ADDENDUM 4 - 7460 - 19829G - US Highway 380 Waterline Geotechnical Report
The seal appearing on this
document was authorized by
James F. Phipps, P.E. 84778 on
May 2, 2019.
geotechnical and construction materials consultants
May 2, 2019
Report No. 19829G
Birkhoff, Hendricks & Carter, LLP
11910 Greenville Avenue, Suite 600
Dallas, Texas 75243
ATTN: Mr. Cooper E. Reinbold, E.I.T.
Phone: 214-361-7900
Email: creinbold@bhcllp.com
RE: Geotechnical Investigation
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
Mr. Reinbold:
Presented herein is the report of a limited geotechnical investigation conducted by Henley-Johnston
& Associates, Inc. for the above referenced project.
We appreciate the opportunity to provide this report to you. If we can be of further service or if
you desire any additional information, please do not hesitate to call.
Signed,
HENLEY-JOHNSTON & Associates, Inc.
Benjamin Clarke, E.I.T. James F. Phipps, P.E.
Project Manager Vice President
Firm Registration No.: F-1238
Copies submitted (2) Birkhoff, Hendricks & Carter, LLP – Mr. Cooper E. Reinbold, E.I.T., Mr. Gary Hendricks, P.E.
Report No. 19829G May 2, 2019
- 1 -
INVESTIGATION AND ANALYSIS
Introduction
This report presents the results of a limited subsurface investigation performed for proposed 16-
and 20-inch water lines along US Highway 380 and Interstate 35 in Denton, Texas.
The purpose of this investigation was to provide information on the anticipated types of materials
to be encountered during installation of the lines and earthwork criteria for backfill of the utility
trench.
This report is specific to this site. Persons using the recommendations herein for projects and/or
designs not covered by this report do so at their own risk.
Field and Laboratory Investigation
Based on the size and layout of the project, subsurface conditions were evaluated with a total of
four soil borings. Two of the borings were located along the west side of Interstate 35 just south
of US Highway 30, while the remaining borings were located along the east side of Interstate 35
just south of US Highway 380. Locations of the borings were dictated by the client and site
accessibility and are presented on Plate 1. Borings were drilled using a truck-mounted rig
equipped with continuous flight augers and extended to depths of 15 to 20 feet below existing
(April 2019) grades. Drilling and sampling were done in general accordance with ASTM methods
and standards. Relatively undisturbed samples of cohesive soil and weathered shale were
obtained with three-inch diameter thick-walled Shelby tubes. Weathered and unweathered
limestone and unweathered shale were evaluated using the TxDOT Cone Penetration Test
(CPT). Clayey sands and unweathered shale were sampled and evaluated in-situ using
Standard Penetration Test (SPT) [ASTM 1586].
All samples were transported to the Henley-Johnston & Associates, Inc. (HJA) laboratory for
visual classification and testing. Soils were visually classified according to the Unified Soil
Classification System (USCS). Rock materials were described using standard geological
nomenclature. The Boring Logs and a key to terms and symbols used on the logs are attached.
Selected samples were tested to confirm visual classification. Tests conducted included
Atterberg Limits (ASTM D-4318) and moisture content determinations (ASTM D-2216). The
strength properties of selected samples were investigated by the Unconfined Compression test
(ASTM D-2166). Results of these laboratory tests are presented on Plates 2 and 3.
Surface and Subsurface Conditions
Surface Conditions
At the time of the field investigation, the majority of the proposed alignment for the water lines
was being used for commercial purposes.
Report No. 19829G May 2, 2019
- 2 -
Geologic Setting
Review of geologic maps indicates the proposed alignment appears to be within the Lower
Cretaceous Grayson Marl and Main Street Limestone Formation, undivided. Subsurface
conditions consisted of fill materials, clay soils, and clayey sand soils over weathered to
unweathered limestone and weathered to unweathered shale.
Subsurface Conditions
Fill materials were encountered at the surface of Boring No. 4. These fill materials consisted of
dark brown to light brown clay soils that continued to a depth of 9 feet below existing grade. This
fill was moderately plastic (CL) and contained varying amounts of calcareous particles and
subangular gravel.
