Section 27-689. Minimum pile penetrations

(a)  Required by soil bearing
  capacity. The provisions of paragraph one of subdivision (b) of  section
  27-700 of article eight of this subchapter shall apply.
    (b)  Required  for lateral restraint. The provisions of section 27-694
  of this article shall apply.
    (c) Piles located near a lot line. Piles located near a lot line shall
  be designed on the assumption that the adjacent lot will be excavated to
  a depth of ten feet below the nearest legally  established  curb  level.
  Where  such excavation would reduce the embedded length of the pile, the
  portion of the pile exposed shall be considered as providing no  lateral
  or  vertical  support, and the load-carrying determination in accordance
  with the provisions of article eight of this subchapter  shall  be  made
  after  the  resistance  offered by the soil that is subject to potential
  excavation has been discounted.