Geotechnical Engineering

ETTL's Geotechnical Services Include:

• Test Borings
• Soil and Rock Core Sampling
• Groundwater Monitoring Well and Piezometer Installation
• Groundwater Seepage Studies
• Hydrogeological and Geological Studies
• Laboratory and Field Soil Testing

Foundation and Earthwork Recommendations for projects ranging from small commerical to large infrastructure.

Pavement Design

For TxDOT pavement designs, soil samples undergo Texas Triaxial testing to determine its subgrade modulus—one of the strength parameters used in pavement design. These and other data are turned over to ETTL's engineering department for development of the pavement design, following TxDOT formulas that take into consideration such factors as traffic counts and proximity to nearby metropolitan areas. The design will recommend thicknesses and materials for the various layers of the pavement, with options relating to economy, strength, and other factors.

With various other clients, ETTL may use slightly different testing techniques. For example, formulas used by AASHTO (the American Association of State Highway & Transportation Officials) may be employed, and instead of Texas Triaxial testing, California Bearing Ratio (CBR) tests may be used.

Soil Resistivity Testing Services

ETTL works to help clients make sure the grounding systems they are designing (or have already installed) will be compatible with the soil in which they are placed.

Almost everyone recognizes the importance of earth grounding for electrical systems -- the need to provide a low-impedance path to the earth for high currents from lightning strikes and power surges, as well as a path for low currents from RFI (radio frequency interference) and static build-ups -- and also to ensure that non-current carrying metal parts are at ground potential for the sake of personnel safety. What is not as well known is that soil resistivity (electrical resistance of the subsurface) varies widely, often within the same site, depending on soil type and density as well as depth. A soil resistivity "profile" can be crucial to grounding system design. If soil resistance is too high, the system may fail, resulting in loss of (or damage to) highly expensive electrical equipment, such as exists in TV towers, cellular towers, water towers, electrical billboards, elevator electrical systems and other types of installations.

In addition, knowing soil resistivity is important for control of corrosion in buried structure

Forensic Invesitgations & expert witness services

ETTL offers litigation support and expert witness testimony as adjuncts to its environmental, geotechnical, and construction materials engineering services. Our firm has provided forensic services to a wide range of clients, such as project and facility owners, insurance companies, attorneys, manufacturing and other industrial concerns, governmental clients, and individuals. Our forensic investigations may call for any or all of the three services briefed below:

• Data acquisition via actual investigation of site, field testing and/or sampling, and laboratory testing, to gather relevant information and evidence.
• Analysis of data and documentation (environmental and/or construction records) to determine impacts, sources, potential risk and to clarify other pertinent matters.
• Provision of litigation support, including expert witness testimony.