Chemical Grouting and Soil Stabilization

Ground Works Solutions hosts webinar on Restricting Groundwater with Injectable Barriers™

Ground Works Solutions, Inc., a URETEK polyurethane chemical grouting injection provider in 31 U.S. states, recently hosted a webinar on restricting groundwater and contamination migration through the use of an Injectable Barrier™ system. The webinar was well attended and highly informative. To learn more – go to this link.

Trenchless Sewer Repair

ROI through I/I: How I/I mitigation pays for itself with CST trenchless sewer repair solutions

Trenchless Sewer RepairCosts are costs, and one of the major costs for cities is continuous Inflow and Infiltration (I/I) into sewer systems. The increased water into the sewer system leads to higher pumping costs, increased degradation of pumps, higher treatment costs of water that shouldn’t need treatment, and other potentially costly issues such as soil degradation, further damage to the pipe and sinkholes that could cause roadway or structural failure. So how do you deal with I/I and how can you pay for the I/I mitigation?

CST’s URETEK polymer injection applications provide unique solutions for I/I mitigation. We have the proven results of reducing I/I while also having a very quick payback in reducing the associated costs (a recent study shows that I/I in Tennessee equals 44%!).

The URETEK Technologies are highly effective, having the combined effect of sealing the lateral line or manhole while also reestablishing the weight bearing capacity of the soil. The way it works, is a high density structural polymer is injected along the pipe in multiple zones. Once the polymer is injected, it aggressively seeks out the voids and pushes away any water along the structure, forming a water tight seal. The polymer encapsulates the pipe and the joints are sealed against I/I. The injections can occur from the surface or within the pipe itself. View projects and learn more about the process here!

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A Summary of CST Applications

Concrete Stabilization Technologies, Inc. is committed to partnering with our local municipalities, engineers ,and maintenance personnel to provide effective solutions for maintaining and extending the life of infrastructure. Whether it be streets and sub grade, curb and gutter, water and wastewater systems or structures, we have advanced technology to address settlement, erosion, and infiltration issues cities, towns, and counties commonly experience. Our non-destructive, no excavation technologies and processes are the superior alternative to tear out and replace or traditional methods such as compaction grouting. Proven, long lasting, viable solutions extend the use life of municipal infrastructure while keeping you in control of your assets. CST has been solving infrastructure rehabilitation, soil stabilization, and concrete settlement issues for 19 years. Emergency rapid repair, maintenance and rehabilitation services are available for Colorado, Wyoming, Montana, and Utah.

Trenchless Sewer RepairStreets & Subgrade Stabilization
We stabilize weak, poorly compacted or moisture compromised soils of all kinds, in-situ while leveling structures (including pavements) by injection of high-density structural polymer. At-depth injections eliminate common subsurface soil issues. Utilizing the most advanced technologies, our process drives out water, fills underground voids and fissures and expands to densify the ground.

Rehabilitation with polymer Deep Injection Technology is ideal for streets, highways, bridge abutment and approach stabilization, rehabilitation, pavement/curb & gutter alignment and support, taxiways, runways, tunnels, and infrastructure with settlement problems caused by poor underlying soil compaction and moisture issues.

We provide rapid repair of pavement and structures, washout and sink holes, and voids.

Utility Repair & Rehabilitation

Infrastructure Rehabilitation: Regardless of age or construction of a structure, inflow, infiltration, and exfiltration through cracks, and leaking joints, cause additional expense in both unnecessary water treatment, and repair of settled roadways, sidewalks, and other structures. Our in situ, zero excavation rehabilitation methods allow for injection of a high density, hydro-insensitive polymer to quickly eliminate infiltration into degraded infrastructure and lift, realign, and where needed, stabilize overlying roadways by densifying weak soil, and increasing the collective load bearing capacity.

Manhole Sealing & Encapsulation: We seal, stabilize, and stiffen weak soils around leaking manholes, encapsulating buried infrastructure where soil erosion has created shifts in the drainage structure as well as infiltra-tion of soil. Our technicians are well trained to understand infrastructure systems and how to correctly install polymers to complete the restoration of an infrastructure asset.

Lateral Line Sealing & Stabilization: Sagging lateral lines along with joint and radial cracks cause major disruptions and inefficiencies in storm and sewer drainage systems. As the expanding structural polymer (ESP) is injected, material expansion begins to compact and fill voids around the lateral lines. Outcropping of polymer occurs, confirming voids are filled, as well as eliminating further infiltration.

