Divers Assist in Successful Extraction of 170 foot Oscillator Casing. During the planning of the upcoming underground excavation extending San Francisco’s BART subway system and the proposed addition of a station for the future high speed rail network, city engineers worried about the possibility of destabilizing the foundation of one of the city’s tallest mixed-use high rise’s. Becho, Inc. was contracted to construct a buttress shoring wall detailing 207 secanted shafts of connecting underground pilings (207 - 7 foot diameter by 250 foot deep) using Oscillator Technology…