PPI’s Geophysical Services Department was created in 2014 in response to a Client’s need to evaluate foundation bearing capacity at remote Project Sites with minimal site disturbance. Since 2014, PPI has compiled a lengthy geophysical project resume using a combination of surface seismic methods and resistivity. PPI has developed particular expertise with karst, sinkhole, and mine feature investigations.
Geophysical studies can add tremendous value to traditional subsurface investigation programs. Subsurface investigation can often be an iterative process, especially when investigations are focused on identifying voids, specific contact zones, or other anomalies in the subsurface. PPI’s extensive engineering, drilling, and geophysical services resources allow us to design, execute, and interpret subsurface investigation programs specific to our Clients’ needs.
PPI has expertise with the geophysical survey methods listed below:
- Multi-Channel Analysis of Surface Waves (MASW)
- Seismic Refraction
- Refraction Microtremor (ReMi)
- Electrical Resistivity Tomography (ERT);
- Resistivity; and
- Ground Penetrating Radar
Bring the Noise: Surface seismic methods require a seismic source. The PEG 40 brings the noise: a 40-kg hammer is powered by an elastomer band, striking an impact plate and creating a seismic source that can overcome background noise. The PEG 40 allows PPI to collect quality geophysical survey data, even in environments with considerable background noise.
Karst Characterization and Structural Sinkhole Rims: PPI utilizes a combination of surface seismic methods and subsurface drilling during performance of karst characterization studies throughout the region. Use of geophysics is particularly useful when the project objective is definition of a structural sinkhole rim. Geophysical survey can provide a large amount of data in a short amount of time. PPI likes to say that geophysical survey helps us decide where to drill first.
In Our Backyard: PPI is headquartered in Springfield, Missouri. Most of PPI’s staff lives in Southwest Missouri – many on property that is sinkhole-impacted. This comes in handy when PPI procures new geophysical equipment – PPI’s Geophysics Department can always go back out to our staff’s backyard, and see how our new equipment or methodology compares to previously completed geophysical surveys of the same sinkhole area.
The cross section below shows one of our staff’s test sinkholes – a traditional, bowl-shaped depression that is dry during normal conditions, but ponds water during periods of heavy rainfall.
Mr. Brandon Parrish, P.E., Vice President – Engineering, Ph.: (417) 864-6000, [Email]