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Irrigation Head Gate Void Fill Erosion Control Soil Stabilization

Problem

Erosion of support soils beneath this concrete head gate had happened over time caused by turbulent water eroding soils beneath the inlet floors and undermining the structure. The voids created beneath the inlet had grown large enough that the foundation of the structure was compromised. In high water events, the undercut of the water could potentially wash out the entire head gate.
FC Excavation, the general contractor responsible for repair of the head gate was hired to provide a permanent solution to stop water from undercutting and carrying soil away from beneath the floor of the structure. An in situ solution, that would not require excavation or ripping out and replacing the concrete was preferred. They were also looking to make the repair during the fall when water was not being diverted through the head gate and have it solid before irrigation started in the Spring.

Solution

Concrete Stabilization Technologies partnered with Josh Frappart of FC Excavation in designing a permanent solution to fill voids and create an impermeable curtain wall beneath the head gate to support the structure and prevent future erosion.

Upon investigation of the site, it was discovered that voids as large as 2 cubic yards exist-ed beneath the head gate. To create a stronger base, the FC Excavation crew first added rock and soil into the large voids. Injections were then made into the soil, creating support pressure and filling the voids.

The hydro-insensitive expanding structural polymer (ESP) consolidates and strengthens the weak base soil and lenses out to fill voids, reinforces and densifies the soil, and creates a permanent barrier against water erosion.

Once the crew had finished injections, the contractor brought in rip rap to be placed on top of the repaired area.

Result

The entire repair of this undermined head gate was completed in 6 hours.

The expanding structural polymer installed by CST’s technicians efficiently and effectively rehabilitated this irrigation head gate with ZERO EXCAVATION.

The ESP used to repair the head gate will effectively mitigate against future erosion. The impervious barrier created beneath the structure will divert water from forming a channel beneath the head gate.

CST’s expanding structural polymer repair process is highly effective for preventing seepage and controlling erosion caused by water. Because of its hydro-insensitive characteristics, the ESP can be installed in wet environments and does not degrade in water. This in situ repair process saves irrigation districts and land owners the high cost and downtime of rip out and replace while providing a permanent solution.

Challenge

  • Create a permanent solution to undermining and channeling caused by water.
  • Fill voids without having to excavate the structure.
  • Consolidate the soil and rock material into an effective support system for the structure.

Benefits

  • ZERO EXCAVATION in situ repair process.
  • Hydro-Insensitive material.
  • Easily reach areas where large equipment would cause damage, or unable to access.
  • Effective rehabilitation of existing infrastructure eliminates cost of rip out and replace.
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Drain Pan Void Fill Structural Support CDOT Region 1

A drain pan structure running adjacent to US-287 near Broomfield Colorado had experienced significant voids of varying severity beneath the structure. The drain pan was designed to move water away from the roadway during water events and run off; however, due to issues with the design of this particular structure, water was running beneath the concrete and eroding areas beneath the pan. The integrity of the structure was compro-mised due to the weakened and eroded supporting soil.

CDOT needed an effective solution to treat and repair the almost 800 foot long problem section of drain pan that would not only fill the voided areas, but also protect it against additional damage and structural failure that may also effect the safety of the adjacent highway.

A thorough evaluation of the site was conducted prior to design of the repair plan for the drain pan. It was determined that the more severe voids were located on the uphill slope area of the structure. Alternate solutions, including a flowable fill, were taken into account while determining the most effective way to treat the area. However, due to the advanced features of CST’s proprie-tary injection process, and the unique characteristics of the specialized expanding structural polymer, it was determined that filling the voided areas using this process would most effectively and most efficiently solve the problem. Injections were made directly through the drain pan, filling voids, and strengthening the supporting soils.

The entire stretch of affected drain pan was void filled and stabilized in four days without any disruption to traffic flow along the adjacent highway.

The treatment method allowed CDOT to extend the use life of the structure and avoid the expense of tearing out and replacing the structure.

The specifically designed repair not only eliminated the void space beneath the pan and strengthened the soils, but also provided protection to the structure against future erosion.

