EXECUTIVE DIRECTOR UPDATE Dewatering and Groundwater Control M any deep foundation construction sites require control of groundwater during excavation or some type of dewatering to ensure workable, dry, safe and stable working conditions. Following DFI’s 2016 International Conference on Deep Foundations, Seepage Control and Remediation in New York last fall, where such techniques were discussed, we were prompted to dedicate a special issue to this theme. A section of the conference proceedings contains 9 papers on cutoffs for dewatering applications and temporary cofferdams, with an additional 12 papers also addressing these topics. The proceedings are available at www.dfi.org on the ‘Publications’ page. Following the announcement of the May/June 2017 magazine theme, technical articles were submitted that address different aspects of this important subject. Articles include the cover story on the use of a diaphragm wall and a dewatering system for the construction of the Al Ghazala Intercontinental hotel in Libya, dewatering challenges faced on projects in New York City, and the development of dewatering guidelines for use in Abu Dhabi. It may seem simple to dewater an excavation, as the author of the article “The Secret to Dewatering” (pg. 83) refutes, it is often common to have seepage issues on projects, which can result in costly delays and change orders. By providing these case histories here, we hope to assist our readers in determining the best method for their next project or consider similar solutions when (or, preferably, before) a problem arises. Other resources on this topic include DFI’s Slurry Wall Committee and Seepage Control Working Group. The Slurry Wall Committee provides guidance and education on techniques for building concrete walls in soft earth near open water or in a high groundwater table area. The 38 members of this committee are experienced in the design and construction of these elements for temporary and per- manent works, and are dedicated to assisting our members and other s in the indus t ry in expanding their knowledge in this area. If you have not reviewed their publication titled, Industry Practice Stan- dards and DFI Practice Guidelines for Structural Slurry Walls, it is worth the read, and is available at www.dfi.org on the Theresa Engler Executive Director [email protected] ‘Publications’ page. The committee is currently finalizing its Guide to Selection of Cutoff Methods. So, keep an eye out for announcements on this guide’s availability. Also in progress is a DFI Committee Project Fund awarded research effort to develop consensus guidelines for the design and detailing of reinforced concrete diaphragm wall construction in regions of high seismicity. DFI’s Seepage Control Working Group Through these activities, DFI hopes to assist in the prevention or mitigation of problems that could arise when groundwater control difficulties are encountered and dewatering techniques are needed on your projects, thus minimizing your risk in the future. provides a collaborative forum for industry and federal and state agencies to discuss best practice issues for seepage control and foundation improvement for water infrastructure projects, such as dams and and Remediation track during the DFI 41 Annual Conference on Deep Foundations in N.Y., and then, shortly thereafter, held a workshop in northern California to discuss technical and management issues related to specifications for levee cutoff wall projects us ing t renching and soi l mixing techniques. The workshop goal was to align expectations and understanding among all parties, so that future specifications will produce high-quality cutoff wall design and construction with fewer problems during construction. A report on the results levees. This group led the Seepage Control st of and discussions during the workshop should be released within the next few months, and will include the presentations given during the workshop as well as discussion summaries, action items and recommendations. If you have a strong interest in dewatering and groundwater control, I encourage you to read the technical articles provided in this issue and the papers in last year’s annual conference proceedings, as well as attend a meeting of the Slurry Wall Committee and Seepage Control Working Group, or join to contribute to their ongoing work. Through these activities, DFI hopes to assist in the prevention or mitigation of problems that could arise when ground- water control difficulties are encountered and dewatering techniques are needed on your projects, thus minimizing your risk in the future. If you have suggestions for future magazine issue themes that will help you in your day-to-day work, please send your requests to [email protected]. DEEP FOUNDATIONS • MAY/JUNE 2017 • 9
