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GFA INTERNATIONAL
FLORIDA’S LEADING ENGINEERING SOURCE
Report of Geotechnical Exploration
Worsnop Residence
10701 South Ocean Drive (Lot 634)
Jensen Beach, Florida
May 5, 2021
GFA Project No. 3330.2100052.0000
For: Lois Denise Worsnop
Since 1988
Florida’s Leading Engineering Source
Environmental • Geotechnical • Construction Materials Testing • Threshold and Special Inspections • Plan Review & Code Compliance
607 NW Commodity Cove • Port St. Lucie, Florida 34986 • (772) 924-3575 • (772) 924-3580 (fax) • www.teamgfa.com
OFFICES THROUGHOUT FLORIDA
May 5, 2021
Ms. Lois Denise Worsnop
10701 South Ocean Drive (Lot 634)
Jensen Beach, Florida 34957
Subject: Report of Geotechnical Exploration
Worsnop Residence
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida
GFA Project No. 3330.2100052.0000
Dear Ms. Worsnop:
GFA International, Inc. (GFA) has completed the subsurface exploration and geotechnical
engineering evaluation for the above referenced project in accordance with the geotechnical
and engineering service agreement for this project. The scope of services was completed in
accordance with our Proposal No. 21-6679.00 dated February 23, 2021, planned in conjunction
with and authorized by you.
EXECUTIVE SUMMARY
The purpose of our subsurface exploration was to classify the nature of the subsurface soils and
general geomorphic conditions at the site and evaluate their impact upon the proposed
construction. This report contains the results of our subsurface exploration and our engineering
interpretations of these with respect to the project characteristics described to us, including
providing recommendations for foundation design.
Per our prior telephone discussions and email correspondence, GFA understands that you plan
to construct a new residence to replace the existing modular home at 10701 South Ocean Drive
(Lot 634) in Jensen Beach, Florida. Design details, plans, or anticipated foundation loads for
the planned residence are not available at this time.
The recommendations provided herein are based upon the above considerations. If the stated
conditions are incorrect or if the project description is revised, please inform GFA so that we
may review our recommendations with respect to any modifications.
One (1) standard penetration test (SPT) boring, advanced to an approximate depth of 40 feet
below the existing ground surface, was completed for this study. The subsurface soil conditions
encountered in the boring generally consisted of very loose to medium dense fine sand (SP)
and sand and cemented sand (GP) to the termination depth. As an exception, a layer of very
loose organic clayey fine sand containing some fibrous organics (SC-OL) was present from a
depth of approximately 7 to 8.5 feet below the ground surface.
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 2 of 10
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Based on the results of our field exploration, the very loose fine sand and organic soils present
between approximate depths of 4 and 10 feet are not suitable for support of the new residence
upon conventional shallow foundations due to the potential for the occurrence of excessive total
and differential settlements and associated structural distress. Therefore, GFA recommends
that either helical pile foundations or in-situ soil improvement be considered for this site.
For the helical pile alternative, the piles would be designed and positioned to support the
structure foundations and ground floor slab. To obtain the design axial capacity (to be
determined by the project structural engineer), the piles will likely have to be installed and
seated into the sand and cemented sand (GP) soils encountered below a depth of 23.5 feet in
boring B-1. Note that the actual length of the installed helical piles will depend on achieving the
required torque and corresponding design capacity.
As an alternative to helical pile foundations, in-situ soil improvement consisting of shallow soil-
mix columns could be performed below the structure footprint so that the residence could utilize
a conventional shallow foundation system. This technique consists of advancing a rotary tool
into the ground to a depth of 10 feet or deeper below the surface at several locations while
injecting lean Portland cement grout into the soils. During withdrawal from the ground, the
mixing head continues to rotate to further blend the soil and grout.
For either of the above approaches, the near surface subgrade soils should be densified by
compaction from the stripped surface prior to placing fill to attain design grade. The top 2 feet
below stripped grade should be compacted to a minimum of 95 percent of modified Proctor
(ASTM D 1557) maximum dry density. In general, fill required to attain design grades should be
placed in 12-inch thick lifts and compacted to achieve the same criteria stated above.
