Alchatek Blog

One Atlanta Plaza experienced significant settling of sidewalks and approach slabs around the perimeter of the building, creating safety hazards for pedestrians and visitors. The multi-story structure includes underground parking levels supported by piles, which remained stable, but the transition areas connecting to surrounding sidewalks were built on compacted fill. Over time, differential settlement occurred between the pile-supported structure and the soil-supported approach slabs, with some areas dropping approximately half an inch. Building management had previously attempted fixes by creating concrete "ramps" at transition points, but these temporary solutions continued to deteriorate as settlement progressed.

Initial Assessment

Engineers inspected the site and identified that the compaction difference between the soil immediately adjacent to the building foundation and the surrounding area was causing uneven settlement. This resulted in cracking of curbs, trip hazards at entrance points, and visibly sagging pavement sections, particularly noticeable at the approach to the parking garage. The most affected areas showed clear separation between the stable pile-supported structures and the settling exterior slabs. Entrance points where the differential settlement created ADA (Americans with Disabilities Act) compliance issues, and potential liability for trip-and-fall incidents were of particular concern. This problem stemmed primarily from inadequate soil compaction during the original construction.

Proposed Solution

Alchatek recommended a two-phase approach to address both the underlying soil conditions and the visible settlement. First, AP Soil 600, a single-component polyurethane product designed for soil stabilization and permeation, would be injected to densify the loose soil beneath the affected slabs. Following soil treatment, two-component polyurethane foam, AP Lift 475, would be used to lift the settled concrete sections back to their proper elevation. This non-invasive approach would eliminate the need for demolition and replacement of concrete, allowing for minimal disruption to building operations while providing a long-lasting solution.

Procedures

1. Technicians established injection points in a grid pattern, spacing them approximately 3-4 feet across the affected areas.
2. Saw cuts were made at key joints to free slabs from binding against adjacent concrete, allowing for controlled lifting without creating additional stress.
3. In the initial phase, AP 600 was injected through small drilled holes to stabilize the underlying soil and prevent future settlement.
4. After the soil stabilization phase, AP 475 was injected in multiple passes, starting from the areas closest to the building and moving outward.
5. Elevation was carefully monitored throughout the lifting process using zip levels and dial indicators to ensure proper alignment and prevent cracking.

Results

The rehabilitation project restored proper elevations at all transition points around the building, eliminating tripping hazards and improving aesthetics and safety. The lightweight polyurethane material added minimal load to the treated areas while effectively compacting and stabilizing the underlying soil.

From a financial perspective, this approach delivered significant cost savings compared to traditional repair methods. Concrete replacement would have required demolition, disposal, and new concrete installation, which is why the two-phased remediation project resulted in a 90% reduced cost compared to traditional replacement methods.

Want more information on geotech products?

Attention Geotech Professionals!

Alchatek is exhibiting at the DFI S3: Slopes, Support and Stabilization Conference.

Where: Madison Marriott West in Madison, Wisconsin

When: August 5–7, 2025

Click Here for Registration Info

Visit us at Booth 302 to explore our advanced polymer solutions, including single and two-component polyurethanes for soil stabilization, groundwater control, and deep foundation support, addressing challenges like unstable slopes, soft ground, and deep excavation shoring for geotechnical projects.

Learn How Alchatek Helps You

At Booth 302, you can meet with our experts to learn how Alchatek empowers your geotechnical projects with cutting-edge technologies.

We support geotech professionals in three key ways:

• Innovative Polymer Solutions: Our advanced polyurethane grouts and foams provide robust solutions for curtain grouting, point grouting, and ground improvement, ensuring stability for slopes, excavations, and deep foundations.
• Expert Technical Support: We offer comprehensive training and ongoing assistance, leveraging our proven track record with industry leaders to optimize your project outcomes.
• Environmentally Safe Materials: Our NSF/ANSI/CAN 61-certified, chemically inert polymers ensure safety and compliance in sensitive environmental areas.

Want more information on Alchatek products?

This post is part of the Alchatek Contractor Lens series, featuring views, news & case studies written by our customers. This article was written by Jay Silver and originally posted on the Helicon blog.

When Excavation Gets Tight, Think Beyond Sheet Piles

Excavating near an existing structure — like a home, commercial building, or utility line — often requires soil support to avoid collapse or damage. For decades, the go-to solution has been sheet piling: driving steel sheets into the ground to create a temporary shoring wall.