Residual clay soils were present below the fill materials in Boring No. 4 and at the surface of
Boring Nos. 1 through 3. These clays were dark brown to light brown in appearance, moderately
plastic (CL), contained varying amounts of calcareous particles and limestone fragments. This
clay continued to depths of 4 to 19 feet below existing grades.
Clayey sand soils were encountered underlying the clays in Boring No. 1. These clayey sands
were fine-grained, very dense (relative density), light brown in appearance, and continued to a
depth of 13-1/2 feet below existing grade.
Weathered shale was encountered underlying the clay soils in Boring Nos. 3 and 4. This
weathered shale was soft (rock hardness classification), laminated in structure, light brown, light
gray, and gray in appearance, and continued to depths of 18 to 20 feet below existing grades. It
should be noted that Boring No. 4 terminated within the weathered shale at a depth of 20 feet.
Unweathered shale was encountered underlying the clayey sand soils in Boring No. 1 and below
the weathered shale in Boring No. 3. This unweathered shale was firm, dark gray in
appearance, laminated in structure, and extended through the termination depths of the borings.
Weathered limestone was present below the clay soils in Boring No. 2. This weathered
limestone was tan in appearance, moderately hard, and continued to a depth of 12 feet below
existing grade. Unweathered limestone was encountered underlying the weathered limestone.
This unweathered limestone was hard, gray in appearance, and extended through the
termination depth of the boring.
Ground Water
Ground water was encountered in Boring No. 1 during the field investigation at a depth of 10 feet
below existing grade, and at a depth of 6 feet below existing grade at end of day observations.
The presence and depth to ground water will vary depending upon seasonal rainfall amounts.
When present, ground water should be expected to perch above the unweathered rock,
migrating through the open cracks, fissures, and fractures of the overlying weathered rock and
overburden soils.
Report No. 19829G May 2, 2019
-3 -
Excavations
Per Federal regulations, any excavation over 20 feet in depth will require an engineered
excavation and safety plan prepared by a licensed engineer. Soils encountered within the
borings consisted of fill materials, CL clays, and clayey sands over weathered to unweathered
limestone and shale. These soils should be classified as Type C soils per OSHA Excavation
Standards CFR 29, Part 1926, Sub-Part P, Appendix A. Clay soils along the water lines may be
laid back on a temporary slope of 1:Horizontal to 1:Vertical up to a maximum slope height of 20
feet.
For retention system design, the on-site soils may be considered to exert an equivalent fluid
pressure of 50 pcf considering active conditions against any shielding or temporary shoring.
All spoils and construction materials should be kept a minimum of 4 feet from the edge of the
trench. Water should not be allowed to pond along the edge of or within the bottom of the
trench.
Earthwork Recommendations
On-site soils to be used all fill should be cleaned of all debris and rock fragments over 3-inches in
nominal diameter. These materials should be placed in maximum eight-inch loose lifts and
compacted to a minimum of 95% of the maximum density as determined by ASTM D-698.
Moisture content should be at least +2 percentage points above optimum.
Excavated limestone used as fill should be reduced to a maximum nominal diameter of 3 inches
and placed in maximum 8-inch loose lifts. Limestone fragments should be compacted to a
minimum of 95% (ASTM D-698) with moisture contents between –2 and +3 percentage points of
optimum.
Construction Testing and Observation
It is recommended that all backfill materials within the trench be tested for moisture and density
at a rate of one test per foot of fill for every 300 linear feet of excavation (NCTCOG Public Works
Construction Standards, Fifth Edition – 2017, Item 504.5.3.2). Field density tests should be
taken during placement of trench backfill. Excavating and evaluating fill materials within test pits
should not be permitted. Provisions should be made to permit safe access to the utility trench
during placement of fill to allow for testing of the backfill materials for adequate moisture and
density.
