Abstract:
The control of groundwater has always been a part of civil / geotechnical engineering & the deep foundation construction industry, but in recent decades, the geotechnical community has decided to say little to nothing technical about groundwater control. This change is probably to avoid ‘ differing site’ condition claims. While saying nothing is common, many firms also opt NOT to provide the data needed to perform the analyses required by their specifications. This is problematic.
As engineers / hydrogeologists who prepare these submittals for contractors, we review many geotechnical reports. As you would expect, they vary greatly; however, there is a recent trend of supplying little to none of the parameters needed for hydrogeologic/dewatering analyses, thereby forcing the contractor’ s designer to use subjective tabulated values, past local experience, and judgment as the basis for the specified technical design submittal. Obviously, some projects require more information than other projects, but in 2023 no project should be founded on no data.
Based on more than 40 years of Northwest area dewatering design experience, this paper will present:
- Examples of problems and solutions when the specifications confuse the practice of geotechnical engineering with hydrogeology,
- Dewatering induced settlement and risk management strategies,
- Recommendations for the minimum data that should be in a geotechnical report when portions of the project may be below the water table,
- Recommendations for geotechnical reports completed before the maximum depth of excavations is known.
At the time of bidding a ‘ hard-money project’ , the only data available is in the contract documents, and all parties are best served when quality contractors can use quality data to provide quality submittals.
Key Words: Groundwater, Dewatering, Geotechnical, Hydrogeologic, Recommendations, Specifications