WoldWide Drilling Resource

40 JULY 2019 WorldWide Drilling Resource ® Purple Line Construction Ramps Up Compiled by Caleb Whitaker, Associate Editor, WorldWide Drilling Resource ® The Purple Line is a 16-mile light rail line in Maryland, which will extend from Bethesda to New Carrollton. It will provide a direct connection to the Metrorail Red, Green, and Orange Lines; at Bethesda, Silver Spring, College Park, and New Carrollton. The Purple Line will also connect to Amtrak and local bus services. It is one of the first U.S. rail projects to connect suburbs without requiring riders to travel through a city, and will operate mainly in ded- icated or exclusive lanes, allowing for fast, reliable transit operations. Installation of erosion and sediment control measures, clearing and grub- bing, grading, and building demolition is in progress. At the Bethesda Station South Entrance, which encompasses a shaft and cavern in rock, drilling of sol- dier piles for the support of excavation in the overburden has also begun. The extensive utility work includes water, sewer, and power lines. Underground portions of the project will be excavated by cut-and-cover and the New Austrian tunneling method (NATM). Work on the Bethesda station and the direct elevator connection to the Red Line platform means blasting at the site of an old Apex building. The construction team is excavating what will be a 150-foot shaft for an elevator bank, improved ven- tilation for the Metro station, and the connection to the cavern which will serve as the Purple Line stop’s mezzanine. The shaft will also be the connection for a second entrance to the Bethesda Metro station, far below the Purple Line tracks. When crews hit bedrock, explosive blasting is planned for the shaft. Crews will try to blast early in the morning every day throughout most of 2019. Like the work along the entire Purple Line route, this construction is being done right next to, and across from existing buildings with offices, apartments, and hotel rooms. The project has promised to remain within tight limits on vibration and noise to prevent any damage to the buildings or Metro line below, as well as to reduce the significant incon- venience of five years of construction work. For now, crews are digging a tunnel about 20 feet high and 40 feet wide. After the tunnel breaks through at the other end, crews will go back through to dig another 10 feet down, making room for the concrete which will eventually hold the tracks. All work on the tunnel, including the tracks, is scheduled to be finished in 2021, and the rail line would open in 2022. The tunnel is below the water table, so sump pumps are in place to get rid of water coming in through drainage holes drilled to relieve pressure. The water is pumped into a settlement tank to remove solids, before the treated water is put into a storm drain. Once the tunnel is completed, a waterproofing membrane will be installed. The drain holes will be sealed, and a permanent liner will be added with the goal of keeping the tunnel completely dry. Photos of Purple Line construction, courtesy of Traylor Bros., Inc. EXB The 8th Edition of The Water Expo will be held August 28-29, once again at the Miami Airport Convention Center, in Miami, Florida. This bilingual trade show and conference is loaded with equipment, technologies, products, panel sessions, and seminars for wastewater, water quality, sewer infrastructure, environmental services, portable sanitation, and high pressure industries. Visit with manufacturers, distributors, buyers, professionals, operators, and contrac- tors from Latin America, the Caribbean, and the U.S. at indoor and outdoor exhibits, live demos, special courses, happy hour party, and more. Go to www.thewaterexpo for more information. Where are you planning to go? How about including this show: Join WWDR See more events at www.worldwidedrillingresource.com online issue.