Report_Geotechnical.pdf

SOILS AND FOUNDATIONS

REPORT NO. 01-21

PROJECT: PR FS ROUTE 27 SLIDE SITE FAA

LANDSLIDES REPAIR

FS ROUTE 27, MP 1.1

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

US DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

QUANTUM PARK

22001 LOUDON COUNTY PARKWAY

BUILDING E-2, SUITE 200

ASHBURN, VIRGINIA 20147

MARCH 2021

TABLE OF CONTENTS

1. INTRODUCTION

1.1. General

1.2. Project Location

1.3. Background

2. GEOLOGY

2.1. Regional Geology

3. SUBSURFACE EXPLORATION PROGRAM

3.1. Drilling, Sampling, Equipment, and Testing

3.2. Laboratory Testing

4. SUBSURFACE CONDITIONS

4.1. General Stratification

4.2. Groundwater

5. DESIGN ANALYSIS AND RECOMMENDATIONS

5.1. Design Alternatives

5.2. Design Analysis

5.3. Recommendations

6. REFERENCES

7. DISCLAIMER/LIMITATIONS CLAUSE

APPENDICES

Appendix I – Figures

Appendix II – Geotechnical Data Report

Appendix III – Design Analysis

Appendix IV – Site Photographs

Note: Design changes subsequent to publication of this report and prior to the project’s advertisement will be documented by a memo attached after the title page.

LANDSLIDE REPAIRS

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 3 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

SOILS AND FOUNDATIONS

REPORT NO. 01-21

LANDSLIDES REPAIR

FS ROUTE 27, MP 1.1

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

1. INTRODUCTION

1.1. General

This report presents the results of the subsurface exploration, laboratory testing, geotechnical analysis, and evaluations and recommendations for the repair of two (2) landslides along Forest Service (FS) Route 27 in El Yunque National Forest.

1.2. Project Location

The project includes the repair of two (2) landslides along FS Route 27 within El Yunque National Forest in Rio Grande and Naguabo municipalities. Both sites are located within a mountain ridge. The first site is located close to STA 10+20 in the Southwest side of the ridge. The second site is located in the Northeast side of the ridge. Vicinity maps are shown in Figures No. 1 through No. 3 in Appendix I.

1.3. Background

El Yunque National Forest was devastated by Hurricane Maria on September 20, 2017, which caused widespread road damages that included landslides and embankment washouts.

2. GEOLOGY

2.1. Regional Geology

The Geologic Map of The El Yunque Quadrangle, Puerto Rico, by Victor M. Seiders (1971) indicates that the project sites are located within Unnamed Volcanistic Rocks, which consists of marine deposites, volcanic sandstone, fine volcanic breccia, and mudstone od the Lower Cretaceous Age. The geologic map of the project area is included in Figure No. 4 in Appendix I.

3. SUBSURFACE EXPLORATION PROGRAM

3.1. Drilling, Sampling, Equipment, and Testing

A subsurface exploration program consisting of soil borings and rock coring was conducted to characterize subsurface conditions at the subject sites. Drilling was performed by MGV Geotechnical Group, PSC between August 27, to August 31, 2018 . A Cone Penetrometer Test (CPT) test was performed by Jaca and

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 4 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

Sierra Engineering, PSC in August 08, 2019. A total of four (4), and the CPT soil borings were performed in this study. Detail information of the subsurface exploration, exploration location plan, and logs are included in Appendix II.

3.2. Laboratory Testing

A laboratory testing program was conducted on representative soil samples recovered during the subsurface exploration. The primary purpose of the testing program was to aid in the classification and evaluation of the engineering properties of soils present at the site. Laboratory tests included natural moisture content (AASHTO T-265), Atterberg limits (AASHTO T-89 & T-90), particle size analysis (AASHTO T-88), and classification (AASHTO M-145) of soil samples. All tests were conducted in accordance with applicable ASTM/AASHTO standard test methods. The results of the laboratory testing program are included in Appendix II.

4. SUBSURFACE CONDITIONS

4.1. General Stratification

Boring logs describing the subsurface conditions encountered in each boring are located in Appendix II. A brief description of the soils encountered during our subsurface exploration are presented below. It should be noted that the stratification lines designating the interfaces between soil types on the boring logs, represent approximate boundaries. The transition between materials may be gradual. One or more of the units may be absent at specific locations. Site observations reveal the presence of large boulders outcrops at differents locations. Coubles and boulders may be encountered at different depths and locations along the sites.

▪ Fill

Fill material consisting primarily of silty sand, and sandy silt with some gravel was encountered and extended to depths of 2 ft to 6 ft below existing site grades. SPT N-values recorded ranged from 3 to 38 blows per foot (bpf) indicating loose to dense relative densities.

▪ RS - Residual Soil –Silty Sand,Sandy Silt, SiltyClay, and Clay

Underneath the fill layer, residual soils consisting primarily of silty sand and, sandy silt were encountered and extended to the termination depth of the borings, which range between 30 ft to 40 ft below existing grade. N-values ranged from 4 to 15 bpf, indicating very loose to medium dense relative densities. Silty Clay and Clay soils were encountered from 40 ft to termination depth of the CPT boring. Cone tip resistance varied from 200 psi to 700 psi indicating firm to very stiff consistencies.

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 5 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

4.2. Groundwater

Groundwater was not encountered in the SPT borings exploration. It was encountered at an approximate depth of 50 ft below existing site grade in the CPT borings. However, changes in groundwater levels could be expected due to seasonal variations, precipitation, evaporation, and surface water runoff.

5. DESIGN ANALYSIS AND RECOMMENDATIONS

5.1. Design Alternatives

Landslides occur as a result of unbalanced pressures along the sloping ground. The presence of water acts as a trigger mechanism by increasing the driving forces and/or reducing the shear strength of the in-situ materials. To mitigate slope stability problems, two general approaches can be used. One approach is to reduce the driving forces and increasing shear strength by lowering the groundwater table by improving the surface and subsurface drainage systems. The second approach is to increase the resisting forces by buttressing the slope, adding a retaining structure, or by reinforcing the embankment fill.