We appreciate the opportunity to be of service during this phase of the project and look forward
to a continued association. Please do not hesitate to contact us if you have any questions or
comments, or if we may further assist you as your plans proceed.
Respectfully Submitted,
GFA International, Inc.
Florida Registry No. 4930
This item has been digitally signed and sealed by John Kent, P.E. on the date
adjacent to the seal. Printed copies of this document are not considered signed
and sealed and the signature must be verified on any electronic copies.
John Kent, P.E. Erik Soderstrom, E.I.
Sr. Project Engineer Geotechnical Department Manager
Florida Registration No. 63218
Distribution: Lois Denise Worsnop 1 pdf
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 3 of 10
____________________________________________________________________________________
TABLE OF CONTENTS
1.0 INTRODUCTION ................................................................................................................. 4
1.1 Scope of Services ........................................................................................................... 4
1.2 Project Description .......................................................................................................... 4
2.0 OBSERVATIONS ................................................................................................................ 4
2.1 Site Description ............................................................................................................... 4
2.2 Field Exploration ............................................................................................................. 4
2.3 Visual Classification ........................................................................................................ 5
2.4 Geomorphic Conditions ................................................................................................... 5
2.5 Hydrogeological Conditions ............................................................................................. 6
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS.............................................. 6
3.1 General ........................................................................................................................... 6
3.2 Helical Pile Foundations .................................................................................................. 6
3.3 Shallow Soil Mixing ......................................................................................................... 8
3.4 Site Preparation .............................................................................................................. 8
3.5 Fill Placement and Compactioin ...................................................................................... 8
3.6 Quality Control and Vibration Monitoring ......................................................................... 9
4.0 REPORT LIMITATIONS ...................................................................................................... 9
5.0 BASIS FOR RECOMMENDATIONS ..................................................................................10
Appendix A - Vicinity Map
Appendix B - Test Location Plan
Appendix C - Notes Related to Borings
Appendix D - Log of Boring Records
Appendix E - Discussion of Soil Groups
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 4 of 10
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1.0 INTRODUCTION
1.1 Scope of Services
The objective of our geotechnical services was to collect subsurface data for the subject project,
summarize the test results, and discuss any apparent site conditions that may have
geotechnical significance for the proposed residential construction. The following scope of
services is provided within this report:
1. Prepare boring logs depicting the subsurface soil conditions encountered during our field
exploration.
2. Review the soil samples obtained during our field exploration for classification and additional
testing if necessary.
3. Evaluate the existing soil conditions found during our exploration with respect to helical pile
foundations or shallow soil-mix column ground improvement for the proposed construction.
4. Provide recommendations for site preparation and earthwork construction.
1.2 Project Description
Per our prior telephone discussions and email correspondence, GFA understands that you plan
to construct a new residence to replace the existing modular home at 10701 South Ocean Drive
(Lot 634) in Jensen Beach, Florida. Additional information or plans for the proposed construction
are not available at this time.
The recommendations provided herein are based upon the above considerations. If the stated
conditions are incorrect or if the project description is revised, please inform GFA so that we
may review our recommendations with respect to any modifications.
2.0 OBSERVATIONS
2.1 Site Description
Per our prior telephone discussions and email correspondence, GFA understands that you plan
to construct a new residence to replace the existing modular home at 10701 South Ocean Drive
(Lot 634) in Jensen Beach, Florida. Design details, plans, or anticipated foundation loads for
the planned residence are not available at this time.
2.2 Field Exploration
One (1) standard penetration test (SPT) boring, advanced to an approximate depth of 40 feet
below the existing ground surface, was completed for this study. The approximate boring
location is illustrated on the Test Location Plan in Appendix B.
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 5 of 10
____________________________________________________________________________________
The Standard Penetration Tests (SPT) were performed in general accordance with ASTM D
1586, “Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of
Soils.” The SPT test procedure consists of driving a 1.4-inch I.D. split-barrel sampler into the
soil profile using a 140-pound hammer falling 30 inches. The number of blows per foot, for the
second and third 6-inch increment, is referred to as the N-value. The N-value has been
empirically correlated with various soil properties and provides an indication of soil strength.
