§ 1.07 TUNNELING PIPE.
   (A)   Prior to commencement of work, the engineer shall approve the method to be used, such as auguring or drilling, jacking or hand mining as shown on the plans.
   (B)   If the pipe is to be augured, the casing shall be thoroughly cleaned out upon completion of the operation and before the pipe is installed as shown on the plans.
   (C)   If the pipe is to be jacked, an engineer approved plug shall be used in the end of the leading pipe.
   (D)   The contractor shall be responsible to maintain the correct vertical and horizontal alignment. Chocks/spacers will be required and shall be spaced no less frequently than six foot on center, with an additional spacer within one foot of each end of the casing pipe.
   (E)   If any voids wider than one inch occur between the bore hole and the outside of the casing pipe, they shall be filled with sand or flowable mortar.
   (F)   Where tunneling operations are used below or adjacent to building and structures or under paved surfaces or railroads, the contractor is fully responsible to use such methods and care to prevent settlement of said structures or surfaces, and to maintain traffic at all times on such streets or railroads.