PLATE 1
LEGEND
SOIL BORING
HJA No.:
DATE:
19829G
APRIL 2019
TEXAS FIRM REGISTRATION NO. F-1238 BORING LOCATION PLAN235 MORGAN AVE. DALLAS, TX 75203 I 214.941.3808 I WWW.HJA-ENG.COM
3
4
US HIGHWAY 380 WATERLINE
US HIGHWAY 380 AND I-35
DENTON, TEXAS
1
2
GEOTECHNICAL INVESTIGATION
REPORT NO. 19829G
US HIGHWAY 380 WATERLINE
US HIGHWAY 380 AND I-35
DENTON, TEXAS
Plate 2
SUMMARY OF INDEX PROPERTIES
BORING
NUMBER
DEPTH
(ft.)
LIQUID
LIMIT
(%)
PLASTIC
INDEX
DUW
(pcf)
FINER
#200
(%)
MOISTURE
CONTENT
(%)
UNIFIED SOIL
CLASSIFICATION
1 0.0 – 1.0 14.6
1 1.0 – 2.0 11.4
1 2.0 – 3.0 35 22 118.2 12.8 CL
1 3.0 – 4.0 16.0
1 4.0 – 5.0 18.5
1 5.0 – 6.0 21.8
1 8.5 – 10.0 21.7
2 0.0 – 1.0 22.9
2 1.0 – 2.0 18.3
2 2.0 – 3.0 16.3
2 3.0 – 4.0 35 22 15.8 CL
2 4.0 – 5.0 13.5
2 5.0 – 6.0 116.8 17.2
2 6.0 – 7.0 14.7
3 0.0 – 1.0 28.9
3 1.0 – 2.0 11.1
3 2.0 – 3.0 14.8
3 3.0 – 4.0 17.3
3 4.0 – 5.0 16.6
3 5.0 – 6.0 22.8
3 6.0 – 7.0 21.7
3 7.0 – 8.0 42 28 18.9 CL
3 8.0 – 9.0 21.4
3 9.0 – 10.0 102.9 24.5
3 14.0 – 15.0 22.1
4 0.0 – 1.0 14.9
4 1.0 – 2.0 13.1
4 2.0 – 3.0 17.7
GEOTECHNICAL INVESTIGATION
REPORT NO. 19829G
US HIGHWAY 380 WATERLINE
US HIGHWAY 380 AND I-35
DENTON, TEXAS
Plate 3
SUMMARY OF INDEX PROPERTIES
BORING
NUMBER
DEPTH
(ft.)
LIQUID
LIMIT
(%)
PLASTIC
INDEX
DUW
(pcf)
FINER
#200
(%)
MOISTURE
CONTENT
(%)
UNIFIED SOIL
CLASSIFICATION
4 3.0 – 4.0 109.6 20.5
4 4.0 – 5.0 22.4
4 5.0 – 6.0 22.1
4 6.0 – 7.0 48 32 23.4 CL
4 7.0 – 8.0 24.1
4 8.0 – 9.0 28.8
4 9.0 – 10.0 25.8
4 14.0 – 15.0 19.7
4 19.0 – 20.0 23.7
SUMMARY OF UNCONFINED COMPRESSION TESTS - SOIL
BORING
NUMBER
DEPTH
(ft.)
