(A)   Whenever it is necessary to break through existing pavement for excavation purposes and where trenches are to be four feet or over in depth, the pavement in the base shall be removed to at least six inches beyond the outer limits of the sub-grade that is to be disturbed in order to prevent settlement, and a six-inch shoulder of undisturbed material shall be provided in each side of the excavated trench. The face of the remaining pavement shall be approximately vertical. A power-driven concrete saw shall be used so as to permit complete breakage of concrete pavement or base without ragged edges. Asphalt paving shall be scored or otherwise cut in a straight line. No pile driver may be used in breaking up the pavement. 
('69 Code, § 18-53)
   (B)   Tunnels under pavement shall not be permitted except by permission of the City Engineer and if permitted shall be adequately supported by timbering and back-filling under the direction of the City Engineer. 
('69 Code, § 18-54) (Ord. 0-74-3, passed 2-11-74)  Penalty, see § 10.99