DRILLED DISPLACMENT PILE PERFORMANCE IN COASTAL PLAIN AND RESIDUAL SOILS

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1 DRILLED DISPLACMENT PILE PERFORMANCE IN COASTAL PLAIN AND RESIDUAL SOILS Presented by: W. Morgan NeSmith, P.E. Berkel & Company Contractors Inc SC Engineering Conference Myrtle Beach SC 11 June 2015

2 Berkel & Company Contractors, Inc Founded by Mr. Charles J. Berkel in 1959 San Francisco Kansas City Corporate Office Louisville Baltimore / Washington D.C. Atlanta Houston Orlando

3 Scope of Presentation (Case- History) Project Details What are Drilled-Displacement Pile? Local Geology Test Piles Supplementary CPTs Modifications to Displacement Tool Conclusions

4 Project Location Aiken SC

5 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 C ~ 120 pile ~ Cut-Off elevations: 0 to -5 Area B ~ 700 pile ~ Cut-Off elevations: -22 to -39

24-inch diameter Partial Displacement Piles (APG-PD) Specified

6 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

7 Terminology for Piles Cast-in-place piles installed by single-pass, rotary drilling processes Continuous Flight Auger European Screw Piles ACIP aka Augercast (APG) European CFA Displacement Pile (APG-D) Intermediate (Partial) Displacement

8 Example of Augercast Pile and Displacement Piles 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

9 4-0 +/ /- Fixed-Mast Platform Crane-Mounted Platform

10 Fixed Mast Platforms Overview of Drilling Platform and Sensors

11 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

12 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.

14 APG and Displacement Tooling CONVENTIONAL ACIP TOOL INTERMEDIATE (PARTIAL) DISPLACEMENT TOOL DRILLED DISPLACEMENT TOOL 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

15 Berkel Displacement Pile Tool Stem, smaller than flighting Reverse flighting Stem becomes progressively larger, terminating in the displacing element Displacing element. Same diameter as the flighting below +- 3 feet, regular flighting, 12 to 18 diameter

16 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.

17 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.

18 DD Pile Design Recommended method in FHWA Geotechnical Engineering Circular (GEC) No. 8, Design and Construction of Continuous Flight Auger Piles Nesmith, W.M. (2002). Static Capacity Analysis of Augered, Pressure-Injected Displacement Piles. Geotechnical Special Publication No M.W. O Neill and F. C. Townsend (Eds.). ASCE. February. Volume 1. pp

19 Intermediate (Partial) Displacement Pile System

20 Intermediate Displacement Tooling CONVENTIONAL ACIP TOOL INTERMEDIATE (PARTIAL) DISPLACEMENT TOOL DRILLED DISPLACEMENT TOOL

21 For design, use full displacement method with factor for amount of partial displacement

22 Conventional ACIP Auger Stem Partial Displacement Auger Stem Partial Displacement Auger Used at this Job Site

23 LOCAL GEOLOGY Elevation 0 Coastal Plain Elevation ~ -55 Elevation ~ -85 Residual Soil Partially Weathered Rock (PWR)

24 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.

25 Example Boring

26 24-inch APG-PD Tooling 18 inch Dams 24 inch Flight with 18 inch Dams

27 Test Pile Program Depth = 0 Coastal Plain Depth ~ 50 to 60 - ft Depth ~ 85 to 90 - ft Residual Soil Partially Weathered Rock (PWR)

28 Supplementary Test Pile Program Depth = 0 Coastal Plain Depth ~ 55 to 60 ft Depth ~ 85 to 90 ft Residual Soil Partially Weathered Rock (PWR)

29 Test Pile 1 Coastal Plain Residual Soil Partially Weathered Rock (PWR)

30 Test Pile 2 Coastal Plain Residual Soil Partially Weathered Rock (PWR)

31 Test Pile 3 Coastal Plain Residual Soil Partially Weathered Rock (PWR)

32 Test Pile 5 Coastal Plain Residual Soil Partially Weathered Rock (PWR)

33 Test Pile 4 Coastal Plain Residual Soil Partially Weathered Rock (PWR)

34 Analysis of Pile Behavior During Loading TP-1: Typical Behavior TP-4: Atypical Behavior structural issues suspected from results

35 Test Pile 4A Results Coastal Plain Residual Soil Partially Weathered Rock (PWR) Fine-Grained material observed during installation!!!

36 Test Pile 4A Results TP4A was tested 7 and 16 days after installation

37 Results of TP-4A & TP-5 Fine-Grained material observed during installation!!!

38 Example Boring

39 CPT Supplementary Increase in pore pressure with advancement of cone in clayey silt fine grained Classification: very stiff fine grained residual soils

40 Supplementary Site Characterization Very Stiff high plasticity fine-graded residual material Modifications to APG-PD Tool Pore pressure of material due to displacement is detrimental to grout column σ = σ u Probably not

41 Modified APG-PD Tool Modified tooling by taking dams out

42 Test Pile 4A2 Coastal Plain Residual Soil Partially Weathered Rock (PWR)

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

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

43 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

CPT MEASUREMENTS NEAR DRILLED DISPLACEMENT PILES

CPT MEASUREMENTS NEAR DRILLED DISPLACEMENT PILES Timothy C. Siegel, P.E., Member, Geo-Institute P. Ethan Cargill, P.E., Member, Geo-Institute Willie M. NeSmith, P.E., Member, Geo-Institute Berkel & Company