But sheet piles come with serious downsides:

• High cost
• Vibration risks to nearby structures
• Heavy equipment needs
• Limited accessibility in tight areas

Today, there’s a smarter, faster, and more cost-effective alternative for excavation support: polyurethane injection permeation grouting.

What Is Polyurethane Grout Injection for Excavation Assist?

Helicon uses a permeation grout called AP Soil 600, a low-viscosity polyurethane resin, to stabilize soil and build a temporary underground wall. This non-expanding material seeps into fine-grained soils (like sand), then hardens into a concrete-like mass — turning unstable ground into a solid excavation shoring wall.

This “grout curtain” supports the soil adjacent to your dig site, providing excavation assist without the need for steel sheets or heavy machinery.

Common Use Cases for Polyurethane Shoring Walls

Excavations next to homes or commercial buildings

Tight-access job sites where pile driving equipment won’t fit

Urban infill projects with vibration-sensitive neighbors

Value-engineered alternatives to high-cost sheet pile installation

Projects with depth requirements up to ~15 feet

Sheet Piles vs. Polyurethane Injection

How It Works: The Grout Curtain Process

1. Plan and Mark
The contractor provides excavation depth and layout. Helicon’s team maps out injection lines using stakes or string to ensure precision.

2. Drill Injection Holes
Using compact equipment, injection rods are installed at a slight 3–5° angle away from the excavation. Rods are spaced 18″ apart, and for depths >8 feet, a second staggered row is added 18″ behind the first.

3. Inject AP Soil 600 Grout
Each rod is used to inject grout in 1-foot intervals from bottom to top:

• Start 2 feet below planned excavation depth
• Inject 1 gallon per vertical foot
• Grout permeates and hardens in ~2 minutes per foot
• Stops 1 foot below surface to avoid breakout

The non-expanding grout permeates the soil, turning it into a rigid, cohesive wall capable of holding back earth during excavation.

4. Excavate Safely
Once cured (typically within 24 hours), excavation can begin — but mechanical equipment must stay 2+ feet away from the grout wall. Final trim is done by hand or hydro-vac.

Soil Types That Work Best

AP Soil 600 is designed for permeation, not expansion. It’s ideal for:

✅ Sand
✅ Fine silts
✅ Granular soil types

⚠️ Less effective in:

• High plasticity clay (which resists permeation and may not need shoring)
• Organic material or very dense clay (which can fracture or lens)

That’s why soil boring reports or geotechnical testing are important for project design.

Depth Recommendations

Helicon’s polyurethane grout walls are most effective up to 15 feet. Beyond that, multiple injection rows become inefficient, and other structural shoring may be needed.

Cost Savings & ROI

Switching from sheet piles to Helicon’s polyurethane grout method can save:

• Tens of thousands on residential jobs
• Up to six figures on larger commercial projects

Savings come from:

• No need for steel or removal
• Smaller crews and equipment
• Shorter install times
• No costly vibration damage

Combine with Underpinning When Needed

When adjacent structures need more than soil support, Helicon can pair permeation grouting with:

• Push piers (steel-driven deep supports)
• Drilled piers (poured concrete or steel)

This hybrid approach is ideal for:

• Older buildings
• Structures with active settlement
• High-load foundations near deep excavation

Real-World Examples

On a commercial project, the contractor and engineer originally planned to use traditional sheet piles for shoring to support the foundation of a commercial building. Helicon collaborated with the engineer to develop a value-engineered alternative: a polyurethane grout curtain combined with steel push piers installed under the building’s foundation. The shoring wall and underpins were completed within five days, excavation proceeded safely, and the client saved over $300,000 compared to the original sheet pile proposal.

On a recent project with access constraints, Helicon installed a polyurethane grout curtain within 2 feet of a residential foundation. Traditional sheet piles weren’t an option due to equipment access and budget. The wall was in place within two days, excavation followed safely, and the client saved over $70,000 compared to a sheet pile proposal.

