Geotechnical Services

Geotechnical investigations are required for many projects, especially in areas with unusual or challenging geology. R. W. Gillespie & Associates' staff of professional engineers, certified geologists, and other engineers, scientists, and technicians make an exceptional team in terms of advanced educational background and project experience. This base of knowledge is supported by the latest technologies for analyzing site characteristics and building materials applications.

Foundation Investigations

Our staff members have experience investigating sites representing a wide range of types of geologic situations, from steep slopes to submarine. Investigations have been conducted for both pre-development and post-development evaluations, correction of construction hazards, and for a wide array of structures and deep foundations including piles and drilled piers. Subsurface exploration methods range from conventional boring and sampling techniques to sophisticated, in-situ testing such as borehole pressure meter. Where applicable, field instrumentation including vibrating wire piezometers, settlement platforms, inclinometers, and seismographs are employed to monitor and verify performance during construction.

Slope Stability/Landslides

Strength and safety of earthen slopes and embankments are issues common to site design in steep slope areas and landslide risk analyses. Our professional staff members have evaluated landslides and slopes in sixteen states, and have designed hundreds of projects addressing these situations. Projects have ranged from minor sloughs to landslides covering 30 acres. Recent studies have included stability of soft clays along an actively eroding marine shoreline and a riverbank subject to long-term sloughing.

Dam Safety

Principal and senior engineers have extensive experience in geotechnical investigations required for design of dams and diversion structures. Dam failure investigations, safety inspections, and seepage and stability enhancement projects have also been completed. Experience includes work in high risk seismic areas and on structures which previously had failed on multiple occasions.

Problem Sites

Evaluation and design of solutions to problem site situations have been conducted by our staff. Collective expertise represents a wide range of situations, ranging from reconfiguring slopes for a hillside subdivision to a building project where a Richter magnitude 4.5 earthquake occurred during construction.

Pavement Design and Evaluation

Numerous road and pavement projects have been performed in New England and other climates. These have included subgrade evaluation and pavement design for miles of public highways, as well as truck access roads, parking, and airport pavements. Projects have involved new construction, analysis and design of rehabilitation projects, and examinations and future performance predictions of existing roadways.

Resource Evaluations

Our services to evaluate potential sources of sand, gravel, and crushed rock have increased in response to the growing demand for these resources for new construction. Our expertise lies in locating and quantifying potential sources of aggregate based upon scientific understanding supported by high technology. Geologic mapping, aerial photography, test pits, and borings are used to explore and evaluate potential sites. Samples recovered during the exploration phase are returned to the laboratory for testing specific to an intended use of the material. Site resources are quantified with respect to types of material and potential uses and values. As part of the resource study, we also project and evaluate impacts to groundwater flow, quantity, quality, and recharge.

Construction Consultation

Issues related to geotechnical engineering, geology, geohydrology, or environmental science often arise during construction of a facility. Our collective staff experience includes construction of a wide variety of facilities, from buildings, tanks, pipelines, and landfills, to waterfront structures and marine facilities. When these issues arise, our construction consultation services can help owners and constructors develop and evaluate alternative methods to achieve project design requirements in the most timely and cost-effective manner. We provide construction expertise in the areas of earthwork, rock excavation, dewatering and slope stability; management of contaminated soils and groundwater; pile capacity, wave equation, and load testing; monitoring the effects of construction on temporary and permanent facilities including settlement, lateral displacement, and groundwater impacts; and specialty foundation construction such as slurry trenches, composite landfill liners and covers, mini piles, underpinning, tiebacks, and soil and rock anchors.