Application of Multiple Excavation Support Systems in Brown Field Project-Paper

Paper

Pdf Summary

The paper describes excavation support for a new Coke Dry Quenching (CDQ) system built within an operating steel plant, alongside an existing Coke Wet Quenching facility. Deep chamber foundations and conveyor tunnels had to be constructed in restricted space near heavily loaded structures, active rail tracks, and numerous underground utilities, without interrupting plant operations.<br /><br />Ground conditions were highly variable: slag-rich fill and porous residual soils overlay weathered mica schist, with groundwater and seepage increasing the risk of collapse. To address these constraints, the project used a combination of support methods selected for each excavation stretch: pressure grouting to strengthen loose ground; soil nailing and shotcrete where space allowed; contiguous bored piles beside heavily loaded foundations; and micropiles near shallow utilities and lightly loaded foundations. Open excavation with benches was used where sufficient space was available.<br /><br />Design and construction were adapted as work progressed. Variable rock conditions, obstructions in old fill, collapsing drill holes, and unexpectedly high grout and shotcrete consumption required changes to pile socket depths, nail layouts, and construction methods. Stability was reassessed for different construction stages and site conditions, with continuous surveying, visual inspections, and camera monitoring.<br /><br />The combined systems successfully stabilized the excavations and enabled construction within the operating plant and project schedule. The authors emphasize detailed planning, close collaboration among the client, consultant, and contractor, and revising designs during execution without compromising safety. They also recommend treating slope stabilization in brownfield sites holistically, carefully managing surface runoff and seepage, and installing geotechnical instruments to monitor ground movement and groundwater conditions.

Keywords

excavation support

Coke Dry Quenching

brownfield construction

soil nailing

micropiles

contiguous bored piles

pressure grouting

shotcrete

slope stabilization

geotechnical monitoring