Geotechnical and Geophysical Expertise for Gemini Solar

Our team conducted both initial geotechnical evaluation (Phase 1) and design-level geotechnical evaluation (Phase 2), which were crucial for understanding subsoil conditions across the expansive project site. We performed Ojjo foundation installation observation for the foundation systems that support the bifacial photovoltaic (PV) modules mounted on horizontal single-axis trackers. These insights enabled safe, efficient structural designs tailored to the unique soil characteristics of the Mojave Desert.  

The geotechnical evaluation for the Gen-Tie lines focused on assessing general subsurface soil conditions along the alignments and providing information and recommendations related to geotechnical aspects of the project. The total alignment length of the Gen-Tie lines is approximately 10 miles. 

We delivered advanced geophysical investigations to map subsurface conditions with precision. This informed foundation designs and minimized the risk of subsurface anomalies interfering with construction or long-term performance—an essential step for a project of this scale. As part of these services, our team conducted seismic refraction and ReMi (microtremor) surveys at multiple locations to evaluate P-wave and shear wave velocities, which helped assess seismic site class and inform pile design. Seismic refraction surveys were performed at nine locations, and ReMi surveys were completed to a nominal depth of 100 feet. We also completed resistivity testing (Wenner four-pin method) to support corrosion potential evaluations critical to the long-term durability of subsurface infrastructure. 

As part of Quality Assurance, our teams performed construction materials testing both on-site and in our accredited laboratory. This included testing for concrete, aggregates, and soils used in building electrical equipment pads, inverter stations, and access roadways. Testing also supported other site components including switchgear and transformer foundations, fencing, and the operations and maintenance building. We also provided special inspection services for earthwork, structural elements, and electrical infrastructure to ensure full compliance with regulatory and client standards. 

In addition, Ninyo & Moore, a SOCOTEC Company, performed the initial observation of the Ojjo foundation installation as part of a testing program to evaluate both axial and lateral capacity. This testing supported the foundation system for PV solar panels mounted on single-axis tracking systems and was essential to validating design assumptions prior to construction.