Terrestrial/underground applications

Service specifications for ground and subway applications

Terrestrial and subway applications of trenchless technologies cover a wide range of solutions for buried installations in urban, industrial and infrastructure areas. Their analysis and implementation are based on the following technical and planning parameters:

• Scope of application: Crossings under urban roads, highways, freeways, railroads, industrial environments, congested utility areas and areas where open cut excavation is not feasible due to impact, depth or interference.

• Selection of the appropriate method: The decision between microtunneling, pipe jacking, Direct Pipe®, HDD or mechanized tunneling depends on the geotechnics, water table, depth of the route, length of the crossing and environmental constraints.

• Ground conditions: Cohesive, sandy, silty, mixed or rocky soils. The presence of groundwater, permeability, strength and stability directly influence the choice of shield type or drilling system.

• Diameters and types of conduction: Depending on the service (sewerage, water supply, electricity, telecommunications or industrial pipelines), the solution may adopt non-visitable pipes or lined visitable tunnels.

• Typical lengths of the crossings: From short sections for urban crossings to larger crossings under critical infrastructures or large industrial facilities, depending on the method and logistics of the work.

• Civil works requirements: Attack and reception shafts for microtunneling, jacking and Direct Pipe®, drilling platforms for HDD, portals for mechanized tunneling and access areas compatible with the operation of specialized machinery.

• Interference and existing services: Identification and protection of pipelines, cables, foundations and other nearby infrastructure. This analysis determines elevations, alignment, control methods and preventive measures.

• Quality control and traceability: Monitoring of excavation parameters, guidance and face pressure in pressurized methods, alignment verification, tightness tests, geometric control, CCTV inspection and as-built records.

• Security and environment: Risk assessment in confined spaces, traffic and pedestrian management in urban areas, vibration control and minimization of impacts on third parties during execution.