Geotechnical Investigation & Report
DAC performs reconnaissance and customized subsurface exploration as required for each site. Standard sampling of subsurface materials permits field inspection and testing as well as laboratory testing of selected samples. Pertinent geologic and geohazard maps of the site are reviewed as part of our investigation program. The collected data is used for our engineering analysis and preparation of recommendations for design and construction of the project. Our recommendations will be presented in a geotechnical report for the project.
DAC provides recommendation for design of different types of foundations for every project. These will include bearing capacity values for shallow foundations as well as evaluation of foundation settlements. For deep foundations, parameters such as allowable skin friction, pile driving parameters, lateral load capacity, dynamic and vibration analyses are provided. Feasibility, design parameters and capacities for other types of foundations such as micro piles, stone columns, raft, and mat slabs are provided as required by the specifics of a project.
Slope Stability Analysis
DAC performs stability analysis and evaluation of soil and rock slopes. Natural slopes as well as cuts and embankments are analyzed and evaluated for stability under long-term and transient conditions, including seismic conditions. We have extensive experience in slope stability analysis and evaluation from our dam safety and embankment engineering projects.
Geologic Hazard Evaluation
DAC provides geologic hazard evaluation for projects that need such a study as per requirements of national and local building codes. Many geologic hazards are critical in high risk seismic zones and require thorough evaluation. DAC has extensive experience in performing cost effective evaluation of the potential site geologic and seismic hazards.
Many sites in California, in general, and the Bay Area, in particular, consist of saturated soils that have a potential for liquefaction under seismic conditions. DAC’s liquefaction study focuses on determination of the site subsurface characteristics and evaluation of liquefaction potential as well as liquefaction susceptibility of the project site. The study includes engineering analyses to determine ground settlements due to liquefaction and soil densification.
Due to damaging impact of fault movement on buildings, determination of active fault systems is important for sites where known active fault movement is present or where other active faults not previously investigated may be present. DAC performs fault investigation including trenching, monitoring, and petrographic analyses. Stability analysis and evaluation of soil and rock slopes. Natural slope stability analysis and evaluation from our dam safety and embankment engineering projects.
Pavement analysis & Design
Pavement design includes evaluation of subgrade conditions and consideration of wheel loads and number of repetitions. DAC has extensive experience in design of concrete and asphalt pavements as well as design of overlays for light and heavy traffic loads.
Design of embankments requires consideration of subgrade and embankment settlements. The evaluation of subgrade compressibility and stability would be a major issue and compaction of the embankment and the material of the embankment fill are evaluated.
Darius has over 15 years of experience designing and monitoring earth and rockfill embankment dams. In addition, he has performed safety evaluation of concrete as well as embankment dams and their foundations.
Unstable soil poses problems for foundations and pavements. Techniques have been developed for stabilization of such soils for minimizing adverse impact on supported developments. These methods include lime and cement treatment, wick draining, stone columns and more. DAC’s experience provides evaluation of feasibility and effectiveness of the soil stabilization method for each site.
Soil & Rock Anchors
In the design of retaining walls, when the lateral loads are excessive, techniques such as soil nailing, ground anchors and tiebacks are used to support the wall. DAC has the knowledge and experience to provide cost-effective, efficient design and application of soil and rock anchors.
Dewatering & Groundwater Control
Excavation under high ground water table will require dewatering as well as stabilization of excavation walls. Dewatering may impact the settlement of adjacent structures. It is therefore important to have a control over groundwater system in order to perform the excavation safely and minimize the potential for settlement of other structures.
Forensic services include assessment of causes of foundation failure.