Geo_Rpt_12-16_WA_RIDGE_MAIN_(1)_Final_Geotech_Report.pdf

FINAL GEOTECHNICAL REPORT

WA RIDGE MAIN(1), MAIN AVENUE ACCESS IMPROVEMENTS

WESTERN FEDERAL LANDS GEOTECHNICAL REPORT NO. 12‐16

November 10, 2016

Prepared for:

Federal Highway Administration

Western Federal Lands Division

Prepared by:

Final Geotechnical Report Main Avenue Access Improvements

BLANK PAGE

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TABLE OF CONTENTS

1. Introduction

1.1 Project Description

1.2 Geologic Setting and Conditions

1.3 Field Investigations

1.4 Subsurface Condtions

1.5 Groundwater

1.6 Infiltration

1.7 Laboratory Testing

2. Seismic

2.1 Design Ground Parameters and Site Classification

2.2 Seismic Hazards

3. Culvert Foundation

3.1 General

3.2 Construction sequence

3.3 Spread Footings

4. Cut Slopes

5. Fill Slopes

6. Retaining Wall Recommendations

6.1 Walls

7. Pavement

8. References

LIST OF TABLES

Table 1 – Summary of Borings

Table 2 – Summary or Test Pits

Table 3 ‐ Groundwater Measurement in Explorations near the Refuge Headquarters Building

Table 4 ‐ Ground Motion Parameters for Site Class E (AASHTO, 2014)

Table 5 ‐ Bearing Resistance for Culvert Spread Footing Foundation Design

Table 6 ‐ Planned Fill Walls

Table 7 – Pavement Design Parameters

LIST OF FIGURES

Figure 1 – Project Vicinity and Location

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1. INTRODUCTION

This Geotechnical Report has been prepared by WSP|Parsons Brinckerhoff (PB) for use on the Main

Avenue Access Improvements Project (Project). It is intended to be the source of geotechnical information used to support the preliminary design of the Project. The recommendations contained in this report are based on site‐specific geotechnical data gathered for this project.

1.1 PROJECT DESCRIPTION

The Project is intended to provide greater connectivity between the City of Ridgefield (City) and the

Carty Unit of the Ridgefield National Wildlife Refuge (Refuge), in Clark County, Washington. The project alignment is approximately 2,200 feet long, located along Main Avenue between Depot Street and

NW 291st Street. The project location is shown on Figure 1. Within Ridgefield city limits, Main Avenue has sidewalks, curbs, and sufficient lane width (35 feet) to safely accommodate pedestrians and vehicles. Beyond the city limits, Main Avenue narrows to a 22‐foot wide, two‐lane rural road. There is currently no walking path along Main Avenue, forcing pedestrians visiting the Carty Unit and Refuge to walk in the vehicle travel lane.

The Project would provide a multi‐use path from the City to the Refuge along Main Avenue. Additionally, the existing undersized culvert at Gee Creek would be replaced with either a larger culvert or bridge. An unnamed tributary to Gee Creek (referred to as Boutwell Creek) would be realigned to its historic alignment and a fish passage culvert for this creek would be installed. It is anticipated the project would require embankment fill and cuts along the right of way and retaining walls may be required. Pavement rehabilitation along the project alignment is anticipated, with full reconstruction of the roadway at the new culvert/bridge tie‐ins.

The project alignment begins approximately 700 feet north of Depot Street at an elevation of 50 feet.

The existing roadway descends to a minimum elevation of approximately 22 feet and crosses Gee Creek and its associated floodplain on an embankment up to 14 feet in height. In the project vicinity the floodplain elevation is approximately 17 to 20 feet. The alignment continues toward the Refuge headquarters building and reaches a maximum elevation of approximately 105 feet at the northern terminus.

Vegetation at the site generally consists of floodplain forest with underbrush and ash, alder, and cottonwood trees at lower elevations with oak woodlands on the hill slope and a meadow/field at the highest elevations near the Refuge entrance.

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Figure 1 – Project Vicinity and Location.

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1.2 GEOLOGIC SETTING AND CONDITIONS

The project site is located within the Portland Basin of the Puget Willamette Lowland. The lowland extends from Puget Sound, south into the Willamette Valley of west central Oregon. Ridgefield lies in the northern part of the Portland Basin which generally has low topographic relief (Evarts, 2004). The northern Portland Basin is flanked by the Coast Range to the west and the foothills of the Cascade

Mountains to the east.

Approximately 16 million years ago the Portland Basin was flooded with basalt flows of the Columbia

River Basalt Group which originated in eastern Washington and Oregon. Subsequently the basin was filled with sedimentary deposits of the ancient Columbia River and its tributaries (Sandy River

Mudstone, Troutdale Formation). Sedimentation continued during the Quaternary consisting of

Pleistocene aged cataclysmic flood deposits and Holocene aged alluvium. The deepest parts of the basin are believed to consist of as much as 550 meters of unconsolidated sediments (Evarts, 2004).

The surficial geology of the site has been mapped and described on the Geologic Map of the Ridgefield

Quadrangle, Clark and Cowlitz Counties, Washington (Evarts, 2004). The southern terminus of the project alignment is mapped as cataclysmic flood deposits (Qfs) consisting of unconsolidated clay, silt, and fine to medium sand. At Gee Creek alluvium (Qa) consisting of unconsolidated sediments underlying the modern floodplains of the Columbia River and local tributaries is mapped. The northernmost ~1,500 feet of the alignment is mapped as semi consolidated pebble and cobble gravel conglomerate (Qtc), however, the soils encountered in these locations were generally silty sands and sandy silts.

1.3 FIELD INVESTIGATIONS

A geotechnical site investigation was conducted in accordance with the previously approved investigation plan in the vicinity of Main Avenue between Monday, April 4 and Friday, April 8, 2016.

Western States Soil Conservation, Inc. was the on‐site contractor who performed the drilling and test pit excavations under the direction of PB. All boreholes were advanced using a CME 850 rubber tracked drill rig using hollow stem auger (HSA), mud rotary and HQ wireline coring methods. Test pits were advanced with a Takeuchi TB 235 rubber tracked excavator. Evan Garich and Kyle Romney were the on‐site representatives for PB logging soil stratigraphy, soil samples, and performing infiltration tests. A total of

12 boreholes, 8 test pits, and 2 infiltration tests were performed. One boring (I‐1) was completed as a monitoring well. A bulk soil sample was obtained from Gee Creek by hand. Exploration locations were located in the field with a cloth tape. Approximate station and offset were estimated based on the field measured locations. Surface elevations of the explorations were estimated based on the existing topographic survey. Table 1 and

Table 2 summarizes the explorations performed. Figure 2 (included at the end of this report) displays the approximate locations of the borings and test pits. Draft exploration logs are displayed in Appendix A.

Selected photographs from the exploration program are presented in Appendix D.

Soil samples were obtained at 2.5 to 5‐foot intervals. Disturbed samples were obtained following the

Standard Penetration Test (SPT) using 2‐inch and 3‐inch OD split spoon samplers. Relatively undisturbed

November 2016 Page | 4 samples were obtained using thin walled tubes hydraulically advanced in soft to stiff fine‐grained material. Several bulk samples were obtained in each test pit. Pavement cores were extracted from the existing AC with an 8‐inch core barrel. Two of the four pavement cores did not remain intact during coring advancement. Bulk samples of base and subgrade material were obtained from the pavement borings. Representative soil sample were retained and transported to laboratory for testing.