The upper 4 feet of the boring were advanced by hand augering due to potential near surface
buried utility line conflicts. The augered portion of the boring was performed in general
accordance with ASTM D 1452, “Standard Practice for Soil Exploration and Sampling by Auger
Borings.” Hand Cone Penetrometer (HCP) tests were conducted at approximate one-foot depth
intervals in the augered portion of the boring. The HCP test, in conjunction with information
about the soil type, is empirically correlated to the relative density of subsurface soils.
Site specific survey staking of the boring was not provided for our field exploration. The
indicated depth and location of the boring was approximated based upon existing grade and by
estimating distances and relationships to the existing residence and other landmarks at the site.
2.3 Visual Classification
Soil samples recovered from our field exploration were returned to our laboratory where they
were visually classified by a geotechnical engineer in general accordance with the Unified Soil
Classification System (ASTM D 2487). After reviewing the samples, no laboratory testing was
deemed necessary. The samples will be retained in our laboratory for 30 days and then
discarded unless we are notified otherwise in writing.
The recovered samples were not evaluated, either visually or analytically, for chemical
composition or environmental hazards. GFA will be pleased to perform these services for an
additional fee, if required.
2.4 Geomorphic Conditions
The geology of the site as mapped on the USDA Soil Survey website consists of Arents, 0 to 5
percent slopes (4). Arents are areas where the soils have been generally altered by
grading, shaping, and covered with fill. Therefore, the soils can be variable. Note that the
Soil Survey generally extends to a maximum depth of 80 inches below ground surface and is
not indicative of deeper soil conditions.
The boring log resulting from our field exploration is presented in Appendix D - Log of Boring
Records. The log contains the soil descriptions, the standard penetration test (SPT) N-values,
and the hand cone penetrometer (HCP) values logged during the drilling and sampling activities.
The soil boring data is specific to the boring location only and the soil conditions may vary
between the strata interfaces indicated on the log. The soil classifications and descriptions
shown on the log are based upon visual characterizations of the recovered samples using the
Unified Soil Classification System. See Appendix E - Discussion of Soil Groups, for a detailed
description of soil groups.
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 6 of 10
____________________________________________________________________________________
The subsurface soil conditions encountered in the boring generally consisted of very loose to
medium dense fine sand (SP) and sand and cemented sand (GP) to the termination depth. As
an exception, a layer of very loose organic clayey fine sand containing some fibrous organics
(SC-OL) was present from a depth of approximately 7 to 8.5 feet below the ground surface.
2.5 Hydrogeological Conditions
On the date of our field exploration (April 20, 2021), groundwater was encountered in the boring
at a depth of approximately 6 feet below the existing ground surface. The groundwater table will
fluctuate seasonally depending upon local rainfall and other site specific and/or local influences,
including tidal variations in the adjacent Jensen Beach Inlet. Brief ponding of stormwater may
occur across the site after heavy or extended rainfall events.
No additional evaluation was included in our scope of work in relation to the wet seasonal high
groundwater table or any existing well fields in the vicinity. Well fields may influence water table
levels and cause significant fluctuations. If a more comprehensive water table analysis is
necessary, please contact our office for additional guidance.
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS
3.1 General
Our geotechnical engineering evaluation of the site and subsurface conditions at the property,
with respect to the planned construction, and our recommendations for site preparation and
foundation support, are based upon (1) our site observations, (2) the field data obtained, and (3)
our understanding of the project information and structural conditions as presented in this
report. If the stated conditions are incorrect, or if the project description is revised, please
inform GFA so that we may review our recommendations with respect to any modifications.
We note that the applicability of geotechnical recommendations is very dependent upon project
characteristics, specifically (1) improvement locations, (2) grade alterations, (3) and actual
applied structural loads. For that reason, GFA must be provided with and review the preliminary
and final site and grading plans, and structural design loads to validate all recommendations
provided in this report. Without performing this review, our recommendations should not be
relied upon for final design or construction of any site improvements.
