Attachment H - Final Geotechnical Exploration Memorandum.pdf

Devil’s Kitchen Dam Geotechnical Exploration Memorandum

May 2020

GEOTECHNICAL EXPLORATION MEMORANDUM

Auxiliary Spillway Rehabilitation Devil’s Kitchen Dam

Crab Orchard National Wildlife Refuge Project No. 061491

Prepared For

U.S. FISH AND WILDLIFE SERVICE

Falls Church, Virginia

Prepared By

Camp Hill, Pennsylvania May 2020 i May 2020

Table of Contents

1. PROJECT DESCRIPTION AND LOCATION

2. SUBSURFACE EXPLORATION

3. LABORATORY TESTING PROGRAM

4. SUBSURFACE EXPLORATION FINDINGS

5. REFERENCES

Figures Figure 1. Road Section and Preliminary Rehabilitation Concept Figure 2. Test Pit Locations

Tables Table 1. Summary of Test Pits

Appendices Appendix A Typed Engineers’ Test Pit Logs Appendix B Laboratory Soil Test Results

Page 1 May 2020

1. Project Description and Location

Devil’s Kitchen Dam is a high hazard concrete gravity dam owned by the U.S. Fish and Wildlife Service (USFWS) and located on the Crab Orchard National Wildlife Refuge in Williamson County, Illinois. The dam’s auxiliary spillway is located about 800 feet north of the dam’s left abutment. The crest elevation of the existing auxiliary spillway earth berm is El. 513.0 feet (NAVD88). The primary access road to the dam crosses the auxiliary spillway, so overtopping or breaching of the auxiliary spillway earth berm prevents access to the dam. The auxiliary spillway berm was overtopped for the first time after 47 years of operation in 2006, and then again in 2008, 2017 and 2018. The USFWS is concerned with the frequency of auxiliary spillway activation and the resulting disruption and costly erosion damage.

A reinforced concrete parapet is proposed to replace the existing auxiliary spillway earth berm. The auxiliary spillway crest elevation will also be increased by one foot. The proposed parapet is located at the upstream edge of the concrete road slab immediately downstream of the existing auxiliary spillway berm. The concrete road section and a preliminary rehabilitation concept are shown in Figure 1.

A subsurface exploration consisting of five test pits was completed at the auxiliary spillway in February 2020 for conceptual alternative evaluations and design of the proposed spillway. The subsurface exploration plan was approved by the USFWS in February 2020.

Figure 1. Road Section and Preliminary Rehabilitation Concept

2. Subsurface Exploration

Five test pits were excavated at the auxiliary spillway of Devil’s Kitchen Dam on February 27, 2020. A Case 580 backhoe was supplied and operated by USFWS personnel.

Test pit locations are shown in Figure 2. Gannett Fleming provided full-time observation of the subsurface exploration. Observations from the subsurface exploration and results of laboratory testing of test pit soil samples are presented in this report.

Page 2 May 2020

The test pits were excavated in the auxiliary spillway to sample overburden soils and verify the depths of the reinforced concrete cutoffs at the upstream and downstream edges of the roadway slab as shown in Figure 1. Soil samples were retained in labeled bags for subsequent laboratory testing.

Figure 2. Test Pit Location Plan

Visual soil descriptions were developed in the field based on guidance from the Unified Soil Classification System (USCS), ASTM D2488 (Description and Identification of Soils). Gannett Fleming’s geotechnical engineer drafted field test pit logs based on observations during excavation and sampling operations. Field and laboratory USCS classifications were incorporated into typed test pit logs, which are included in Appendix A.

Soil samples were collected for laboratory testing, and the remaining material was used as backfill and compacted using the bucket of the backhoe.

Table 1: Summary of Test Pits

Test Pit Purpose

Approximate Ground Surface

Elevation (ft., NAVD88)

Total Depth

(ft.)

