Box jacking for tunnels

A trenchless method for underground construction feats

Box jacking is a trenchless construction technique used to install precast reinforced concrete structures beneath existing infrastructure such as roads, highways, and railways, without disrupting surface operations. It is ideal for building underpasses, pedestrian crossings, and utility corridors in dense urban environments. VSL offers comprehensive box jacking solutions, integrating design, jacking operations, and ground treatment to ensure stability, safety, and schedule control.

Technical Advantages of the Box Jacking Method

The box jacking method offers a controlled, low-impact tunneling solution that enables safe, efficient construction beneath active infrastructure.

Allows underpasses or crossings to be constructed without stopping traffic or rail services.

A controlled, predictable solution for working under sensitive infrastructure.

Construction of the precast structure can proceed in parallel with preparatory works.

Ideal for constrained urban environments or areas with difficult access.

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VSL’s Box Jacking Services

VSL delivers end-to-end box jacking solutions, combining engineered precast structures, precise jacking operations, and ground stabilization techniques to ensure safe and efficient tunnel installation.

Precast Box Design and Fabrication

VSL provides custom-engineered precast segments designed for the jacking process, accounting for:
• Structure geometry
• Soil pressure and jacking force
• Waterproofing and joint details
The precast elements are typically fabricated off-site to ensure quality and minimize on-site disruptions.

Jacking Operations

Using hydraulic jacks, the box is pushed incrementally through a prepared excavation. VSL ensures alignment accuracy through real-time monitoring.
Key elements of execution include:
• Reaction frame and jacking system setup
• Thrust pit construction
• Lubrication systems to reduce skin friction
• Grouting around the box post-installation

Ground Improvement and Soil Stabilization

To control ground behavior during jacking and prevent settlement, VSL integrates ground improvement techniques such as:
• Jet grouting
• Compensation grouting
• Soil freezing or dewatering (as required)

Why choose VSL for Box Jacking?

  • Trenchless construction expertise

    Proven experience delivering underpass and utility crossings using box jacking.

  • Integrated delivery

    From precast design to soil treatment and hydraulic jacking, all phases are handled in-house.

  • Urban project experience

    Operates in low-clearance, high-traffic environments with minimal disturbance.

  • Customized solutions

    Box design, ground control, and jacking method adapted to soil conditions and client constraints.

FAQ about Box Jacking

These are some of the most common questions we receive. Got another one? Reach out to us!

Box jacking is used to construct underpasses, pedestrian tunnels, utility crossings, and culverts beneath live roads or railways without surface interruption.

Box dimensions and jacking length depend on site constraints, ground conditions, and allowable surface movement. VSL performs detailed engineering studies for each project.

VSL uses real-time monitoring and, when required, ground improvement methods such as compensation grouting or soil stabilization to minimize movement.

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Need to build under existing infrastructure without disrupting service?

Contact VSL today to explore how our box jacking solutions can support your project.