In tunneling and heavy civil construction, this marks the critical point where crews excavating from opposite directions finally meet. It requires precise surveying to ensure both headings align perfectly in elevation and coordinate. On a smaller scale, it refers to punching through an existing structural wall during a renovation or addition.
The laser alignment is dead on, so we should hit breakthrough on the drainage tunnel right before the end of the shift.
Ventilation dynamics change instantly at breakthrough, so crews must be ready to adjust air handlers immediately to manage dust and exhaust.
Also heard as
- holing through
Related terms
Cut and cover
A shallow tunneling method where a trench is excavated, roofed over, and buried.
Earthmoving
The process of excavating, transporting, and grading soil and rock to prepare a construction site.
Viaduct
A multi-span bridge structure carrying a road or railway over a valley, gorge, or other low ground.