Michigan Municipalities: Spring Runoff Causes Slope Stabilization Concern

As Michigan’s winter turns to early spring rains, municipalities need to keep a watchful eye on erosion control and slope destabilization possibilities around rivers, roadways, commercial sites and any site where excess water and loose soil conditions could trigger unwanted soil movements.

G2 Consulting Group, a Troy-based leader in geotechnical, environmental, and construction engineering services, works with communities, state agencies, commercial property owners and homeowners on preventative slope stabilization designs, and, when necessary, remediation efforts to repair failures.

“Snowmelt and spring rains are the two most common causes of soil erosion on Michigan slopes,” said Mark Smolinski, P.E., G2 principal. “Since slopes are common around important natural and made-made environments, it’s important to monitor and plan for a potential destabilization event, where soil can easily spill into waterways, onto roads, or even impact commercial and residential structures.”

G2 Consulting Group works with clients across all stages of slope management, often beginning with a risk assessment and analysis to help property owners identify problem areas. Slope stabilization efforts run the gamut, from easy and low cost to more complex engineering projects:

  • Slope geometry: When there’s available land nearby, one of the most cost effective solutions is simply to remove soil from the slope, thereby lessening the severity of the slope and the likelihood of a slide.
  • Water drainage: Since water is a primary trigger of destabilization events, drains and culverts can be installed to improve soil conditions.
  • Soil improvement: Soil conditions can also be improved mechanically through compaction, mixing and other remedies or chemically by adding cement or other aggregates.
  • Natural slope support: Plants, bushes, and trees can be planted, with their root structures significantly aiding stabilization while also enhancing natural beauty.
  • Engineered slope support: Ranging from simple netting and geosynthetic reinforcements to more complex implementation of anchors, piles, and retention walls, G2 offers solutions for even the most severe and perilous terrain.

“It’s impossible to reinforce all slopes in the state, and we know many city managers will wake up to news of a slope failure in their area,” Smolinski said. “In those cases, we’re able to respond quickly, assess the problem and identify remedies that make the most sense at the particular site.”

G2 Consulting Group has more than 30 years working on Michigan slopes, from investigating subsurface conditions, performing visual surveys of slopes, and providing design solutions to prevent and remediate slope erosion or global slope failure. Please contact G2 to learn more.

Tech Talk: Thermal Integrity Profiling

G2 Consulting Group uses the latest technologies and processes to ensure it consistently delivers Smart. Results. Fast. to our clients. Thermal Integrity Profiling (TIPTM), a state-of-the-art method of evaluating the integrity of augured concrete foundations, is one of those technologies, and G2 is one of the few construction engineering services firms in Michigan to offer this capability.

TIP is a non-destructive testing method that measures the heat generated by curing concrete to monitor and assess the quality of drilled shafts. By analyzing temperatures along the entire depth of the foundation, concrete deficiencies or defects can often be detected early in the process.

TIP testing requires Thermal Wire® Cables to be attached to the pile cage or center bar before it’s placed into the drilled hole. Thermal acquisition ports are then attached to each cable, usually added after the concrete is poured, to record the curing temperatures at a multitude of points at various locations and depths.

G2 Consulting staff analyzes the resultant data showing the relationship between thermal heat at various depths with regard to the total volume of concrete poured in the pile. If the average temperatures at depth remain consistent and in-line with expectations, then the shaft can be considered uniform in shape, quality and integrity. Higher than expected temperatures in a particular zone may indicated bulges or deformities, whereas lower temps typically are found where insufficient concrete quality or cross section reductions are present. Thermal Integrity Profiling can detect these anomalies which are usually present at multiple points along the thermal wire cables at the same depths, providing additional confirmation of the condition.

G2 has successfully used TIP processes on many projects in Michigan. Our staff are trained and certified to perform this analysis, helping clients ensure their projects are built on a solid foundation.

Unique Shaft System Facilitates Rehab of Interceptor

The Oakland-Macomb Interceptor Drain (OMID) is a 50-year-old concrete system bordering Oakland and Macomb Counties in southeast Michigan. Authorities targeted more than seven miles of this large diameter interceptor sewer – 40 feet below a busy county road (M 59) – as a priority for evaluation and repair to avoid catastrophic failure.  This project is part of a $160 million effort that has been under construction since 2009.  Given the unique opportunity the project afforded to have access to this critical trunk sewer, the owner’s objective was to perform as many repairs possible.

Lanzo Trenchless Technologies was selected to  provide multiple rehabilitation services, including  high volume sewage control management, cementitious grout in place liners, fully deteriorated model CIPP, large bore spot repairs, cementitious grouting of voids, access manhole restoration, localized crack/failure repairs using chemical grout and CCTV.  Challenges included working in and around flow that could not be disrupted during the construction process.  Work was difficult and dangerous, and required extreme care in safety consideration, monitoring and management.

One of the first tasks of the project was to tunnel a shaft down to the 96-inch diameter sewer crown, create access and build a platform for staging of both the chemical and cementitious grouting activities within the pipeline. Lanzo retained the services of G2 Consulting Group to design two 16-foot diameter corrugated steel liner shafts to gain access to the existing sanitary interceptor approximately 20 to 25 feet below ground surface.  To meet project requirements, G2 designed a shaft system that is uncommon for this part of Michigan.