Table 1 – Summary of Borings

Boring Identification

Type Depth (ft.) Station, Offset

B‐1 Bridge 60 23+70, 6’R

B‐2 Bridge 60.8 24+53, 7’L

P/E‐1 Pavement/Embankment 36.5 22+28, 9’R

E‐2 Embankment 30.4 25+60, 65’L

E‐3 Embankment 25.5 26+85, 52’L

E‐4 Embankment 21.5 28+10, 64’L

P‐2 Pavement Core 6.5 28+72, 7’L

C‐1 Cut 21.0 29+90, 40’L

C‐2 Cut 39.0 30+73, 50’L

P‐3 Pavement Core 6.5 33+20, 6’R

P‐4 Pavement Core 6.5 39+34, 6.5’R

I‐1 Infiltration/Monitoring 26.5 39+23, 129’L

Table 2 – Summary or Test Pits

Test Pit Identification

Depth (ft.) Station, Offset Groundwater depth (ft.)

Notes

TP‐1 9 25+00, 83’L 3.0

TP‐2 9 25+85, 53’L 4.5

TP‐3 8.5 26+65, 35’L 3.0

TP‐4 8.5 28+25, 73’L 4.0

TP‐5 7 30+22, 20’L 3.0

TP‐6 6.5 31+73, 19’L 2.0

TP‐7 9 38+50, 105’L 6.5 *Infiltration test

TP‐8 8.5 38+50, 185’L 7.3 *Infiltration test

Note ‐ *See Infiltration section for discussion/recommendations.

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1.4 SUBSURFACE CONDTIONS

The subsurface conditions along the alignment are interpreted to consist of the following soil and rock units:

Embankment Fill: Very soft/very loose to loose/firm silty gravel, silty sand, and sandy silt (GM, SM, ML) with SPT N values ranging from 0 (weight of hammer) to 10. This unit is found in the embankment and extends from the ground surface to a maximum depth of approximately 10 feet and is underlain by alluvium.

Alluvium: Very soft to firm/loose sandy silt and silty sand (ML, SM) with SPT N values ranging from 0 (weight of rod) to 9. Most blow counts were 2 or less. This unit is up to approximately 23 feet in thickness and found below the embankment fill and within the Gee Creek floodplain.

Cataclysmic flood deposits: Soft/very loose to hard/dense silty sand to silt (SM, ML) with SPT N values ranging from 3 to 37. This unit was encountered from the ground surface to a maximum depth of 37 feet in the explorations located about the Gee Creek floodplain. This is the only soil unit interpreted to be present in boring I‐1, which was advanced to a depth of 26.5 feet.

Conglomerate: Medium dense to very dense sandy silty gravel (GM) with SPT N values ranging from 14 to refusal. This unit is located below the alluvium and cataclysmic flood deposits at a minimum depth of approximately 19 feet. This unit was found to be approximately 22 feet thick in the two borings that were advanced to bedrock. The majority of borings advanced terminated in this unit.

Columbia River Basalt: Fresh medium strong basalt. This unit was encountered at a depth of 58 and 52 feet in borings B 1 and B 2, respectively. No borings extended beyond this unit.

1.5 GROUNDWATER

Groundwater in the vicinity of the project is interpreted to generally be within 5 feet of the ground surface. Explorations on the hillslope and in the Gee Creek floodplain encountered groundwater at depths of 2 to 4.5 feet below ground surface. Groundwater observations in the vicinity of the Refuge headquarters building are presented in Table 3. Dewatering would likely be required for any excavations extending below the adjacent Gee Creek level. It is recommended to minimize the depths of the footings to the extent practicable to reduce the need for dewatering during construction.

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Table 3 ‐ Groundwater Measurement in Explorations near the Refuge Headquarters Building

Exploration Identification

Date Groundwater Depth (ft.)

TP‐7 4/6/16 6.5

TP‐8 4/6/16 7.3

I‐1 4/20/16 4.8

I‐1 5/25/16 7.1

I‐1 8/5/16 9.5

1.6 INFILTRATION

Infiltration testing was performed at test pits TP‐7 and TP‐8. The infiltration tests generally followed the single ring falling head test method as outlined in the Clark County Stormwater Manual (2015). During the presoak period no drop in water was measured in TP‐7 and the infiltration test was stopped. TP‐8 was allowed to presoak overnight. During the test an uncorrected infiltration rate of 0.07 inches per hour was measured. A minimum correction factor (factor of safety) of 2 is recommended in the Clark

County Stormwater Manual. However, based on the shallow groundwater level encountered and testing performed for this project as well as a previous project (GRI, 2010), the on‐site soils are considered unsuitable for infiltration. A design infiltration rate of 0.0 inches per hour is recommended.

1.7 LABORATORY TESTING

Laboratory testing was performed on representative soil samples obtained during subsurface explorations to assist in the classification and evaluation of engineering properties of the soils.

Laboratory testing results are presented in Appendix B. The following tests were performed:

Moisture Content ASTM D2216

Moisture and Density ASTM D7263b

#200 Wash ASTM D1140

Particle Size Analysis ASTM D422

Atterberg Limits ASTM D4318

Direct Shear ASTM D3080 (modified)

Triaxial Shear Strength ASTM D4767

Consolidation ASTM D2435

Rock Unconfined Strength ASTM D7012

Organic Content ASTM D2974

Sulfate ASTM D4327 pH ASTM G51

Resistivity ASTM G57

R‐value ASTM D2844/CT 301

Cation Exchange Capacity ASTM D7503

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2. SEISMIC

2.1 DESIGN GROUND PARAMETERS AND SITE CLASSIFICATION

Design ground motions at the site have been developed using the U.S. Geological Survey (USGS) seismic design mapping tool following the 7th Edition of the AASHTO LRFD Bridge Design Specifications

(AASHTO, 2014). The design ground motion parameters are based on a 7 percent probability of exceedance in 75 years, a recurrence interval of approximately 1,000 years. These ground motion parameters were developed based on a site location of 45.826 degrees N, 122.747 degrees W. The soil type was assessed to be “Soft Soil” (Site Class E) based on boring SPT N values. Table 4 provides a summary of the site specific ground motion parameters.

Table 4 ‐ Ground Motion Parameters for Site Class E (AASHTO, 2014)

Parameter Value

Site Class E

Site Class B PGA (g) 0.26

Design Acceleration Coefficient, AS (g) 0.36

Short Period Acceleration Coefficient, SDS (g) 0.90

Long Period Acceleration Coefficient, SD1 (g) 0.69

Seismic Design Category D

2.2 SEISMIC HAZARDS

2.2.1 GROUND SHAKING

Earthquakes from both mapped faults and unknown crustal faults could result in strong ground shaking at the project site. Ground shaking is responsible for generating high inertial forces and excessive dynamic movements that can impart unacceptable damage to structures. Ground shaking should be mitigated by using the design ground motions and site classification given in Section 2.1. With no known active faults crossing the project site, a surface fault rupture is not expected during a seismic event.

