Local treatment of irregular parts of dam foundation: local treatment of irregular parts such as holes, pits, overhanging rock mass and steps shall be carried out by way of backfilling concrete or shotcrete. Concrete backfill shall be carried out in accordance with the above specifications and shall be treated not less than three days prior to foundation covering. Shotcrete shall be applied in the designated area, and the surface on which the shotcrete operation will be performed shall be kept clean and wet, and there shall be no water in the pits. Shotcrete shall meet the requirements of technical specifications.