Capital Projects and Facilities fileCapital Projects and Facilities Department P.O. Box 30 1925 Trinity Drive, Suite C Los Alamos, New Mexico 87544 ... gravel, basalt, and asphalt

Terracon Consultants, Inc. 4905 Hawkins NE Albuquerque, New Mexico 87109 P [505] 797-4287 F [505] 897-4287 Terracon.com

January 12, 2012 Capital Projects and Facilities Department P.O. Box 30 1925 Trinity Drive, Suite C Los Alamos, New Mexico 87544 Attn: Mr. Steven Huebner P: [505] 663-1778 M: [505] 795-1589 E: [email protected] Re: Preliminary Geotechnical Engineering Report Nature Center

2600 Canyon Road Los Alamos County, New Mexico

Terracon Project No. 66115057 Dear Mr. Huebner: Terracon has completed the preliminary geotechnical engineering exploration for the proposed Nature Center project to be located in Los Alamos County, New Mexico. Refer to the Site Location Map, Figure A1, for the project location. The scope of the services performed for this project included site reconnaissance by a field engineer, a subsurface exploration program, and laboratory testing. The purpose of these services is to provide preliminary geotechnical engineering data for the future design and construction of foundation, pavements, and other earth connected phases of the project.

1.0 PROJECT DESCRIPITION

ITEM DESCRIPTION

Structure The project will include the construction of a new building, asphalt concrete pavement, Portland cement concrete curb, gutters, and/or sidewalks, and drainage structure upgrades.

Location 2600 Canyon Road in Los Alamos, New Mexico.

Grading At or near existing site grade (assumed).

Preliminary Geotechnical Engineering Report Nature Center ■ Los Alamos County, New Mexico January 12, 2012 ■ Terracon Project No. 66115057

Reliable ■ Responsive ■ Convenient ■ Innovative 2

2.0 SUBSURFACE EXPLORATION AND TESTING PROCEDURES A total of three (3) test borings were drilled at the site using a CME-75 truck-mounted drilling rig. Test borings were drilled to a depth of about 26-½ feet below existing site grade at the approximate locations shown on Figure A2, Boring Location Plan. Lithologic logs of the test borings were recorded by a field engineer during the drilling operations. At selected intervals, samples of subsurface materials and penetration tests were taken by driving split-spoon or ring-lined barrel samplers using a 140-pound hammer falling 30 inches. The number of blows required to advance the samplers the last 12 inches, or less if hard materials were present, of an 18-inch sampling interval was recorded as the standard penetration resistance value (N). The samples were sealed in the field and then returned to our laboratory for testing and classification. An automatic SPT hammer was used to advance the split-barrel samplers. The effect of the automatic hammer's efficiency has been considered in our interpretation and analysis. Groundwater measurements were made in the test borings during and at the completion of drilling.

3.0 LABORATORY TESTING PROGRAM Selected soil samples were tested for the following engineering properties:

Gradation Plasticity Index Water Content Dry Density Soluble Sulfate Content Consolidation

As part of the testing program, the soil samples were examined in the laboratory by the field engineer. Based on the material’s texture and plasticity, the soil samples were described and classified in accordance with the attached General Notes and the Unified Soil Classification System, respectively. The estimated group symbols for the Unified Soil Classification System are shown in the appropriate column on the boring logs. A brief description of the Unified System is included in the appendix.

4.0 SUBSURFACE CONDITIONS 4.1 Subsurface Conditions Specific conditions encountered at the boring locations are indicated on the individual boring logs. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Details for the borings can be



found on the attached boring logs. Based on the results of the borings, subsurface conditions on the project site can be generalized as follows:

Description Approximate Depth to

Bottom of Stratum (feet) Material Encountered Consistency/Density

Stratum 1 10 to 22

Fill comprised of silty sand with varying amounts of

gravel, basalt, and asphalt concrete debris.

