The time and cost of a project of pipe ramming or microtunnelling depend on the combination of geometry, geotechnics, depth, diameter, length, water table, type of TBM, borehole design, logistics, permits, expected production and level of construction risk. They are not calculated only per linear meter: a short work can be complex and costly if it requires deep shafts, water control, urban diversions or a specific TBM.
In projects of pipe ramming y microtunneling in terrestrial and subway applications, Eurohinca analyzes these factors to estimate technical feasibility, execution performance, equipment required, ancillary civil works and risks that may affect the budget or schedule.
Factors most influencing time and cost
Diameter of the conduction: conditions the type of TBM, the size of the pipes, the thrust required, the transport logistics, the lifting equipment, the excavated volume and the dimensions of the shafts.
Length of the section: influences the advance time, ground-pipe friction, lubrication requirements, possible intermediate stations, tool wear, guidance control and shift organization.
Depth of execution: The deeper the well, the greater the requirements for excavation, support, safety, pumping, hoisting, ventilation, access and shaft design tend to increase.
Geotechnics and hydrogeology: the presence of rock, boulders, mixed terrain, abrasive soils, cavities, fills, high permeability or high water table can affect performance, tool wear, face stability and TBM selection.
Water table and water pressure: when relevant groundwater is present, it may be necessary to work with closed shields, pumping systems, reinforced sealing, auxiliary treatments or hydro-shield for water-logged terrain.
Type of tunnel boring machine and excavation system: the choice of tunnel boring machine -open shield, EPB tunnel boring machine or hydroshield - affects equipment, production, face control, management of excavated material and auxiliary costs.
Attack and reception wells: the design, depth, dimensions, support, waterproofing, and accessibility of the vertical pits for driving and microtunneling may represent a relevant part of the total project time and cost.
Environment and interference: working under roads, railroads, existing utilities, urban areas, waterways or critical infrastructure increases the requirements for control, permitting, monitoring, safety and coordination. At infrastructure crossings, These factors can be decisive.
Site logistics: access, space availability, stockpiles, pipeline transportation, cranes, energy, water, sludge or excavated material management, time restrictions and road occupancy directly influence performance.
Permits and administrative conditions: Authorizations from roads, railroads, coasts, waterways, the environment, municipalities or utility owners may condition deadlines, work windows, protection measures and required documentation.
Quality, safety and control: quality plans, tests, auscultation, topographical control, HSE documentation, inspections, production records and final construction dossier are also part of the actual cost of execution.
Level of uncertainty: The less information available - for example, limited geotechnical expertise or poorly defined services - the greater the risk of contingencies, modifications, shutdowns, cost overruns or schedule extensions.
Why the cost should not be valued only per linear meter
In driving and microtunneling, the cost per meter can vary greatly because fixed and variable items are involved. Equipment mobilization, shafts, TBM, auxiliary plant, logistics, permits and technical controls can weigh as much as the linear advance of the tunnel.
Therefore, two projects with the same length can have very different budgets if the depth, diameter, type of terrain, water table, urban environment or excavation system change.
How to improve time and cost estimation
To obtain a reliable assessment, it is advisable to provide from the outset the ground plan and longitudinal profile, diameter, length, depth, geotechnics, water table, affected services, preliminary location of wells, work restrictions, known permits and target time. With this information, Eurohinca can identify risks, select the construction method and prepare a technical-commercial offer adjusted to the actual scope.
Minimum checklist to estimate time and cost: plant, profile, diameter, length, depth, slope, geotechnics, water table, affected utilities, infrastructure crossed, well spacing, access, hourly restrictions, permits, piping system, tolerances and target time.
Request a technical time and cost estimate for pipe ramming or microtunnelling attaching plans, longitudinal profile and available geotechnical data.
ES 
EN 
FR 