employed, with strict protection measures implemented to safeguard the installed equipment and surrounding operating facilities throughout the works.