Various alternatives were considered given their feasibility and effectiveness for landslides stabilization, subsurface conditions, constructability, cost, and our experience with similar projects. A brief discussion of each alternative is presented below.

▪ Alternative No. 1 – Road Re-Alignemnt and Flattening the East Embankment Slope

This alternative will require re-aligning the road to the west, and flattening the east embankment with a 1V:2.25H slope. The re-alignment will shift the road approximately 45 ft. This alternative, will require large cut and fill volumes, and the removal of a mound in the east side embankment. The road re-alignment is likely to trigger environmental site assessments.

▪ Alternative No. 2 – Gravity Gabion Wall

This alternative consists of re-establishing the roadway and stabilize the slope by constructing a gravity gabion wall. These walls are typically constructed by filling pre-assembled wire baskets with clean 4” to 8” rock. These walls are self-draining and can sustain a considerable deformation and differential settlements.

The gabion facing would allow for vegetation growth and may mimic the surrounding landscape.

▪ Alternative No. 3 – Anchored Soldier Pile Wall with Pre-cast Concrete Lagging

This alternative consists of re-establishing the roadway and stabilize the slope by constructing an anchored soldier pile wall with precast concrete lagging. The retaining wall system is composed of vertical steel H- Piles embeded into stiff or dense strata. Ground anchors are used to enhance the external and global stability of the system. These wall systems are also self draining. The wall can have stone shape facing to mimic the surrounding historical walls.

▪ Alternative No. 4 – Shored Gabion Faced MSE Wall

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 6 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

This alternative consists the construction of a shored gabion face mechanically stabilized earth (MSE) wall.

The alternative will not require road re-alignment, or impact traffic within the construction area. The shoring system will be composed of soil nails. The wall offers the advantage of limiting the amount of excavation and backfill behind the wall.

▪ Alternative No. 5 – Reinforced Soil Slope (RSS)

Reinforced soil slopes are constructed using common construction materials, and conventional equipment and techniques, providing an economical and durable structure. It is a cost-effective, self-draining, and can tolerate larger differential settlements compared to other repair alternatives and they can be more esthetically pleasant.

▪ Alternative No. 6 – Rock Buttress

This alternative consists of stabilizing the slope by constructing a rock buttress. It is build by placing large rocks in a steep slope configuration to provide a buttress effect to the unstable slope. A large volume of rocks will be needed.

It is our opinion that the most cost effective remedial actions are to repair the first site with a hybrid system of a Gravity Gabion wall over a Rock Buttress, and the second with an Anchored Soldier Pile wall.

5.2. Design Analysis

The design of the structures was conducted using limit equilibrium methodology, in general accordance with the design concepts and procedures presented in FHWA Publication FHWA-IF-99-015, “Geotechnical Engineer Circular No. 4 – Ground Anchors and Anchored Systems” and following “AASHTO LRFD Bridge Design Specifications, 9th Ed.” (2020) design requirements. A summary of soil engineering parameters assumed in the external and global stability analyses are presented in Table No. 1 and *RS:

Residual Soils

Table No. 2.

A uniform distributed live surcharge load of 250 psf was applied along the travelway to account for traffic loading following (AASHTO-LRFD, 2020)– Section 3.11.6.4 requirements.

Table No. 1: Summary of assumed engineering properties for analysis and design.

Material Type Unit Weight

(pcf) Cohesion

(psf)

Internal Friction Angle ϕ (°) Granular Backfill 110 – 120 0.0 34° – 36° Aggregate Base 115 – 120 0.0 34° – 36°

Riprap 130 – 140 0.0 44° – 46° Gabion Basket 110 – 115 Infinite Strength

Fill – Silt Sand and Sandy Silt with gravel (SM-ML) 105 - 115 0.0 24° – 28° RS* – Silty Sand and Sandy Silt (SM-ML) 105 – 120 0.0 - 100 28° – 30°

RS – Silty Clay and Clay 120 – 130 500 - 1500 26° – 30°

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 7 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

*RS: Residual Soils

Table No. 2: Presumptive ultimate unit bond strength of ground anchors.

Material Type qBond (ksf) Residual Soils 3.5 – 8.5

The selected load factors and combinations are presented in Table No. 3. The factors follow (AASHTO- LRFD, 2020). The resistance factor used for design is presented in Table No. 4 to Table No. 5.

Table No. 3: Retaining walls design load factors and combinations.

Load Combination EH EV ES LS Strength I (Max) 1.50 1.35 1.50 1.75 Strength I (Min) 0.90 1.00 0.75 1.75

Service I 1.00 1.00 1.00 1.00 Extreme Event I 1.00 1.00 1.00 0.00 or 0.50

Table No. 4: Anchored Soldier Pile wall design resistance factors.

Analysis Resistance Factor Axial Compressive Resistance of Vertical Elements Φ: 0.50

Side Resistance in Sand β-method Φ: 0.55 Passive Resistance of Vertical Elements Φ: 0.75

Anchor Pullout Resistance Φ: 0.65 Anchor Tensile Resistance Φ: 0.80

Pile Shear Resistance Φ: 1.00 Overall/Global Φ: 0.75 (FS:1.3)

Overall/Global Extreme Event I Φ: 0.9 (FS:1.1) Table No. 5: Gravity Gabion Wall design resistance factors.

Analysis Resistance Factor Sliding Φ: 0.90 Bearing Φ: 0.45

Overall/Global Φ: 0.75 (FS:1.3) Internal Stability – Joint Resistance Φ: 0.75

Internal Stability - Overturning Φ: 1.00 Overall/Global Extreme Event I Φ: 0.9 (FS:1.1)

External and internal stability analysis computations were performed using PTC Mathcad Prime v. 6.0 software program by Computer Software Company (PTC) Inc, and global/overall and compound stability analysis using the computer program Slide2 v. 9.0 by Rocscience, Inc. Design calculations and computer output files are included in “Appendix IV – ”. The design calculations and computer files provide walls models, soil input engineering properties, calculated Capacity Demand Ratio (CDR), factors of safety, and a summary of design results.