TP-1

Verify depth of road slab downstream cutoff;

Evaluate backfill 516 8.3

TP-2

Verify depth of road slab upstream cutoff;

Evaluate backfill or native soils for competency 514 5.8

TP-3

Verify depth of road slab upstream cutoff;

Evaluate backfill or native soils for competency 514 6.1

TP-4

Verify depth of road slab downstream cutoff;

Evaluate backfill 510 1.9

TP-5

Sample native overburden soils in the area of the ASW berm 511 10.0

N

Flow

Page 3 May 2020

3. Laboratory Testing Program

Laboratory soil testing was performed on test pit samples by Navarro & Wright Consulting Engineers, Inc. in Camp Hill, Pennsylvania. Soil testing included five (5) USCS classification tests that included natural moisture content, sieve gradation, hydrometer and Atterberg limits.

Laboratory test results are included in Appendix B. The USCS classification shown with soil descriptions on the test pit logs are shown in capital letters (e.g., CL) for samples that have been laboratory classified and are shown as lower case (e.g., cl) for field (visual) classifications.

4. Subsurface Exploration Findings

Soils encountered during the 2020 subsurface exploration were laboratory classified as Lean Clay (CL), Lean Clay with Sand (CL), and Sandy Silty Clay (CL-ML). Grain-size distribution curves are provided in Appendix B.

TP-1 and TP-4 were excavated at the downstream edge of the reinforced concrete road slab to verify the depth of the concrete cutoff. It was verified during excavation of Test Pit TP-1 that the downstream cutoff extends to 8.3 feet below top of road. The fill encountered at the downstream face was laboratory classified as Sandy Silty Clay (CL-ML). Test Pit TP-4 was excavated to verify the depth of the cutoff in an area closer to the center of the auxiliary spillway where there was no apparent rip rap at the surface. However, Test Pit TP-4 was terminated before reaching the scheduled excavation depth due to standing water and difficulties excavating because of the presence of large rip rap. Water was encountered at 1.3 feet depth below top of road slab.

Test Pits TP-2 and TP-3 were excavated at the upstream edge of the reinforced concrete road slab to verify the depth of the cutoff at the left and right sides of the auxiliary spillway respectively. The bottom of the cutoff was measured at 5.2 and 5.3 feet below top of slab in Test Pits TP-2 and TP-3 respectively. The fill encountered in Test Pits TP-2 and TP-3 was similar to the fill encountered in Test Pit TP-1 and was laboratory classified as Lean Clay with sand (CL).

Test Pit TP-5 was excavated in the approach upstream of the existing earth berm auxiliary spillway to sample overburden soils. Soils encountered in Test Pit TP-5 appeared to be natural with no obvious characteristics of fill materials. The soils were consistent in gradation and color to the fill materials encountered in Test Pits TP-1, TP-2, TP-3 and TP-4. Below the topsoil layer, two layers were encountered and tested for USCS classification within the 10-foot depth of Test Pit TP-5. The upper layer was Lean Clay (CL) described as moist to wet and soft to medium stiff. Pocket penetrometer tests on representative samples had an average value of 1.0 tons per square foot (tsf). The lower layer was also Lean Clay (CL) and was described as moist and stiff to very stiff. Pocket penetrometer tests averaged 2.75 tsf.

Page 4 May 2020

5. References

American Society for Testing and Materials, ASTM D2487, “Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)”.

American Society for Testing and Materials, ASTM D2488, “Standard Practice for Description and Identification of Soils (Visual-Manual Procedure)”.

Gannett Fleming, Devil’s Kitchen Dam Auxiliary Spillway Study, February 2019

U.S. Department of Interior, Bureau of Reclamation (USBR), 2001, Engineering Geology Field Manual, 2nd ed.

GEOTECHNICAL EXPLORATION MEMORANDUM

[Type text] May 2020

APPENDIX A

Began 8:20AM.

7.5': Soil transitions from moist to wet.

Verified concrete face extends down to at least 8.0 feet depth below top of road.

Began backfill at 8:40AM. Used bucket to compact backfill.

El. 515.6

El. 507.7

4.0 - 5.0 S-1

0.0'-0.4': Reddish brown Clayey SAND (sc), moist, loose, [Topsoil] 0.4'-8.3': Reddish brown Sandy Silty CLAY (CL-ML), moist to wet, medium stiff to stiff, Sand is fine to coarse. [Fill]

Bottom of Test Pit at 8.3 feet.