2.2.2 LIQUEFACTION/LATERAL SPREADING

The AASHTO LRFD Seismic Bridge Design Specifications recommend performing liquefaction screening for sites with a Seismic Design Category (SDC) B and Acceleration Coefficient, As, of 0.15 or higher

(AASHTO, 2012) and when the following conditions present:

The maximum groundwater elevation is within 50 feet of the ground surface

Low plasticity soils with SPT resistances, (N1)60, less than 25 blows per foot are present

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The sands and silts sampled during the geotechnical investigation were generally low to non‐plastic. The liquefaction susceptibility of 24 soil samples were screened according to methods proposed by a) Bray and Sancio (2006) and b) Boulanger and Idriss (2006). According to the screening criterion approximately

25 to 50 percent of the samples are considered susceptible to liquefaction.

The liquefaction susceptibility of sand and silt was evaluated according to the SPT based procedure in

Youd et al. (2001) in which a factor of safety against liquefaction is calculated. An interactive deaggregation was performed to analyze the components of the probabilistic seismic hazard (USGS, 2002). The principal source contributions to the hazard are “random” crustal faults (55 percent ‐ M 5.96, R 12.1 km) and a Cascadia Subduction Zone interface event (35 percent ‐ M 9.00, R 94.9 km). A Portland

Hills Fault event contributes approximately 4 percent of the probabilistic hazard. Given the comparatively minor contribution to the hazard of the Portland Hills Fault, this event was not considered further in the liquefaction assessment. Ground motion prediction equations (attenuation relationships) were used to develop an input peak ground acceleration (PGA) for the liquefaction assessment. A PGA of

0.18 g was calculated for the “random” crustal event and a PGA of 0.19 g was calculated for the Cascadia event. The PGA magnitude pairs were input in the liquefaction assessment and it was determined the

Cascadia event resulted in lower factors of safety against liquefaction.

Based on the conditions discussed above, liquefaction is expected to occur at the project site during a design seismic event. Soils overlying the dense gravels are expected to liquefy. These soils were encountered at depths up to approximately 36 feet. Post‐liquefaction induced vertical settlement for all soil layers that resulted in factors of safety against liquefaction initiation less than 1.2 was estimated using the procedure proposed by Ishihara and Yoshimine (1992). Because of the heterogeneous nature of the natural soil deposits, settlements are expected to vary greatly across the site. The calculations indicate the vertical settlement could range from negligible to as much as about 18 inches.

3. CULVERT FOUNDATION

3.1 GENERAL

The existing culvert at the Gee Creek crossing is a 10‐foot diameter corrugated metal culvert. A tributary to Gee Creek, “Boutwell Creek” runs along the road on the east side and crosses through a 12‐inch diameter cross drain before entering Gee Creek. When Gee Creek water levels rise from storm events, the capacity of this driveway cross drain is exceeded and the roadway and embankment become inundated, scouring the embankment both upstream and downstream of the roadway. A large precast arch culvert is being considered to replace the existing 10‐foot diameter structure, and a 10‐foot diameter pipe to carry the Boutwell Creek under the road with dispersion into the wetlands along west edge of the roadway.

Spread footings, driven piles, and micropiles were initially considered as foundation alternatives based on site conditions, subsurface conditions, seismicity, scour, constructability, and loading.

Electro‐chemical classification tests (resistivity and pH) indicate the soils at the site are non‐aggressive, with the exception of the resistivity of sample S‐3 (elevation 8.4 feet) at bore hole B‐2 which came back

November 2016 Page | 9 at 2,000 ohm‐cm. This is less than the 3,000 ohm‐cm typically used as a minimum standard. However, the low resistivity at this location does not present a long‐term risk to the project because this material would be removed to facilitate construction of the culvert, and elsewhere along the project there are no metallic elements that would be in contact this material.

Design recommendations for riprap protection against contraction scour at the culvert spread footing and additional details are provided in the hydraulics report.

3.2 CONSTRUCTION SEQUENCE

For the arch culvert being considered, the construction stages generally would consist of the following:

install dewatering measures, excavate and remove existing culvert, excavate down to gravel layer

(approximately located between elevations ‐8 and ‐2 feet), construct working platform, construct new culvert foundation, assemble and place new culvert on foundation, backfill the new culvert, construct retaining walls at inlet and outlet, and finally, construct the roadway.

3.3 SPREAD FOOTINGS

Spread footings are recommended to support the new arch culvert. Factors that led to the recommendation of this foundation alternative include:

Proximity of competent native gravel layer to proposed footing depth

Groundwater control measures and temporary excavation support would already be in place for the removal of the existing culvert

No additional specialty equipment would be required for foundation construction

Footings should bear on a gravel leveling pad; either the medium‐dense to dense gravel layer that was encountered between elevations of ‐2.2 feet and ‐8.3 feet in borings drilled near the culvert or on imported gravel extending from bottom of footing to native gravel layer. The latter would require over excavation and replacement. Imported gravel material should meet the requirements of either

Foundation Fill (FP‐14 Subsection 704.01) or Select Borrow (FP‐14 Subsection 704.07). Gravel leveling pad should extend 1 foot horizontally from the face of the footing and project downward to native gravel layer at a slope no steeper than 1V:2H.

3.3.1 BEARING RESISTANCE AND SETTLEMENT

Bearing resistance was computed for various footing widths according to Section 10.6.3.1.2a in AASHTO

(2014), and summarized in Table 5. The soil foundation layer was modeled using a friction angle of 36 degrees, total unit weight of 135 pcf, and no cohesion. Strength limit and extreme limit state bearing resistances were computed by multiplying the nominal bearing resistance by resistance factors of 0.45 and 0.90, respectively. The service limit state resistance values were computed by determining the bearing pressure to achieve 1 inch of settlement, according to the Hough method described in Section

10.6.2.4.2 of AASHTO (2014). Table 5 summarizes the various bearing resistances for various effective footing widths.

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Table 5 ‐ Bearing Resistance for Culvert Spread Footing Foundation Design

Footing Width, Bmod

Nominal (Ultimate)

Strength I Limit State

Extreme I Limit State

Service I Limit State

(ft) (ksf) (ksf) (ksf) (ksf)

4 16.2 7.3 14.6 18.2 6 19.6 8.8 17.7 8.6 8 23.0 10.4 20.7 5.6

10 26.4 11.9 23.8 4.2 12 29.7 13.4 26.7 3.4

3.3.2 SPREAD FOOTING CONSTRUCTION CONSIDERATIONS

It is recommended that measures be taken to lower groundwater levels below depth of excavation and

Gee Creek be rerouted temporarily around excavation without affecting the integrity of the temporary excavation support. Excavation should extend to the gravel layer the entire length and width of spread footings. Footing construction will require substantial dewatering in order to achieve a suitably dry excavation. Assuming a groundwater table at elevation 12 feet and a footing bottom‐of‐concrete placed at elevation ‐1, roughly 15 feet of dewatering should be planned for at the southern footing and roughly

20 feet of dewatering should be planned for at the northern footing. Dewatering is anticipated to be required to limit lateral groundwater inflow and sidewall instability. The elevation of the gravel layer may vary across the excavation, but is assumed to be located at elevations ‐3 feet and ‐8 feet for the southern and northern footings, respectively. Design of anticipated temporary dewatering and excavation support will be the responsibility of the contractor. Prior to footing placement, the bearing surface should be prepared according to FP‐14 Subsection 208.08. Settlements are not expected to exceed ¼‐inches beneath the spread footings for a properly prepared or constructed bearing surface.

