Traversing California, the Rocky and Coastal Mountain Ranges dictate the geological composition of the landscape. Located on the San Andreas fault system, the area experiences frequent mini quakes and the occasional larger one. A side effect of the quakes are landslides. Despite the hazards, California is recognized for its incredible beauty. Just some of the sights people travel from around the world to see includes Glacier Point, Zabriskie Point, Morro Rock, and Bodega Head.
Source: DVIDS - News - Geologists and Geotechnical engineers dig deep to provide flood risk management At the Arcadia flood risk management project, in Arcadia, Wisconsin, geotechnical staff are gathering data using a unique method of subsurface exploration. The Cone Penetrometer Test, or CPT, is one method used to identify and characterize soils. The CPTs were conducted with assistance from the Savannah District geotechnical and geology branch. “We benefited from their expertise and cooperation,” said Greg Wachman, senior geotechnical engineer. In CPTs, a device with a conical tip and metal sleeve measure penetration resistance as it’s pushed into the ground. Those measurements are used to characterize the soils’ engineering properties. For example, the forces on the device as it’s pushed through a soft clay are very different from those as it’s pushed through a dense sand, Wachman said. The device also records pore water pressure, which aids in understanding soil permeability and groundwater characteristics. CPTs vs. soil borings A CPT is most useful when used together with standard soil borings, Wachman explained. A soil boring drills into the ground to retrieve physical samples. In contrast, with a CPT, the soil is never seen. CPTs are significantly faster than standard borings and provide continuous test data with depth. With a soil boring, samples are collected about every 5 feet, or change in material, so it’s possible to miss important information. One limitation of the CPT, due to excessive friction, is that it may not be extended to the same depth as a soil boring. The CPTs at Arcadia are being pushed to approximately 60-70 feet, whereas a soil boring can be performed in excess of 100 feet. “By doing some CPTs next to soil borings – where we know what the soils are – we can increase the likelihood that we [...]