The outer wall is calculated according to the length of the centerline as shown in the drawing; The internal wall shall be calculated according to the net length of the bottom of the trench, and the volume of the internal and external protruding parts (buttress, chimney attached to the wall, etc.) shall be included in the earthwork quantities of the trench. The earthwork backfilling in the calculation list includes the transportation within the specified range, and the earthwork excavation, sloping, and other construction increases of the borrow backfilling are included in the quotation, while in the quota, the quota calculation shall be checked