Once the bearing surface is approved by the CO, footing construction should commence immediately to reduce the likelihood of subgrade disturbance. Properly constructed footings should be promptly backfilled with compacted gravel prior to placing the arch culvert.

4. CUT SLOPES

Approximately 350 feet of the existing alignment is located adjacent to a cut slope to the west. The existing cut slope generally ranges from 1V:1.5H to 1V:1H and is up to 12 feet in height. The existing cut slope is heavily vegetated with grasses, ferns, ivy, and blackberry bushes. Based on observations during site visits, the existing cut slope appears stable, no slumping or seeps were observed on the face of the cut slope. During the geotechnical exploration, however, a seep originated from the drainage ditch, and continued to flow through the roadside ditch as the base of the cut slope.

Test pits TP‐5 and TP‐6 were advanced into the existing cut slope. Soils were visually observed to consist of loose silty sand. Groundwater was observed flowing into the test pits at a depth of 2 feet and 3 feet below the level of the existing ground surface. The sidewalls of the test pits continually sloughed below the groundwater level.

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Existing conceptual cross sections show a proposed cut slope up to 10 feet in height. Based on the observed conditions on site and the proposed cross section, a cut slope of 1V:2H or flatter is recommended. Cut slopes should be vegetated as soon as possible after exposure to minimize erosion and slumping. Surface water runoff should be collected and directed away from the face of the slope and erosion control best management practices (BMPs) should be followed until permanent vegetation is fully established on the slopes.

5. FILL SLOPES

The existing embankment fills slopes are generally between 1V:2H and 1V:1.5H, up to approximately 16 feet in height, and appear to be stable. Based on our slope stability analyses of the proposed embankment, a fill slope angle of 1V:2H is recommended, which also applies to fill slopes directly above the culvert. Slope stability analyses were performed to determine factors of safety against slope failure for end‐of‐construction, long term static, and seismic conditions. Soil stratigraphy and properties were based on boring logs and laboratory test results, and a conservatively high groundwater table was assumed. A uniform traffic load of 250 psf and a Coefficient of Horizontal Acceleration, kh = 0.13, were used. Analyses indicate acceptable factors of safety against slope failure for all three loading conditions.

These include 1.1 at end‐of‐construction (a short‐term condition), 1.3 for long‐term static conditions, and 1.1 under seismic loading. Constructed slopes that are not composed of angular granular backfill should be vegetated as soon as possible after grading to provide for protection against erosion. Surface water runoff should be collected and directed away from the face of the slope, and erosion control

BMPs should be followed until permanent vegetation is fully established on the slopes.

On‐site soil obtained in areas of cuts is expected to consist of silty sand and sandy silt (AASHTO group classification A‐4), and will likely be above the optimum moisture content when exposed. The material will require drying in order to achieve proper compaction, a process that would be impractical during wet weather construction. However, if onsite soils are allowed to dry to moisture contents suitable for placement and compaction, they are considered acceptable for use as embankment fill. Imported material used as embankment fill should meet the requirements of unclassified borrow (FP‐14

Subsection 704.06). Material should be placed in loose lifts not exceeding 8 inches in thickness and compacted to at least 95% of its maximum dry density as defined by ASTM D695.

Embankment subgrades will consist of very soft/very loose alluvial soils. The material will be above optimum moisture content when exposed and susceptible to disturbance. Groundwater is expected at the surface during wet weather and within approximately 3 feet at other times of the year. Construction vehicle operation may be difficult during periods of wet weather, especially when standing moisture is present at the surface. On‐site soils will generally provide inadequate support of construction equipment during wet weather conditions. It is recommended that subgrades be protected from equipment traffic.

Monitoring the rate and amount of embankment settlement during construction is recommended, per

FP‐14 Section 621, to ensure structures and pavements are placed following the majority of settlement.

Laboratory test results indicate the embankment and retaining wall backfill will be constructed on

November 2016 Page | 12 moderately overconsolidated silts and clays. Embankments are estimated to experience between 1 and

4 inches of consolidation settlement below the constructed embankment. Two inches is considered a reasonable best estimate of settlement. The rate of consolidation is difficult to quantify due to the stratigraphic uncertainty and limitations of the laboratory testing, but it is estimated that 90% of consolidation settlement will occur within one to two months following the completion of embankment construction. Five settlement plates are recommended to monitor the magnitude and rate of settlement. A settlement plate detail is provided in Appendix E. Four of the settlement plates should be placed near the embankment centerline at approximately Stations 22+25, 23+00, 25+25, and 26+50. A fifth settlement plate should be placed near the culvert and associated retaining wall (Station 24+35 with a 25 foot LT offset).

6. RETAINING WALL RECOMMENDATIONS

Retaining structures are planned as part of the culvert system to limit the footprint of fill areas and to reduce right‐of‐way impacts within the project area. Table 6 summarizes major features of each wall.

Specific recommendations are provided in the sections that follow.

Table 6 ‐ Planned Fill Walls

Wall No. Beginning Station End Station Wall Length Offset Maximum Height

(ft) (ft) (ft)

1 23+69 24+49 96 35 Right 26 2 23+72 24+52 96 40 Left 26

6.1 WALLS

A contractor‐designed retaining wall is proposed to be constructed along both faces of the new culvert.

Each wall will consist of a 40‐foot long wall running parallel with the roadway with two adjoining 28‐foot long wing walls at a 45 degree angle tapering to the ground. The walls will meet the requirements of FP‐

14 Section 257. All wall types listed in FP‐14 Section 257 are considered acceptable, with the exception of Gabions and Rockeries. Sliding, overturning, and bearing evaluations of the wall should be based on an active equivalent fluid density of 35 pcf and a uniform horizontal pressure of 80 psf corresponding to a 250 psf surcharge load at the ground surface. Resistance to sliding will be provided by the contact between the retaining wall and the supporting subgrade. A friction factor of 0.4 is considered reasonable. The recommended minimum reinforcement length is 17 feet (0.7*H). Bearing capacity for the wall facing should be evaluated using a nominal bearing pressure of 12,900 psf (which is based on a footing width of 2 feet).

In addition to the previously discussed settlement plates, settlement of retaining walls should be monitored with survey targets. We recommend targets be established within two feet of the ground surface at the wall face, near the groin of each wingwall (four total for the project). Placement of any wall facing elements should be delayed until the walls and backfill have achieved at least 90% of the expected consolidation settlement.

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The first lift of retaining wall backfill should be placed on suitably prepared subgrade according to FP‐14

Subsection 208.08. Compacted backfill soil should meet the requirements of select granular backfill (FP‐

14 Subsection 704.08). It is recommended that the wall facing footings (if any) bear on a gravel leveling pad; either the medium‐dense to dense gravel layer that was encountered between elevations of ‐2.2 feet and ‐8.3 feet in borings drilled near the culvert, or on imported gravel extending from bottom of footing to native gravel layer. The latter would require over excavation and replacement, and will encounter groundwater as discussed previously in Section 3.3.2. Gravel leveling pad should extend 1 foot horizontally from the face of the footing and project downward to native gravel layer at a slope no steeper than 1V:2H.

Construction activities and final embankment slopes may impact wetlands. Based on field investigations, weak subgrade soils are not expected to be encountered. However, relatively thin (1 to 2 feet), localized deposits of soft silt or clay may be present and should be excavated and replaced to provide adequate embankment and retaining wall support.

