Mexico’s Mixed Ground Crossings
The central Mexican state of Guanajuato is surrounded by mountains and is traditionally known for its abundant silver and gold mines, but its latest resource may be far more valuable: Water. The Santa Maria River and a reservoir created by the newly constructed El Realito Dam are some of the most untouched and pristine water resources in arid Central Mexico. In order to supply potable water to a rapidly growing population, a mega pipeline is being built, stretching more than 80 miles between Guanajuato and the neighboring state of San Luis Potosí. TheMuch of the hard, packed ground in this area of Mexico consists of consolidated, cemented cobbles that can be difficult to excavate. The path of the 36-in. diameter pipeline travels into and out of densely populated urban areas and below roads, rail and waterways. Cut-and -cover was only an option for some of the pipeline, and microtunneling could only be used in soft ground portions, which left multiple hard and mixed ground crossing sites. Enter the Small Boring Unit (SBU): Local subcontractor Ingeniería en Túneles y Redes, S.A. de C.V. (INTUR) needed a swift solution for mixed conditions that were hard enough to break bullet bits. Their use of two SBUs, a 36-in. and 54-in. model, on multiple crossings up to 500 ft long was ultimately successful and tested the mettle of SBU technology.