According to AASHTO 11.5.4.2, a seismic design shall not be considered mandatory for walls located in Seismic Zones 1 through 3, or for walls at Sites where the site adjusted peak ground acceleration is less than or equal to 0.4g, unless one or more of the following is true:

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 8 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

▪ Liquefaction induced lateral spreading or slope failure, or seismically induced slope failure, due to the presence of sensitive clays that lose strength during the seismic shaking, may impact the stability of the wall for the design earthquake.

▪ The wall supports another structure that is required, based on the applicable design code or specification for the supporting structure, to be designed for seismic loading and poor seismic performance of the wall could impact the seismic performance of that structure.

In addition, according to C11.5.4.2, paragraph 7, a seismic analysis should be considered mandatory if the wall is located in seismic zone 2 or higher, and if either of the following is greater than 30 feet:

▪ The exposed wall height plus the average depth over the width of the wall of any soil surcharge present.

▪ For tiered walls, the sum of the exposed height of all the tiers plus the average soil surcharge depth.

Based on the above listed criteria, it was concluded that both sites requires a complete seismic evaluation.

For this analysis, it was assumed an allowable lateral deformation was established based on the flexible nature of the types of structure. See the evaluation calculations in “Appendix IV – ” for details.

5.3. Recommendations

5.3.1. Site No. 1 – Rock Buttress and Gravity Gabion Wall

A gravity gabion wall over a rock buttress is recommended. The rock buttress will have a base of 15 ft and a slope 1V:1.5H or flatter. The gravity gabion wall will have a maximum height of 9.0 ft and a minimum base of 9.0 ft over the rock buttress. The segment of excavation in front of the historic concrete wall shall be limited to 2 ft in front of the historic wall.

5.3.1. Site No. 2 – Anchored Soldier Pile Wall

A soldier pile wall and precast reinforced concrete lagging, with a maximum height of 32.0 ft, and a backslope 1V:2H or flatter is recommended for this site. It is anticipated that the soldier piles be embeded a minimum of 20 ft below required excavation depth and will require five (5) rows of ground anchors with a minimum tensile resistance of 281 kips.

5.3.2. Subsurface Water Drainage System

All walls shall include a subsurface water drainage system composed of granular backfill and a perforated diameter pipe or similar. The drainage system is surrounded by a filter fabric to prevent the migration of fines. To keep wildlife out of the retaining wall drainage system a 1/4” mesh should be installed to cover the pipe outlet.

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 9 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

6. REFERENCES

AASHTO-LRFD. (2020). AASHTO LRFD Bridge Design Specification (9th ed.). Washington, D.C.:

American Association of State Highway and Transportation Officials.

FHWA. (2009). Geotechnical Engineer Circular - Ground Anchors and Anchored Systems. Washington

DC: FHWA.

FHWA. (2014). Standard Specifications For Construction of Roads and Bridges on Federal Highway

Projects (FP-14). US Department of Transportation. Washington D.C.: US Department of Transportation.

FHWA. (2015). Strength Characterization of Open-Graded Aggregates for Structural Backfills - FHWA-

HRT-15-034. McLean: FHWA.

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

PAGE 10 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

7. DISCLAIMER/LIMITATIONS CLAUSE

The subsurface explorations and tests described in this report have been conducted in accordance with standard practices and procedures (except as specifically noted). The results of these exploration and tests represent conditions at the specific locations and dates indicated. Subsurface conditions between these locations may vary. The Geotechnical Design Analyses and Recommendations Sections of this report include interpretations and recommendations developed by the Government in the process of preparing the design. These interpretations are not intended as a substitute for the personal investigation, independent interpretation, and judgment of the Contractor. Our analysis and recommendations are based on boring logs and subsurface profiles prepared by others.

Prepared by:

Jonathan Herrera-Roldán, P.E.

Geotechnical Engineer

Reviewed by:

Mounir Abouzakhm, P.E.

Division Geotechnical Engineer

PROJECT: PR ERFO FS 2017-1(3)

RIO GRANDE & LUQUILLO MUNICIPALITIES, PUERTO RICO

PAGE 11 DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

ASHBURN, VA

APPENDICES

RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

Appendix I – Figures

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RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

Figure No. 1

Figure No. 2

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RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

Figure No. 3

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RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

Figure No. 4: Geologic Map of The El Yunque Quadrangle, Puerto Rico, by Victor M. Seiders (1971).

Map Legend

Marine deposited, clinopyroxene-bearing, andesite to basaltic(?), thick to very thick bedded, moderately sorted, grayish-green, chiefly noncalcareous, volcanic sandstone and fin volcanic breccia with subordinate dark gray to pale green cherry mudstone. Volcaniclastic rock composed chiefly of angular volcanic rock and mineral grains, locally contain moderately abundant altered perlite and pumice with globular and attenuated vesicles. Contains rare volcanic quartz grains. In large part contact metamorphosed. Exposed thickness about 1,500m.

Light gray, medium to coarse grained rock forming the bulk of the Río Blanco stock in the southeastern part of the quadrangle. A typical mineral composition is about 26% quartz, 5% orthoclase, 55.8% plagioclase, 7.3% hornblende, 3.6% biotite, 0.7% iron oxides, 0.2% apatite, and 1.4% fine grained alteration products and accessory minerals (including zircon, tourmaline, sphene, and epidote). Orthoclase locally is absent. Typically shows only slight alteration, is unfoliated, contains abundant angular to well rounded more mafic xenoliths, and sparse mafic to aplitic dikes. In part hornblende crystals and elongated xenoliths have parallel orientation. Exposed contacts with country rocks are distinct and dip steeply.