7. PAVEMENT

The existing pavement along the project alignment is generally in good condition. Fatigue cracking was not observed along the alignment. Minor rutting and potholing was observed from approximate STA

21+00 to 22+50. The thickness of AC at this location was measured to be 2.5 inches in boring P/E‐1. AC thickness observed in the three other pavement cores ranged from 5 to 6 inches. If resurfacing is desired outside the limits of full roadway reconstruction a minor (2 inch) overlay is recommended. The pavement design and recommendations will be updated based on laboratory testing.

Pavement recommendations for the Project have been developed following Chapter 11 of the Project

Development and Design Manual (PDDM) and the Clark County standard roadway plans using the procedures of the 1993 AASHTO Guide for Design of Pavement Structures (AASHTO, 1993). Design recommendations are based on a 20‐year design life. It is assumed that the roadway will be fully reconstructed where the embankment will be raised. A peak hour traffic count and analysis was performed by Kittelson & Associates in 2009 which provided 2015 and 2026 peak hour traffic volumes.

The difference between the 2015 and 2026 traffic volumes were used to determine an annual growth rate. Weekday peak hour volumes were converted to average daily traffic (ADT) by assuming the peak hour volume represents 8 percent of the daily traffic volume. Pavement design parameters are presented in Table 5.

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Table 7 – Pavement Design Parameters

Parameter Value

One Way ADT (2015) 500

One Way ADT (2026) 1000

Annual Growth Rate 6.5%

Percent Trucks 5%

Design Life 20 years

End of Construction 2018

Calculated ESAL’s 547,000

Design ESAL’s 550,000

Subgrade Modulus 5,000 psi

Reliability Level (rural collector) 85%

Standard Deviation 0.49

Layer Coefficient ‐ AC 0.42

Layer Coefficient – Agg. Base 0.14

Initial Serviceability 4.2

Terminal Serviceability 2.5

Serviceability Loss 1.7

Main Avenue along the project alignment is classified as a Rural Major Collector by Clark County. The

Clark County standard pavement section for a Rural Major Collector of A‐4 subgrade is 6 inches of asphalt concrete (AC) over 13 inches of aggregate base. Based on the parameters above, a calculated pavement section of 6 inches of AC over 8 inches of aggregate base was determined to be adequate from purely a structural perspective. However, given the wet conditions along the project site, coupled with a desire to provide a low maintenance roadway, a more substantial pavement section meeting the

Clark County minimum standard is recommended.

A multi‐use path section has been developed considering the City of Ridgefield and Clark County standard pavement sections. Similar to the discussion above, a more robust section is recommended.

For an AC surfaced path, 3 inches of HMAC over 6 inches of crushed aggregate is recommended.

Additionally, it is recommended that the crushed aggregate extend 1 foot beyond the edge of the multi‐ use path.

November 2016 Page | 15

8. REFERENCES

American Association of State Highway and Transportation Officials (AASHTO), 1993; AASHTO Guide for

Design of Pavement Structures

American Association of State Highway and Transportation Officials (AASHTO), 2012, Guide

Specifications for LRFD Seismic Bridge Design, 2nd Edition with 2012 Interim Revisions

American Association of State Highway and Transportation Officials (AASHTO), 2014, LRFD Bridge

Design Specifications, 7th Edition

Boulanger, R. W., and I. M. Idriss. 2006. “Liquefaction Susceptibility Criteria for Silts and Clays,”

Journal of Geotechnical and Geoenvironmental Engineering. American Society of Civil

Engineers, Reston, VA, Vol. 132, No. 11, pp. 1413–1426

Bray, J. D. and Sancio, R. B. (2006) “Assessment of the liquefaction susceptibility of fine grained soils,” Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 132, No. 9, pp.

1165‐1177

Clark County Stormwater Manual, 2015, Book 1, Applicability, BMP Selection, and Submittal, November

24, 2015

Evarts, R.C., 2004, Geologic Map of the Ridgefield Quadrangle, Clark and Cowlitz Counties, Washington, Scientific Investigations Map 2844, U.S. Geological Survey

GRI, 2010, Geotechnical Investigation, Ridgefield National Wildlife Refuge Pedestrian Bridge, Ridgefield, Washington, September 8, 2010

Ishihara, K., and Yoshimine, M. 1992. “Evaluation of settlements in sand deposits following liquefaction during earthquakes.” Soils and Foundations, JSSMFE, Vol. 32, No. 1, March, pp. 173‐188

Kittelson & Associates, Inc., 2009, Traffic Impact Analysis for the Proposed Nature Center – Ridgefield

National Wildlife Refuge, Ridgefield, Washington, September 7, 2009

U.S. Geological Survey, 2002; National Seismic Hazards Mapping Project, 2002 Interactive

Deaggregation, https://geohazards.usgs.gov/deaggint/2002/U.S. Geological Survey, 2008;

Quaternary Fault and Fold Database of the United States, http://earthquake.usgs.gov/hazards/qfaults/

Youd, T.L et al. (2001). “Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and1998

NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils.” ASCE Journal of

Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 10, pp. 817‐833

OHPx

OHPx

OHPx

UGTx

UGTx

UGTx

UGTx

UGTx

UGTx

UGTx

UGTx UGTx

Gx

Gx

Gx

Gx

Gx GxGxGx

Gx

U G

P x

Wx

Wx

UCx

UCx

UCx

UCx

UCx

UCx

UCx

UCx

UCx

UCx

O H

P x

P/E-1 B-1

B-2

E-2

TP-1

TP-2

B-2

LEGEND:

K:\80498_WFLHD_IDIQ\16F05001_80498A_Ridgefield\CADD\working\RidgeField-Borehole-sheets, 5/10/2016 9:05:21 AM

FIGURE 2:

EXPLORATION LOCATION PLAN

BORE HOLE

TEST PITTP-1WA RIDGE MAIN (1)

RIDGEFIELD MAIN AVE

ACCESS IMPROVEMENTS

O H

P x

O H

T x

X

Gx Gx

Gx Gx

Gx Gx

GxGx

UGTx

UGTx UGTx

UGTxUGTxUGTx

OHPx OHPx

OHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPx

OHPx

OHPx

OHPx

OHPx

GxGxGx Gx

Gx Gx

Gx

Gx

UGTxUGTxUGTxUGTx UGTx

UGTx

UGTx

UGTx

E-3 E-4

P-2

C-1 C-2

P-3

TP-3

TP-4

TP-5

TP-6

LEGEND:

K:\80498_WFLHD_IDIQ\16F05001_80498A_Ridgefield\CADD\working\RidgeField-Borehole-sheets, 5/10/2016 9:05:21 AM

B-2 BORE HOLE

TEST PITTP-1 FIGURE 2:

EXPLORATION LOCATION PLAN

WA RIDGE MAIN (1)

UGTxUGTxUGTx

UGTxUGTxUGTxUGTxUGTx

Gx

Gx GxGxGxGxGxGx

OHTx OHTx

OHTx

UGTx UGTx

UGTx

Gx

Gx

Gx Gx

OHPx OHPx

OHPx OHPx

OHPx OHPx

OHPx P-4

I-1

TP-7

TP-8

K:\80498_WFLHD_IDIQ\16F05001_80498A_Ridgefield\CADD\working\RidgeField-Borehole-sheets, 5/10/2016 9:05:21 AM

B-2

LEGEND:

BORE HOLE

TEST PITTP-1 FIGURE 2:

EXPLORATION LOCATION PLAN

WA RIDGE MAIN (1)

November 2016 Page | A‐1

APPENDIX A: CONCEPTUAL ALIGNMENT PLAN

P C

.9

D I

.8

.0

-8.5753%

300' VC

K = 33

Curve= MAIN-1

D

R= 350.00'

T= 137.40'

L= 261.86'

CP

CP

CUYD

EXC.