Project: Devils Kitchen Auxiliary Spillway

E Coordinate: 760932.2 ft

N Coordinate: 357197.0 ftContractor: USFWS

Operator: Kevin Reichert

Logged By: D. Snyder

Date Started: 2/27/20

Date Finished: 2/27/20

Offset: 24.9 ft D/S

Total Depth of Test Pit: 8.3 ft

Ground Surface Elevation: +516.0 ft

GROUNDWATER OBSERVATIONS

Purpose: Verify depth of road slab downstream cutoff; Evaluate backfill.

Test Pit Dimensions: 10' long x 3.5' wide x 8.3' deep Termination: Locate bottom of road slab cutoff.

Abandonment: Test pit backfilled with excavated soils compacted with backhoe bucket.

Additional Remarks: None.

Photographic Log: Yes

Log Checked By: D. Snyder, 5/20

Excavation Equipment: Case 580 Super M BackhoeAt Dry After 0 Hrs

Line & Station: 5+66 P

Sheet: 1 of 1

TEST PIT LOG

USCS Remarks

Test Pit Number: TP-1

Depth (Ft.)

Sample No.

Description Of Materials

DAM TEST PIT LOG DEVILS KITCHEN ASW TEST PITS.GPJ 5/7/20

Began 9:00AM.

Began backfill 9:20AM. Used bucket to compact backfill.

El. 513.6

El. 508.2

4.0 - 5.0 S-1

0.0'-0.4': Gray Poorly Graded GRAVEL with sand (gp), moist, loose, [Fill] 0.4'-5.8': Reddish brown Lean CLAY with sand (CL), moist, stiff, [Fill]

Bottom of Test Pit at 5.8 feet.

Project: Devils Kitchen Auxiliary Spillway

E Coordinate: 760915.5 ft

N Coordinate: 357170.1 ftContractor: USFWS

Operator: Kevin Reichert

Logged By: D. Snyder

Date Started: 2/27/20

Date Finished: 2/27/20

Offset: 1.5 ft U/S

Total Depth of Test Pit: 5.8 ft

Ground Surface Elevation: +514.0 ft

GROUNDWATER OBSERVATIONS

Purpose: Verify depth of road slab upstream cutoff; Evaluate backfill or native soils for competency.

Test Pit Dimensions: 7.5' long x 3' wide x 5.8' deep Termination: Locate bottom of road slab cutoff.

Abandonment: Test pit backfilled with excavated soils compacted with backhoe bucket.

Additional Remarks: None.

Photographic Log: Yes

Log Checked By: D. Snyder, 5/20

Excavation Equipment: Case 580 Super M BackhoeAt Dry After 0 Hrs

Line & Station: 5+48 P

Sheet: 1 of 1

TEST PIT LOG

USCS Remarks

Test Pit Number: TP-2

Depth (Ft.)

Sample No.

Began 9:35AM

2.8': Concrete face has a 4-inch ledge that continues down roughly vertical.

5.2': Verified concrete face extends down to at least 5.2 feet depth below top of road.

Began backfill at 9:55AM. Used bucket to compact backfill.

El. 513.5

El. 512.5

El. 511.6 El. 511.4

El. 507.9

5.2 - 6.1 S-1

0.0'-0.5': Reddish brown Clayey SAND (sc), moist, loose, [Topsoil] 0.5'-1.5': Reddish brown Clayey SAND (sc), moist, medium compact, [Fill]

1.5'-2.4': Brown Silty SAND (sm), wet, loose, includes lenses of poorly-graded sand with silt (sp-sm). [Fill]

2.4'-2.6': Yellowish orange Clayey SAND (sc), wet, dense, [Fill] 2.6'-6.1': Reddish brown Lean CLAY with sand (CL), moist, medium stiff, [Fill]

Bottom of Test Pit at 6.1 feet.

Project: Devils Kitchen Auxiliary Spillway

E Coordinate: 761317.6 ft

N Coordinate: 356920.8 ftContractor: USFWS

Operator: Kevin Reichert

Logged By: D. Snyder

Date Started: 2/27/20

Date Finished: 2/27/20

Offset: 1.4 ft U/S

Total Depth of Test Pit: 6.1 ft

Ground Surface Elevation: +514.0 ft

GROUNDWATER OBSERVATIONS

Purpose: Verify depth of road slab upstream cutoff; Evaluate backfill or native soils for competency.

Test Pit Dimensions: 6' long x 3' wide x 6.1' deep Termination: Locate bottom of road slab cutoff.

Abandonment: Test pit backfilled with excavated soils compacted with backhoe bucket.

Additional Remarks: None.

Photographic Log: Yes

Log Checked By: D. Snyder, 5/20

Excavation Equipment: Case 580 Super M BackhoeAt Dry After 0 Hrs

Line & Station: 58 P

Sheet: 1 of 1

TEST PIT LOG

USCS Remarks

Test Pit Number: TP-3

Depth (Ft.)

Sample No.

Began 8:00AM.

Riprap is difficult to excavate due to large size relative to backhoe bucket.

1.9': Test pit terminated due to standing water and difficult excavation. Backfilled upon completion.

El. 509.2

El. 508.1

0.8 - 1.2 S-1

0.0'-0.8': Brown Silty SAND with gravel (sm), moist, loose, Soil with riprap cobbles and boulders with typical minimum dimension of 6 inches and maximum dimenstion of 3 feet.

[Riprap] 0.8'-1.9': Brown Clayey GRAVEL with sand (gc), wet, medium compact, Soil with riprap cobbles and boulders with typical minimum dimension of 6 inches and maximum dimenstion of 3 feet. [Riprap]

Bottom of Test Pit at 1.9 feet.

Project: Devils Kitchen Auxiliary Spillway

E Coordinate: 760970.1 ft

N Coordinate: 357129.5 ftContractor: USFWS

Operator: Kevin Reichert

Logged By: D. Snyder

Date Started: 2/27/20

Date Finished: 2/27/20

Offset: 24.8 ft D/S

Total Depth of Test Pit: 1.9 ft

Ground Surface Elevation: +510.0 ft

GROUNDWATER OBSERVATIONS

Purpose: Verify depth of road slab downstream cutoff; Evaluate backfill.

Test Pit Dimensions: 5' long x 3' wide x 1.9' deep Termination: Locate bottom of surficial soil.

Abandonment: Test pit backfilled with excavated rip rap compacted with backhoe bucket.

Additional Remarks: None.

Photographic Log: Yes

Log Checked By: D. Snyder, 5/20

Excavation Equipment: Case 580 Super M BackhoeAt 1.3 ft After 0 Hrs

Line & Station: 4+83 P

Sheet: 1 of 1

TEST PIT LOG

USCS Remarks

Test Pit Number: TP-4

Depth (Ft.)

Sample No.

Began 10:30AM

2.0': Some perched water draining into test pit from 2 to 3 feet depth. Flow stopped after a minute. USFWS staff report pool El. 508.9 feet today.

S-1: P.P. = 1.0 tsf

S-2: P.P. = 2.75 tsf

S-3: P.P. = 2.75 tsf

Began backfill at 10:45AM. Used bucket to compact backfill. End of all test pit activities at 11:10AM.

El. 510.6

El. 508.0

El. 501.0

2.0 - 3.0

4.0 - 5.0

8.0 - 9.0

S-1

S-2

S-3

0.0'-0.4': Reddish brown Clayey SAND (sc), moist, loose, [Topsoil] 0.4'-3.0': Reddish brown Lean CLAY (CL), moist to wet, soft to medium stiff

3.0'-10.0': Brownish orange Lean CLAY (CL), moist, stiff to very stiff, Soil appears to be natural soil but is very similar to fill observed in Test Pits TP-1, TP-2, & TP-3

Bottom of Test Pit at 10.0 feet.

Project: Devils Kitchen Auxiliary Spillway

E Coordinate: 761284.8 ft

N Coordinate: 356903.4 ftContractor: USFWS

Operator: Kevin Reichert

Logged By: D. Snyder

Date Started: 2/27/20

Date Finished: 2/27/20

Offset: 28.0 ft D/S

Total Depth of Test Pit: 10.0 ft

Ground Surface Elevation: +511.0 ft

GROUNDWATER OBSERVATIONS

Purpose: Sample native overburden soils in the area of the ASW berm.

Test Pit Dimensions: 6' long x 4' wide x 10' deep Termination: Maximum backhoe excavation depth or top of rock if encountered.

