mr. nathan anderson, pe · 2020-01-31 · geotechnical engineering and testing • 421 north...

IOWA MINNESOTA WISCONSIN

Factual Geotechnical Report:

Proposed Hardin County Wetland E Avenue and Highway 175 Radcliffe, Iowa CVT# 14937.19.IAW

Prepared for:

Mr. Nathan Anderson, PE WHKS & Co.

Certification:

I hereby certify that this engineering document was prepared by me or under my

direct personal supervision and that I am a duly licensed Professional Engineer

under the laws of the State of Iowa.

June 7, 2019

(signature) (date)

Printed or typed name: Matthew J. Reisdorfer, PE.

License number: 22234 .

My license renewal date is December 31, 2019 .

Pages or sheets covered by this seal:

M i n n e s o t a I o w a W i s c o n s i n

TABLE OF CONTENTS

A. Introduction .......................................................................................................................2

A.1. Purpose ................................................................................................................................... 2

A.2. Scope ...................................................................................................................................... 2

A.3. Boring Locations and Elevation ................................................................................................. 3

A.4. Geologic Background ............................................................................................................... 3

B. Subsurface Data .................................................................................................................3

B.1. Stratification ............................................................................................................................ 3

B.2. Penetration and Laboratory Test Data ...................................................................................... 4

B.3. Groundwater Data ................................................................................................................... 5

C. Level of Care .......................................................................................................................5

Appendix .................................................................................................................................6

Soil Boring Location Sketch

Log of Boring # 1-8

Legend to Soil Description

Hardin County Wetland June 7, 2019

Project: 14937.19.IAM Page - 2


Chosen Valley Testing, Inc. Geotechnical Engineering and Testing • 421 North Georgia Avenue • Mason City, IA 50401 • Telephone (641) 201-1050 • [email protected]

Mr. Nathan Anderson, PE June 7, 2019

WHKS & Co

2905 South Broadway

Rochester, MN 55904

[email protected]

Re: Proposal for Factual Geotechnical Evaluation

Hardin County Wetland

E Avenue and Highway 175

Radcliffe, Iowa

CVT Proposal Number: 14937.19.IAM

Dear Mr. Anderson:

This factual report was prepared to assist planning for the proposed Hardin County Wetland near Radcliffe,

Iowa. Our services were authorized by Mr. Nathan Anderson of WHKS.

A. Introduction

The intent of this report is to present our results to the client in the same logical sequence that led us to arrive

at the opinions and recommendations expressed. Since our services must often be completed before the design,

assumptions are sometimes needed to prepare a proper evaluation and to analyze the data. A complete and

thorough review of this entire document, including the assumptions and the appendices, should be undertaken

immediately upon receipt.

A.1. Purpose

This factual report was prepared to assist planning for the proposed Hardin County Wetland near Radcliffe,

Iowa. Our services were authorized by Mr. Nathan Anderson of WHKS.

A.2. Scope

To obtain data for analysis, our services included a total of 8 penetration test borings. The borings were drilled

to depths of about 10 to 30 feet below the surface. Our engineering scope consisted of providing a factual

discussion of the soils and materials encountered during our exploration.




A.3. Boring Locations and Elevation

The desired borings locations were indicated to Chosen Valley Testing on site plans provided by the client.

The Boring Location Sketch in the Appendix shows the approximate locations drilled. Elevations were

estimated using LiDAR from the Iowa DNR. These elevations should be considered approximate.

A.4. Geologic Background

A geotechnical report is based on subsurface data collected for the specific structure or problem. Available

geologic data from the region can help interpretation of the data and is briefly summarized in this section.

Area geologic maps indicate that the natural upper soils are primarily alluvial (river-deposited) sand and clay

mixtures overlying glacial till deposits of clay, silt and sand mixtures. Bedrock is expected to be 100 to 200

feet below the surface and consist of dolomite and limestone of the Gilmore City Formation and Kinderhookian

Formation.

B. Subsurface Data

Methods: All of the borings were performed using penetration test procedures (Method of Test D1586 of the

American Society for Testing and Materials). This procedure allows for the extraction of intact soil specimen

from deep in the ground. With this method, a hollow-stem auger is drilled to the desired sampling depth. A 2-

inch OD sampling tube is then screwed onto the end of a sampling rod, inserted through the hole in the auger's

tip, and then driven into the soil with a 140-pound hammer dropped repeatedly from a height of 30 inches above

the sampling rod. The sampler is driven 18-inches into the soil, unless the material is too hard. The samples are

generally taken at 2½ to 5-foot intervals. The core of soil obtained is classified and logged by the driller and a

representative portion is then sealed in a jar and delivered to the soils engineer for review.

B.1. Stratification

At the surface, most of the borings encountered about 2 to 6 ½ feet of topsoil. The topsoil consisted of both

slightly organic lean clay and slightly organic clayey sand.

Below the topsoil layer in Boring B-3, alluvial lean clay was encountered, to a depth of about 6 ½ feet. The

alluvial clay was followed by slightly organic lean clay to a depth of about 11 ½ feet.

Sand with clay was met below the topsoil in Boring B-7, to a depth of about 9 feet. The sand with clay was

followed by silty sand to the borings termination depth of about 11 feet below the surface.

With the exception of Borings B-3, B-7 and B-8, glacio-fluvial (weathered till) lean clays were encountered

below the topsoil layer in the borings, to depths of about 4 to 17 ½ feet.

Glacial till consisting mostly of sandy lean clay and lean clays was met below the topsoil layer in Boring B-8,

and below the slightly organic lean clay and fluvial lean clay layers. With the exception of Boring B-7, the

borings terminated in glacial clays at depths of about 11 to 31 feet below the surface.




The following simplified cross-section summarizes the boring data. For more detailed information, please refer

to the Log of Boring sheets in the Appendix.

1095.0

1100.0

1105.0

1110.0

1115.0

1120.0

1125.0

1130.0

1135.0

1140.0

1145.0

1150.0

B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8

Approximate Assigned Elevation (feet)

Boring Number

Topsoil

Sand w/ Clay

Fluvial Clay

Alluvial Clay

Slightly Organic Clay

Silty Sand

Glacial Clay

Below Boring

B.2. Penetration and Laboratory Test Data

The number of blows needed for the hammer to advance the penetration test sampler is an indicator of soil

characteristics. The number of blows to advance the sampler 1 foot is called the penetration resistance or “N”-

value. The results tend to be more meaningful for natural mineral soils, than for fill soils. In fill soils, compaction

tests are more meaningful.

Penetrations resistance values ("N" Values) of 2 to 11 blows per foot (BPF) were recorded in the topsoil,

alluvial clay, fluvial clay, slightly organic clay and glacial clays, indicating they were soft to rather stiff, but

were generally soft to medium. N-values of 2 to 9 BPF were recorded in the sand with clay and silty sand,

indicating they were very loose to loose.

A key to the descriptors used to qualify the relative density of soil (such as soft, stiff, loose, and dense,) can be

found on the Legend to Soil Description in the Appendix.

A pocket penetrometer was used to provide additional data on the compressive strength of cohesive soils. The

clays returned values of ½ to 2 ½ tons per square foot (tsf).




B.3. Groundwater Data

During the drilling operation, the drillers may note the presence of moisture on the sampling instrument, in the

cuttings, or within the borehole. These observations are recorded on the boring logs. The water level may vary

with weather; time of year and other factors and the presence or absence of water during the drilling is subject

to interpretation and is not always conclusive.

Water was encountered in some of the borings during drilling, at depths of about 8 to 15 feet below the surface.

Water levels were also measured in some of the borings after drilling was completed, with post drilling water

levels ranging from 1 to 21 feet below the surface. Elevated moisture contents were noted in several of the

clay samples. Groundwater levels at the site are expected to fluctuate seasonally with nearby creeks and rivers,

as well as with local weather patterns.

C. Level of Care

The services provided for this project have been conducted in a manner consistent with that level of care and

skill ordinarily exercised by members of the profession currently practicing in this area, under similar budget

and time constraints. This is our professional responsibility. No other warranty, expressed or implied, is made.




Appendix

Soil Boring Location Sketch

Log of Boring 1-8

Legend to Soil Description

PP = 2.0 tsf

PP = 2.0 tsfMC = 14.1%

2.0

6.5

11.0

1133.0

Elevations estimated usingIowa DNR LiDAR

CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9

Slightly Organic CLAYEY SAND brown, moist.(Topsoil)

LEAN CLAY with SAND trace of gravel, brown,wet, rather soft.

(Glacio-fluvium)

SANDY LEAN CLAY trace of iron staining toabout 9 feet, trace of gravel, brown to about 9 feet,then becoming gray, wet, rather stiff.

(Glacial Till)

End of boring.Boring sealed upon completion

1137.5

4

4 PP = 2.5 tsfMC = 16.6%

11

PP = 1.25 tsf

SC

CL

CL

10

DATE: 6/4/2019

Tests and Notes

LOCATION:

Elev. DepthDescription of Materials(ASTM D 2487/2488)

WL

See attached sketchLOCATION:

1128.5

B-01 page 1 of 1

0.0

BORING: B-01

14937.19.IAM

USCSSymbol

SCALE: 1" = 4'

14937.19.IAM

Design Phase Geotechnical Evaluation



Radcliffe, Iowa

BPF

CHOSEN VALLEY TESTING

L O G O F B O R I N G

1139.5

PROJECT:

PP = 1.75 tsfMC = 25.7%

CLOL

CL

CL


CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9

PP = 1.5 tsf

MC = 20.0%

Water encountered at about15 feet during drilling.PP = 2.25 tsfMC = 24.4%

PP = 1.25 tsfMC = 25.4%

PP = 1.0 tsfMC = 27.2%

2.0

17.5

31.0

1133.4

1117.9

1104.4

PP = 0.5 tsf

PP = 0.5 tsfMC = 19.4%

2

2

3

9

2

6

8

7

6

SCALE: 1" = 4'

BPFElev.USCSSymbol

Tests and NotesDepth

See attached sketch

14937.19.IAM




Radcliffe, Iowa

LOCATION:LOCATION:

DATE: 6/4/2019

Description of Materials(ASTM D 2487/2488)

WL

Slightly Organic LEAN CLAY dark brown toblack, wet.

(Topsoil)

LEAN CLAY with SAND dark brown, wet, soft torather stiff.

(Glacio-fluvium)

Becoming gray.

With seams of coarse grained, water bearing sand.Becoming very wet.

LEAN CLAY gray, wet to very wet, medium.(Glacial Till)



B-02 page 1 of 1


1135.4

PROJECT:

0.0

BORING:

14937.19.IAM

B-02

MC = 27.9%

CLOL

CL

CLOL

CL

CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9

MC = 9.7%

MC = 20.7%

PP = 1.5 tsf

1099.3

PP = 0.75 tsfMC = 28.3%

PP = 1.0 tsfMC = 26.5%

2.0

6.5

11.5

31.0

1128.3

1123.8

1118.8

PP = 0.75 tsfMC = 29.4%

3

4

2

6

4

2

4

6

9


See attached sketch


SCALE: 1" = 4'

Elev.USCSSymbol

Tests and NotesDepth BPF

LOCATION:LOCATION:

DATE: 6/4/2019


WL

LEAN CLAY with seams of sand to about 14 feet,gray, wet to very wet, soft to rather stiff.

(Glacial Till)


LEAN CLAY with SAND dark brown, wet, soft torather stiff.

(Alluvium)

14937.19.IAM




Radcliffe, Iowa

Slightly Organic LEAN CLAY dark brown toblack, wet.

(Topsoil)


B-03 page 1 of 1

Slightly Organic LEAN CLAY with seams ofsand, black, wet, soft to medium.

(Alluvium)

1130.3

PROJECT:

14937.19.IAM

B-03BORING:

0.0

PP = 2.0 tsfMC = 25.4%

CLOL

CL

CL

PP = 0.75 tsf

CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9

PP = 0.5 tsfMC = 19.4%

PP = 0.5 tsf

Water encountered at about15 1/2 feet during drilling.

Water encountered at about21 feet after drilling.

PP = 0.75 tsfMC = 26.1%

PP = 0.75 tsfMC = 27.7%

6.5

11.5

31.0

1123.5

1118.5

1099.0

PP = 0.75 tsfMC = 28.0%

3

2

2

3

4

4

5

7

9

PP = 0.5 tsfMC = 33.5%

SCALE: 1" = 4'

BPFElev.USCSSymbol

Tests and NotesDepth

See attached sketch

14937.19.IAM




Radcliffe, Iowa


LOCATION:LOCATION:

DATE: 6/4/2019


WL

Slightly Organic LEAN CLAY black, wet, soft.(Topsoil / Alluvium)

LEAN CLAY with SAND with seams of coarsegrained, water bearing sand, gray, very wet, soft.

(Glacio-fluvium)

LEAN CLAY gray, wet to very wet, rather soft torather stiff.

