Soil Quality Interpretation
The stability of soils is a paramount consideration in your pre-construction planning. Faults and fractures present unusual hurdles for developers and emphasize the necessity to understand the physical characteristics of a given parcel of land. Our geoscientists, geophysical technicians and cartographers, are trained to evaluate the results of seismic velocity testing to provide that necessary comprehension. We can tell you everything you need to know about your soil before you lay the first footing or drive the first piling. You’ll know how deep to set your piers, the capacity it can entertain, and even the soil friction acting on the pier.
Downhole/Crosshole Geophysical Surveys
In order to characterize the subsurface conditions/structure, we apply seismic geophysics. Compression and shear wave velocity measurements are made between a series of two or more, pre-drilled and outfitted boreholes created for the purposes of the crosshole survey, which contain geophones that record the arrival of the seismic waves from the energy source (down-hole hammer). By recording the compression and shear wave velocities between boreholes we are able to calculate Poisson’s ratio, ‘ν’ (nu), which describes the expansion or contraction of a material and thus, paint a comprehensive picture of the underlying soil/sediment/rock mechanics for engineering purposes. Determining the number of holes to drill for this evaluation is entirely up to the client and is often a matter of budget consciousness. Notice that EMC will be more than happy to help you find a suitable contractor to drill the boreholes, but we are not equipped to conduct that portion of the work.
Downhole seismic is accomplished by using a single drilled and outfitted hole with a sledge hammer as the source on the surface. Here, we measure the vertical changes in seismic wave velocity at multiple intervals with geophones in the borehole and travel-time plots and velocity graphs for both compression and shear waves are recorded with a seismograph. While the downhole application is not as exhaustive as the crosshole survey, it is lower resolution. However, both are highly reliable.
Applications Include:
- Soil/Sediment/Rock Mechanics
- Bedrock Depth
- Depth to Water Table
- Stratigraphy
Downhole Logging Services
Before we’re finished, we’ll test our results and compile electronic logs (e-logs) that determine the extent of soil layers and will even identify, when applicable, the vertical extent of plumes. In the end, you’ll have an accurate picture of the soil stability hundreds of feet below the surface.
Possible Equipment Engaged:
