A Full-Scale Field Study on Bearing Characteristics of Cast-in-Place Piles with Different Hole-Forming Methods in Loess Area

Table 1

Comparison of all 3 types of cast-in-place piles.

Type	Tool	Applicable condition	Advantage	Disadvantage
Rotary drilling pile (RDP)	Rotary drilling rig	Clay, silty soil, sand, artificial filled soil	The hole-forming speed is fast and the quality is high; construction site is clean.	The weight of the equipment is large and the construction ground needs to be treated; need to keep the head pressure in the hole.
Manual digging pile (MDP)	Man, spade	The bearing stratum is above the groundwater level, and the pile diameter is 800–2000 mm.	Strong bearing capacity of a single pile; easy to clear holes and check hole formation.	It is difficult to make holes below the groundwater level; there is a great danger in the process of digging holes.
Impact drilling pile (IDP)	Impact drilling rig	Clay, silty soil, sand layer, and gravel soil layer	Strong applicability; lower platform requirements and lower costs.	The drilling efficiency is low; it is difficult to make a circular hole; accidents are easy to occur; the depth and diameter of the hole are small.