(Glacial Till)



B-04 page 1 of 1


1130.0

PROJECT:

0.0

BORING:

14937.19.IAM

B-04

Water encountered at about10 feet during drilling.PP = 2.0 tsfMC = 10.9%

2.0

4.0

11.0

1134.4

1125.4


CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9

Slightly Organic LEAN CLAY black.(Topsoil)

LEAN CLAY with SAND brown, very wet, soft.(Glacio-fluvium)

SANDY LEAN CLAY trace of gravel, brown toabout 9 feet, then becoming gray, wet, soft tomedium.

(Glacial Till)


1132.4

3

2 PP = 0.5 tsfMC = 18.4%

8

PP = 0.5 tsf

CLOL

CL

CL

4

DATE: 6/4/2019

Tests and Notes

LOCATION:


WL


B-05 page 1 of 1

0.0

BORING: B-05

14937.19.IAM

USCSSymbol

SCALE: 1" = 4'

14937.19.IAM




Radcliffe, Iowa

BPF



1136.4

PROJECT:

PP = 2.0 tsfMC = 13.8%

2.0

4.0

11.0

1137.8

1128.8


CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9


LEAN CLAY with SAND brown, very wet, soft.(Glacio-fluvium)

SANDY LEAN CLAY trace of gravel, brown toabout 9 feet, then becoming gray, wet, rather soft tomedium.

(Glacial Till)


1135.8

2

5

PP = 1.0 tsf

8

PP = 2.0 tsfMC = 15.5%

CLOL

CL

CL

7

DepthElev. Tests and NotesDescription of Materials(ASTM D 2487/2488)

WL

LOCATION:LOCATION:See attached sketch

DATE: 6/4/2019

B-06

0.0

14937.19.IAM

BORING:PROJECT:

B-06 page 1 of 1

BPFUSCSSymbol

14937.19.IAM




Radcliffe, Iowa

1139.8

SCALE: 1" = 4'



4.0

9.0

11.0

1132.3

1127.3

PP = 0.25 tsf

Water encountered at about1 foot after drilling.

CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9

POORLY GRADED SAND with CLAY mostlymedium grained, brown, water bearing, very loose toloose.

(Glacio-fluvium)

SILTY SAND brown, water bearing, loose.(Glacial Till)


1125.3

2

2

Water encountered at about8 feet during drilling.

9

Slightly Organic LEAN CLAY black, wet, soft.(Topsoil)

CLOL

SPSC

SM


7

DATE: 6/4/2019

Tests and Notes

LOCATION:


WL


B-07 page 1 of 1

0.0

BORING: B-07

14937.19.IAM

USCSSymbol

SCALE: 1" = 4'

14937.19.IAM




Radcliffe, Iowa

BPF



1136.3

PROJECT:

PP = 1.25 tsfMC = 15.6%

2.0

11.0

1143.6

1134.6

PP = 0.5 tsfSANDY LEAN CLAY trace of gravel, brown,wet, soft to medium.

(Glacial Till)

CV

T S

TA

ND

AR

D

14

93

7.1

9.I

AM

(H

AR

DIN

CO

UN

TY

WE

TL

AN

D).

GP

J

LO

G A

GN

NN

06

.GD

T

6/1

0/1

9


B-08 page 1 of 1

7

2

PP = 2.25 tsf6

PP = 2.0 tsfMC = 15.7%

CLOL

CL


Trace of iron staining.

4

WLElev.0.0

DATE: 6/4/2019


LOCATION:LOCATION:See attached sketch


1145.6

14937.19.IAM

B-08

Depth

BORING:PROJECT:


14937.19.IAM




Radcliffe, IowaSCALE: 1" = 4'

BPF Tests and Notes


USCSSymbol

GROUPSYMBOL

SOIL GROUP NAMES & LEGEND

PRIMARILY ORGANIC MATTER, DARK IN COLOR, AND ORGANIC ODOR

BLOWS/FOOT* CONSISTENCY

SAMPLE TYPES

Job No. 14937.19.IAM

GRAVELS WITH FINES

>12% FINES

2.0 - 4.0OVER 4.0

TERM

TraceWith

Modifier

0.50 - 1.0

1.0 - 2.0

0 - 0.250.25 - 0.50

GW

GP

GM

GC

SW

SP

SM

SC

CL

ML

OL

CH

MH

OH

PT

CLEAN GRAVELS

<5% FINES

WATER LEVEL (WITH TIME OF)

MEASUREMENT

0 - 4

4 - 10

10 - 30

30 - 50

OVER 50

LIQUID LIMIT (%)

CH

0

10

20

30

40

50

60

70

80

PLASTICITY INDEX (%)

SIZE

< 12 in.3 in. - 12 in.