Loose to Dense

Stratum 3 26-½ Tuff bedrock. Firm to Hard

Samples retrieved during the field exploration were taken to the laboratory for further observation by the project geotechnical engineer and were classified in accordance with the Unified Soil Classification System (USCS) and by the American Association of State Highway and Transportation Officials (AASHTO) classification system. Laboratory tests were conducted on selected soil samples and the test results are presented on the attached laboratory test sheets. Laboratory test results indicate that the surface and near surface fill soils exhibit low compressibility potentials at in-situ moisture contents. The near surface fill soils have a moderate to high potential for compression and a non- tendency for expansion when wetted under typical foundation loads. However, based upon the granular nature and low moisture content of the soils, the tests may reflect some sample disturbance. It is our opinion that the near surface fill soils have a moderate to high tendency for compression/consolidation and a non- tendency for expansion, when elevated in moisture content. When water is added to samples of laboratory compacted near-surface soils, we anticipate that the compacted soils will exhibit low compressive and non- to low expansive potential when subjected to light loading conditions such as those imposed by floor slabs. The in-situ moisture contents of the fill ranged from 3 to 22% and the bedrock ranged from 6 to 16%. Laboratory test results indicate the on-site soils exhibit a soluble sulfate concentration of 73 mg/kg.

5.0 GROUND WATER INFORMATION Groundwater was not observed in the test borings at the time of field exploration, nor when checked upon completion of drilling. These observations represent groundwater conditions at the time of the field exploration and may not be indicative of other times, or at other locations. Groundwater conditions can change with varying seasonal and weather conditions, and other factors.



It is our experience that zones of perched and/or trapped groundwater may also occur at times in the subsurface soils overlying bedrock, on top of the bedrock surface or within permeable fractures in the bedrock materials. The location and amount of perched water is dependent upon several factors, including hydrologic conditions, type of site development, irrigation demands on or adjacent to the site, fluctuations in water features, seasonal and weather conditions. Fluctuations in groundwater levels can best be determined by implementation of a groundwater monitoring plan. Such a plan would include installation of groundwater monitoring wells, and periodic measurement of groundwater levels over a sufficient period of time. The possibility of groundwater fluctuations should be considered when developing design and construction plans for the project.

6.0 PRELIMINARY ANALYSIS AND RECOMMENDATIONS

6.1 Geotechnical Considerations The site appears to be suitable for the proposed construction based upon geotechnical conditions encountered in the test borings. However, existing fill soils were encountered in the borings and will require particular attention during design and construction. The existing fill on the site contained varying amounts of construction debris consisting of asphalt concrete and basalt. Based upon information provided by LAC, there is no documentation regarding the placement of fill materials on the project site. Support of footings, floor slabs, and pavements on or above existing fill soils is discussed in this report. However, even with the recommended construction testing services, there is an inherent risk for the owner that compressible fill or unsuitable material within or buried by the fill will not be discovered. This risk of unforeseen conditions cannot be eliminated without completely removing the existing fill. Based on the data generated as part of the current studies, it is our opinion that the existing fill containing debris is uncontrolled and was not properly placed and compacted. In addition, we recommend that supplemental test pits and borings be performed to better assess the nature and composition of the fill. Based on the geotechnical subsurface exploration, the laboratory test results, and our engineering analyses, the proposed building structures can be supported on a spread footing foundation system bearing on a zone of newly placed engineered fill. In addition, a slab-on-grade floor system supported on a zone of newly placed engineered fill can be used, provided some movement can be tolerated. Existing fill containing debris and loose existing fill should be completely removed and replaced as engineered fill beneath foundations, slabs, and pavements. Partial removal of the existing uncontrolled fill containing debris could be considered beneath pavements, provided that an increase in potential movement and future



maintenance can be tolerated. In addition, a geogrid should be placed if this option is utilized to further reduce potential movement and future maintenance. On-site fill soils should be suitable for use as engineered fill beneath the foundation systems, floor slabs and pavements; however, some moisture conditioning and processing will likely be necessary. In addition, the fill will need to be screened of all debris larger than three (3) inches in diameter. The debris could be reused if properly processed to a maximum size of three (3) inches in diameter and properly blended with on-site or imported soils.

6.2 Corrosivity Laboratory test results indicate the on-site soils exhibit a soluble sulfate concentration of 73 mg/kg. Results of soluble sulfate testing indicate that ASTM Type I/II Portland cement is acceptable for all project concrete on and below grade. Foundation concrete should be designed for low sulfate exposure in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4.

7.0 EARTHWORK

7.1 Site Preparation Strip and remove existing fill, pavements, debris, soil/debris stockpiles, and other deleterious materials from proposed construction areas. Exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. Evidence of underground facilities and utilities were observed near the project site during the site reconnaissance. Therefore, such features could be encountered during construction. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction.

