Dewatering operations are an inherent part of most shoring and deep excavation projects undertaken by Trevi, as excavation depths frequently extend below the natural groundwater table.
Dewatering systems are designed to temporarily lower and control groundwater levels, ensuring dry and safe working conditions during excavation. Depending on site-specific hydraulic and geotechnical conditions, these systems typically consist of deep wells equipped with submersible pumps or wellpoint systems arranged and sized according to the required discharge capacity.
The design of a dewatering system is a highly engineering-driven process, based on detailed site investigation and hydrogeological analysis. Field testing—such as pumping and rising head tests—combined with advanced numerical modelling allows to estimate soil permeability and predict the behaviour of groundwater during excavation phases.
This approach enables the optimization of the system layout, including the number, depth, and spacing of wells, as well as the required pumping rates to achieve the target drawdown while minimizing impacts on surrounding structures and the environment.
Dewatering is typically implemented in stages, in parallel with excavation progress. Groundwater levels are progressively lowered to match excavation levels, allowing safe installation of structural elements such as diaphragm walls, anchors and slabs.
During operations, continuous monitoring is critical. Standpipes, piezometers and observation wells are installed both داخل and outside the excavation area to track groundwater levels and verify system performance in real time.
This monitoring ensures that design assumptions are met and allows for timely adjustments if required.
In major projects, dewatering systems may include multiple wells arranged in lines along the excavation perimeter or within the excavation footprint, with carefully defined spacing and pump capacity to ensure effective and controlled groundwater drawdown.
Dewatering activities are maintained until the structure reaches sufficient weight and stability to counteract groundwater uplift pressures acting on the foundation raft and underground structures.
The integration between dewatering design and structural solutions—such as diaphragm walls and anchoring systems—is a key aspect of Trevi’s approach. This integrated methodology allows to optimize both performance and cost efficiency, ensuring safe excavation, structural stability and long-term reliability of the works.