Site No. 1 – Gravity Gabion Wall and Rock Buttress

Site No. 2 – Anchored Soldier Pile Wall

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RIO GRANDE & NAGUABO MUNICIPALITIES, PUERTO RICO

DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

Appendix II – Geotechnical Data Report

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MGV GEOTECHNICAL GROUP, PSC

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Landslide at FS-27 El Yunque Río Grande, Puerto Rico November 3rd, 2018

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MGV GEOTECHNICAL GROUP, PSC

“Marine-deposited, clinopyroxene-bearing, andesitic to basaltic(?), thick- to very thick bedded, moderately sorted, grayish-green, chiefly noncalcareous, volcanic sandstone and fine volcanic breccia with subordinate dark-gray to pale-green cherty mudstone. Volcaniclastic rocks composed chiefly of angular volcanic rock and mineral grains, locally contain moderately abundant altered perlite and pumice with globular and attenuated vesicles. Contains rare volcanic quartz grains, in large contact metamorphed. Exposed thickness about 1,500 m..”

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MGV GEOTECHNICAL GROUP, PSC

Standard Practice for Description and Identification of Soils (Visual-Manual Procedure)

Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass

Standard Test Method for Particle-Size Analysis of Soils

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Slope Stability-Geotechnical Engineering and

Geomorphology

Soldier Pile Systems

Soil Strength and Slope Stability

Slope Stability 2000, Prooceedings of Sessions of Geo-

Denver 2000, Manual on Estimating Soil Properties for Foundation

Design

Seiders, V.M., 1971 Geology of the El Yunque Quadrangle, Puerto Rico

Map I-658

Engineering and Design-SLOPE STABILITY, USGS, 1967 El Yunque Quadrangle, Puerto Rico 7.5-Minute Series (Topographic)

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MGV GEOTECHNICAL GROUP, PSC

CROSS SECTIONS

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FS-27 El Yunque Río Grande, Puerto Rico

MGV GEOTECHNICAL GROUP, PSC

BORINGS LOGS

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0.0

-0.6

-1.2

-1.8

-2.4

-3.0

-3.7

-4.3

-4.9

-5.5

-6.1

-6.7

-7.3

-7.9

-8.5

-9.1

Fill: silty coarse to fine sand, little coarse to fine subangular gravel, no plasticity, moist, yellowish red.

SILT, trace fine sand, yellowish red, low plasticity, moist, white and black mottled.

As above.

As above.

As above.

As above.

As above. (SM, A-4(1))

As above.

As above.

As above.

As above.

As above.

As above.

As above.

As above.

END OF BORING

9.7

30.0

30.3

29.7

30.1

28.3

26.4

28.4

34.1

30.8

29.1

32.0

31.7

31.9

30.0

33 38 5

BORING NO. B-1

SHEET 1 OF MGV Geotechnical Group, PSC JOB NO. 1832

PROJECT Landlside at FS-27 El Yunque LOCATION Pico del Este, SAMPLER:

TYPE SPT SIZE 1.375" I.D.

HAMMER: WT 140# DROP 30"

DATE STARTED 8/28/18

COMPLETED 8/28/18

DRILL MACHINE CME-45

DRILLER E. Garcia

GROUND ELEV.

DESCRIPTION: L. Addarich APPROVED: M. Garcia DEPTH OF HOLE 30 FINAL WATER DEPTH: ft. INITIAL WATER DEPTH: ft. WATER TABLE N.D.

U.S.C.S. - UNIFIED SOIL CLASSIFICATION SYSTEM DESIGNATION. UNLESS OTHERWISE SPECIFIED, ARBITRARY COORDINATES USED.

NF, WATER TABLE NOT FOUND. *qu - UNCONFINED COMPRESSION STRENGTH; REPORTED VALUES

WN,WP,WL AND IP - NATURAL WATER CONTENT, PLASTIC LIMIT, OBTAINED FROM:

LIQUID LIMIT AND PLASTICITY INDEX (IP A. POCKET PENETROMETER

WL - WP) RESPECTIVELY. B. SPRING TEST

MATERIAL DESCRIPTION

Wn

MOISTURE CONTENT

Wp Wl Ip qu*

STRENGTH

(TSF)

PROPERTIES VS. DEPTH

102030405060708090 N value Wn

PL

LL

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0.0

-0.6

-1.2

-1.8

-2.4

-3.0

-3.7

-4.3

-4.9

-5.5

-6.1

-6.7

-7.3

-7.9

-8.5

-9.1

Fill: sandy silt, coarse to fine sand, little coarse to fine subangular gravel, no plasticity, moist, yellowish red, yellowish brown, brown.

As above.

FIll: silty clay, some coarse to fine sand, trace coarse to fine subangular gravel, trace roots, medium plasticity, moist, yellowish red.

SILT, trace coarse to fine sand, trace coarse to subangular gravel, low plasticity, moist, yellowish red, white and black mottled.

As above, some coarse to fine sand.

As above, trace fine sand, without gravel.

As above.

As above. (SM, A-5(1))

As above.

As above.

As above.

As above.

As above, little coarse to fine sand, yellowish brown, white mottled. (SM, A 2-

4(0)) As above.

As above.

As above.

24.6

26.1

35.8

38.8

39.1

33.8

34.2

24.8

34.0

31.0

33.5

30.6

22.1

19.4

23.9

22.7

NP

NV

NP

BORING NO. B-2

SHEET 1 OF MGV Geotechnical Group, PSC JOB NO. 1832

PROJECT Landlside at FS-27 El Yunque LOCATION Pico del Este, SAMPLER:

TYPE SPT SIZE 1.375" I.D.

HAMMER: WT 140# DROP 30"

DATE STARTED 8/28/18

COMPLETED 8/28/18

DRILL MACHINE CME-45

DRILLER E. Garcia

GROUND ELEV.

DESCRIPTION: L. Addarich APPROVED: M. Garcia DEPTH OF HOLE 40 FINAL WATER DEPTH: ft. INITIAL WATER DEPTH: ft. WATER TABLE N.D.

U.S.C.S. - UNIFIED SOIL CLASSIFICATION SYSTEM DESIGNATION. UNLESS OTHERWISE SPECIFIED, ARBITRARY COORDINATES USED.