Safety Guidelines

• Injection starts 2’ below excavation depth
• Do not excavate within 24” of cured grout with equipment
• Always hand dig near the grout wall
• Excavation limit line should be marked 33” back from rods (accounting for rod angle)

Why Engineers and Contractors Choose Helicon

• Florida-based foundation experts
• Proven track record in geotechnical solutions
• Fast mobilization and project turnaround
• Seamless integration with GCs, engineers, and owners
• Full service: injection + underpinning + stabilization

Optimize Your Excavation Support Plan

If you’re a contractor, builder, or geotechnical engineer working on an excavation project in tight quarters, don’t default to sheet piles. Helicon’s polyurethane injection method is often:

• Faster
• Cheaper
• Cleaner
• More flexible

Helicon specializes in value-engineering shoring solutions that reduce project costs and risks while maintaining structural safety and soil integrity.

Let’s Put Your Excavation Project on Solid Ground

Have a project where you’re excavating near a structure? Let’s collaborate. Helicon offers:

• Free project consultations
• Soil review and injection layout planning
• Rapid response teams for tight timelines

Want more information on Alchatek's geotech solutions?

Attention Engineers!

Alchatek is exhibiting at the International Conference on Transportation & Development and the International Airfield & Highway Pavements Conference, held at the Renaissance Phoenix Glendale Hotel & Conference Center, 9495 Entertainment Boulevard, Glendale, Arizona 85305, from June 8–11, 2025. Visit us at Booth 201 to explore our advanced polymer solutions, including two-component structural polyurethanes for concrete leveling and void fill and one-component polyurethanes for soil stabilization and leak seal, addressing infrastructure challenges like cracked pavement, sinking slabs, leaking culverts, and unstable soil for DOT and airport projects.

Learn How Alchatek Helps You

At Booth 201, you can meet with our experts to learn how Alchatek supports your infrastructure initiatives with our environmentally friendly NSF/ANSI/CAN 61-certified technologies.

We benefit engineers in three key ways:

• Connections with Experienced Contractors: We partner you with skilled, vetted contractors trained in our advanced polymer solutions for high-quality project execution.
• PDH Credit Lunch and Learn Presentations: We offer in-office presentations providing Professional Development Hours (PDH) credits, equipping your team with the latest geotechnical and infrastructure repair techniques.
• Assistance with Project Specifications: Our experts collaborate to develop precise, project-specific specifications, ensuring compliance and optimal performance.

Want more information on Alchatek products?

The owner of a gas manufacturing facility contacted a Georgia-based contractor regarding significant floor settlement issues, with a warehouse slab dropping approximately 3-4 inches. The settlement made issues for the forklift traversing in and out of the warehouse and posed a risk to the workers.

Initial Assessment

Upon arrival at the site, the team conducted a thorough investigation. Using a probe, voids were identified beneath the slab, with the probe sinking up to 2 feet in some areas. A Dynamic Cone Penetrometer test revealed large voids 2-4 feet below the slab.  Poor drainage was evident, with improper crowning causing water to flow towards the building instead of away from it. Interestingly, a layer of unusually hard clay was noticed outside the building, suggesting possible prior remediation attempts.

Proposed Solution

AP Lift 430 was chosen for this project, providing an excellent injectable polyurethane grout solution. With its impressive 22x expansion capability and 7,200 psf compressive strength, it’s ideal for warehouse slabs that support heavy equipment. The grout’s hydrophobic properties ensure long-term stability by blocking water infiltration that could otherwise lead to void formation.

Procedures

1. Deep Injection (Void Fill)

• 32 injection points were established in a grid pattern (16 on each side) at 4 ft apart.
• At each point, the team injected 15-20 pounds of material at about 5 feet depth.
• A slight lift (approximately 1/16 inch) during this phase indicated successful void filling.

2. Slab Lifting

• Additional holes were drilled next to the wall, 3 feet from the wall, and 9 feet from the wall (6 feet from the first row).
• Injection began from the holes nearest to the wall and moved outward.
• Multiple passes were made, with some areas requiring 3-4 injections.
• Gradual lifting was employed to prevent slab cracking.
• Dial indicators were used to ensure even lifting across the warehouse floor.

Results

The project successfully stabilized the warehouse floor and restored it to its proper level. Effective void-filling addressed the underlying instability, providing a solid foundation for the slab. Success was evident in the restored functionality of the warehouse space and the elimination of safety hazards posed by the uneven floor. The property manager was pleased with the work and requested additional slab lifting services for their other facilities.