Corrugated Metal Pipe Repair: Our CMP repair process extends the life of the culvert, eliminates all existing void space, and stabilizes the soil be-neath the culvert. In situ repairs thus restore proper flow. Costs and disruption are greatly reduced, when compared to traditional tear out and replace. When working for railroads, there is no track downtime involved. For cities and towns, no road closures, and traffic interruption is minimal.

Outfall RepairAdditional Repair Processes for:

  • Prevention of water intrusion & water piping
  • Erosion control through sealing and fortifying
  • Elimination of ponding & settlement
  • Leak sealing against hydrostatic pressure
  • Leak sealing against running water
  • Groundwater cut-off around existing structures
  • Curtain walls, cut-off walls, & retention systems
  • Abandonment of pipeline & ducts in-place
  • Remediation of water retaining structures such as dams, dikes, levees, weirs, berms, and reservoirs
  • Remediation of subgrade vaults, conduits, tunnels, lift-stations, and utilidors
  • Remediation of washouts, dam overflow structures, spillways, levees, elevator pits, and tunnels
  • Remediation of water treatment facilities
  • Improvement of the design life of infrastructure
  • Culvert stabilization and realignment
  • Emergency & maintenance/rehabilitation for natural disasters
  • Foundation repair on existing structures
  • Airfield and runway rehabilitation, slab realignment, sub grade soil stabilization

CST uses the URETEK Technologies and is the Rocky Mountain Region’s licensed URETEK affiliate. URETEK has proven success with over 100,000 projects, a world wide network of engineers, affiliates and satisfied customers.

Key Benefits for Engineers, Municipalities, and Government Agencies:

  • Non-Disruptive , No Excavation, In Situ Repairs
  • Proven Technology
  • Long Lasting Repairs
  • Materials are NSF/ANSI Standard 61 Approved Safe For Potable Water
  • Work Around Customer’s Requirements—Off Hours, Nights, Weekends if
    Required
  • Trained Technicians and State of the Art Injection Equipment, Surgically
    Precise Repairs & Consistent Results
Frost Heave HW70

Frost Heave Mitigation of a Wyoming Highway

Abstract – Frost Heave Mitigation Using URETEK 486Star

This project investigated a novel procedure for frost heave mitigation to reduce or prevent subgrade freezing by use of a chemical grout injection process at the top of the subgrade. Controlled injection of URETEK 486Star, an expanding structural polymer foam, created a continuous three inch thick layer of insulation that significantly reduced the heat loss from the deeper soil and prevented the upward movement of water from the warmer regime under the foam to the upper frozen regime above the foam, preventing segregational freezing in the upper zone. The construction time for the 170 foot section was one week for injection and milling the surface. Construction was contained in one lane, leaving a lane open for the entire duration without a detour, increasing safety and minimizing impact for the driving public.

Additionally, a procedure is developed for estimating the thickness of the foam layer required for other sites with different average temperatures.

Objectives

  • Can foam be injected nondestructively to level the road surface and make the road safer to drive without full reconstruction?
  • Will the foam layer provide a sufficient thermal barrier to prevent heat loss and reduce frost heave?
  • Will a continuous layer of foam create a barrier to vertical water movement and reduce spring thaw degradation?

Background

  • This section of Highway WY-70 was constructed in the early 1980’s. The highway crosses a crystalline caprock ridge outcrop that the contractor had difficulty removing.
  • The contractor was allowed to alter the design to leave the ridge intact and place three feet of compacted silty sand fill over the rock with the sub-base and base course on top over a distance of 150 feet.
  • Lateral drains and cross drains have not completely removed the water under the pavement. .
  • The combination of a frost susceptible silty sand, extended cold temperatures and the availability of water provide the necessary pieces for segregational frost heave.
  • Measured heaves of three inches and reported heaves of four to six inches created a dangerous bump over a short distance of 75 feet. In addition, a drain installed over the caprock was backfilled with non-heaving backfill which created a dip significant enough to flip snowmobiles off of trailers when traveling faster than the posted speed.

