Site Investigations

Depending on the nature of the project, the site investigation may require expertise in engineering geology, geotechnical engineering, materials engineering and forensics. Yeh’s professional staff has the expertise in these areas to develop and implement an efficient and effective site investigation program.


Our staff has drilled in rugged mountain conditions with steep terrain and limited access. Our projects have also required drilling in sensitive alpine, desert and historic site conditions which require not only specialized drilling equipment but also a thorough understanding and appreciation of the impacts from the investigation activities.


Our geologic site investigations also include the visual evaluation and measurement of the site features, such as bedrock outcrops; bedding, joint, and fracture density, strike and dip; geomorphology and erosion features; rockfall source potential; landslide delineation and activity; pavement conditions and past maintenance activities; and forensic evidence.


The site investigation requires proper selection and testing of the soil, bedrock and materials samples obtained during the field work. Yeh and Associates has an in-house laboratories in each of our offices. Our laboratories are extensively equipped and staffed with trained, qualified personnel and overseen by a registered professional engineer. The laboratories are capable of performing soil and rock property tests and an array of asphalt, concrete, masonry and steel tests. The Denver office laboratory is certified by AMRL and CCRL.