Repair costs came in under budget for this project.

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Railroad Subgrade Soil Stabilization Lift, and Re-alignment

A 70 foot section of railroad track near Green River, Wyoming had experienced ongoing settlement issues. During springtime, and high water events, the area required weekly re-compaction and leveling. The replaced ballast would continually sink into the wet subgrade soils.

A factor that contributed to the problem, is that the area is located at a drainage point of the surrounding hillsides.

Settlement of the subgrade soils was a continual problem for the railroad as well as the unsafe conditions for freight trains and their personnel travelling over this section of track.

Keeping the track open and safe was a major concern for the Rail Company.

CST partnered with Watco Rail representative Neal Ward to design an effective repair solution for the settled areas of track.

An initial site survey was conducted on all areas of the settled rail. Areas for treatment were identified and a site specific injection design was created to lift the settled areas, and stabilize the subgrade soils beneath the track and ballast to mitigate against any future settlement.

CST installed a high density structural polymer at pre-determined depths to treat weak soil and lift the settled track sections. Crews alternated between sections to allow train traffic to continue through the area.

All sections of settled track and weak soil zones were stabilized.

Injections made into the weak soil zones effectively pushed water away from the areas, and provided a protective barrier beneath the ballast, to stabilize and protect the area against future settlement.

Railroad track was lifted, and realigned to provide a stable, safe passage of the company’s freight trains and personnel traveling across the tracks.

All work was completed in a matter of 3 working shifts without major closure or disruption to trains traveling through.

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Concrete Slab Lift Asphalt Pavement Lift Soil Stabilization – Pueblo, CO

This highway roundabout located in Pueblo West, Colorado had experienced settling of between 2 to 3 inches in areas of the concrete panels. The settlement had occurred as a result of poorly compacted soils. The settlement of the slabs had created a negative drainage situation, causing water to pool against the curb and gutter instead of draining away from the structure as originally designed.

As part of a larger paving project, Martin Marietta, a heavy highway contractor working on the section of roadway that included this roundabout, needed a solution to lift the settled concrete panels and correct the drainage issues the settlement had caused without ob-structing traffic flow through the rounda-bout and connecting roadways.

CST partnered with Martin Marietta to create a repair plan that would allow traffic to continue to flow through the roundabout while the panels and adjoining asphalt were lifted back to original profile. CST’s technologies were used to repair the settled slabs and pavement. The process employs injecting an expanding structural polymer that densifies and compacts soil, fills voids, and lifts settled concrete and asphalt. A rubberized barrier was used to assist injection crews in staging and protecting injection hoses across the roadway which allowed traffic to safely continue through the roundabout during the repair process. Martin Marietta used a water truck to wet down the roadway and panels to assist CST’s injection crew in locating and correcting the areas of settlement prior to beginning injections.

The settlement and soil compaction issues were efficiently and effectively addressed and corrected while allowing traffic to continue use of the roundabout and roadways during the repair. The con-crete panels and adjacent asphalt pavement were lifted back to original design profile which corrected the drainage problem.

The repair was completed in less than a day, preserving the existing concrete, correcting drainage, and guarding against future damage erosion, settlement, or damage to this roundabout structure and adjacent roadway.

CHALLENGES
Maintaining traffic flow during repair.
Safely staging injection equipment in the roundabout area.
Restore drainage away from the concrete panels.

BENEFITS In situ, no excavation repairs
Little to no downtime
Fast, cost -effective, permanent
Preserves and extends the life of existing structures & pavement

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Mine Shaft Head Frame Footer Foundation Stabilization

The head frame support leg foundation on one of the Tronox Alkali Corporation mine shafts had experienced settlement. As a result, movement of the footings had caused the head frame and shaft bucket to shift from center. The issue was discovered as crews and equipment were being lowered and retrieved from the mine shaft.

Tronox Mine Foreman Todd Jackson contacted John Eddins, P.E. with JFC Engineers and Surveyors to investigate the problem. The goal was to find a solution that would effectively align the shaft and mitigate the issue of potential future tilt or settlement.