7.2 Excavation It is anticipated that shallow excavations for the proposed construction can be accomplished with conventional earthmoving equipment. Excavations penetrating the hard materials or large debris may require the use of more specialized heavy-duty equipment to facilitate break-up and removal. Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project. Depending upon depth of excavation and seasonal conditions, groundwater may be encountered in excavations on the site. Pumping from sumps may be utilized to control water within excavations. Based upon the subsurface conditions determined from the geotechnical exploration, subgrade soils exposed during construction are anticipated to be relatively stable. However, elevated



moisture contents were encountered at some boring locations. The stability of the subgrade may be affected by precipitation, repetitive construction traffic or other factors. If unstable conditions develop, workability may be improved by scarifying and drying. Overexcavation of wet zones and replacement with granular materials may be necessary. Use of lime, fly ash, kiln dust, cement or geotextiles could also be considered as a stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction. Lightweight excavation equipment may be required to reduce subgrade pumping. The individual contractor(s) is responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. Excavations should be sloped or shored in the interest of safety following local, and federal regulations, including current OSHA excavation and trench safety standards.

8.0 GENERAL COMMENTS Terracon should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The preliminary analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

Source: USGS 7.5-Minute Topographic Map Edition “Guaje Mountain”, New Mexico, United States, dated 2002.

Project Mngr:

Nature Center 2600 Canyon Road

Los Alamos County, New Mexico

SITE LOCATION MAP

MJDDrawn By:

Checked By:

Approved By:

N/A

MEA

MEA

Project No. 66115057

Scale

File No.

Date:

1” ≈ 1000’

12/2011

4905 Hawkins, NE Albuquerque, New Mexico 87109 505.797.4287 Fax: 505.797.4288

FIG No.

1

APPROXIMATE SITE LOCATION

B 01B-01

B-02B-03

BORING LOCATION PLAN

Nature Center2600 Canyon Road

Los Alamos, New MexicoA24905 Hawkins St. NE

Albuquerque, New Mexico 87109Phone: 505.797.4287 Fax 505.797.4288

66115057

NTS

1/2012

MJD

MEA

MEAB-01 Boring Location

10

26.5

FILL: SILTY SAND with GRAVEL; withasphalt concrete debris, brown to black,loose

BEDROCK: TUFF; grey, medium hard tohard

Boring Terminated at 26.5 Feet.

SS

RS

SS

SS

SS

SS

SM

SM

1

2

3

4

5

6

6

15

42

46

50

32

18

6

18

18

18

18

121

22

12

6

8

7

7

UN

CO

NF

INE

DS

TR

EN

GT

H,

psf

TESTS

DESCRIPTION

Nature Center

The stratification lines represent the approximate boundary lines

SITE

BORING STARTED

CME-75

WL

WL

WL

BORING COMPLETED

APPROVED MEA

MJDFOREMANRIG

12-21-11WD

66115057

Los Alamos CountyCLIENT

LOG OF BORING NO. B-01

JOB #

GR

AP

HIC

LO

G

between soil and rock types: in-situ, the transition may be gradual.

Page 1 of 1

PROJECT

12-21-11

NE

WATER LEVEL OBSERVATIONS, ft

2600 Canyon RoadLos Alamos, NM

SAMPLES

US

CS

SY

MB

OL

WA

TE

RC

ON

TE

NT

, %

TY

PE

NU

MB

ER

5

10

15

20

25

DE

PT

H,

ft.

RE

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VE

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, in

.

DR

Y U

NIT

WT

pcf

SP

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9 6

611

5057

.GP

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1/

12/1

2

0.4

22

26.5

Approximately 5 inches Asphalt ConcreteFILL: SILTY SAND with GRAVEL; withasphalt concrete and basalt debris, brownto black, medium dense to dense

BEDROCK: TUFF; grey, firm


SS

RS

SS

SS

SS

SS

SM

SM

SM

SM

SM

1

2

3

4

5

6

40

50/0.5

10

13

33

29

16

4

16

16

16

18

96

13

16

11

12

18

12

UN

CO

NF

INE

DS

TR

EN

GT

H,

psf

TESTS

DESCRIPTION

Nature Center


SITE

BORING STARTED

CME-75

WL

WL

WL

BORING COMPLETED

APPROVED MEA

MJDFOREMANRIG

12-21-11WD

66115057



JOB #

GR

AP

HIC

LO

G


Page 1 of 1

PROJECT

12-21-11

NE



SAMPLES

US

CS

SY

MB

OL

WA

TE

RC

ON

TE

NT

, %

TY

PE

NU

MB

ER

5

10

15

20

25

DE

PT

H,

ft.

