When Hurricane Harvey hit Houston in August of 2017, the Lumpkin Road detention pond flooded and receded multiple times and performed exactly as engineered. Some areas of Houston received 40 inches (1 meter) of rain in less than 48 hours, but there are no signs of movement or distress with the walls. A case study of these 20-foot high detention basin gravity retaining walls is published on Redi-Rock’s website and was recently updated with the news of its successful performance during the epic flooding during Harvey. Read the rest of the story from Redi-Rock.
On September 17, CALTRANS and Kiewit Pacific held a "tunnel excavation celebration" to kick off the start of tunnel construction on The Devil’s Slide Tunnels project on California State Route 1 (the Pacific Coast Highway) in San Mateo County between the town of Montara to the south and the city of Pacifica to the north. The project involves the creation of a separated two-lane road, one lane in each direction. This road will pass through twin tunnels, over twin bridges and connect with an existing non-separated two-lane road at each end. The new road will be approximately 6,500 feet long, made up of the roughly 4,000-foot twin tunnels, the 1,500-foot north approach road (which includes the 1000-foot parallel bridges), and the 1,000-foot south approach road. Upon completion, the new road will bypass geologically unstable portions of existing Route 1, sections of roadway subject to lengthy closures, high maintenance costs over the years, and risk of permanent failure. Thanks Geology.com for the heads up. [Read on for more background, photos, maps, and movies!] (Images by CALTRANS)