How do you avoid hydrofracture on major horizontal directional drilling (HDD) crossings where thegeotechnical investigation indicates very soft organic materials to depths of 50 to 60 feet below the ground surface?How do you protect critical flood control levees against excessive settlement for large HDD crossings? Answers tothese questions were required during the design of three significant gas pipeline crossings of the Sacramento River.At the request of the Port of West Sacramento, the US Army Corps of Engineers is planning to deepen the DeepWater Shipping Channel in the Sacramento River, which connects the Port to San Francisco Bay. Due to thisplanned dredging, three Pacific Gas & Electric natural gas pipelines that cross beneath the river in the vicinity of RioVista, CA must be replaced. The three crossings range in diameter from 12 to 36 inches and in length from 3,700 to4,700 feet. Due to the challenging geotechnical conditions, environmental concerns, and flood control levees, theHDD intercept method will be required. This paper discusses how the design of these crossings addressed projectchallenges.
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