Want more information on lifting slabs with polyurethane?

Essential Details

Dates/Pricing (Discount Deadline Extended!)

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of the day, March 2nd. $745 March 3rd and later. ($50 discount for each additional participant.)

Location

Atlanta, GA

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.

Essential Details

Dates/Pricing

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of the day, February 25th. $745 February 26th and later. ($50 discount for each additional participant.)

Location

Atlanta, GA

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.

Essential Details

Dates/Pricing

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of day, February 25th. $745 February 26th and later. ($50 discount for each additional participant.)

Location

To Be Determined
(in Georgia)

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.

At a new solar field installation in North Florida, there were areas of bad soil where the H piles were not passing the loading and pull testing.  Solar panels lay at an angle, and if a strong wind is coming from one direction, it can try to “lift” the panel and pile.  Conversely, a strong wind coming from the opposite direction creates a downward force and can drive the supporting pile into the soil.

Powerful Polymers

The general contractor contacted the grouting specialists at Stable Soils and asked if they could use cement grout to try and lock the piles into place. Because of the tight confines between rows of piles, the specialist suggested a polyurethane permeation grout, Alchatek's AP Soil 600. The required installation equipment is more compact and it is a lot cleaner to install than cement. AP Soil 600 is moisture-activated (the same as Gorilla Glue), but it only takes about 5% moisture in the soil to make it react.  AP Soil 600 is heavier than water by design, and it is also hydrophobic.  As it soaks in, it pushes through the moisture and displaces it.  Once it cures, the sand is locked together. As the AP Soil 600 soaks into the damp sand, it reacts and produces carbon dioxide.  The CO² creates a swelling effect, driving the resin further into the sandy soil.

Painless Procedures

Around 20 test piles were installed at the solar field.  AP Soil 600 was injected right against the steel at a depth between 3 and 4 feet.  About 1/3 of the piles received 1-1/2 gallons.  Another third received 1 gallon, and the final third was injected with 3/4 of a gallon.  All of the piles passed the pull testing and compression testing.  The project was awarded, and around 4000 piles were injected in total.  It was a complete success.

Fast forward to 2022 at a massive solar field installation in Ft. Green, Florida.  Like many solar fields, it was not necessarily on the best land.  The site was a filled-in phosphate mine, so the soil was layered with bands of clay, sand, and mine tailings. Once again, there were sections of the solar field where the piles were not passing the pull testing, load testing, and lateral testing.

Polyurethane grouting was proposed but the manufacturer of the components wanted the proposed material to go through more vetting.  Primarily they wanted to know if the polyurethane grout would last for the 25-year service lifespan of the solar field.  Job histories, accelerated testing results, and chemical resistance data was provided, to their satisfaction.

For this project, the owners wanted to get engineers involved in the grouting portion of the installation.  Mathers Engineering was in charge, and they contracted Madrid Engineering to handle the soil testing. Testing showed that there were layers of clay and sand (referred to as zebra striping), so the grout was targeted in the sandy areas.  The thought was that the permeated sand would be locked in between layers of clay, thus improving both compression and pull strength. 

For this installation, the same three different volumes of AP Soil 600 were tested.  Once again, only 3/4 of a gallon was deemed sufficient to pass the testing, so that was what was used.  5000 piles were injected on this project, about 90% of them with AP Soil 600.  There were some areas of organic soils, and for those, AP Fill 700 was injected and tested successfully.  AP Fill 700 has over 30X expansion and works well at improving organic soils.  The work was completed in the Spring of 2022, and the solar field went into service.

Rapid Results

In the Fall of 2022, disaster struck Ft. Green, a location unfortunately positioned directly in the path of a Category 3 hurricane. The storm’s ferocity was evident as it swept through, leaving behind a trail of destruction in its wake. Trees were toppled, and the solar field, designed to endure winds exceeding 100 MPH, faced unprecedented damage. The wind from the hurricane’s eyewall proved too powerful, driving piles of solar panels into the ground. Despite their robust design, many panels were shredded, and a significant number of the piles suffered movement, highlighting the sheer force of nature’s fury.

