Sinkholes at the Dead Sea have threatened tourists and forced Israeli (and perhaps Jordanian)authorities to close various facilities and cancel development plans to avoid these geologic hazards. These are not your typical Karst sinkholes. According to a recent AP article, they are caused by the erosion of salt deposits by fresh water as a result of the lowering of the water level. This is a human caused phenomenon as current size of the Dead Sea is just 1/3 of its size in 1960 since water has been diverted from the Jordan River, its main tributary to be evaporated for its phosphates. At the end of the article is an interesting note that the World Bank is currently evaluating a proposal to replenish the Dead Sea by digging a $15 Billion canal from the Red Sea, about 100 miles away. (Photo by urban_hipster)
It takes planning and good leadership to decide on an effective solution to problems associated with a building asset. Recently, a large wholesale warehouse facility in Cincinnati began to experience large sinkholes across a significant portion of their customer parking lot. Unable to determine the problem at that time, store management was forced to close a portion of the parking lot, inconveniencing their customers. This particular parking lot is unusual in that a drainage system is located directly under the parking lot, consisting of a network of pipes spanning 250 feet in length and 12” in diameter. Joint separations in the underground drainage piping had caused enough soil erosion to create sinkholes in the asphalt. Engineers were concerned that other unknown sinkholes could cave in anytime, resulting in further costly damage, and potentially posing safety hazards to customers.
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On June 11, 2002, a 150-foot wide and 60-foot deep sinkhole opened up in Pine Hills, Florida and came within a few feet of two 3-story appartment buildings. Geotechnical and Environmental Consultants (GEC) was contacted by the owner of the site to design emergency temporary and permanent stabilization measures to protect the buildings. The sinkhole mitigation began with a chemical stabilization of the soil using an injected sodium silicate chemical grout (incidentally, that work was performed by John N. Puder, Inc., recently acquired by Moretrench) to stabilize the sands underneath the buildings and adjacent to the sinkhole. After some GPR surveys, borings and other investigations, final sinkhole repair consisted of a 200-foot long wall omprised of interlocked 36-inch diameter steel tubular piles that extended to a depth of 50 feet. They were driven by Giken America Corp. using the press-in method which helped to avoid damage to the adjacent buildings. The entire stabilization was completed within 1-month of the initial sinkhole collapse! Click through for this fascinating video. (Photo credit Giken America Corp. by way of GEC)