Based on the results of our field exploration, the very loose fine sand and organic soils present
between approximate depths of 4 and 10 feet are not suitable for support of the new residence
upon conventional shallow foundations due to the potential for the occurrence of excessive total
and differential settlements and associated structural distress. Therefore, GFA recommends
that either helical pile foundations or in-situ soil improvement be considered for this site.
3.2 Helical Pile Foundations
Helical piles consist of galvanized steel shafts with helical flight augers on the bottom shaft. The
shaft sections are bolted together as they are augered into the subsurface. The torque applied
to the piles during drilling is correlated to the axial compression capacity of the helical pile. The
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 7 of 10
____________________________________________________________________________________
steel shafts are cut at the appropriate cut-off elevations, and typically pile caps, grade beams, or
footings are cast on the top of the helical piles.
To obtain the design axial capacity (to be determined by the project structural engineer), the
helical piles will likely have to be installed and seated into the sand and cemented sand (GP)
encountered below a depth of 23.5 feet in boring B-1. The actual design of the piles (number,
depth, spacing, etc.) will be performed by a structural engineer or a deep foundation specialty
contractor. Note that the actual length of the installed helical piles will depend on achieving the
required torque and corresponding design capacity.
GFA recommends that the piles be spaced at least 3 diameters (largest helical diameter) apart
center-to-center. Each pile must be installed with a minimum of twice its design capacity. The
capacity of several piles must be verified by shear pins or other calibration techniques as
required by the 2020 Florida Building Code, Seventh Edition as discussed below.
In accordance with Section 1810.3.3.1.9 of the 2020 Florida Building Code, Seventh Edition, the
allowable axial design load, Pa, of helical piles should be determined as follows:
Pa = 0.5 Pu (Equation 18-4)
where Pu is the least value of:
1. Sum of the areas of the helical bearing plates times the ultimate bearing capacity of the
soil or rock comprising the bearing stratum.
2. Ultimate capacity determined from well-documented correlations with installation
torque.
3. Ultimate capacity determined from load tests.
4. Ultimate axial capacity of pile shaft.
5. Ultimate axial capacity of pile shaft couplings.
6. Sum of the ultimate axial capacity of helical bearing plates affixed to the pile.
Helical pile design and installation is proprietary in nature. The locations and required capacity of
the piles must be designed by a structural engineer or other qualified professional. It is
recommended that a representative of GFA monitor the helical pile installation in
accordance with the Florida Building Code.
We estimate that properly designed and installed helical piles will experience total in-service
settlement on the order of one-half (0.5) inch or less. Differential settlement is estimated not to
exceed one-quarter (0.25) inch.
Required fill and backfill around pile caps and grade beams should consist of clean sand having
less than 5 percent fines (percent of dry weight passing the U.S. No. 200 sieve). The fill should
be placed in 8-inch maximum thick lifts with each lift compacted to at least 95 percent of
modified Proctor (ASTM D 1557) maximum dry density. Achieving the recommended level of
compaction should be confirmed by performing field density tests.
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 8 of 10
____________________________________________________________________________________
3.3 Shallow Soil-Mixing
As an alternative to helical pile foundations, in-situ soil improvement consisting of shallow soil-
mix columns can be performed below the structure footprint so that the residence can utilize a
conventional shallow foundation system. This technique consists of advancing a rotary tool into
the ground to a depth of 10 feet or deeper below the surface at several locations while injecting
lean Portland-cement grout into the soils.
Shallow soil mixing is performed using a 16-inch proprietary mixing head attached to a hollow
stem drilling tube driven by a high torque rotary drilling machine capable of developing 4,000 to
10,000 ft-lbs. of torque. Neat Portland cement is mixed with a horizontal mixer manufactured by
ChemGrout or equivalent. The neat cement grout is thoroughly mixed at a W/C ratio of 0.05/1 to
0.07/1, depending on ambient conditions and other factors and pumped through the hollow stem
rotary drilling rig to the mixing head rotating at a rate of 20 to 60 RPM. The penetration rate
depends on the soil porosity. Larger soil voids require a slower rate to allow the volume
pumped to match or exceed the void volume. A steel rebar (size #6 to #8) is inserted vertically
into the grout immediately upon completion of the grout column.