Stabilizing the foundation of the head frame support and correcting the tilt to safely allow mine crews to use the equipment to access the mine shaft was critical.

JFC Engineers contacted CST to help deter-mine the best solution to stabilize and realign the structure.

CST partnered with JFC Engineers and performed a thorough site investigation. It was determined that the back leg of the head frame foundation would be treated using the Uretek Technologies to stabilize, lift, and realign the structure.

Dynamic Cone Penetrometer tests were performed to determine the condition of soils below the frame’s legs. The tests and analysis revealed that the soil would need to be treated at two depths to lift and to stabilize the soils to assure no future settlement would occur. Injections were made at two depths under the foundation and at the toe of the foundation to mitigate potential slide or settlement in the soils. The treatment was to obtain the target realignment of the structure and the foundation stabilization with minimal disruption to the structure or operations.

Injection probes were placed through the asphalt and into the soils at depth. Injections were made while closely monitoring elevations for movement.

The mine shaft footer foundation was stabilized and the shaft frame vertically realigned. Due to the surgical precision of the injection process, no additional stress to the structure or horizontal movement occurred during the lift. Voids were eliminated beneath the footings, ensuring a strong and stable base to support the heavy load.

The project was completed with minimal disruption and without having to take the equipment off line during the repair. The equipment was immediately put back into use with all repairs done in only two shifts. Most importantly, stability was restored quickly and efficiently, extending the safe use-life of this industrial structure.

“The project was well planned and executed. The back leg foundations were lifted to the established target elevations which brought the head frame structure to verti-cal plumb. The client expressed their ap-preciation and satisfaction with the results” -John Eddins, P.E., JFC Engineers & Surveyors

CHALLENGES
Stabilize the soil beneath this large piece of equipment without having to take the shaft offline or deconstruct the head frame.
Correct the tilt of the head frame to bring the shaft bucket operation back to center.”

BENEFITS
In Situ, Fast, No-Dig Process
Ability to Lift Heavy Loads with Surgical Precision
Long Lasting Repair
Extends Use Life of Existing Structures

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Colorado Bridge Approach Slab Settlement Lift

Bridge Approach Slab Settlement Repair – Crystal Valley Parkway, CO

Asphalt Pavement Lift of a Bridge Departure where the Subgrade had settled and the pavement needed to be lifted

In Castle Rock, CO, along the Crystal Valley Parkway, the Town of Castle Rock, CO was experiencing bridge approach slab settlement of 1,900 SF of bridge approach, departure, and sleeper slabs on two bridge ends and adjoining pavement. Settlement of adjacent sidewalk had also occurred causing an unsafe driving situation as well as dangerous conditions to pedestrians utilizing the crossover sidewalk area. The unstable subgrade reaching below the sleeper slab would need to be treated to stabilize the area before mill and fill of asphalt pavement could be performed.

Bridge Approach Slab Settlement Solution

CST partnered with the Town of Castle Rock, utilizing their Deep Injection process to treat unstable soil, lift the slabs, and realign sidewalk and pavement areas. Dynamic Cone Penetrometer soil tests were performed to correctly identify the weak soil zones. Injection tubes were placed at depth and expanding structural polymer injected to densify and provide stabilization of subgrade soils. Once the soil is stabilized, injections are continued to provide lift and realignment of the slabs and overlying pavement. The CST Deep Injection process provides proper support to the soil and heavy sleeper slabs to mitigate against future bridge approach slab settlement and movement, while also providing a solid subgrade for pavement.

Repairs were made in two shifts while allowing traffic to continue utilizing the area vs. time and money spent to reroute. Foundation soils were significantly strengthened to mitigate against future settlement. Bridge approach and departure slabs were lifted back to original elevation as well as stabilization and lift of sidewalk areas. Subgrade soils were quickly and effectively stabilized to provide a strong base for asphalt pavement mill and fill operations. The added benefit of water cutoff effectively arrests soil erosion within the area. Significant savings to municipalities and tax payers vs. alternative methods of rip out and replace. Extended use life of the bridge, sidewalk, and pavement.