RE

CO

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, in

.

DR

Y U

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pcf

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9 6

611

5057

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DT

1/

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17.5

26.5

FILL: SILTY SAND with GRAVEL variesto WELL-GRADED GRAVEL with SAND;with asphalt concrete debris, brown toblack, loose to medium dense

BEDROCK: TUFF; grey, firm to mediumhard


SS

RS

SS

SS

SS

SS

SM

GW

SM

SM

1

2

3

4

5

6

6

18

12

4

31

22

16

6

14

14

18

18

104

16

3

13

14

15

16

UN

CO

NF

INE

DS

TR

EN

GT

H,

psf

TESTS

DESCRIPTION

Nature Center


SITE

BORING STARTED

CME-75

WL

WL

WL

BORING COMPLETED

APPROVED MEA

MJDFOREMANRIG

12-21-11WD

66115057



JOB #

GR

AP

HIC

LO

G


Page 1 of 1

PROJECT

12-21-11

NE



SAMPLES

US

CS

SY

MB

OL

WA

TE

RC

ON

TE

NT

, %

TY

PE

NU

MB

ER

5

10

15

20

25

DE

PT

H,

ft.

RE

CO

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, in

.

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1/

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2

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

NP

NP

22

NP

NP

31

GRAIN SIZE DISTRIBUTION

10.0ft

2.5ft

5.0ft

10.0ft

2.5ft

5.0ft

65.2

50.4

36.5

%Clay

B-01

B-02

B-03

100 1403 2

COBBLESGRAVEL SAND

SILT OR CLAY

4

B-01

B-02

B-03

14 16 20 30 401.5 3

%Gravel %Sand %Silt

Specimen Identification

Specimen Identification

Classification

5041 3/4 1/23/8

LL PL

GRAIN SIZE IN MILLIMETERS

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

D10

fine coarse medium

6

0.627

1.416

10.171

9.5

25

37.5

0.137

2.77 0.496

200

coarse

D100 D60

6 810

D30

CuPI Cc

20.51

3.3

23.9

62.1

31.4

25.7

1.4

1.52

60

fine

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

NP

NP

9

SILTY SAND(SM)

SILTY SAND with GRAVEL(SM)

WELL-GRADED GRAVEL with SAND(GW)

Project: Nature CenterSite: 2600 Canyon Road Los Alamos, NMJob #: 66115057Date: 1-12-12T

C_G

RA

IN_S

IZE

661

150

57.G

PJ

TE

RR

AC

ON

.GD

T

1/12

/12

0

1

2

3

4

5

6

7

81 10 100 1,000 10,000

CONSOLIDATION TEST

AX

IAL

ST

RA

IN,

%

PRESSURE, psf

Project: Nature CenterSite: 2600 Canyon Road Los Alamos, NMJob #: 66115057Date: 1-12-12

