Drill Displacement Pile (DDP) system is a deep, full displacement, structural pile, and ground improvement method used to support very heavy foundation loads. The DDP offers a well-defined, full displacement, steel-reinforced, concrete pile, with reliable, high capacity support of heavy foundation loads on soft soil. The large cavity expansion effect of the displaced soil produces the higher strength and ground improvement of the system. DDP construction produces low noise and no vibrations with low spoil from the displacement tool. A DDP is used in the same way as a driven pile; to support heavy structures on soft and weak soil at deeper more competent soil. The DDP gains strength at deeper soil for high end bearing capacity and through soil layers to achieve high side friction capacity and end bearing. DDP strength is greatly enhanced by the displacement of soil laterally and the pressure grout effect during construction. DDP is essentially the “spoil-less” and higher capacity version of auger cast pile.
Support structural slabs, high load density pile caps, structural mats, slope/embankments, and industrial foundations. The ideal applications for DDP occur at:
Soft and loose soil sites and bay mud / sensitive soil sites.
Contaminated soil and undocumented debris fill sites.
Groundwater protection regions.
Sensitive project sites near critical structures.
Sites near occupied offices and in dense urban areas.
DDP 4-Step Construction Process
Heavy crowd + high torque = drill displace to the design depth. Install cavity expansion.
Withdraw auger, pump concrete under pressure. Install pressure grout effect.
Install rebar cage into fresh concrete to form DDP.
Finished pile cap with ground improvement and DDP.
The Drill Displacement Pile (DDP) method is a great improvement to common auger cast pile construction. The DDP displacement tool is shaped to laterally displace and compact the soil at the edges into the ground. The displacement tool and the pressure grout effect result in a coarse sided pile with finished diameters greater than 100% of the neat tool diameter. The soil displacement produces cavity expansion effects that 1) increase shear strength, 2) increase density, 3) increase over-consolidation, 4) reduce void ratio, and 5) increase stiffness & modulus of the surrounding soil. These physical benefits of DDP construction result in reliable, high capacity, deep foundation piles.
Engineered steel rebar cages are installed into the structural grout to resist the vertical, lateral, and uplift demands. DDP with an expanded base can achieve much higher end bearing capacity than traditional concrete piers and driven concrete piles. An expanded base is created with displacement and pressure grout methods during installation. Full-scale, instrumented, load tests are performed on DDP to confirm vertical bearing and uplift capacity. Lateral load tests can be performed to confirm lateral pile capacity.
Farrell uses heavy, fixed mast, piling drill rigs to install DDP. Farrell operates Leibherr, Casagrande, and Bauer rigs. These rigs install DDP to depths of 20 to 85 feet (6 to 26m). Farrell installs DDP with full displacement tool diameters of 14” (356mm), 16” (406mm), 18” (457mm), and 24” (610mm). Partial displacement DDP tools are used in dense soil regions. The rigs are equipped with electronic monitoring to record drill torque, drill depth, drill speed, concrete pump pressures, and concrete volume for engineer review.
Drill Displacement Pile DDP is a well-defined, high capacity, deep foundation pile that supports your project to Go Vertical with Confidence®!
Drill Displacement Pile
Geologic Hazard Application
85 ft (26 m)
Sand (SP, SM, SC)
Silt (ML, MH)
Clay (CL, CH)
Bearing Capacity Range
100 kips (445 kN) to 500 kips (2224 kN)
Deep Pile with Ground improvement
High bearing capacity
16" 18" 24" diameters
Grout with low spoil
Flat stable pad
Farrell Design-Build Inc. | Sacramento 530.621.4867 | Irvine 949.428.9596