Subsidence and Pressure Grouting in Houston, TX
Pier-A-Mid Inc. takes pride in having extensive experience handling projects involving subsidence and pressure grouting in Houston, TX. Our team of highly trained structural rehabilitation professionals uses state-of-the-art equipment to address your unique needs.
Subsidence Grouting
Rapid groundwater depletion is one of the leading causes of subsidence, a process where areas of land cave in or sink. Groundwater found in the Earth’s strata formation has hydraulic head pressure. However, when this water supply is consistently depleted, the pressure is reduced and the overburden decreases. This depletion occurs in the lower depths sand/silt lens, affecting various structures and land values. Subsidence grouting addresses this problem by preventing the soil mass at grade from acting like a bowl that accumulates water where it never has before.
Pier-A-Mid Inc.’s patent-pending subsidence grouting method does not involve installing bell bottom piers, driven piers, columns, or footers to lift structures. Usually, bell bottom piers and footers can only be installed above water tables in formations. On the other hand, driven piers can only support the weight of the driven column’s diameter.
Driven columns or cylinders measuring 6” or 2’ in diameter are not enough to support the load of sinking buildings. This situation especially holds true if these components are placed in soils whose load-bearing capacity is only 1,500 pounds per square foot (psf).
Our subsidence grouting method involves driving or drilling a 3” pipe into the formation to find weak zones at depths of -20’ and lower. These zones are in aquifers, sand/silt lenses in clay formations, and water zones in rock formations. We hydraulically pump a stiff, low-mobility cement grout (i.e., a 1.5”–2” slump grout) into these voids.
The grout squeezes out any remaining groundwater. As lateral pressure increases in the injected zone, the overburden starts to heave. The formation above the lens starts lifting everything from the zone to the structure at grade or below grade. Our subsidence grouting process raises structures in floodplains, locations experiencing flooding due to rainwater, and areas near rivers that overflow their banks. This process does not deal with the differential movement of roads, floor slabs, or structures at grade.