The contractor and the Geotechnical Engineer typically discuss options for grout design,
penetration rate, and grout volume. A test grout column should be performed prior to production
grouting for the Engineer to observe grout column form. A load test can be performed to
determine the capacity of the column.
3.4 Site Preparation
Initial site preparation should consist of removing all structures, concrete slabs, surface
vegetation, near surface roots, and other deleterious materials within, and to five (5) feet
beyond, the perimeter of the construction footprint. Foundations and below grade remains of
former structures located within the footprint of the construction should also be removed.
Similarly, irrigation and utility lines should be removed or properly abandoned so that they will
not adversely impact new overlying structures.
3.5 Fill Placement and Compaction
Prior to placing fill to attain design grade, the stripped surface should be compacted until the
upper 2 feet of soil achieves at least 95 percent of modified Proctor maximum dry density
(ASTM D 1557). We recommend using a steel drum vibratory roller having sufficient static
weight and vibratory impact to achieve the required compaction. Due to the proximity of the
site to the adjacent residences, GFA recommends that the roller operate in the static
mode. Density tests should be performed on the compacted surface at a frequency of not less
than one test per 2,500 square feet, or a minimum of three (3) tests, whichever is greater. The
density tests should be performed using either the nuclear method (ASTM D 6839) or the sand
cone method (ASTM D 1556). Hand Cone Penetrometer (HCP) tests may also be performed to
evaluate soil density.
Fill should be inorganic (i.e., contain less than 5 percent by weight organic material) and
classified as SP, SW, GP, GW, SP-SM, SW-SM, GW-GP, or GP-GM. GFA does not
recommend using fill materials having silt/clay-size soil fines contents exceeding 12
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 9 of 10
____________________________________________________________________________________
percent. In general, fill required to attain design grades should be placed in maximum 12-inch
thick loose lifts and compacted to at least 95 percent of modified Proctor maximum dry density
(ASTM D 1557). Each lift of fill should be compacted and tested prior to the placement of the
next lift. Density tests should be performed within the fill at the same frequency noted above.
3.6 Quality Control and Vibration Monitoring
We strongly recommend that a GFA representative be on site during the helical pile installation
or the soil mixing operations. This is necessary to determine if the work is being performed in
accordance with the project plans and specifications, provide an accurate record of the pile
installation or soil mixing, and afford an opportunity to correct any anomalous conditions that
may be encountered.
The proposed construction will be close to nearby residential structures and roadways that
could be susceptible to damage from vibrations generated at the site during site preparation and
foundation installation. We recommend that these structures and other bordering landmarks be
monitored using a seismograph to determine the extent of vibration absorption they are
experiencing during all aspects of construction. The seismograph used for monitoring at the site
should have the capability to measure ground velocities along vertical, transverse, and
longitudinal axes. The project Structural Engineer should establish allowable ground velocities
that the bordering facilities can safely withstand without incurring damage. A proposal for GFA
personnel to provide the vibration monitoring during construction will be provided upon request.
4.0 REPORT LIMITATIONS
This consulting report has been prepared for the exclusive use of Ms. Lois Denise Worsnop and
members of the design team for the proposed new residence located at 10701 South Ocean
Drive (Lot 634) in Jensen Beach, Florida. This report has been prepared in accordance with
generally accepted local geotechnical engineering practices; no other warranty, either express
or implied, is made.
The evaluation submitted in this report is based in part upon the data collected during a field
exploration. However, the nature and extent of variations throughout the subsurface profile may
not become evident until construction. If variations then appear evident, it may be necessary to
reevaluate information and professional opinions provided in this report. In the event changes
are made in the nature, design, or location of the proposed residence, the evaluation and
opinions contained in this report should not be considered valid unless the changes are
reviewed, and conclusions modified or verified in writing by GFA.
