Subway No. 7 Extension

To provide easy access to the west side of mid-town Manhattan, New York City Transit is planning to extend the No. 7 Subway train currently terminated at the Time Square station towards the Jacob K. Javits Convention Center on Eleventh Avenue. The proposed alignment will extend across 15 city blocks and over the Lincoln Tunnel and the Penn-Central rail tunnels. Subsurface conditions along the proposed alignment feature various thicknesses of man-made fill and glacial soils over an undulating bedrock surface at variable depths.

YU & Associates (YU) is supervising and providing QA/QC for all geotechnical field investigation and testing work being performed on busy city streets with restrictive working schedules. Traffic control and existing utility conflict investigation and identification are required. Oriented rock coring, packer testing and down whole geophysical testing are part of the investigation program. YU is also analyzing the stability of the tunnel/cavern structures and estimating the movements of adjacent building foundations using the finite difference program FLAC.