PEAK
STRESS
(psi)
FAILURE
STRAIN
(%)
MATERIAL DESCRIPTION
1 2.0 – 3.0 74.5 6.3 CLAY, very stiff to hard, dark brown
2 5.0 – 6.0 15.6 7.5 CLAY, very stiff to hard, brown and light brown
3 9.0 – 10.0 21.9 6.2 SHALE, weathered
4 3.0 – 4.0 19.1 9.3 FILL: CLAY, very stiff to hard, brown and light brown
Strata symbols
LOW PLASTICITY CLAYS,
SANDY CLAYS, OR GRAVELLY
CLAYS (CL)
CLAYEY SAND OR CLAYEY
GRAVELLY SAND (SC)
SHALE, unweathered
HIGH PLASTICITY CLAYS (CH)
LIMESTONE, weathered
LIMESTONE, unweathered
SHALE, weathered
FILL
Misc. Symbols
Ground Water During Drilling (ft)
Pocket Penetrometer (tsf)
Standard Penetration (BPF)
TxDOT CPT (inches per 100
blows)
LEGEND, LITHOLOGY, SOIL CONSISTENCY
& RELATIVE ROCK HARDNESS
# OF BORINGS:4
PROJECT No.:19829G
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
DRILL DATE:4/23/19
TEXAS FIRM REGISTRATION NO. F-1238 METHOD:Shelby Tube to 20'
asdf
FOR SANDS, GRAVELS, & SANDY SILTS FOR CLAYS AND SANDY CLAYS
Modified from Peak, Hanson & Thornburn (1974)
(COHESIVE SOILS)
Modified from Peak, Hanson & Thornburn (1974)
Consistency Standard Penetration Resistance
(N)
Consistency Unconfined
Compression (tsf)
Standard
Penetration
Resistance (N)
Very Soft Less than 0.25 Less than 2
Very Loose Less than 4
Soft 0.25 to 0.5 2 to 4
Loose 4 to 10
Medium Stiff 0.5 to 1.0 4 to 8
Medium Dense 10 to 30
Stiff 1.0 to 2.0 8 to 15
Dense 30 to 50
Very Stiff 2.0 to 4.0 15 to 30
Very Dense Greater than 50 Hard Greater than 4.0 Greater
than 30asdfasdf
RELATIVE HARDNESS MODIFIERS (ROCK)
(RELATED TO FRESH SAMPLE)
Modified from SCS EWP, Tech Guide No. 4
Hardness Rule of Thumb Test
Soft Permits denting by moderate finger pressure
Resists denting by fingers but can be penetrated
by pencil point to medium to shallow depth (No. 2 pencil)Firm
Very shallow penetration of pencil point, can be
scratched by knife and in some instances cut with knifeMod. Hard
Hard No pencil penetration, can be scratched with knife,
can be broken by light to moderate hammer blows
Very Hard Cannot be scratched by knife, can be broken
by repeated hammer blows
asdf
Soil Samplers
Undisturbed thick wall
Shelby tube
Auger bag sample
Split Spoon
TxDOT CPT
LEGEND, LITHOLOGY, SOIL CONSISTENCY
& RELATIVE ROCK HARDNESS
# OF BORINGS:4
PROJECT No.:19829G
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
DRILL DATE:4/23/19
TEXAS FIRM REGISTRATION NO. F-1238 METHOD:Shelby Tube to 20'
asdf
FOR SANDS, GRAVELS, & SANDY SILTS FOR CLAYS AND SANDY CLAYS
Modified from Peak, Hanson & Thornburn (1974)
(COHESIVE SOILS)
Modified from Peak, Hanson & Thornburn (1974)
Consistency Standard Penetration Resistance
(N)
Consistency Unconfined
Compression (tsf)
Standard
Penetration
Resistance (N)
Very Soft Less than 0.25 Less than 2
Very Loose Less than 4
Soft 0.25 to 0.5 2 to 4
Loose 4 to 10
Medium Stiff 0.5 to 1.0 4 to 8
Medium Dense 10 to 30
Stiff 1.0 to 2.0 8 to 15
Dense 30 to 50
Very Stiff 2.0 to 4.0 15 to 30
Very Dense Greater than 50 Hard Greater than 4.0 Greater
than 30asdfasdf
RELATIVE HARDNESS MODIFIERS (ROCK)
(RELATED TO FRESH SAMPLE)
Modified from SCS EWP, Tech Guide No. 4
Hardness Rule of Thumb Test
Soft Permits denting by moderate finger pressure
Resists denting by fingers but can be penetrated
by pencil point to medium to shallow depth (No. 2 pencil)Firm