GFA should be provided the opportunity to review the final design plans and specifications to
determine if GFA’s recommendations have been properly interpreted, communicated, and
implemented. If GFA is not afforded the opportunity to participate in construction related
aspects of foundation installation recommended in this report or any report addendum, GFA
cannot accept responsibility for the interpretation of our recommendations made in this report or
in a report addendum for foundation performance.
Worsnop Residence Geotechnical Exploration Report
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida May 5, 2021
GFA Project No. 3330.2100052.0000 Page 10 of 10
____________________________________________________________________________________
5.0 BASIS FOR RECOMMENDATIONS
The recommendations presented in this report are based on the data obtained from the boring
performed at the location indicated on the Test Location Plan in Appendix B. This report does
not reflect any variations which may occur away from the boring. While the boring is
representative of the subsurface conditions at its location and vertical reach, local variations
characteristic of the subsurface soils of the region are anticipated and may be encountered. The
delineation between soil types shown on the boring log is approximate and the descriptions
represent our interpretation of the subsurface conditions at the designated boring location on
the specific date drilled.
Any third-party reliance of our geotechnical report or parts thereof is strictly prohibited without
the expressed written consent of GFA International, Inc. The applicable SPT methodology
(ASTM D 1586) and auger boring methodology (ASTM D 1452) used in performing the boring,
and for determining penetration resistance and soil relative density, is specific to the sampling
tools utilized and does not reflect the ease or difficulty to advance other tools or materials.
Appendix A - Vicinity Map
Site Vicinity Map
Worsnop Residence
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida
PROJECT NO: 3330.2100052.0000 DRAFTED BY: JR REVIEWED BY: JK DATE: 5/4/2021
gfhgfghfgh
N
Site Location
Appendix B - Test Location Plan
Test Location Plan
Worsnop Residence
10701 South Ocean Drive (Lot 634), Jensen Beach, Florida
PROJECT NO: 3330.2100052.0000 DRAFTED BY: JR REVIEWED BY: JK DATE: 5/4/2021
gfhgfghfgh
N Legend
Approximate 40’ Standard Penetration Test Boring Location
B-1
Appendix C - Notes Related to Borings
NOTES RELATED TO BORING RECORDS AND
GENERALIZED SUBSURFACE PROFILES
1.Groundwater levels (if encountered) were recorded either during or following the boring completion on
the date indicated. Fluctuations in groundwater levels are common - see the report text for a discussion.
2.The boring locations were identified in the field by estimated distances and offsets from existing reference
marks and/or other site landmarks.
3.The completed boreholes were backfilled to adjacent site grade using drilling spoils and patched with
asphalt cold mix in pavement areas.
4.The Log of Boring records represent our interpretation of soil conditions based on visual classification of
the soil samples recovered from the borings.
5.The Log of Boring records are subject to the limitations, conclusions, and recommendations presented in
the report text.
6.The Standard Penetration Test (SPT) N-values contained on the Log of Boring records refer to the total
blow counts of a 140-pound drop hammer falling 30 inches required to drive a split-barrel sampler a total
distance of 12 inches into soil strata at specific depth intervals.
7.The Hand Cone Penetrometer (HCP) values contained on Log of Boring records and the Cone
Penetration Test (CPT) values contained on the Cone Penetration Sounding logs refer to the cone tip
resistance recorded when pushing the cone tip into the soil strata at specific depth intervals.
8.The soil and/or rock strata interfaces shown on the Log of Boring records are approximate and may vary
from those shown on the logs. The soil and/or rock descriptions shown on the Log of Boring records refer
to conditions at the specific location tested. Soil/rock conditions may vary between test locations.