NF, WATER TABLE NOT FOUND. *qu - UNCONFINED COMPRESSION STRENGTH; REPORTED VALUES

WN,WP,WL AND IP - NATURAL WATER CONTENT, PLASTIC LIMIT, OBTAINED FROM:

LIQUID LIMIT AND PLASTICITY INDEX (IP A. POCKET PENETROMETER

WL - WP) RESPECTIVELY. B. SPRING TEST

MATERIAL DESCRIPTION

Wn

MOISTURE CONTENT

Wp Wl Ip qu*

STRENGTH

(TSF)

PROPERTIES VS. DEPTH

102030405060708090 N value Wn

PL

LL

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-9.8

-10.4

-11.0

-11.6

-12.2

As above.

As above. (SM, A-4(0))

As above.

As above.

END OF BORING

25.3

27.1

29.7

33.6

34 40 6

BORING NO. B-2

SHEET 2 OF MGV Geotechnical Group, PSC LOCATION Pico

CODE NO. 1832

MATERIAL DESCRIPTION

Wn

MOISTURE CONTENT

Wp Wl Ip qu*

STRENGTH

(TSF)

PROPERTIES VS. DEPTH

102030405060708090 N value Wn

PL

LL

Page A - 58

0.0

-0.6

-1.2

-1.8

-2.4

-3.0

-3.7

-4.3

-4.9

-5.5

-6.1

-6.7

-7.3

-7.9

-8.5

-9.1

50/3

79/9

Fill: silty coarse to fine sand, little coarse to fine subangular gravel, no plasticity, dry, brown.

No recovery.

Fill: silt, trace coarse to fine sand, low plasticity, moist, yellowish red.

SILT, trace fine sand, low plasticity, moist, yellowish red, white and black mottled.

As above.

As above. (ML, A-4(0))

As above, little coarse to fine sand.

As above, trace coarse to fine sand.

As above.

As above.

As above. (ML, A-5(6))

As above.

As above.

As above.

As above.

END OF BORING

5.5

20.6

43.1

27.5

29.4

31.7

31.1

43.8

34.4

32.4

37.1

49.1

41.6

32.6

BORING NO. B-3

SHEET 1 OF MGV Geotechnical Group, PSC JOB NO. 1832

PROJECT Landlside at FS-27 El Yunque LOCATION Pico del Este, SAMPLER:

TYPE SPT SIZE 1.375" I.D.

HAMMER: WT 140# DROP 30"

DATE STARTED 8/27/18

COMPLETED 8/27/18

DRILL MACHINE CME-45

DRILLER E. Garcia

GROUND ELEV.

DESCRIPTION: L. Addarich APPROVED: M. Garcia DEPTH OF HOLE 30 FINAL WATER DEPTH: ft. INITIAL WATER DEPTH: ft. WATER TABLE N.D.

U.S.C.S. - UNIFIED SOIL CLASSIFICATION SYSTEM DESIGNATION. UNLESS OTHERWISE SPECIFIED, ARBITRARY COORDINATES USED.

NF, WATER TABLE NOT FOUND. *qu - UNCONFINED COMPRESSION STRENGTH; REPORTED VALUES

WN,WP,WL AND IP - NATURAL WATER CONTENT, PLASTIC LIMIT, OBTAINED FROM:

LIQUID LIMIT AND PLASTICITY INDEX (IP A. POCKET PENETROMETER

WL - WP) RESPECTIVELY. B. SPRING TEST

MATERIAL DESCRIPTION

Wn

MOISTURE CONTENT

Wp Wl Ip qu*

STRENGTH

(TSF)

PROPERTIES VS. DEPTH

102030405060708090 N value Wn

PL

LL

Page A - 59

0.0

-0.6

-1.2

-1.8

-2.4

-3.0

-3.7

-4.3

-4.9

-5.5

-6.1

-6.7

-7.3

-7.9

-8.5 wh wh wh wh wh wh wh wh wh 50/3

50/1 wh

50/3

50/1

Clayey SILT, trace fine sand, trace roots, Medium plasticity, moist, yellowish red.

SILT, trace fine sand, Low plasticity, moist, yellowish red, white mottled.

As above.

As above.

As above. (SM, A-5(1))

As above.

As above.

As above.

Sandy SILT, coarse to fine sand, yellowish brown, yellowish red.

SILT, trace coarse to fine sand, low plasticity, moist, yellowish brown. (SM, A-

4(2)) As above.

As above.

As above.

Sandy SILT, Coarse to fine sand, no plasticity, moist, brown.

END OF BORING

46.5

38.2

41.8

32.2

30.2

35.0

36.7

38.1

25.0

32.6

41.1

29.9

13.1

BORING NO. B-4

SHEET 1 OF MGV Geotechnical Group, PSC JOB NO. 1832

PROJECT Landlside at FS-27 El Yunque LOCATION Pico del Este, SAMPLER:

TYPE SPT SIZE 1.375" I.D.

HAMMER: WT 140# DROP 30"

DATE STARTED 8/31/18

COMPLETED 8/31/18

DRILL MACHINE CME-45

DRILLER E. Garcia

GROUND ELEV.

DESCRIPTION: L. Addarich APPROVED: M. Garcia DEPTH OF HOLE 28 FINAL WATER DEPTH: ft. INITIAL WATER DEPTH: ft. WATER TABLE N.D.

U.S.C.S. - UNIFIED SOIL CLASSIFICATION SYSTEM DESIGNATION. UNLESS OTHERWISE SPECIFIED, ARBITRARY COORDINATES USED.