ClassificationSpecimen Identification , pcf WC,%

Notes: Results may reflect some sample distubance

5.0ft SILTY SAND with GRAVEL (SM) 121 12B-01

TC

_CO

NS

OL_

ST

RA

IN 6

611

5057

.GP

J T

ER

RA

CO

N.G

DT

1/

12/1

2

0

1

2

3

4

5

6

7

81 10 100 1,000 10,000

CONSOLIDATION TEST

AX

IAL

ST

RA

IN,

%

PRESSURE, psf



Notes: Results may reflect some sample disturbance

5.0ft SILTY SAND with GRAVEL (SM) 96 16B-02

TC

_CO

NS

OL_

ST

RA

IN 6

611

5057

.GP

J T

ER

RA

CO

N.G

DT

1/

12/1

2

0

1

2

3

4

5

6

7

81 10 100 1,000 10,000

CONSOLIDATION TEST

AX

IAL

ST

RA

IN,

%

PRESSURE, psf



Notes: Results may reflect some sample disturbance

5.0ft WELL-GRADED GRAVEL with SAND(GW) 104 3B-03

TC

_CO

NS

OL_

ST

RA

IN 6

611

5057

.GP

J T

ER

RA

CO

N.G

DT

1/

12/1

2

B-01 2.5 22

B-01 5.0 12 120.5

B-01 10.0 NP NP NP 9.5 31 SM 6

B-01 15.0 8

B-01 20.0 7

B-01 25.0 7

B-02 2.5 NP NP NP 25 26 SM 13

B-02 5.0 16 95.6

B-02 10.0 11

B-02 15.0 12

B-02 20.0 18

B-02 25.0 12

B-03 2.5 16

B-03 5.0 31 22 9 37.5 1 GW 3 104.5

B-03 10.0 13

B-03 15.0 14

B-03 20.0 15

B-03 25.0 16

PlasticLimit

PlasticityIndex

MaximumSize(mm)

%<#200Sieve

SUMMARY OF LABORATORY RESULTS

Satur-ation(%)

VoidRatio

Dry UnitWeight

(pcf)

WaterContent

(%)

LiquidLimitBorehole

Sheet 1 of 1

Depthft

USCSClass-

ification

Project: Nature CenterSite: 2600 Canyon Road Los Alamos, NMJob #: 66115057Date: 1-12-12T

C_L

AB

_SU

MM

AR

Y 6

6115

057

.GP

J T

ER

RA

CO

N.G

DT

1/1

2/12

DRILSS: ST: RS: DB: BS:

The pene(RS)fallin

WATWL: WCIDCI:

Watetimesperm DEShaveGraiand accoin-pla

UCo

Stre

1,2,4,

Rev 04

LLING & SAMPSplit SpooThin-WalleRing SamDiamond BBulk Samp

number of bloetration with a 1) the penetrationg 30 inches, re

TER LEVEL MEWater Lev

: Wet Cave Dry Cave

er levels indicas and other loc

meability soils, t

SCRIPTIVE SOe more than 50ned Soils havesilts if they are

ording to the reace relative den

CONSIS

Unconfined ompressive ength, Qu, psf

< 500 500 – 1,000 ,000 – 2,000 ,000 – 4,000 ,000 – 8,000

8,000+

RELATIVE P

Descriptive Tof other cons

TraceWith

Modifie

RELA

Descriptive Tof other cons

TraceWith

Modifie

4/10

PLING SYMBOon - 1-3/8" I.D., 2ed Tube – 2” Opler - 2.42" I.D.Bit Coring - 4", ple or Auger Sa

ows required to140-pound hamon value is repoeported as “blow

EASUREMENTvel in in

ated on the borations across ththe accurate de

OIL CLASSIFIC% of their dry w

e less than 50%e slightly plasticlative proportionsity and fine-g

STENCY OF FI

f

Standard Por N-val

Blow

0 -2 -4 -

8 -15 -

> 3

ROPORTIONS

Term(s) stituents

er

ATIVE PROPO

Term(s) stituents

er

OLS: 2" O.D., unless

O.D., 3" O.D., un., 3" O.D., unlesN, B

ample

o advance a smmer falling 30 orted as the nuws per foot,” an

T SYMBOLS: WWAB

ring logs are thhe site could va

etermination of g

CATION: Soil cweight retained

% of their dry wec or non-plasticns based on g

grained soils on

INE-GRAINED

Penetration lue (SS)

ws/Ft.

- 1 - 4 - 8 - 15 - 30 30

S OF SAND AN

PerDry

15

RTIONS OF F

PerDry

5

GENE

otherwise notenless otherwisess otherwise no

standard 2-inchinches is consi

umber of blowsnd is not conside

S: While SD: While D

B: After Bo

he levels measary. In perviousgroundwater le

classification is on a #200 siev

eight retained oc. Major constitrain size. In ad

n the basis of th

D SOILS

Consistency

Very SoftSoft

Medium StifStiff

Very StiffHard

ND GRAVEL

rcent of y Weight

< 15 5 – 29 ≥ 30

INES

rcent of y Weight

< 5 5 – 12 > 12

RAL NOT

ed e noted oted

h O.D. split-spoidered the “Sta

s required to adered equivalen

Sampling Drilling oring

sured in the bos soils, the indicvels may not b

based on the ve; their principon a #200 sievetuents may be ddition to grada

heir consistency

RE

y Sta

o

ff

Maj

TES

HPAHRW

oon sampler (Sndard Penetrat

dvance the samt to the “Standa

BAN

orings at the timcated levels mae possible with

Unified Soil Clpal descriptors ae; they are prinadded as mod

ation, coarse-gry.

