Geotechnical Services


Foundation Design

Yeh has vast experience designing foundations for both horizontal and vertical construction projects, from retaining walls and single and multi-span bridge structures to high rise buildings, office complexes, commercial buildings, cell phone towers, and storage silos. We have extensive experience working with diverse foundation types including spread footings, mat foundations, driven piles, micropiles, drilled shafts, and composite systems incorporating deep foundations with ground anchors.

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Pavement Design

Yeh is a leader in providing pavement design recommendations for Portland cement concrete (PCC) pavements and hot bituminous (asphalt) pavements, on existing roadway rehabilitation and new surfaces. Our staff is also fully versed in the design of hot and cold recycled asphalt pavements. We provide a range of services from a fully-integrated subgrade and pavement design to pavement section design. For existing roadways, we provide pavement condition surveys, subgrade evaluation and recommendations for rehabilitation, resurfacing, and restoration.


Site Investigation

Our in-depth knowledge of geotechnical drilling methods allows the firm to realistically scope geotechnical projects and efficiently complete subsurface exploration programs in any setting. From urban settings to rugged mountain environments, Yeh’s regional experience provides the advantage of seasoned personnel who know the geotechnical properties of a wide range of geologic formations and their derivative soils.



Geographic Information System (GIS) Capability

Yeh brings an efficient team of GIS professionals with complementary strengths to assist with its GIS needs. We use the full ArcGIS suite at the Arc/Info license level, including the Network Analyst, Spatial Analyst, 3D Analyst, and GPS Analyst software extensions. In addition to Yeh’s GIS staff, we have an internal team of skilled field personnel utilizing Trimble GeoXH sub-meter accuracy GPS units with external antennae for reliable capture of field assets.


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 Geologic Hazards

Our experienced staff provides services in the evaluation and mitigation of geologic hazards including rockfall, debris/mud flows, landslides, avalanches, collapsible soils, sensitive and swelling clays, and mining hazards. Our evaluations entail engineering geology, geomorphology, climate and hydrology mechanics, hazard mapping, and the effects of human-induced changes to surface drainage and loadings.


Rock Slope Stability

Our staff is highly experienced in evaluating rock characteristics, rock deformation and rock slope stability, and designing excavations throughout the US. Our services include geologic mapping, evaluating rock slope stability and rock fall hazards, designing new excavations in rock, and stabilization measures for existing rock slopes. Our staff has developed rock sculpting methods to simulate weathered rock slopes in aesthetically sensitive areas and is trained in traditional methods to gather rock structure data using line surveys and window mapping techniques.

 Geotechnical Instrumentation and Monitoring

Yeh uses a variety of instrumentation methods to measure conditions such as settlement, lateral movement, structural distortion, soil and rock slope deformations, tunnel deformation, water pressure, soil pressure, and foundation response. Our instrumentation engineers have developed instruments for measuring in-situ strain, high tech crack gauges, tape extensometers for measuring rock deformation, borehole extensometers, liquid level, and inverted pendulum devices to measure slope movement. Because we’ve designed the tools, we can deliver customized instrumentation programs that fit our client’s needs.