What criteria does an engineering firm use to decide whether a route is “constructible” without a trench?

Q: What criteria does an engineering firm use to decide whether a route is “constructible” without a trench?

An engineering firm considers a trenchless route “buildable” when it is executable with manageable occupancy and permitting, controlled risk, and a realistic construction sequence. Key criteria are usually: (1) implementation and occupancy: space, access, phasing and traffic plan; (2) permitting and permit holders: identified competent body and clear requirements; (3) existing services: reliable inventory and protection strategy/coordination with operators; (4) sufficient geotechnics to choose method without relying on assumptions; (5) constructability of design: feasible entrances/exits, sequencing and ancillary works (e.g., shafts); and (6) risks/contingencies: feasible risks/contingencies, risks/contingencies and risks/contingencies, and (7) feasibility of design: feasible entrances/exits, sequencing and ancillary works (e.g., shafts). (5) constructability of design: feasible entrances/exits, sequence and ancillary works (e.g. shafts); and (6) decidable risks/contingencies prior to start-up to avoid redesigns or shutdowns.

An engineering considers a layout to be “buildable” without a trench when, based on the information available, it can be executed with acceptable occupancies and permits, controlled risk y real production margin without surprises that would force a stoppage or redesign on site. These are the most important criteria:

1) “Does it fit” in the city? Implementation and occupation

There is reasonable space for implementation (stockpiles, access, security), especially if the method requires work to be concentrated at specific points (e.g., if the method requires the concentration of work at specific points). Microtunnel o Pipe jacking).
The road occupation is processable (phases, detours, access to garages/shops, emergencies).

2) Permits and “holders” identified from the start

It is clear who authorizes the junction (roads, railroad, confederation, port, city hall) and what do you ask for (documentation, work windows, supervision, guarantees).
The route avoids “red spots” (easements, environmental impacts, protected areas) or already has a strategy to manage them.

3) Interference and existing services under control

Reasonable inventory of services affected (water, gas, MV/LV, fiber, sanitation) and plan to coexist with them (protection, specific diversions, coordination with operators).
The route does not depend on “assumptions”: if there is uncertainty, prior verification is planned (without turning the meeting into an eternal campaign).

4) Geotechnics sufficient to choose a method without guessing

There is geotechnical or, at least, reliable information from nearby works to confirm that the planned method is consistent (without going into fine calculation yet).
If key data is missing, you define which test/tasting is needed and where, so as not to redesign later.

5) Constructability of the design (what usually “breaks” projects).

Feasible entry/exit points, clear sequence of work and, if applicable, definition of ancillary works such as Vertical wells.
Operation/service requirements (commissioning, continuity, maintenance access) compatible with the solution.

6) “Decidable” risks and contingencies before start-up

Top 3-5 risks are identified (e.g. permits, access, services, logistics) and a mitigation plan is in place.
If the project is green, a support from Technical assistance and engineering to close inputs and avoid iterations.