AN INNOVATIVE GEOTECHNICAL TECHNOLOGY TO DETERMINE SUBSURFACE CONDITIONS ALONG LIMITED ACCESS AREAS IN THE APPALACHIAN REGION

Geohazards such as unstable slopes along pipeline rights-of-way have a high potential to affect the integrity of pipeline infrastructure. In the Appalachian region of the United States, the majority of the slope movements along ROWs are shallow in nature but occur on steep slopes or areas with difficult access. Traditionally geotechnical investigations are performed to determine the subsurface conditions used for mitigation of these geohazards; and these are typically conducted with heavy tracked drill rigs or all-terrain-vehicles or ATVs. The heavy equipment is also often associated with a higher risk of safety, due in part to the drilling on steep slopes and the winching of the drill rig.

WSP conducted an extensive search on innovative types of DCP’s and found a state-of-the-art automatic DCP that can reach a maximum depth of approximately 25 feet (actual depth depends on field conditions). The DCP (manufactured by Sol Solutions and is known as the PANDA) has a calibrated automatic driving hammer and can be easily deployed to the field with a battery powered driving unit. This device also has an onboard computer that collects data to be analyzed and correlated to SPT values.

WSP has recently utilized the Panda DCP system on two shallow landslide mitigation designs in the Appalachian basin. We will present the results of these two case studies to demonstrate the accuracy of the results when performing DCP subsurface investigations to aid in geotechnical mitigation design. Both mitigation designs were implemented effectively and the results of the DCP were confirmed during construction. These case studies also outline typical cost savings of using this system compared to traditional geotechnical drilling investigation. WSP will also present how the geotechnical data is uploaded, correlated, and presented.