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DRILLED DISPLACMENT PILE PERFORMANCE
IN COASTAL PLAIN AND RESIDUAL SOILS
Presented by:
W. Morgan NeSmith, P.E.
Berkel & Company Contractors Inc.770.941.5100
mnesmith@berkelapg.com
SC Engineering Conference
Myrtle Beach SC11 June 2015
San Francisco
Kansas CityCorporate Office
Houston
Orlando
Baltimore / Washington D.C.
Atlanta
Louisville
Berkel & Company Contractors, Inc
Founded by Mr. Charles J. Berkel in 1959
• Scope of Presentation (Case- History)
Project Details
What are Drilled-Displacement Pile?
Local Geology
Test Piles
Supplementary CPTs
Modifications to Displacement Tool
Conclusions
Project Location – Aiken SC
Project Details - Aiken SC :
Industrial Facility with 19 separate structures
Total number of piles ~ 1000
Area A
~ 120 pile
~ Cut-Off elevations: 0 to -3
Area B
~ 700 pile
~ Cut-Off elevations:
-22 to -39
Area C
~ 120 pile
~ Cut-Off elevations: 0 to -5
Project Details- Aiken SC:
Loads:Compressive Loads: 200 to 350 tons
Tension Loads: 0 to 50 tons
Lateral Loads: 0 to 19 tons
• 24-inch diameter Partial Displacement
Piles (APG-PD) – Specified
• Berkel was responsible for pile length
• Effective Length Ranging from 40’ to 65’
Cast-in-place piles installed by
single-pass, rotary drilling processes
Terminology for Piles
Continuous Flight Auger European Screw Piles
ACIP
aka Augercast
(APG) European CFA
Intermediate (Partial) Displacement
Displacement Pile (APG-D)
Gaspar Coelius granted patent for
cast-in-place screw pile in 1960
Analogous to augered… .. And to displacement
From De Cock and Imbo, Transportation Research Record 1447
Example of Augercast Pile and Displacement Piles
Fixed-Mast Platform Crane-Mounted Platform
4’-0” +/-
30’-0” +/-
Fixed Mast Platforms
Overview ofDrilling
Platformand Sensors
PLATFORM FEATURES
• 150,00 to 200,000 ft-lb torque
• 40,000 to 80,000 lb crowd
• Fixed mast for stability, inclinometer
with display in operator’s compartment
• Grout pressure, measured at top of tools,
is displayed in operator’s compartment
• Real-time display of installation
parameters (depth, KDK pressure,
Installation Effort, grout pressure)
pressure
Primary Drilling Parameters
(Recorded at 1 Reading per Second)• Time: Recorded by an internal counter and referenced to
the initial date and time input by the operator at the beginning of the project.
• Depth: From proximity switch that measures rotation of the main winch supporting the drilling turntable and drilling tools.
• Hydraulic Fluid Pressure driving turntable (i.e. KDK Pressure): From in-line pressure transducer.
• Rotations (of drilling tools): From proximity switch on turntable.
CONVENTIONAL ACIP TOOL DRILLED DISPLACEMENT TOOLINTERMEDIATE (PARTIAL)
DISPLACEMENT TOOL
APG and Displacement Tooling
Displacement leads to increased horizontal stresses (and densification)for higher shaft resistance in many soils
Grout/soil interface is a more effective load transfer interface than pre-cast or steel/soil
Berkel Displacement Pile Tool
Figure 1. Berkel Displacement Tool
Stem becomes
progressively larger,
terminating in the
displacing element
+- 3 feet, regular flighting,
12” to 18” diameter
Reverse flighting Displacing element. Same
diameter as the flighting
below
Stem, smaller than flighting
DD PILE INSTALLATION METHOD
• Tool advances as a screw in low
to medium consistency soils.
• In dense soils, material
transported up the auger to the
displacing element. Material in
auger flights is compressed; thus
no stress relief in the zone
adjacent to the auger.
DD PILE GROUTING• When the target level has been
reached, pumping of grout is
begun. Grout pressure is
monitored by the operator Lift
off and withdrawal rate are
varied to maintain pressure
where possible.
• Tool is rotated during
withdrawal and material which
falls around stem is captured
and displaced.
• Typically get grout return only
after tip is at or near ground
surface.
DD Pile Design
Nesmith, W.M. (2002). “Static Capacity Analysis of Augered, Pressure-Injected Displacement Piles”.