#4 sieve to 3 in.#200 sieve to #4 sievePassing #200 sieve

TERM

BoulderCobbleGravelSand

Silt or Clay

SAND & GRAVEL

CRITERIA FOR ASSIGNING SOIL GROUP NAMES

-

-

-

MC

OC

CN

DD

PP

RV

SA

P200

>50% OF COARSEFRACTION PASSESON NO 4. SIEVE

RELATIVE DENSITY

(RECORDED AS BLOWS / 0.5 FT)

CL

SILT & CLAY

NUMBER OF BLOWS OF 140 LB HAMMER FALLING 30 INCHES TO DRIVE A 2 INCH O.D.

(1-3/8 INCH I.D.) SPLIT-BARREL SAMPLER THE LAST 12 INCHES OF AN 18-INCH DRIVE

(ASTM-1586 STANDARD PENETRATION TEST).

*

BLOWS/FOOT*

WELL-GRADED GRAVEL

POORLY-GRADED GRAVEL

SILTY GRAVEL

CLAYEY GRAVEL

WELL-GRADED SAND

POORLY-GRADED SAND

SILTY SAND

CLAYEY SAND

LEAN CLAY

SILT

ORGANIC CLAY OR SILT

FAT CLAY

ELASTIC SILT

ORGANIC CLAY OR SILT

PENETRATION RESISTANCE

Hollow Stem

LEGEND TO SOIL

DESCRIPTIONS

FINES CLASSIFY AS ML OR CL

FINES CLASSIFY AS CL OR CH

PI>7 AND PLOTS>"A" LINE

PI>4 AND PLOTS<"A" LINE

LL (oven dried)/LL (not dried)<0.75

PI PLOTS >"A" LINE

PI PLOTS <"A" LINE

LL (oven dried)/LL (not dried)<0.75

COMPRESSIVE

STRENGTH (TSF)

Chosen Valley Testing

-

CLEAN SANDS

<5% FINES

SANDS AND FINES

>12% FINES

INORGANIC

MOISTURE CONTENT

ORGANIC CONTENT

CONSOLIDATION

DRY DENSITY

POCKET PENETROMETER

R-VALUE

SIEVE ANALYSIS

% PASSING #200 SIEVE

LIQUID LIMIT

PLASTISITY INDEX

SWELL TEST

Unconsolidated Undrained triaxial

LL

PI

SW

UU

PERCENT

< 55 - 12> 12

Relative Proportions of Fines

Standard Penetration Test

VERY SOFTSOFTRATHER SOFTMEDIUMRATHER STIFFSTIFFVERY STIFFHARD

UNIFIED SOIL CLASSIFICATION (ASTM D-2487/2488)

ML

MH

-

-

-

-

-

-

-

-

TEST SYMBOLS

PERCENT

< 1515 - 29> 30

ORGANIC

Relative Proportions of Sand and Gravel

0 - 12 - 34 - 56 - 89 - 1213 - 1617 - 30OVER 30

INORGANIC

TERM

TraceWith

Modifier

Grain Size Terminology

Cu>4 AND 1<Cc<3

Cu>4 AND 1>Cc>3

FINES CLASSIFY AS ML OR CL

FINES CLASSIFY AS CL OR CH

ORGANIC

VERY LOOSE

LOOSE

MEDIUM DENSE

DENSE

VERY DENSE

GRAVELS

0 10 20 30 40 50 60 70 80 90 100 110 120

MATERIALTYPES

Cu>6 AND 1<Cc<3

Cu>6 AND 1>Cc>3

CVT 14937.19.IAM (HARDIN COUNTY W

ETLAND).GPJ 6/6/19

PEAT

SANDS

SILTS AND CLAYS

LIQUID LIMIT>50

SILTS AND CLAYS

LIQUID LIMIT<50

>50% OF COARSEFRACTION RETAINED

ON NO 4. SIEVE

HIGHLY ORGANIC SOILS

COARSE-G

RAINED SOILS

>50% RETAINED ON

NO. 200 SIEVE

FINE-G

RAINED SOILS

>50% PASSES

NO. 200 SIEVE

PLASTICITY CHART

"A" LINE

CL-ML

mr. nathan anderson, pe · 2020-01-31 · geotechnical engineering and testing • 421 north...

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