15# main pier, the equipment invested by our company in the early stage of construction is the same as that of 14# main pier. After the completion of 36 main piers with a diameter of 2800mm rock-socketed piles, we used two rotary excavators (including an SR280 rotary excavator) to construct the main bridge pier (deep foundation pit excavation) AB surrounding piles. It is the scene of the construction of the retaining pile by the rotary excavator