NF, WATER TABLE NOT FOUND. *qu - UNCONFINED COMPRESSION STRENGTH; REPORTED VALUES

WN,WP,WL AND IP - NATURAL WATER CONTENT, PLASTIC LIMIT, OBTAINED FROM:

LIQUID LIMIT AND PLASTICITY INDEX (IP A. POCKET PENETROMETER

WL - WP) RESPECTIVELY. B. SPRING TEST

MATERIAL DESCRIPTION

Wn

MOISTURE CONTENT

Wp Wl Ip qu*

STRENGTH

(TSF)

PROPERTIES VS. DEPTH

102030405060708090 N value Wn

PL

LL

Page A - 60

FS-27 El Yunque Río Grande, Puerto Rico , 2018

MGV GEOTECHNICAL GROUP, PSC

CLASSIFICATION AND DIRECT

SHEAR TESTS

Page A - 61

T h e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/12/18

BOR. 1 S#7

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

silty sand #4 #10 #20 #40 #100 #200

100.0 99.9 96.5 83.5 59.4 47.8

33 38 5

0.6016 0.4613 0.1541 0.0856

SM A-4(1)

F.M.=0.78

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 1 Sample Number: 7 Depth: 12'-14' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 0.0 0.1 16.4 35.7 47.8 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Particle Size Distribution Report

Page A - 62 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/13/18

BOR. 2 S#8

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

silty sand .375 #4 #10 #20 #40 #100 #200

100.0 98.2 95.9 92.6 78.1 55.6 47.7

37 42 5

0.7509 0.5910 0.1837

0.0916 0.0395 0.0104

0.0061 29.94 1.39

SM A-5(1)

F.M.=1.00

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 2 Sample Number: 8 Depth: 14'-16' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 1.8 2.3 17.8 30.4 47.7 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 63 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/13/18

BOR. 2 S#13

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

.50 .375 .25 #4 #10 #20 #40 #100 #200

100.0 99.4 97.2 95.3 90.6 78.8 61.4 37.5 28.2

NP NV NP

1.9197 1.3344 0.3999

0.2587 0.0858 0.0433

0.0264 15.17 0.70

SM A-2-4(0)

F.M.=1.70

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 2 Sample Number: 13 Depth: 24'-26' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 4.7 4.7 29.2 33.2 28.2 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 64 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/12/18

BOR. 2 S#18

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

silty sand #10 #20 #40 #100 #200

100.0 96.3 81.7 53.7

43.0 34 40 6

0.6301 0.4973 0.1895 0.1179

SM A-4(0)

F.M.=0.87

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 2 Sample Number: 18 Depth: 34'-36' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 0.0 0.0 18.3 38.7 43.0 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 65 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/12/18

BOR. 3 S#6

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

sandy silt #4 #10 #20 #40 #100 #200

100.0 99.7 93.8 80.8 58.9 50.1

34 37 3

0.6940 0.5317 0.1578

ML A-4(0)

F.M.=0.84

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 3 Sample Number: 6 Depth: 10'-12' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 0.0 0.3 18.9 30.7 50.1 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 66 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/12/18

BOR. 3 S#11

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

sandy silt .25 #4 #10 #20 #40 #100 #200

100.0 99.8 99.7 98.1 93.1 74.0 61.9

32 42 10

0.3588 0.2733

ML A-5(6)

F.M.=0.45

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 3 Sample Number: 11 Depth: 20'-22' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 0.2 0.1 6.6 31.2 61.9 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 67 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/13/18

BOR. 4 S#5

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

silty sand #4 #10 #20 #40 #100 #200

100.0 99.6 93.9 79.8 54.3 43.5

38 45 7

0.7002 0.5478 0.1895

0.1140 0.0446 0.0139

0.0083 22.93 1.27

SM A-5(1)

F.M.=0.92

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 4 Sample Number: 5 Depth: 8'-10' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 0.0 0.4 19.8 36.3 43.5 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 68 e se r e su lts a re fo r th e e xc lu si ve u se o f t h e c lie n t f o r w h o m th e y w e re o b ta in e d

T h e y a p p ly o n ly to s a m p le s te st e d a n d a re n o t i n d ic a tiv e o f a p p a re n tly id e n tic a l s a m p le

Tested By: N. LAZARO Checked By: MARCUS GARCIA VINCENTY, PE

MGV-GES LAB, INC.

Dorado, Puerto Rico

09/12/18

BOR. 4 S#10

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= AASHTO=

silty sand .25 #4 #10 #20 #40 #100 #200

100.0 99.8 99.5 96.8 86.7 62.1 48.2

27 37 10

0.5337 0.3963 0.1351 0.0821

SM A-4(2)

F.M.=0.70

Pico del Este, El Yunque, Rio Grande

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: Boring 4 Sample Number: 10 Depth: 18'-20' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine % Fines

0.0 0.0 0.2 0.3 12.8 38.5 48.2 in in in

1½ in in

¾ in

½ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

Page A - 69

Client: MGV Geotechnical Group Project Name: El Yunque Landslide Project Location: Pico del Este, El Yunque, PR

GTX #:

Test Date:

Tested By: md Checked By: njh Boring ID:

Sample ID: 1 Depth, ft: 18-20 Visual Description:

Test No.:

Initial Diameter, in:

Initial Height, in:

Initial Mass, grams:

Initial Dry Density, pcf:

Initial Moisture Content, %:

Initial Bulk Density, pcf:

Initial Degree of Saturation:

Initial Void Ratio:

Final Dry Density, pcf:

Final Moisture Content, %:

Final Bulk Density, pcf:

Normal Stress, psf:

Maximum Shear Stress, psf:

Shear Rate, in/min:

Sample Type:

Estimated Specific Gravity:

Liquid Limit:

Plastic Limit:

Plasticity Index:

% Passing #200 sieve:

Soil Classification:

Group Symbol:

Notes: Moisture content obtained before shear from sample trimmings

Moisture Content determined by ASTM D2216

Atterberg Limits determined by ASTM D4318

"---" indicates testing required to determine these values was not requested.

41.8

Values for cohesion and friction angle determined from best-fit straight line to the data for the specific test conditions. Actual strength parameters may vary and should be determined by an engineer for site-specific conditions.

