Engineering Geophysics

Engineering Geophysical Surveys, Olson EngineeringOlson performs geophysical investigations for civil structures, geotechnical site investigations, and geological characterization. Because of the cross-over between Olson’s Non-destructive Testing (NDT) and engineering geophysical service capabilities, our clientele can cover a broad spectrum of service needs from the scale of small structures to exploration scale geophysical investigations. In the last decade, the success of using geophysics in urban settings has surprised many clients. New approaches to old problems are where we excel; in urban settings the challenges are many, but not insurmountable. We complete approximately 100 geophysics projects per year, throughout the U.S. and internationally. The group of geophysicists at Olson has a wealth of experience conducting engineering geophysical project work. They enjoy the unique applications, difficult problems, use of state-of-the-art instrumentation and software to conduct safe and fulfilling field work. This is our bread-and-butter.

Olson successfully applies seismic, electrical, electromagnetic, magnetic, and ground penetrating radar geophysical methods for engineering applications. Our goal, on every project, is to meet or exceed the objectives. When it comes to complex engineering or geologic problems, it may be necessary to use multiple methods. Olson will work with you and the client owners to create a field program that is objective driven, but budget conscious as well. We understand the need to be competitively priced, in order to help you win the program as a whole.

Applications to engineering/geologic problems include subsurface imaging for:

  • Depth-to-bedrock or thickness of overburden
  • Geometry of bedrock
  • Competency of bedrock - for foundation design or excavation needs (e.g., rippability)
  • Lateral variability of soil stiffness
  • Vertical variability of soil stiffness
  • Low-strain elastic constants
  • Presence (or absence) of caliche
  • Presence of faults
  • Depth to water table
  • Dam stability
  • Dam seepage
  • Levee assessment
  • Foundation and/or abutment characteristics for dams and levees
  • IBC Site Classification - Vs30 (meters)
  • Obstacles to construction – for pipelines, cut-off walls, MSE walls, utilities, or retention ponds
  • Landslide and slope monitoring; slide plane detection
  • Karst – in limestone and dissolution in gypsiferous bedrock settings
  • Lithologic changes – lateral and vertical, particularly in soil deposits
  • Reuse of foundations – particularly for bridges
  • Man-induced collapse features (engineering failures)
  • Quality control for ground improvement (e.g., DDC, soil-mix columns, or jet grouting)
  • 1D, 2D or 3D assessment of small or large sites for geologic anomalies
  • Permafrost thickness and stiffness
  • Soil and bedrock characterization below active rivers
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Our geological and engineering clients appreciate that we make a concerted effort to understand the project objectives; but additionally, we want to understand the purpose of the program.  A quick example is measuring the depth-to-bedrock, a routine geophysical survey; this represents the objective. However, when we understand that the purpose of the study is to design a sophisticated foundation for a complex and extremely high-load facility, we can adjust our field survey parameters to provide more than depth, but also the low-strain elastic moduli of the subsurface to facilitate the structural engineer’s needs.  Our geophysicists have specialty training in soils and rock mechanics, geology and groundwater.  This permits our staff to interact with a wide variety of clients at a technical level, providing more confidence in the application of geophysics and the use of the results.  We are proud that we take the time to provide more than data, more than interpreted earth-models of the subsurface.  Our clients enjoy the interaction with our staff as we integrate their data (e.g., geologic or geotechnical information) to achieve more than the objective, but satisfy the purpose of their program.  We know drilling, understand sampling techniques and how they need to ‘ground-truth’ our geophysical results & interpretations.  It is this understanding of both geotechnical site investigation techniques and geophysical imaging benefits and limitations that increases our ability to deliver a better product.

The staff has both OSHA HAZWOPER and MSHA health and safety training, with annual refresher courses.  The group is skilled at addressing the ‘devil-in-the-detail’ for engineering needs of precision and accuracy.  We regularly integrate our client’s data, and also export our end results in a format for direct use in Acad, MINEX, and GIS for our clients.   We have Acad and GIS capabilities, but prefer to export out data for use by specialists in the client’s staff, but the background for these database systems affords top-level discussions on how to present the data.

It is our goal to provide the most accurate information from the subsurface for your geologic or engineering problem, with the most effective approach (i.e., geophysical method), and do it in the most economical fashion possible.  We understand engineers better than most, because half of Olson Engineering is staffed by engineers; they continually push the geophysical group to produce usable results.  Our product will result in reduced risk for your engineering needs.   Please contact us to determine if engineering geophysics can aid your program goals; if we or geophysics cannot, we will tell you upfront.  We do not need another project as much as we need satisfied clients.