Proposed Solution

A standard technique to control frost heave is to place several layers of foam insulation panels below the sub-base course. This requires a full reconstruction of the site. A process was proposed to inject a three inch thick layer of a two part structural polymer foam, URETEK 486Star #3, at the bottom of the sub-base without removing the existing road surface.

Construction

Concrete Stabilization Technologies, Inc (CST) injected the foam through a series of 3/4 inch diameter, 18 inch deep holes drilled through the road surface on a 6 foot grid. Three inches of foam were injected over the area with the most heave. Additional injections provided tapered zones to smooth the transition from the original road surface to the full thickness zone.

The process required two trucks and a four person crew to complete the work in four days. All the work was performed in one traffic lane at a time while keeping the other lane open for traffic. Because of the poor road surface before the injection, the surface was milled at a later time. The subsequent road surface was sufficiently leveled to make the mediation unnoticeable.

Injection and Instrumentation Locations

  • Thirty survey points at 10 feet centers were measured over a 300 foot distance on five rows located at:
    • The centerline of the road,
    • The centers of the two lanes, and
    • The north and south edges of the lanes.
  • Five piezometers located in the north and south shoulders of the road.
  • Six boreholes with thermistors to measure the temperatures in the soil profile. One thermistor in each hole was located:
    • Above the injection point and the foam layer,
    • Below the foam layer, and
    • Ten inches below the foam.
    • One or two other thermistors were located lower depending on the depth to bedrock.

Results

The upper figure shows the measured elevation changes from the summer baseline along the center of the east bound lane.

    • The thin solid black line shows the heave in January prior to the injection of the foam. The dip at STA 2+10 is the location of a French drain that was backfilled with non-heaving sand.

 

  • The heavy black line shows the foam thickness averaging 3 inches with tapered edges to the east (STA 2+40 to 2+70) and west (STA 1+70 to 1+40).

 

 

  • The colored lines show the elevation differences in the two winters after injection. The total heave over the treated zone is generally less than 0.5 inches and is less than the natural heave outside the treated zone. The lower figure

 

 

  • shows the elevation changes along the centerline of the west bound lane. Substantial heave is shown where the foam thickness is only 1.0 to 1.5 inches.

 

 

 

The upper figure shows the measured elevation changes from the summer baseline along the center of the east bound lane.

  • The thin solid black line shows the heave in January prior to the injection of the foam. The dip at STA 2+10 is the location of a French drain that was backfilled with non-heaving sand.
  • The heavy black line shows the foam thickness averaging 3 inches with tapered edges to the east (STA 2+40 to 2+70) and west (STA 1+70 to 1+40).
  • The colored lines show the elevation differences in the two winters after injection. The total heave over the treated zone is generally less than 0.5 inches and is less than the natural heave outside the treated zone. The lower figure
  • shows the elevation changes along the centerline of the west bound lane. Substantial heave is shown where the foam thickness is only 1.0 to 1.5 inches.

The lower figure shows the elevation changes along the centerline of the west bound lane. Substantial heave is shown where the foam thickness is only 1.0 to 1.5 inches.

This figure shows the elevation changes along the centerline of the west bound lane. Substantial heave is shown where the foam thickness is only 1.0 to 1.5 inches.

The heavy black line in the below graph shows the thickness of the foam being about 3 inches under the east bound lane and tapering to zero under the west bound lane.

  • The thin colored line is the measured heave in the year before construction.
  • The other colored lines are the measured heaves during the two winters after construction.
  • The heave on the south edge (-12 feet) is caused by edge effects and local freezing.
The heavy black line in this graph shows the thickness of the foam being about 3 inches under the east bound lane and tapering to zero under the west bound lane. The thin colored line is the measured heave in the year before construction. The other colored lines are the measured heaves during the two winters after construction. The heave on the south edge (-12 feet) is caused by edge effects and local freezing.

Conclusions

  • Transferability of the control strategy is possible if the weather conditions in the new corridor are similar (i.e. defined by the same weather variables) to the corridor where the control strategy was developed.
  • It would be beneficial to train the decision trees with the storm data collected at the new corridor.
  • The system should be monitored till it is recommending desirable speed limits based on real time weather and traffic information.
  • From the simulation results it is observed that proposed control strategy is performing slightly better than WYDOT’s manual protocol.
  • If the control strategy is to transfer a completely new corridor, it would be ideal to collect some storm data and train the decision trees before using the control strategy in real time.