Very shallow penetration of pencil point, can be
scratched by knife and in some instances cut with knifeMod. Hard
Hard No pencil penetration, can be scratched with knife,
can be broken by light to moderate hammer blows
Very Hard Cannot be scratched by knife, can be broken
by repeated hammer blows
asdf
0
3
6
9
12
15
18
21
CLAY, with limestone fragments, very stiff to hard, dark brown
CLAYEY SAND, fine-grained, very dense, light brown
SHALE, laminated, firm, dark gray
TOTAL DEPTH: 15.0'
50=3.75"
60
LOG OF BORING PROJECT No.:19829G
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
BORING No.:1
STATION:
DRILL DATE:4/23/19 SHEET:1 of
METHOD:Shelby Tube w/Split Spoon to 15'LOCATION:See Plate 1
GROUND ELEVATION:
Ground Water During Drilling (ft.):10'
dfs
Ground Water After Drilling (ft.):6'DEPTH(feet)SYMBOLSAMPLESMATERIAL DESCRIPTION
ELEVATION(feet)RECOVERED (ft.)CORE
RQD (%)1 2 3 4 +++POCKET PENETROMETER (tsf)
10 20 30 40 50 60STANDARD PENETRATION (BPF)
1 2 3 4 5 6
TxDOT CPT (inches per 100 blows)
1
0
3
6
9
12
15
18
21
CLAY, calcareous, very stiff, dark brown
CLAY, with limestone fragments, very stiff to hard, brown and light
brown
LIMESTONE, weathered, moderately hard, tan
LIMESTONE, hard, gray
TOTAL DEPTH: 15.0'
1.5"
0.75"
LOG OF BORING PROJECT No.:19829G
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
BORING No.:2
STATION:
DRILL DATE:4/23/19 SHEET:1 of
METHOD:Shelby Tube to 15'LOCATION:See Plate 1
GROUND ELEVATION:
Ground Water During Drilling (ft.):DRY
dfs
Ground Water After Drilling (ft.):DRYDEPTH(feet)SYMBOLSAMPLESMATERIAL DESCRIPTION
ELEVATION(feet)RECOVERED (ft.)CORE
RQD (%)1 2 3 4 +++POCKET PENETROMETER (tsf)
10 20 30 40 50 60STANDARD PENETRATION (BPF)
1 2 3 4 5 6
TxDOT CPT (inches per 100 blows)
1
0
3
6
9
12
15
18
21
CLAY, very stiff, dark brown
CLAY, with limestone fragments, very stiff, brown and light brown
SHALE, weathered, laminated, soft, light brown and gray
SHALE, laminated, firm, dark gray
TOTAL DEPTH: 20.0'
6.75"
LOG OF BORING PROJECT No.:19829G
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
BORING No.:3
STATION:
DRILL DATE:4/23/19 SHEET:1 of
METHOD:Shelby Tube to 20'LOCATION:See Plate 1
GROUND ELEVATION:
Ground Water During Drilling (ft.):DRY
dfs
Ground Water After Drilling (ft.):DRYDEPTH(feet)SYMBOLSAMPLESMATERIAL DESCRIPTION
ELEVATION(feet)RECOVERED (ft.)CORE
RQD (%)1 2 3 4 +++POCKET PENETROMETER (tsf)
10 20 30 40 50 60STANDARD PENETRATION (BPF)
1 2 3 4 5 6
TxDOT CPT (inches per 100 blows)
1
0
3
6
9
12
15
18
21
FILL: CLAY, with subangular gravel, very stiff to hard, brown and
light brown
FILL: CLAY, calcareous, stiff to very stiff, dark brown and brown
CLAY, calcareous, very stiff, brown
CLAY, with calcareous nodules, very stiff, light brown
SHALE, weathered, laminated, soft, light brown and light gray
TOTAL DEPTH: 20.0'
LOG OF BORING PROJECT No.:19829G
US Highway 380 Waterline
US Highway 380 and I-35
Denton, Texas
BORING No.:4
STATION:
DRILL DATE:4/23/19 SHEET:1 of
METHOD:Shelby Tube to 20'LOCATION:See Plate 1
GROUND ELEVATION:
Ground Water During Drilling (ft.):DRY
dfs
Ground Water After Drilling (ft.):DRYDEPTH(feet)SYMBOLSAMPLESMATERIAL DESCRIPTION
ELEVATION(feet)RECOVERED (ft.)CORE
RQD (%)1 2 3 4 +++POCKET PENETROMETER (tsf)
10 20 30 40 50 60STANDARD PENETRATION (BPF)
1 2 3 4 5 6
TxDOT CPT (inches per 100 blows)
1