Geotechnical Special Publication No. 116. M.W. O’Neill and F. C. Townsend (Eds.). ASCE. February. Volume
1. pp. 1088 – 1097
Recommended method in FHWA Geotechnical Engineering Circular (GEC) No. 8, “Design and
Construction of Continuous Flight Auger Piles”
Intermediate (Partial) Displacement
Pile System
CONVENTIONAL ACIP TOOL DRILLED DISPLACEMENT TOOLINTERMEDIATE (PARTIAL)
DISPLACEMENT TOOL
Intermediate Displacement Tooling
For design, use full displacement method with factor for amount of partial displacement
Partial Displacement Auger Used at
this Job Site
Conventional ACIP Auger Stem
Partial Displacement Auger Stem
LOCAL GEOLOGYElevation 0
Elevation ~ -55
Elevation ~ -85
Coastal Plain
Residual Soil
Partially Weathered Rock (PWR)
What does that mean ?Residual Soil:
Weathered in place from underlying
Bedrock – typically granite / gneiss in the
southeast with more schist in the northeast
Weathers to PWR (N > 100) to silty sand to
sandy silt to silty clay closer to ground
Coastal Plain:
Divided into the lower and upper plain.
The upper Coastal Plain is then divided into
the Aiken Plateau, the Richland Red Hills,
and the High Hills of Santee. All of which are
remains of land left by the constantly moving
sea of the Pliocene. Six steep slopes at the
edge of high ground and seven terraces
create the surfaces of the lower Coastal
Plains. These terraces represent the seven
cycles of the receding ocean of two Pliocene,
four in the Pleistocene, and one in Holocene.
Terraces are temporary oceans floors that go
from the sea level rise and fall over time.
Example
Boring
24-inch APG-PD Tooling
18 inch Dams
24 inch Flight
with 18 inch
Dams
Test Pile Program
Depth = 0
Depth ~
50 to 60 - ft
Depth ~
85 to 90 - ft
Coastal Plain
Residual Soil
Partially Weathered Rock (PWR)
Depth = 0
Depth ~
55 to 60 ft
Depth ~
85 to 90 ft
Coastal Plain
Residual Soil
Partially Weathered Rock (PWR)
Supplementary Test Pile Program
Test Pile 1
Coastal
Plain
Residual
Soil
Partially
Weathered
Rock (PWR)
Test Pile 2
Coastal
Plain
Residual Soil
Partially
Weathered
Rock (PWR)
Test Pile 3
Coastal
Plain
Residual
Soil
Partially
Weathered
Rock (PWR)
Test Pile 5
Coastal
Plain
Residual
Soil
Partially
Weathered
Rock (PWR)
Test Pile 4
Coastal
Plain
Residual
Soil
Partially
Weathered
Rock (PWR)
Analysis of Pile Behavior During Loading
TP-1: “Typical” Behavior
TP-4: Atypical Behavior
structural issues suspected from results
Test Pile 4A Results
Coastal
Plain
Residual
Soil
Partially
Weathered
Rock (PWR)
Fine-Grained material observed during installation!!!
Test Pile 4A Results
TP4A was tested 7 and 16 days after installation
Results of TP-4A & TP-5
Fine-Grained material observed during installation!!!
Example
Boring
CPT Supplementary
Increase in pore pressure
with advancement of cone
in clayey silt fine grained
Classification: very stiff
fine grained residual soils
Supplementary Site
Characterization
Very Stiff high plasticity fine-graded residual
material
Pore pressure of material due to displacement is
detrimental to grout column
Modifications to APG-PD
Tool
σ′ = σ − 𝑢
Probably not
Modified APG-PD Tool
Modified tooling by taking dams out
Test Pile 4A2
Coastal
Plain
Residual
Soil
Partially
Weathered
Rock (PWR)
www.berkelandcompany.com
• Given 24 inch pile, depth was determined by Berkel
• In Coastal Plain Soils, test piles performed as expected
• In Residual Soils, some indication that large volume of displacement
was detrimental to cast in place piles
• Supplementary CPTs indicated residual soil was more fined grained
and of higher plasticity than originally described
• Tool was modified to reduce the ratio of displacement to removal
• Depth of TP-4 was re-analyzed considering less displacement (slightly
reduce friction values)
• Test results on TP-4 A 2 showed no signs of structural problems and
demonstrated that design loads could be supported
• Final recommendations used a combination of both tools depending
on top-of-pile level and required penetration into residual soil
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