Non-Plastic Non-Plastic Non-Plastic

2.70

1950 3430

112.0

99.4 99.5

79.0 84.0

116.8

79.7

39.1 42.0

67.6 76.271.5

1.23 1.21 1.33

113.2

308780

B-1

DS-4 DS-5 DS-6

2.5

129 128 128

75.5 72.4

32.6 30.3 100.2

2.5

Extruded from tube, cut, trimmed and placed into apparatus at the as-received density and moisture content

37.4

09/14/18

Moist, reddish brown silty sand

2.5

1.0 1.0

76.3

Direct Shear Test of Soils Under Consolidated Drained Conditions by ASTM D3080 intact

1.0

0.0004 0.0004 0.0004

1000 2000

0 1000 2000 3000 4000 5000 6000

S h e ar

S tr e ss p sf

Normal Stress, psf

0.0 0.1 0.2 0.3 0.4 0.5 S h e ar

S tr e ss p sf

Horizontal Deformation, in

1000 2000 4000

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0.0 0.1 0.2 0.3 0.4 0.5

V er ti ca l D e fo rm a ti o n in

Horizontal Deformation, in

1000 2000 4000

Cohesion = 390 psf Friction Angle = 37.3o

Page A - 70

Client: MGV Geotechnical Group Project Name: El Yunque Landslide Project Location: Pico del Este, El Yunque, PR

GTX #:

Test Date:

Tested By: md Checked By: njh Boring ID:

Sample ID: 2 Depth, ft: 10-12 Visual Description:

Test No.:

Initial Diameter, in:

Initial Height, in:

Initial Mass, grams:

Initial Dry Density, pcf:

Initial Moisture Content, %:

Initial Bulk Density, pcf:

Initial Degree of Saturation:

Initial Void Ratio:

Final Dry Density, pcf:

Final Moisture Content, %:

Final Bulk Density, pcf:

Normal Stress, psf:

Maximum Shear Stress, psf:

Shear Rate, in/min:

Sample Type:

Estimated Specific Gravity:

Liquid Limit:

Plastic Limit:

Plasticity Index:

% Passing #200 sieve:

Soil Classification:

Group Symbol:

Notes: Moisture content obtained before shear from sample trimmings

Moisture Content determined by ASTM D2216

Atterberg Limits determined by ASTM D4318

"---" indicates testing required to determine these values was not requested.

47.3

Values for cohesion and friction angle determined from best-fit straight line to the data for the specific test conditions. Actual strength parameters may vary and should be determined by an engineer for site-specific conditions.

Non-Plastic Non-Plastic Non-Plastic

2.70

1040 1770

104.2

95.0 102.2

70.7 75.0

108.9

81.6

45.2 41.0

64.0 74.658.6

1.48 1.34 1.19

115.1

308780

B-2

DS-1 DS-2 DS-3

2.5

116 122 132

68.1 76.9

32.0 31.6 89.9

2.5

Extruded from tube, cut, trimmed and placed into apparatus at the as-received density and moisture content

32.9

09/14/18

Moist, reddish brown silty sand

2.5

1.0 1.0

72.2

Direct Shear Test of Soils Under Consolidated Drained Conditions by ASTM D3080 intact

1.0

0.0004 0.0004 0.0004

499 1000

0 500 1000 1500 2000 2500 3000

S h e ar

S tr e ss p sf

Normal Stress, psf

0.0 0.1 0.2 0.3 0.4 0.5 S h e ar

S tr e ss p sf

Horizontal Deformation, in

499 1000 2000

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.0 0.1 0.2 0.3 0.4 0.5

V er ti ca l D e fo rm a ti o n in

Horizontal Deformation, in

499 1000 2000

Cohesion = 91.7 psf Friction Angle = 40.5o

Page A - 71

GEOTECHNICAL DATA REPORT

Subsurface Exploration for FHWA Eastern Federal Lands

PR FS Route 27 Storm Damage FAA

El Yunque National Forest, Puerto Rico

Schnabel Reference #19C12017.00 September 26, 2019

Page A - 72

September 26, 2019

Mr. Robert A. Morris, PE, DBIA, ENV-SP WSP USA, Inc.

13530 Dulles Technology Drive Dulles Executive Plaza 1, Suite 300 Herndon, Virginia 20171

Subject: Geotechnical Data Report, Subsurface Exploration for FHWA Eastern Federal

Lands Project PR FS Route 27 Storm Damage FAA, El Yunque National Forest, Puerto Rico (Schnabel Reference 19C12017.00)

Dear Mr. Morris:

SCHNABEL ENGINEERING, LLC is pleased to submit this geotechnical data report for this project.

This study was performed in accordance with our proposal dated May 29, 2019, as authorized in Task Order No. 01 (effective July 23, 2019) issued under Professional Services On-Call/Task Order Subcontract, dated July 18, 2019.

INTRODUCTION

Our task order agreement defines the scope of services for this project. The scope of services generally includes Cone Penetrometer Tests (CPTs) and delivery of CPT logs and a soil profile. CPT testing was performed at two (2) locations (CPT19-01 and CPT19-02) to depths of 63.1 and 60.2 ft, respectively. The test locations were performed along the roadway to support landslide stabilization by Eastern Federal Lands Highway Division (EFLHD). This service was conducted under the supervision of a Professional Engineer registered in the Commonwealth of Puerto Rico.

PROJECT DESCRIPTION

The project consists of CPT testing to support landslide stabilization along Forest Service Route 27 (FS-

27) in El Yunque National Forest, Puerto Rico.

GEOLOGY

Review of existing geologic data in our files including the Geologic Map by Seiders [1] and Paper by Scatena [2] indicate that the site is located in the Upland Physiographic Province of Puerto Rico. The geologic stratigraphy at the project site consists of Unnamed Volcaniclastic Rocks consisting of sandstone, breccia, and mudstone of the Cretaceous Age. Geohazards specific to the project site

Page A - 73 includes landslides and earthquakes. Based on the information provided to us, the site has a history of landslides including those whose repairs will be supported by this subsurface exploration. The history of earthquakes within a 150-mile radius was ascertained from USGS seismic maps [3]. M4.5+ earthquakes have frequently occurred about three times per year since 1918. Two M7.0+ earthquakes have occurred between 1918 and 1943.

