Fully understanding underground conditions is the most critical element of geotechnical, hydrogeologic and geoenvironmental evaluations and investigations. At Ardaman & Associates, we employ a wide range of investigative methods, procedures and equipment to explore the subsurface and to characterize soil, rock and groundwater conditions. We use both direct and indirect approaches, incorporating devices that range in complexity from traditional to "state-of-the-art." However, in any particular application, the more sophisticated (and costly) methods may not be essential, yet the more basic approach may not be sufficient to adequately define the underground conditions. Many factors, including budget, schedule, client needs and expectations, as well as standards of practice and technical data requirements, are considered when developing an investigation program. Our objective in all cases is to apply the technology that best satisfies the needs of the project.

Indirect Methods
The indirect approach to evaluating subsurface conditions includes all methods which acquire information without physically invading or penetrating the ground surface. Such methods include interpreting and evaluating aerial photographs, geologic maps, groundwater contour maps, topographic maps and other types of published information, along with geophysical methods such as electromagnetism and ground penetrating radar.

Ardaman & Associates maintains a full library of information relating to geotechnical engineering, hydrology and geoenvironmental sciences. Our librarian makes sure that the most recent maps, photographs, and reports are readily available to our engineers and scientists. Our information resources include a database containing information on over 80,000 projects completed by Ardaman since 1959. These resources are routinely tappedfor preliminary evaluations, to help develop a field investigation program, and to augment the data obtained from the field program.

Ardaman & Associates' personnel are capable of applying and evaluating geophysical investigation procedures. Electromagnetic (EM) surveys provide a means for exploring subsurface conditions using electrical measurements taken at the ground surface, since different soil types exhibit varying conductivity. This approach is also helpful when evaluating contaminated groundwater conditions which often exhibit conductivity that varies significantly from normal background conditions.

Ground Penetrating Radar (GPR) measures return of radar pulses to evaluate the subsurface soil and groundwater profile. This method can be especially helpful in identifying buried objects and refuse, describing shallow rock profiles, and locating anomalies that may be indicative of potential sinkhole conditions.

Direct Methods
A more detailed description of underground conditions at specific locations are revealed with direct investigation methods which obtain information by physically sampling or testing soil, rock and groundwater. The sampling or testing devices are inserted into a borehole advanced into the ground by drilling methods, and either samples are returned to the surface for evaluation and testing, or the properties of the underground profile are measured by in-place testing.

Ardaman & Associates maintains a fleet of more than 25 drilling rigs mounted on various platforms including trucks, all-terrain vehicles, and a barge. These rigs employ both rotary fluid and hollow stem auger methods to perform soil borings.

Soil and rock samples are obtained through the boreholes using a variety of sampling devices. Ardaman's drill crews are well trained and are proficient with all of the drilling and sampling tools at their disposal and they have received the OSHA 40 hour training and annual refresher courses required for working on hazardous waste project.

Ardaman employs numerous in-place testing methods, many of which have been developed in- house, and define the "state-of-the-art" of geotechnical testing. Devices such as the cone penetrometer, flat plate dilatometer, vane shear device, and piezometer probe can evaluate either through direct measurement or empirical correlation, geotechnical properties such as shear strength, compressibility, temperature and pore pressure. In addition, Ardaman & Associates uses equipment for instrumenting soil behavior such as inclinometers for measuring horizontal deformation, vertical settlement profile detection devices, and total earth pressure cells.