Geotechnical Engineering

Soils Investigations

BOTA Consulting Engineers, Inc. personnel capabilities include the full range of geotechnical and geological field investigation and sampling programs. Through participation on some of the largest private-sector and infrastructure projects in the Maryland, District of Columbia and Northern Virginia, our personnel have gained extensive experience evaluating subsurface site conditions and predicting soil and rock behavior for many different types of projects.

We are capable of designing and implementing a wide range of field investigation programs, including sampling and laboratory testing of soil and rock. From rehabilitating existing levee structures to seismically retrofitting bridges, we are capable of performing deep exploration borings where soil and rock cores are retrieved and studied, the permeability of the soil and rock mass is evaluated by water pressure testing, and the seismic wave velocity is determined by performing down-hole geophysical studies.

Our personnel have experience with difficult site access. Limited access and portable drilling equipment has been employed for many difficult access locations such as landslide and slope stability investigations, and the interior of residential and commercial structures. In some instances, cranes were utilized to lower skid-mounted drilling rigs into position.

Each project presents a separate challenge to properly sample the soil and rock materials encountered to appropriately characterize the subsurface materials and the site. Our engineers have extensive experience sampling soils with numerous types of samplers including the Standard Penetration Test (SPT) split-spoon sampler, Shelby-tube sampler, various sizes of Pitcher Samplers, and Fixed-Piston Samplers. Bedrock sampling has been performed using conventional core-barrels, with and without split inner tubes, and wire-line coring and sampling with triple-tube core barrels.

To supplement the subsurface information gathered during drilling and sampling programs, cone-penetrometer soundings (CPT) have been used extensively for projects ranging from liquefaction studies for existing earth dams to deep foundation explorations for high-rise buildings to be constructed over soft soils. Our engineers design laboratory testing programs to characterize subsurface conditions such as compressible soils beneath proposed structures, weak bedrock foundations, and weak soil and rock slopes. To predict soil behavior under proposed construction conditions, we evaluate shear strength, compressibility, expansion potential, gradation, moisture content, and density.

BOTA Consulting Engineers has the capability of determining dynamic soil properties using cyclic triaxial and cyclic simple shear testing, settlement properties by performing consolidation tests on sensitive soils, and index properties using gradation, Atterberg Limits, UBC Expansion Index, moisture content, and dry density testing. For our pavement design and construction projects, R-value, as well as other qualification tests, are employed. We have developed state-of-the-art design parameters and construction recommendations for foundations of various privately and publicly-owned structures.