This video from Herrenknecht AG shows the operation of the enormous tunnel boring machine that will conduct the deep tunnelling for San Francisco's new subway lines. The machine obviates the necessity of tearing up city streets for subway construction, and somehow manages to be gentle enough to avoid shaking the buildings above it. There's a much older version of this monster on display at the fabulous London Transport Museum in Covent Garden that is truly awesome to behold.
A TBM consists of a rotating cutterhead within a cylindrical steel shell that is pushed forward along the axis of the tunnel while excavating the ground through the cutterhead. The steel shield supports the excavated ground as required until the final tunnel lining is built in the rear of the shield. The shield is propelled using hydraulic jacks that thrust against the erected tunnel lining system. The TBM is used in conjunction with a prefabricated ground support system, which consists of pre-cast concrete segments that are bolted and gasketed to form a watertight lining.
Pressure-face TBMs that are capable of exerting a balancing pressure against the tunnel face are used to control excavation rates and groundwater inflow, as well as to maintain stability of the tunnel face.
After completion of TBM excavation and installation of the lining, the temporary rail and conveyor system are removed, the invert is cleaned, and a flat invert for the permanent rail fixation and a raised walkway are constructed as reinforced, cast-in-place concrete. The invert contains embedded pipes and inlets for track drainage.
(Thanks, Fipi Lele!)
Announced today: So It Is, a new album of Cuban-inspired jazz from the monumentally amazing Preservation Hall Jazz Band (previously), due out on April 21. Available today: Santiago, an instrumental track from the album that will MAKE YOU DANCE.
Philips has acquired Luciom, a French startup that makes Li-Fi products, which allow for very fast network connections over short distances by flickering an LED at speeds that are too fast to register on the human eye, and which can ever work in the dark by operating at low dimness settings the human eye perceives […]
Charles Duan from Public Knowledge sends us “a video we put together for Fair Use Week about copyright and fair use, to the tune of ‘Let It Go’ from Frozen, and full of clips of other fair use videos.”
Not all hackers are malicious information thieves—white-hat ethical hackers work with technology companies to ensure the security of their computer systems and user data. With all of today’s high-profile data breaches, ethical hackers are in considerable demand. To learn these critical skills and break into the high-paying cyber security field, try taking the courses in this […]
Making people aware of goods and services in the digital age requires an array of new strategies from social media and email to number-crunching tools like Google Analytics. To get a handle on the techniques used to capture attention and convert traffic into dollars in a crowded online environment, the Full-Stack Marketer Bundle offers 22 hours of training to get […]
Having a luxurious bed isn’t just a fairy tale from a catalog; it is a real, affordable possibility with offerings like this Olive+Owen bedroom set. If you’re thinking of doing some “spring cleaning”, this bed set is an easy way to completely upgrade your room in one purchase.This 20-piece collection has all of the expected slumberland elements, […]