9.Relative density for coarse-grained soils (sands/gravels) and consistency for fine-grained soils (silts/clays)
are described as follows:
Coarse Grained Soils (Sands and Gravels) Fine Grained Soils (Silts and Clays)
SPT
N-Value
HCP Value
(kg/cm2)
CPT Value
(tsf)
Relative
Density
SPT
N-Value
HCP Value
(kg/cm2)
CPT Value
(tsf) Consistency
0-4 0-16 0-20 Very Loose 0-2 0-20 0-3 Very Soft
5-10 17-36 21-40 Loose 3-4 21-35 4-6 Soft
11-30 37-116 41-120 Med. Dense 5-8 >35 7-12 Firm
31-50 117-196 121-200 Dense 9-15 13-25 Stiff
>50 >196 >200 Very Dense 16-30 26-50 Very Stiff
>30 >50 Hard
10.Grain size descriptions are as follows:
Description Particle Size Limits
Boulder Greater than 12 inches
Cobble 3 to 12 inches
Coarse Gravel 3/4 to 3 inches
Fine Gravel No. 4 sieve to 3/4 inch
Coarse Sand No. 10 to No. 4 sieve
Medium Sand No. 40 to No. 10 sieve
Fine Sand No. 200 to No. 40 sieve
Fines (Silt/Clay) Smaller than No. 200 sieve
11.Definitions for modifiers used in soil/rock descriptions:
Proportion Modifier Approximate Root Diameter Modifier
<5% Trace Less than 1/32" Fine roots
5% to 12% Little 1/32" to 1/4” Small roots
12% to 30% Some 1/4” to 1" Medium roots
30% to 50% And Greater than 1" Large roots
Organic Soils: Soils containing vegetative tissue in various stages of decomposition having a fibrous to amorphous
texture. Usually having a dark brown to black color and an organic odor.
Organic Content Modifiers: <25%: Slightly to Highly Organic; 25% to 75%: Muck; >75%: Peat
Appendix D - Log of Boring Records
80
80
80
80
2
1
0
1
1
0
0
0
0
0
2
4
5
7
13
4
5
4
Light brown fine sand, trace shell (SP)
Gray fine sand, little silt, trace shell (SP)
Dark gray organic clayey fine sand, some fibrous organics (SC-OL)
Gray fine sand, little shell (SP)
4.0
7.0
8.5
1
2
3
4
5
6
7
1
WOH
2
20
9
HAMMER TYPE
HOLE DIAMETER 3 in
DRILLER JB/PS
DRILL RIG GeoProbe
METHOD SPT
HOLE DEPTH 40 ft
DATE STARTED 4/20/21 COMPLETED 4/20/21
AT TIME OF DRILLING 6.00 ft
NOTE:
GROUND WATER LEVEL:
DRILLING CONTRACTOR Universal Engineering Sciences
LATITUDE LONGITUDE
SAMPLEGRAPHICLOGBLOWCOUNTSMATERIAL DESCRIPTION
SAMPLENUMBERN VALUE(Continued Next Page)
PROJECT NUMBER 3330.2100052.0000 PROJECT LOCATION 10701 S Ocean Dr Lot 634, Jensen Beach, FL
PROJECT NAME Worsnop Residence
LOG OF BORING B-1
PAGE 1 OF 2
CLIENT Lois Denise Worsnop
DEPTH(ft)5
10
15
20 MOISTURECONTENT (%)FINESCONTENT (%)ORGANICCONTENT (%)SPT LOGS - GFA DATA TEMPLATE.GDT - 5/4/21 07:56 - Z:\PROJECTS\_UES PROJECT SETUP\3330.2100052.0000- WORSNOP RESIDENCE - GEO\21-6679.00 - WORSNOP PROPOSED RESIDENCE - GEO\GEO\APPENDICES NORMAL\SPT LOGS.GPJUniversal Engineering Sciences
607 NW Commodity Cove
Port Saint Lucie, Florida 34986
(772) 924-3575
4
9
17
2
2
6
4
4
5
2
5
2
Gray fine sand, little shell (SP) (continued)
Light gray sand and cemented sand, trace silt and shell (GP)
Gray sand and cemented sand, little silt (GP)
Bottom of borehole at 40.0 feet.
