Sinkhole in Karst Topography being used as a drainage structure
Journal Article Reviews

Mitigation of Karst and Sinkholes for New Hospital Structure

Sinkhole in Karst Topography being used as a drainage structureThe site for the new Harrison County Hospital, approximately 25-miles west of Louisville, Kentucky had 15 sinkholes formed by limestone dissolution, a geomorphologic process referred to as Karst topography.  There were a number of geotechnical engineering and geological engineering challenges associated with the characterization, excavation, backfilling, foundation engineering and other mitigation measures as described by Peggy Hagerty Duffy, P.E. in her article entitled “Karst and Complications” in the August 2008 issue of Civil Engineering Magazine (Duffy, 2008b).

Mitigation measures for the sinkholes included use of graded filters with geotextiles, careful inspection of rock socket foundations along with pilot holes and careful geotechnical inspection throughout the construction process. One particularly interesting aspect of the project is that several of the sinkholes were used as drainage facilities to receive surface water runoff. Read on for a summary of this interesting article. (Photo of sinkhole in Karst Topography being used as a drainage feature, from Duffy (2008b), Civil Engineering Magazine)

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Failures

Johannasburg Sinkhole Opens after Tunnel Collapse

A 12m long sinkhole opened up on Oxford Road in northern Johannesburg South Africa after a partial tunnel collapse in the Gautrain rail tunnel being constructed underneath the road. Eyewitness accounts say there was a broken water pipe flooding the sinkhole, but no word on which occurred first. The road is expected to be closed for 2 weeks. Gautrain representatives said the tunneling would resume after geotechnical/geological investigations into the collapse are completed, which could take "several weeks". (Photo credit: Werner Beukes, Sapa via News24.com)

Via The Star (Zambia) and News24.com (Johannesburg?)

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General

7 Amazing Holes

A colleague of mine (thanks Jamie!) sent me an email with this intriguing title. I have no idea where it originated, but it is an interesting compilation of some amazing photos and short descriptions of various natural and man-made "holes". A few sinkholes, glory holes, and of course open pit mines. By the way I didn’t write (or edit) this, just some minor formatting updates. Check it out. 

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Failures

City of Vancouver sues over failed shoring

The City of Vancouver is suing a developer, excavation contractor and their consulting engineer for the costs of repairs, overtime for city employees and lost revenue from parking meters etc stemming from an apparent failure of a shoring system that formed a 30-meter sinkhole. No mention of the developer’s name or the engineer, but the contractor was Matcon Excavation and Shoring. The site will be the future home of high-rise condominiums…if the City lifts it’s stop work order.

The failure of the shoring caused a break inf a 20-cm water main ultimately flooding the site. It also necessitated the closure of the adjacent street. Of course this invites the whole chicken or the egg scenario. The defendants will probably argue that the water line failed first causing the failure of the shoring, but of course the City Engineer, Tom Timm was not shy about fingering the shoring as being deficient.

"It’s some kind of a failure of the shoring system . . . either a design issue or the way it was put in place."

 

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