CUYD

EMB.

22+0021+0020+0019+00

25 25

30 30

35 35

40 40

45 45

50 50

55 55

60 60

65 65

D.2

STATE PROJECT

NUMBER

SHEET

U

S S u r ft

D c m y fi le s p w p r o d u c ti o n d w a a fb .d g n

WA RIDGE MAIN (1)

A

M

A u g u s t

C h e c k e d b y

D e s ig n e d b y

N

Profile grade

Existing ground

Line to be constructed

BEGIN PROJECT

19+00.00

IMPROVEMENTS

MAIN AVENUE ACCESS

WA RIDGE MAIN (1)

EL=57.80

E=1067619.8126

N=187408.5544

P T

.7

3 2

P I

.5

P C

.8

+0.5074%

Curve= MAIN-1

D

R= 350.00'

T= 137.40'

L= 261.86'

CUYD

EXC.

CUYD

EMB.

28+0027+0026+0025+0024+0023+0022+00

15 15

20 20

25 25

30 30

35 35

40 40

45 45

50 50

55 55

D.3

STATE PROJECT

NUMBER

SHEET

U

S S u r ft m y fi le s p w p r o d u c ti o n d w a a fc .d g n

WA RIDGE MAIN (1)

A u g u s t

C h e c k e d b y

D e s ig n e d b y

N

Existing ground

Profile grade

Line to be constructed

CP

CP

CP

CP

CP

CP

CP

CP

Curve= MAIN-2

D

R= 825.00'

T= 143.91'

L= 284.95'

P T

.7

P C

.6

P T

.8

.4

+9.8

9%

300' VC

K = 32

.9

400' VC

K = 46

SSD = 316'

T

CUYD

EXC.

CUYD

EMB.

34+0033+0032+0031+0030+0029+0028+00

25 50

30 55

35 60

40 65

45 70

50 75

55 80

60 85

65 90

D.4

STATE PROJECT

NUMBER

SHEET

U

S S u r ft m y fi le s p w p r o d u c ti o n d w a a fd .d g n

WA RIDGE MAIN (1)

P

A u g u s t

C h e c k e d b y

D e s ig n e d b y

N

Curve= MAIN-2

D

R= 825.00'

T= 143.91'

L= 284.95'

Line to be constructed

Curve= MAIN-3 D

R= 925.00'

T= 107.08'

L= 213.21'

CPCP

CPCP

CPCP

Profile grade

Profile grade

Existing ground

Existing ground

P C

.0

P T

.1

8 3

9 4

R I P

+1.2096%

R I P

T U

PT

T

U P

T

T

U P

CUYD

EXC.

CUYD

EMB.

40+0039+0038+0037+0036+0035+0034+00

60 60

65 65

70 70

75 75

80 80

85 85

90 90

95 95

100 100

D.5

STATE PROJECT

NUMBER

SHEET

U

S S u r ft m y fi le s p w p r o d u c ti o n d w a a fe .d g n

WA RIDGE MAIN (1)

A u g u s t

C h e c k e d b y

D e s ig n e d b y

N

Profile grade

Existing ground

Curve= MAIN-4

D

R= 950.00'

T= 99.38'

L= 198.04'

CPCP

Line to be constructed

0 4

1 4

P C

.3

PT 43+97.56

R I P

.7

200' VC

K = 29

.7

+8.2

-1.5526%

150' VC

K = 15

SSD = 185'

.7

R I P

T U

PT

T

T

N

CUYD

EXC.

CUYD

EMB.

44+0043+0042+0041+0040+00

75 75

80 80

85 85

90 90

95 95

100 100

105 105

110 110

115 115

D.6

STATE PROJECT

NUMBER

SHEET

U

S S u r ft m y fi le s p w p r o d u c ti o n d w a a ff .d g n

WA RIDGE MAIN (1)

A u g u s t

C h e c k e d b y

D e s ig n e d b y

Profile grade

Line to be constructed

Curve= MAIN-5

D

R= 160.00'

T= 113.36'

L= 197.25'

43+00.00

IMPROVEMENTS

MAIN AVENUE ACCESS

WA RIDGE MAIN (1)

END PROJECT

Existing ground

EL=101.74

E=1067813.6994

N=189774.0780

BLANK PAGE

November 2016 Page | B‐1

APPENDIX B: EXPLORATION LOGS

Asphalt Concrete (0.3 ft thick) Note: Began drilling with an 4-7/8 inch drag bit

Gravel Base (1.5 ft thick) GRAVEL (GM), loose, brown, moist, fine to coarse sand, nonplastic, homogeneous, fine to coarse gravel, subrounded to angular Sandy SILT (ML), soft, brown, moist, low plasticity, fine sand, micaceous

Becomes v. soft and dark gray at 5.5 ft

SILT (ML), v. soft, dark gray to gray, moist, low to nonplastic, fine sand, micaceous, trace to some organics

Silty SAND (SM), v. loose, gray, moist, nonplastic, fine sand, micaceous, trace to some organics

0.3

1.8

7.5

19.3

3-2-1 (10" = 56%)

5' - 6.5'

WOH

(21" = 117%)

10' - 11.5'

2-0-1 (13" = 72%) 17' - 18.5'

1-1-1 (20" = 111%)

20' - 21.5'

Push 150 psi (0" = 0%) 13' - 15'

Piston (24" = 100%)

15' - 17'

Push 200 psi (24" = 100%)

23' - 25'

K. Romney/E. Garich Sunny

DATE STARTED:

0.0

BORING B-1

Sheet 1 of 3

COMPANY:

S A

M P

LE

WATER LEVELS 0 100

HAMMER:

BORING LOG (US Customary Units)

AFTER DRILLING

F ile

: Q :\G

E O

\0

P R

O

JE

C T

S \W

F L

-2

0\

A R

ID

G

E F

IE

LD

\0

IN

V

E S

T

IG

A T

IO

N

\E X

P

LO

R A

T

IO

N L

O G

S \8

A _R

ID

G

F

IE

LD

M

A

IN

A V

E _B

L

0% .G

J

Li b:

Q

:\G E

O \0

S

O F

T W

A R

E \G

IN

T

\L

IB

\F H

W A

LI

B

R A

R Y

.R

E V

-B

JS

.G

LB

ri nt ed : 1

0/

/2

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Western States

LOGGER:

WHILE DRILLING

DRILLER:

NOTES:

TOTAL DEPTH: 60' (BOTTOM ELEV: -35.7')

S A

M P

LE

R

4/5/2016

20 40

PLASTIC LIMIT

3" Shelby Tube

2.5" OD Mod CA Sampler (MC)

STATION, OFFSET:

ELEVATION: 24.3

DRILLING METHODS:

2" OD Split Spoon (SPT)

WATER CONTENT (%)

LIQUID LIMITFIELD

BLOW

COUNT

(Recovery)

Limits

DATE FINISHED:

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0

Jeff Crisman

WEATHER:

NX/HW Casing/Tri-Cone

DRILL: CME 850 Track Rig D

E P

T H ft

4/5/2016

PROJECT: Ridgefield Main Avenue

Automatic Mud Rotary

FIELD "N" VALUE

23+70 6' R

24.3

21.8

19.3

16.8

14.3

11.8

9.3

6.8

4.3

1.8

-0.7

D E

P T

H ft

E

LE

V ft)

RQD (%)

RECOVERY (%)

POORLY GRADED GRAVEL with Cobbles (GP), med.

dense, brown, wet, fine sand, micaceous, fine to coarse gravel, multicolor but predominantly black clasts, 3" cobble in shoe

Note: Driller noted gravel and wood while drilling from 26.5 to 30 ft

Note: Driller switched to 4-7/8" Tri-cone bit

Poor recovery - fine to coarse gravels in sampler but fines washed out

Note: Driller noted sandy conditions from 36 to 39 ft

Sandy SILT (ML), v. hard, olive gray, moist, low plasticity, fine sand, micaceous, streaked orange and red

Sandy GRAVEL with trace silt (GP), v. dense, greenish gray to olive gray, wet, fine sand, mulitcolor sand particles, fine to coarse gravel up to 1 inch, rounded to subrounded clasts, multicolor gravel clasts

Note: Drilled noted dense gravel from 43 to 45 ft

10a

10b

26.5

40.8

43.0

3-1-3 (8" = 44%) 25' - 26.5'

7-13-9 (2" = 11%) 30' - 31.5'

16-20-14 (11" = 61%) 35' - 36.5'

47-69-53 (18" = 100%)

40' - 41.5'

34-50/4" (10" = 104%)

45' - 45.8'

K. Romney/E. Garich Sunny

DATE STARTED:

BORING B-1

Sheet 2 of 3

COMPANY:

S A

M P

LE

WATER LEVELS 0 100

HAMMER:

BORING LOG (US Customary Units)

AFTER DRILLING

F ile

: Q :\G

E O

\0

P R

O

JE

C T

S \W

F L

-2

0\

A R

ID

G

E F

IE

LD

\0

IN

V

E S

T

IG

A T

IO

N

\E X

P

LO

R A

T

IO

N L

O G

S \8

A _R

ID

G

F

IE

LD

M

A

IN

A V

E _B

L

0% .G

Q

:\G E

O \0

S

O F

T W

A R

E \G

IN

T

\L

IB

\F H

W A

LI

B

R A

R Y

.R

E V

-B

JS

nt ed : 1

0/

/2

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Western States

LOGGER:

WHILE DRILLING

DRILLER:

NOTES:

TOTAL DEPTH: 60' (BOTTOM ELEV: -35.7')

S A

M P

LE

R

4/5/2016

20 40

PLASTIC LIMIT

3" Shelby Tube

2.5" OD Mod CA Sampler (MC)

STATION, OFFSET:

ELEVATION: 24.3

DRILLING METHODS:

2" OD Split Spoon (SPT)

WATER CONTENT (%)

LIQUID LIMITFIELD

BLOW

COUNT

(Recovery)

Limits

DATE FINISHED:

25.0

27.5

30.0

32.5

35.0

37.5

40.0

42.5

45.0

47.5

50.0

Jeff Crisman

WEATHER:

NX/HW Casing/Tri-Cone

DRILL: CME 850 Track Rig D

E P

T H ft

4/5/2016

PROJECT: Ridgefield Main Avenue

Automatic Mud Rotary

FIELD "N" VALUE

23+70 6' R

-0.7

-3.2

-5.7

-8.2

-10.7

-13.2

-15.7

-18.2

-20.7

-23.2

-25.7

D E

P T

H ft

E

LE

V ft)

RQD (%)

RECOVERY (%)

BEDROCK - cuttings appear to be basalt fragments similar to basalt cores at boring B-2

No recovery

Bottom of boring at approximately 60 ft below ground surface. Groundwater not measured due to use of Mud Rotary.

Backfilled with bentonite chips to 2 ft bgs, gravel to 1 ft bgs, and then cold patch asphalt

58.0

60.0

50/3" (2" = 83%) 50' - 50.2'

50/2" (2" = 167%) 55' - 55.1'

50/0" (0" = %) 60' - 60'

K. Romney/E. Garich Sunny

DATE STARTED:

BORING B-1

Sheet 3 of 3

COMPANY:

S A

M P

LE

WATER LEVELS 0 100

HAMMER:

BORING LOG (US Customary Units)

AFTER DRILLING

F ile

: Q :\G

E O

\0

P R

O

JE

C T

S \W

F L

-2

0\

A R

ID

G

E F

IE

LD

\0

IN

V

E S

T

IG

A T

IO

N

\E X

P

LO

R A

T

IO

N L

O G

S \8

A _R

ID

G

F

IE

LD

M

A

IN

A V

E _B

L

0% .G

Q

:\G E

O \0

S

O F

T W

A R

E \G

IN

T

\L

IB

\F H

W A

LI

B

R A

R Y

.R

E V

-B

JS

nt ed : 1

0/

/2

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Western States

LOGGER:

WHILE DRILLING

DRILLER:

NOTES:

TOTAL DEPTH: 60' (BOTTOM ELEV: -35.7')

S A

M P

LE

R

4/5/2016

20 40

PLASTIC LIMIT

3" Shelby Tube

2.5" OD Mod CA Sampler (MC)

STATION, OFFSET:

ELEVATION: 24.3

DRILLING METHODS:

2" OD Split Spoon (SPT)

WATER CONTENT (%)

LIQUID LIMITFIELD

BLOW

COUNT

(Recovery)

Limits

DATE FINISHED:

50.0

52.5

55.0

57.5

60.0

62.5

65.0

67.5

70.0

72.5

75.0

Jeff Crisman

WEATHER:

NX/HW Casing/Tri-Cone

DRILL: CME 850 Track Rig D

E P

T H ft

4/5/2016

PROJECT: Ridgefield Main Avenue

Automatic Mud Rotary

FIELD "N" VALUE

23+70 6' R

-25.7

-28.2

-30.7

-33.2

-35.7

-38.2

-40.7

-43.2

-45.7

-48.2

-50.7

D E

P T

H ft

E

LE

V ft)

RQD (%)

RECOVERY (%)

Aggregate Roadway Surfacing (0.1 ft thick) Note: Began drilling with an 4-7/8 inch drag bit

Gravel Base (1.5 ft thick) GRAVEL (GM), loose, brown, moist, fine to coarse sand, nonplastic, homogeneous, fine to coarse gravel, subrounded to angular Sandy SILT (ML), v. soft, gray, moist, low to nonplastic, fine sand, micaceous, trace to some organics

Lean CLAY with sand (CL), v. soft, dark gray, moist, low plastic, fine sand, micaceous, trace to some organics

Sandy SILT (ML), v. soft, gray, moist, low to nonplastic, fine sand, micaceous, trace to some organics

2 inch lens of Silty SAND at 12.3 ft Sandy SILT (ML), same as above, mottled red-orange