Abandonment: Test pit backfilled with excavated soils compacted with backhoe bucket.

Additional Remarks: None.

Photographic Log: Yes

Log Checked By: D. Snyder, 5/20

Excavation Equipment: Case 580 Super M BackhoeAt Dry After 0 Hrs

Line & Station: 84 P

Sheet: 1 of 1

TEST PIT LOG

USCS Remarks

Test Pit Number: TP-5

Depth (Ft.)

Sample No.

GEOTECHNICAL EXPLORATION MEMORANDUM

[Type text] May 2020

APPENDI X B

Size % Finer

3 in 100.00

2 in 100.00

1 1/2 in 100.00

1 in 100.00

3/4 in 100.00

1/2 in 99.50

3/8 in 99.20

No. 4 97.04

No. 10 94.33

No. 40 90.02

No. 60 84.71

No. 100 77.54

No. 200 68.38

49.41

0.020 mm 41.47

29.57

24.21

0.005 mm 19.65

17.26

0.002 mm 13.89

13.30

11.71

COARSE FINE COARSE MEDIUM FINE SILT CLAY

0.0% 3.0% 2.7% 4.3% 21.6% 50.3% 18.1%

COARSE MEDIUM FINE COARSE FINE SILT CLAY

0.0% 0.8% 4.9% 4.3% 21.6% 55.8% 12.6%

Project: Crab Orchard Wildlife Refuge, Il Soil Type:

Boring No.: TP-1

Station: - USCS Classification: CL-ML

Offset: - AASHTO Classification: A-4 (2)

Sample No.: S-1 LL = 25 % PL = 19 %

Depth: 4.0-5.0 ft PI = 6 % w = 20.2%

Spec. Grav.: 2.7 (assumed)

Classification Testing Results

3/16/2020 USCS & AASHTO

By: DFP Ckd: JDP

5.7% 26.0% 68.4% sandy silty CLAY

GRAVEL SAND FINES

GRAVEL SAND FINES

3.0% 28.7% 68.4% i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

.0 m m

.0 m m

.0 m m

0.0010.010.1110100

GRAIN SIZE

(mm)

P e rc e n t

P a s s in g b y

W e ig h t

GRAIN SIZE DISTRIBUTION CURVE

2 in 100.00

1 1/2 in 100.00

1 in 100.00

3/4 in 100.00

1/2 in 100.00

3/8 in 100.00

No. 4 98.92

No. 10 98.27

No. 40 94.32

No. 60 90.47

No. 100 85.93

No. 200 80.63

61.59

0.020 mm 52.73

39.43

34.76

0.005 mm 30.10

25.66

0.002 mm 22.63

21.23

19.60

COARSE FINE COARSE MEDIUM FINE SILT CLAY

0.0% 1.1% 0.7% 4.0% 13.7% 53.1% 27.5%

COARSE MEDIUM FINE COARSE FINE SILT CLAY

0.0% 0.0% 1.7% 4.0% 13.7% 60.9% 19.7%

Project: Crab Orchard Wildlife Refuge, Il Soil Type:

Boring No.: TP-2

Station: - USCS Classification: CL

Offset: - AASHTO Classification: A-6 (9)

Sample No.: S-1 LL = 31 % PL = 18 %

Depth: 4.0-5.0 ft PI = 13 % w = 20.8%

Spec. Grav.: 2.7 (assumed)

Classification Testing Results

3/16/2020 USCS & AASHTO

By: DFP Ckd: JDP

GRAVEL SAND FINES

1.1% 18.3% 80.6%

1.7% 17.6% 80.6% lean CLAY with sand

GRAVEL SAND FINES

i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

.0 m m

.0 m m

.0 m m

0.0010.010.1110100

GRAIN SIZE

(mm)

P e rc e n t

P a s s in g ig h

2 in 100.00

1 1/2 in 100.00

1 in 100.00

3/4 in 100.00

1/2 in 100.00

3/8 in 100.00

No. 4 99.32

No. 10 96.29

No. 40 85.68

No. 60 81.71

No. 100 78.72

No. 200 74.59

57.53

0.020 mm 48.75

38.55

34.47

0.005 mm 30.40

27.95

0.002 mm 24.28

23.46

20.20

COARSE FINE COARSE MEDIUM FINE SILT CLAY

0.0% 0.7% 3.0% 10.6% 11.1% 45.4% 29.2%

COARSE MEDIUM FINE COARSE FINE SILT CLAY

0.0% 0.0% 3.7% 10.6% 11.1% 51.9% 22.7%

Project: Crab Orchard Wildlife Refuge, Il Soil Type:

