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The soil stabilization process that turns lifting contractors into geotech contractors: injecting structural polymer at depth through driven steel tubes — targeting the failed soil itself, designing from DCP data, and estimating with the 15-pound rule. Taught by Colt, Alchatek Technical Training.
After this module, you'll be able to explain how Deep Lock densifies soil at depth, run the shallow-to-deep injection sequence, spec the parts list, read a DCP test and turn it into a multi-level design, estimate volumes with the 15-pound rule, and field-solve the six problems every Deep Lock crew eventually hits.
Traditional lifting attacks settlement from directly under the slab. Deep Lock goes after the actual cause: the weak soil at depth. You drive 1/2″ or 5/8″ OD steel tubing (16–18 gauge) to the depth where the problem lives and inject structural polymer right there — pinpoint placement at the failure zone.
The physics flip is what makes it work: at depth, the surrounding soil is the confinement. The expanding polymer has something to react against in every direction, so the expansion energy goes into compacting and densifying the weak soil instead of lifting what's above. That's also why accidental structure lift is much less of a worry on deep injections — you're deeper, and you're placing far less material per shot than a lifting job.
The mental model that separates pros from guessers: the polymer does not form a neat balloon around the tube tip. It lenses — chasing the paths of least resistance through the soil, fingering outward and intertwining with the fingers from neighboring injection points.
Those intertwined lenses become one connected polymer-and-soil mass tied into the native soil — that's the structure. (It's also why post-injection DCP tests undersell the work: probe just outside the treated mass and the soil drives almost like before. Plate-load and deflectometer tests show the real story.)
Working at a footing? Three options: set the tube ~18 inches off the wall and drive at an angle under the footing; come back further and angle in; or drill straight through the footing and send the tube home. Injecting under a footing also spreads the reaction load across it — more structure to stabilize against.
The Deep Lock kit, with what your customers will actually ask for:
Note: on the MixMaster, Deep Lock runs two-component only — single-component is too slow through that gun.
The Dynamic Cone Penetrometer is the tool that turns Deep Lock from guesswork into engineering: a 66-lb hammer drops on a graduated rod, and you count blows per increment. Single-digit blow counts mean weak soil; consistent double digits mean decent bearing. Fast, widely accepted, relatively inexpensive — and the tool that lets you walk onto a site no engineer has touched and produce a defensible plan your customer can trust.
That's the North Bend, WA story: the original design called for one injection level at -4 ft. The pre-injection DCP showed weak soil from -4 all the way to -15 ft — the design became four levels, a change order in the ~$70K range, and a job that actually held. Inject the original single level and that project comes back under warranty.
Standard grid covers 90% of Deep Lock work — step, drill, repeat. The isometric (diamond) layout earns its extra measuring mainly on containment-wall designs. Either way, the spacing law holds:
Terminology that keeps estimates clean: an injection point is the location; it may have 2, 3, or 4 tubes at different depths. "100 injection points with three tubes each" prices itself.
The roadway culvert: DCP found loose gravel fill worst around -10 to -11 ft. The design ran three to four depth bases on ~3.5-ft intervals, with the outer points tied into native soil on both sides — one continuous polymer structure bridging native ground, across the fill, and back. Tie into native soil whenever the design allows; that's what makes the mass a structure instead of a plug.
Field Museum, Chicago: weak soil from -3.5 to -5 ft under the building. Tubes on 4-ft centers, one injection level at -4, standard 15–20 lbs per tube. Marquee building, textbook design.
The Bozeman lesson — tubes beat material: a garage-to-bedroom conversion settling on two sides. The right design was more tubes at standard volumes; the constraint forced 5-ft centers with doubled material (20–30 lbs per tube at -6 and -10) — and shallow shots found the surface. It finished, but the takeaway is permanent: when forced to choose, add tubes — don't add pounds.
Score at least 4 of 5 to unlock module completion.