Silty SAND (SM), same as above, not mottled

Lean CLAY (CL), same as above

Silty SAND (SM), same as above, trace white nodules

0.2

1.7

4.0

8.0

12.3 12.5

14.3

18.0

23.0

1-1-1 (12" = 67%)

5' - 6.5'

WOH-WOH-1

(20" = 111%)

12' - 13.5'

WOH

(17" = 94%) 15' - 16.5'

WOH

(24" = 133%)

20' - 21.5'

Push 150 psi (28" = 117%)

10' - 12'

K. Romney/E. Garich Rainy

DATE STARTED:

0.0

BORING B-2

Sheet 1 of 3

COMPANY:

S A

M P

LE

WATER LEVELS 0 100

HAMMER:

BORING LOG (US Customary Units)

AFTER DRILLING

F ile

: Q :\G

E O

\0

P R

O

JE

C T

S \W

F L

-2

0\

A R

ID

G

E F

IE

LD

\0

IN

V

E S

T

IG

A T

IO

N

\E X

P

LO

R A

T

IO

N L

O G

S \8

A _R

ID

G

F

IE

LD

M

A

IN

A V

E _B

L

0% .G

Q

:\G E

O \0

S

O F

T W

A R

E \G

IN

T

\L

IB

\F H

W A

LI

B

R A

R Y

.R

E V

-B

JS

nt ed : 1

0/

/2

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Western States

LOGGER:

WHILE DRILLING

DRILLER:

NOTES:

TOTAL DEPTH: 60.8' (BOTTOM ELEV: -39.4')

S A

M P

LE

R

4/4/2016

20 40

PLASTIC LIMIT

2.5" OD Mod CA Sampler (MC)

Rock Core

STATION, OFFSET:

NX/HW Casing/Tri-Cone

ELEVATION: 21.4

DRILLING METHODS:

3" Shelby Tube

WATER CONTENT (%)

LIQUID LIMITFIELD

BLOW

COUNT

(Recovery)

Limits

DATE FINISHED:

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0

Jeff Crisman

WEATHER:

2" OD Split Spoon (SPT)

DRILL: CME 850 Track Rig D

E P

T H ft

4/4/2016

PROJECT: Ridgefield Main Avenue

Automatic Mud Rotary

FIELD "N" VALUE

24+53 7' L

21.4

18.9

16.4

13.9

11.4

8.9

6.4

3.9

1.4

-1.1

-3.6

D E

P T

H ft

E

LE

V ft)

Note: Driller switched to Tri-cone bit at 29.7 ft

Sandy silty GRAVEL (GM), med. dense, dark gray, wet, fine sand, micaceous, fine to coarse gravel, rounded to subangular clasts, multicolored gravel clasts Silty SAND (SM), med. dense, dark gray, wet, fine sand, multicolored sand particles, streaked red and orange

Sandy GRAVEL (GM), v. dense, gray and brown, wet, fine sand, coarse gravel, subrounded to subangular, multicolored gravel clasts

Gravel clasts in shoe

8a

8b

29.7

30.2

33.0

1-0-1 (10" = 56%) 25' - 26.5'

15-16-21 (14" = 78%) 29.7' - 31.2'

42-30-50/5" (13" = 72%) 35' - 36.5'

66-90 (12" = 100%)

40' - 41'

50/2" (1" = 28%) 45' - 45.3'

Push 150 psi (22" = 108%)

28' - 29.7'

K. Romney/E. Garich Rainy

DATE STARTED:

BORING B-2

Sheet 2 of 3

COMPANY:

S A

M P

LE

WATER LEVELS 0 100

HAMMER:

BORING LOG (US Customary Units)

AFTER DRILLING

F ile

: Q :\G

E O

\0

P R

O

JE

C T

S \W

F L

-2

0\

A R

ID

G

E F

IE

LD

\0

IN

V

E S

T

IG

A T

IO

N

\E X

P

LO

R A

T

IO

N L

O G

S \8

A _R

ID

G

F

IE

LD

M

A

IN

A V

E _B

L

0% .G

Q

:\G E

O \0

S

O F

T W

A R

E \G

IN

T

\L

IB

\F H

W A

LI

B

R A

R Y

.R

E V

-B

JS

nt ed : 1

0/

/2

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Western States

LOGGER:

WHILE DRILLING

DRILLER:

NOTES:

TOTAL DEPTH: 60.8' (BOTTOM ELEV: -39.4')

S A

M P

LE

R

4/4/2016

20 40

PLASTIC LIMIT

2.5" OD Mod CA Sampler (MC)

Rock Core

STATION, OFFSET:

NX/HW Casing/Tri-Cone

ELEVATION: 21.4

DRILLING METHODS:

3" Shelby Tube

WATER CONTENT (%)

LIQUID LIMITFIELD

BLOW

COUNT

(Recovery)

Limits

DATE FINISHED:

25.0

27.5

30.0

32.5

35.0

37.5

40.0

42.5

45.0

47.5

50.0

Jeff Crisman

WEATHER:

2" OD Split Spoon (SPT)

DRILL: CME 850 Track Rig D

E P

T H ft

4/4/2016

PROJECT: Ridgefield Main Avenue

Automatic Mud Rotary

FIELD "N" VALUE

24+53 7' L

-3.6

-6.1

-8.6

-11.1

-13.6

-16.1

-18.6

-21.1

-23.6

-26.1

-28.6

D E

P T

H ft

E

LE

V ft)

RQD (%)

RECOVERY (%)

No recovery

BASALT, dark gray to black, fine grained, fresh, med. to strong rock (R3-R4). Discontinuities are widely spaced and in fair condition, CR = 100%, RQD = 100%, joints range from 15 degrees to nearly vertical from assumed horizontal.

Bottom of boring at approximately 60.8 ft below ground surface (bgs). Groundwater not measured due to use of Mud Rotary.

Backfilled with 1 bag bentonite chips to 1 ft bgs, and then cold patch asphalt.

R1

R2

52.0

60.8

50/2" (0" = 0%) 50' - 50.2'

K. Romney/E. Garich Rainy

DATE STARTED:

BORING B-2

Sheet 3 of 3

COMPANY:

S A

M P

LE

WATER LEVELS 0 100

HAMMER:

BORING LOG (US Customary Units)

AFTER DRILLING

F ile

: Q :\G

E O

\0

P R

O

JE

C T

S \W

F L

-2

0\

A R

ID

G

E F

IE

LD

\0

IN

V

E S

T

IG

A T

IO

N

\E X

P

LO

R A

T

IO

N L

O G

S \8

A _R

ID

G

F

IE

LD

M

A

IN

A V

E _B

L

0% .G

Q

:\G E

O \0

S

O F

T W

A R

E \G

IN

T

\L

IB

\F H

W A

LI

B

R A

R Y

.R

E V

-B

JS

nt ed : 1

0/

/2

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Western States

LOGGER:

WHILE DRILLING

DRILLER:

NOTES:

TOTAL DEPTH: 60.8' (BOTTOM ELEV: -39.4')

S A

M P

LE

R

4/4/2016

20 40

PLASTIC LIMIT

2.5" OD Mod CA Sampler (MC)

Rock Core

STATION, OFFSET:

NX/HW Casing/Tri-Cone

ELEVATION: 21.4

DRILLING METHODS:

3" Shelby Tube

WATE…