Boring No.: TP-3

Station: - USCS Classification: CL

Offset: - AASHTO Classification: A-6 (10)

Sample No.: S-1 LL = 34 % PL = 19 %

Depth: 5.2-6.1 ft PI = 15 % w = 18.6%

Spec. Grav.: 2.7 (assumed)

Classification Testing Results

3/16/2020 USCS & AASHTO

By: DFP Ckd: JDP

3.7% 21.7% 74.6% lean CLAY with sand

GRAVEL SAND FINES

GRAVEL SAND FINES

0.7% 24.7% 74.6% i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

.0 m m

.0 m m

.0 m m

0.0010.010.1110100

GRAIN SIZE

(mm)

P e rc e n t

P a s s in g ig h

2 in 100.00

1 1/2 in 100.00

1 in 100.00

3/4 in 100.00

1/2 in 100.00

3/8 in 100.00

No. 4 100.00

No. 10 99.74

No. 40 98.15

No. 60 96.34

No. 100 94.09

No. 200 91.50

68.36

0.020 mm 53.28

40.14

35.03

0.005 mm 29.44

26.52

0.002 mm 24.09

23.36

19.71

COARSE FINE COARSE MEDIUM FINE SILT CLAY

0.0% 0.0% 0.3% 1.6% 6.6% 63.8% 27.7%

COARSE MEDIUM FINE COARSE FINE SILT CLAY

0.0% 0.0% 0.3% 1.6% 6.6% 68.9% 22.6%

Project: Crab Orchard Wildlife Refuge, Il Soil Type:

Boring No.: TP-5

Station: - USCS Classification: CL

Offset: - AASHTO Classification: A-6 (12)

Sample No.: S-1 LL = 33 % PL = 20 %

Depth: 2.0-3.0 ft PI = 13 % w = 25.7%

Spec. Grav.: 2.7 (assumed)

Classification Testing Results

3/16/2020 USCS & AASHTO

By: DFP Ckd: JDP

0.3% 8.2% 91.5% lean CLAY

GRAVEL SAND FINES

GRAVEL SAND FINES

0.0% 8.5% 91.5% i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

.0 m m

.0 m m

.0 m m

0.0010.010.1110100

GRAIN SIZE

(mm)

P e rc e n t

P a s s in g ig h

2 in 100.00

1 1/2 in 100.00

1 in 100.00

3/4 in 100.00

1/2 in 100.00

3/8 in 100.00

No. 4 99.96

No. 10 99.83

No. 40 97.52

No. 60 95.03

No. 100 91.79

No. 200 87.72

63.22

0.020 mm 51.59

38.48

33.83

0.005 mm 28.75

25.58

0.002 mm 22.83

21.78

18.82

COARSE FINE COARSE MEDIUM FINE SILT CLAY

0.0% 0.0% 0.1% 2.3% 9.8% 60.7% 27.0%

COARSE MEDIUM FINE COARSE FINE SILT CLAY

0.0% 0.0% 0.2% 2.3% 9.8% 67.0% 20.7%

Project: Crab Orchard Wildlife Refuge, Il Soil Type:

Boring No.: TP-5

Station: - USCS Classification: CL

Offset: - AASHTO Classification: A-4 (8)

Sample No.: S-3 LL = 29 % PL = 19 %

Depth: 8.0-9.0 ft PI = 10 % w = 19.4%

Spec. Grav.: 2.7 (assumed)

Classification Testing Results

3/16/2020 USCS & AASHTO

By: DFP Ckd: JDP

0.2% 12.1% 87.7% lean CLAY

GRAVEL SAND FINES

GRAVEL SAND FINES

0.0% 12.2% 87.7% i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

.0 m m

.0 m m

.0 m m

0.0010.010.1110100

GRAIN SIZE

(mm)

P e rc e n t

P a s s in g ig h