ELATIVE DENS

ndard Penetraor N-value (SS

Blows/Ft.

0 – 3 4 – 9

10 – 29 30 – 50

> 50

GRA

or Componenof Sample Boulders Cobbles Gravel Sand

Silt or Clay

PLA

T

NonL

MeH

S: Hollow A: Power AA: Hand A

RB: Rock BWB Wash B

SS) the last 12tion” or “N-value

mpler 12 inchesard Penetration

CR: Before CR: After C/E: Not Enc

mes indicated. ay reflect the lo only short-term

lassification Syare: boulders, ccipally describe

difiers and minorained soils are

SITY OF COAR

ation S)

AIN SIZE TERM

nt

12 in3 in. to#4 to #

Pass

ASTICITY DESC

Term P

-plastic Low edium High

Stem Auger Auger (Solid St

Auger Bit Boring or Mud R

2 inches of thee”. For 3” O.Ds using a 140-pn” or “N-value”.

Casing Removasing Removalcountered

Groundwater cation of groun

m observations.

ystem. Coarsecobbles, graveled as clays if thor constituents e defined on the

RSE-GRAINED

Relative D

Very LoLoos

Medium DDens

Very De

MINOLOGY

Particle S

Over 12 in. (30. to 3 in. (300m

o #4 sieve (75m#200 sieve (4.75sing #200 Sieve

CRIPTION

Plasticity Index

0 1-10 11-30 > 30

tem)

Rotary

e total 18-inch. ring samplerspound hammer

val l

levels at otherndwater. In low.

Grained Soils or sand. Fine

hey are plastic,may be addede basis of their

D SOILS

Density

oose se Dense se ense

Size

00mm) mm to 75mm) mm to 4.75mm)

5 to 0.075mm)e (0.075mm)

s r

r w

s e

r

Form 111—6/98

UNIFIED SOIL CLASSIFICATION SYSTEM

Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification

Group Symbol

Group NameB

Coarse Grained Soils

More than 50% retained

on No. 200 sieve

Gravels More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels Less than 5% finesC

Cu ≥ 4 and 1 ≤ Cc ≤ 3E GW Well-graded gravelF

Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF

Gravels with Fines More than 12% finesC

Fines classify as ML or MH GM Silty gravelF,G, H

Fines classify as CL or CH GC Clayey gravelF,G,H

Sands 50% or more of coarse fraction passes No. 4 sieve

Clean Sands Less than 5% finesD

Cu ≥ 6 and 1 ≤ Cc ≤ 3E SW Well-graded sandI

Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI

Sands with Fines More than 12% finesD

Fines classify as ML or MH SM Silty sandG,H,I

Fines Classify as CL or CH SC Clayey sandG,H,I

Fine-Grained Soils 50% or more passes the No. 200 sieve

Silts and Clays Liquid limit less than 50

inorganic PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M

PI < 4 or plots below “A” lineJ ML SiltK,L,M

organic Liquid limit - oven dried < 0.75 OL

Organic clayK,L,M,N

Liquid limit - not dried Organic siltK,L,M,O

Silts and Clays Liquid limit 50 or more

inorganic PI plots on or above “A” line CH Fat clayK,L,M

PI plots below “A” line MH Elastic SiltK,L,M

organic Liquid limit - oven dried < 0.75 OH

Organic clayK,L,M,P

Liquid limit - not dried Organic siltK,L,M,Q

Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles

or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded

gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay

E Cu = D60/D10 Cc = 6010

230

DxD

)(D

F If soil contains ≥ 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

HIf fines are organic, add “with organic fines” to group name. I If soil contains ≥ 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with

gravel,” whichever is predominant. L If soil contains ≥ 30% plus No. 200 predominantly sand, add

“sandy” to group name. M If soil contains ≥ 30% plus No. 200, predominantly gravel, add

“gravelly” to group name. N PI ≥ 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line.

Documents

Capital Projects and Facilities fileCapital Projects and Facilities Department P.O. Box 30 1925 Trinity Drive, Suite C Los Alamos, New Mexico 87544 ... gravel, basalt, and asphalt