Out of 5000 piles injected, only 9 showed any sign of movement.  The polyurethane grout was put to the test and passed with flying colors.  Currently, this field is going through the insurance claim process, but the testing for the repair method has already been completed.  The embedded piles were jacked back up to level and then grouted in place with AP Soil 600.  All of them passed the test; now, the field is waiting for the insurance to be worked out so the rest of the damaged piles can be glued back into place. AP Soil 600 carries the NSF / ANSI 61 rating.  It is safe for contact with potable water, and in this application, it will not leach any chemicals into the soil or groundwater.

Want more information on stabilizing soil with polyurethane?

Foundation foam is a trusted solution for engineers and contractors addressing soil stabilization and structural support challenges. This proven technology effectively tackles issues caused by unstable soil, from erosion to poor compaction. Over the years, it has established itself as an essential tool for maintaining the integrity of buildings, roads, and other infrastructure.

Why Soil Stability Matters

Unstable soil poses significant risks to structures built upon it. For instance, erosion, poor compaction, and freeze-thaw cycles can lead to settling, cracking, and even catastrophic failure. Moreover, these issues often occur deep beneath the surface, making them difficult to address using traditional methods. Therefore, reliable solutions are crucial for ensuring long-term structural integrity.

The Power of Foundation Foam

Foundation foam offers a dependable solution to these challenges. Unlike conventional methods, it can be injected deep into the soil without heavy excavation equipment, allowing for precise soil stabilization and compaction. Furthermore, the foam cures quickly. This rapid curing time significantly reduces project downtime and improves overall efficiency.

One-Component Standard Soil Stabilization

One-component foundation foam products offer durable and effective solutions for standard soil stabilization projects. These products are perfect for soil permeation, spreading through, and strengthening loose or unstable soil.

• AP Soil 600
• AP Fill 700
• AP Fill 720

Their ability to permeate soil makes them excellent choices for addressing issues like erosion, poor compaction, and water infiltration. As a result, these one-component foundation foam solutions can effectively stabilize soil without requiring extensive excavation or heavy machinery.

Two-Component Deep Lock® Stabilization

The Deep Lock® process utilizes two-component foundation foam products for deep soil issues. These include:

• AP Deep Lift 420
• AP Lift 430
• AP Lift 440
• AP Lift 475

The Deep Lock® process allows for soil stabilization at greater depths, thus making it particularly useful for large-scale projects or structures with significant foundation issues. Additionally, this method can achieve soil stabilization and compaction with minimal surface disruption.

Versatility in Application

One of the critical advantages of foundation foam is its versatility. It can be used in a variety of scenarios, including:

• Supporting settled buildings
• Enhancing soil density around pipes and tunnels
• Reinforcing bridge approach slabs
• Strengthening port and airport infrastructure

Foundation foam provides long-lasting support and protection against future settling or erosion in each application. Consequently, it has become a go-to solution for many construction and rehabilitation projects.

Comparing Foundation Foam to Traditional Methods

Compared to traditional soil stabilization methods, foundation foam stands out in several ways. For example, cement pressure grouting requires heavy equipment and can be messy and imprecise. Similarly, helical piers and push piers, while effective, are often more invasive and limited in their application.

In contrast, foundation foam is less invasive, faster to install, and addresses underlying soil issues more comprehensively. Moreover, it can be combined with other methods for even more effective results. Therefore, it offers a more flexible and efficient solution for many soil stabilization projects.

Environmental Considerations

An important aspect of foundation foam is its environmental safety. Alchatek foundation foams are NSF-certified to strict ecological standards. This certification ensures that the cured foam won't negatively impact groundwater quality. As a result, these foundation foams are a responsible choice for projects in environmentally sensitive areas. This rigorous environmental compliance further enhances their appeal as a trusted soil stabilization solution.

Long-Term Benefits

The long-term benefits of foundation foam are substantial. Once cured, the foam creates a stable, water-resistant barrier lasting decades. This longevity translates to reduced maintenance costs and improved structural integrity over time. As a result, property owners can enjoy peace of mind knowing their investments are protected for years to come.

A Solid Foundation for the Future

Consistently providing an effective solution to soil issues, foundation foam has proven instrumental in ensuring the longevity and safety of buildings and infrastructure worldwide. With its track record of success, foundation foam continues to be a go-to choice for construction and rehabilitation projects of all sizes. This time-tested technology remains at the forefront of creating stable and resilient structures for the present and future.

Want more information on stabilizing soil with foundation foam?