A bore is a horizontal hole produced underground primarily for the purpose of installing services. It is the underground tunnel in trenchless construction that's created to house cables, pipes or conduits. A bore is not created using conventional trenching. A bore is, most often, created by a horizontal directional drilling (HDD) rig, a boring machine, or a microtunneling boring machine.
Trenchlesspedia Explains Bore
Boring equipment cuts a bore of varying sizes, depending on the machine's capabilities and design. As the rig or excavator creates the bore, the bore's walls are stabilized by liquid — drilling fluid or, in the case of the excavator and water jet, water — mixing with the bore's wall material to form a thick, stable mud cake on the surface of the bore's wall.
Most bores begin with a pit dug at the entry point of the trenchless work. The bore continues along the design pathway to the end of the work.