23.5
33.5
40.0
8
9
10
11
26
8
9
7SAMPLE GRAPHICLOGBLOWCOUNTSMATERIAL DESCRIPTION
SAMPLENUMBERN VALUEPROJECT NUMBER 3330.2100052.0000 PROJECT LOCATION 10701 S Ocean Dr Lot 634, Jensen Beach, FL
PROJECT NAME Worsnop Residence
LOG OF BORING B-1
PAGE 2 OF 2
CLIENT Lois Denise Worsnop
DEPTH(ft)25
30
35
40 MOISTURECONTENT (%)FINESCONTENT (%)ORGANICCONTENT (%)SPT LOGS - GFA DATA TEMPLATE.GDT - 5/4/21 07:56 - Z:\PROJECTS\_UES PROJECT SETUP\3330.2100052.0000- WORSNOP RESIDENCE - GEO\21-6679.00 - WORSNOP PROPOSED RESIDENCE - GEO\GEO\APPENDICES NORMAL\SPT LOGS.GPJUniversal Engineering Sciences
607 NW Commodity Cove
Port Saint Lucie, Florida 34986
(772) 924-3575
Appendix E - Discussion of Soil Groups
DISCUSSION OF SOIL GROUPS
COARSE GRAINED SOILS
General. A soil is classified as coarse-grained if more than 50 percent of a representative
sample of the material is retained on the No. 200 sieve.
GW and SW Groups. These groups comprise well-graded gravelly and sandy soils
containing little or no plastic fines (less than 5 percent passing the No. 200 sieve). The low
fines content does not noticeably change the shear strength characteristics of these soils
and does not interfere with their free-draining characteristics.
GP and SP Groups. Poorly graded gravels and sands containing little or no plastic fines
(less than 5 percent passing the No. 200 sieve) are in the GP and SP groups. The
materials can be called uniform gravels, uniform sands, or non-uniform mixtures of very
coarse materials and very fine sand, with intermediate sizes lacking (sometimes called
skip-graded, gap-graded, or step-graded). This last group often results from borrow pit
excavation in which gravel and sand layers are mixed.
GM and SM Groups. In general, the GM and SM groups comprise gravels or sands with
fines (more than 12 percent passing the No. 200 sieve) having little or no plasticity. The
plasticity index and liquid limit of soils in these groups plot below the “A” line on the
plasticity chart. The gradation of the material is not considered significant and both well
and poorly graded materials are included.
GC and SC Groups. In general, the GC and SC groups comprise gravelly or sandy soils
containing fines (more than 12 percent passing the No, 200 sieve) having plasticity
characteristics. The plasticity index and liquid limit of soils in these groups plot above the
“A” line on the plasticity chart.
FINE GRAINED SOILS
General. A soil is classified as fine-grained if more than 50 percent of a representative
sample of the material passes the No. 200 sieve.
ML and MH Groups. These groups comprise inorganic silts (ML) and elastic silts (MH)
having either low (L) or high (H) liquid limits, respectively. ML soils have a liquid limit of
less than 50 while MH soils have a liquid limit of 50 and greater. Silts and elastic silts can
also contain varying amounts of sand and gravel. Also included in this group are loess
sediments and rock flours.
CL and CH Groups. These groups comprise low plasticity (lean) clays (CL) and medium
to high plasticity (fat) clays (CH) having either low (L) or high (H) liquid limits, respectively.
CL soils have a liquid limit of less than 50 while CH soils have a liquid limit of 50 and
greater. The low plasticity clays can also be sandy clays or silty clays. The moderate to
high plasticity clays can also be sandy clays and include some volcanic clays.
OL and OH Groups. These groups comprise organic silts and clays. The soils are
characterized by the presence of organic odor and/or dark color. The OL and OH soils
are differentiated by determining and comparing their liquid limit values before and after
oven drying representative soil samples.
HIGHLY ORGANIC SOILS
The highly organic soils are usually very soft and compressible and have undesirable
construction characteristics. Particles of leaves, grasses, branches, or other fibrous
vegetative matter are common components of these soils. They are not subdivided and
are classified into one group with the symbol PT. Peat humus and swamp soils with a
highly organic texture are typical soils of the group.