(01) It avoids the phenomenon of concrete piping in adjacent holes that easily occurs when using super-retarding concrete secant piles to complete cutting and interlocking. At the same time, because conventional concrete is used, the requirements for concrete are reduced, and costs are saved.

(02) Due to the hard cutting process, the disadvantage of being unable to perform B-pile secant construction because of excessive concrete strength of A-pile caused by long single-pile formation time will not occur.

(03) When encountering hard large-area underground obstacles, the full rotary drilling rig can directly remove underground rock layers and obstacles during pile formation, achieving one-time pile formation.

(04) The full casing full rotary drilling rig itself has the function of water-stop wall protection, without the need for additional wall protection measures. It is an energy-saving and environmentally friendly construction process.

(05) According to the grab soil extraction depth, the soil layers can be accurately distinguished, and a suitable pile end bearing layer can be selected.

(06) The soil extracted from the hole has low water content, is convenient for transportation, and there is no concern about mud polluting the environment; the construction site is clean and civilized, making it extremely suitable for construction in urban areas.

(07) Settlement and displacement are easy to control, and construction can be carried out adjacent to nearby buildings and underground pipelines.

(08) The full rotary follow-up drilling and other excavation methods effectively prevent quicksand and mud surges in the hole, and can perform rock socketing, ensuring pile quality.

(09) The second-stage pile performs cutting and interlocking between the two completed first-stage piles. The full casing hole protection method ensures tight interlocking between piles, and the pile concrete solidifies into one body, forming a good overall continuous structure.

(10) The reinforcement ratio is low because the bored secant pile can adopt an arrangement of alternating reinforced concrete piles and plain concrete piles;

(11) The impermeability is stronger because the bored secant pile is constructed continuously, and there are no construction joints between piles, while the construction joints at the panel joints of the underground diaphragm wall are often weak links in seepage prevention;

(12) The construction is flexible because the bored secant pile can turn and change lines as needed during construction, making it more suitable for constructing foundation pits with various planar geometric shapes or various arc shapes.