SITE CONDITIONS

The site is located along FS-27 in El Yunque National Forest, Puerto Rico. A site vicinity map is included as Figure 1. The roadway is a two-lane, asphalt roadway that was constructed within a steep hillside.

Based on the topographic site plan provided by EFLHD, the site grade at the roadway is about EL 2508 in proximity to the CPT tests.

SUBSURFACE CONDITIONS

Subsurface Exploration

Schnabel’s subcontractor, Jaca & Sierra Engineering, PSC (J&S), performed two (2) CPTs (CPT19-01 and CPT19-02) in our presence on August 6, 2019. J&S advanced CPT19-01 and CPT19-02 from 5 ft below the ground surface to practical refusal at depths of 63.1 and 60.2 ft, respectively. The testing started 5 ft below the ground surface at each location due to a dense fill layer present at the surface.

Figure 2 indicates the approximate CPT locations. The proposed locations were established in the field by EFLHD. Elevations were estimated based on topographic site plans provided by EFLHD.

The testing was performed by J&S according to ASTM D 3441 [4] to determine the mechanical properties of the subsurface strata (end bearing and friction resistance) as well as groundwater conditions (pore pressure). The CPT equipment is composed of a 1.44 in diameter cone tip, a friction sleeve, and a pore pressure filter; all manufactured by Vertek ARA. The data acquisition hardware and software used by J&S were DataPack 2000 and CPTDAS [5], respectively. The software used for data processing by J&S was ConePLOT [6]. The test consists of connecting the CPT to a series of steel rods and driving the equipment into the ground at a constant rate while recording continuous measurements of resistance to penetration (friction sleeve), end bearing (cone tip) and pore pressure (pore pressure filter). The CPT and steel rods were advanced by J&S utilizing a CME 55 drilling rig. This data is presented graphically in Appendix A.

Results

The soil parameters measured start increasing throughout the medium-to-stiff clay layer and a considerable increase is observed at about 60 ft as the CPT equipment reached refusal. Table 1 and Table 2 below present a summary of the parameters of each stratum.

Page A - 74

Table 1: CPT19-01 Test Results Summary

Layer Description

Approximate Depth below

Ground Surface (ft)

Approximate Tip

Resistance (psi)

Approximate Sleeve

Stress (psi)

Approximate Pore

Pressure (psi)

Approximate Shear

Strength (psi)

Sandy silt to clayey silt 5- 20 150 - 300 2 - 5 0 - 10 0.75 - 2

Clayey silt to silty clay 20 - 30 200 - 300 5 - 10 0 - 10 1 - 2

Silty clay to clay 30-50 200 - 400 5 - 20 0 - 10 1 - 2

Clay 50 - 63.1 250 - 650 15 - 30 10 - 80* 1 - 3 *refer to CPT logs in Appendix A

Table 2: CPT19-02 Test Results Summary

Layer Description

Approximate Depth below

Ground Surface (ft)

Approximate Tip

Resistance (psi)

Approximate Sleeve

Stress (psi)

Approximate Pore

Pressure (psi)

Approximate Shear

Strength (psi)

Silty clay to clay 5 - 20 150 - 300 5 - 15 0 - 20 0.5 - 1.5

Sandy silt to clay 20 - 40 250 - 650 10 - 30 0 - 30 1 - 3

Clay 40 - 60.2 200 - 700 5 - 35 5 - 20 1 - 5 *refer to CPT logs in Appendix A

The CPT logs are included in Appendix A and include the tip stress, sleeve stress, shear strength, and pore pressures. The soil stratigraphy is presented based on correlations with CPT results [7]. The soil stratigraphy is also presented in the subsurface soil profile (Figure 3).

LIMITATIONS

We have endeavored to complete the services identified herein in a manner consistent with that level of care and skill ordinarily exercised by members of the profession currently practicing in the same locality and under similar conditions as this project. No other representation, express or implied, is included or intended, and no warranty or guarantee is included or intended in this report, or other instrument of service.

Page A - 75

REFERENCES

1. Sanders, V.M. Geologic Map of the El Yunque Quadrangle, Puerto Rico. Department of the Interior, United States Geological Survey, 1971

2. Scatena, F.N. An Introduction to the Physiology and History of the Bisley Experimental Watersheds in the Luquillo Mountains of Puerto Rico. United States Department of Agriculture,

3. Earthquake Hazards Program. United States Geological Survey. Accessed September 23, 2019.

https://earthquake.usgs.gov/earthquakes/map/

4. ASTM Standard D 3441, 2016, “Standard Test Method for Mechanical Cone Penetration Testing of Soils”, ASTM International.

5. Applied Research Associates, Inc. (Vertek) (2000). DataPack 2000 [data acquisition software for

CPT]

6. Applied Research Associates, Inc. (Vertek) (2016). ConePlot [processing and graphing software for CPT]

7. Robertson, P.K., Campanella, R.G., Gillespie, D., and Greig, J. Use of piezometer cone data, IN- SITU ’86 Use of In-situ testing in Geotechnical Engineering, ASCE Specialty Conference, 1986

Page A - 76 https://earthquake.usgs.gov/earthquakes/map/

We appreciate the opportunity to be of service for this project. Please call us if you have any questions regarding this report.

Sincerely, SCHNABEL ENGINEERING, LLC

John J. Kenney, PE Project Engineer

Richard H. Wargo, PE Principal PE License No. 27894

JJK:RW:is

Attachments:

Figure 1: Site Vicinity Map Figure 2: CPT Location Plan Figure 3: Subsurface Profile

Appendix A: Subsurface Exploration Data Appendix B: Project Photo Log

G:\2019\PROJECTS\19C12017 - EL YUNQUE NATIONAL FORREST, PR\03-SE PRODUCTS\03-REPORTS\02-FINAL\TASK 2\PR FS ROUTE 27 STORM DAMAGE FAA

(TASK 2).DOCX

Page A - 77

FIGURES

Figure 1: Site Vicinity Map

Figure 2: CPT Location Plan Figure 3: Subsurface Profile

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Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community Esri, HERE, Garmin, (c) OpenStreetMap…