CA.ERFO.22S01(1).Nacimiento-Ferguson Road.FINAL.Geotechnical Memo.pdf

To: Michael Daigler, Project Manager, CFLHD, Lakewood, CO

From: James Arthurs, Acting Lead Geotechnical Engineer, CFLHD, Lakewood, CO

Through: James Arthurs, Acting Lead Geotechnical Engineer, CFLHD, Lakewood, CO

Subject: Geotechnical Field Reconnaissance and Recommendations, Nacimiento-Ferguson Road (Forest Road 22S01)

1.0 PROJECT BACKGROUND INFORMATION

This geotechnical memorandum presents the field evaluation results, analyses, and recommendations for the reconstruction of Forest Road 22S01 (Nacimiento-Ferguson Road). The roadway was damaged during heavy rainfall events in January 2021 following the Dolan Fire that burned approximately 128,000 acres of land in the Coastal Ranges. The heavy rainfall led to widespread landslides and debris flows in the project area. Roadway repairs are planned as part of the Emergency Relief for Federally Owned Roads (ERFO) program.

The CA ERFO 22S01(1) Project is in Monterey County, California, within the Los Padres National Forest (Figure 1). The site is located approximately 9 miles west of the community of Jolon, California. The road starts at a junction with Mission Road near the Fort Hunter-Ligget Army Base and continues 22 miles west to a terminus intersection with California Highway 1. Based on discussions with U.S. Forest Service personnel, and interpretation of the failure areas, we understand that recent wildfires combined with heavy rains lead to various slope and culvert failures along the project route.

A total of 16 sites were identified in Detailed Damage Inspection Reports (DDIR) prepared by the Los Padres National Forest (LPNF). Of these, 12 sites were identified by the Central Federal Lands Highway Division (CFLHD) of the Federal Highway Administration (FHWA) as ERFO eligible damage sites. A general project site map showing the locations of all damage sites identified by LPNF is presented in Figure 2. Note that Sites 5 and 6 identified on this figure will be combined into a single site for plan development and construction.

Technical Memorandum

Date: January 4, 2023

The roadway is surfaced with asphalt pavement. Traffic counts were not available, but conversations with LPNF indicate that this roadway is an important connection between California SR 1 on the west and the population centers in the Salinas Valley on the east. At the time of the scoping site visit (September 2021), the roadway was closed to public traffic. At the time of the 70% plan review (November 2022), the road remained closed to the general public, but access was allowed for local residents and administrative access.

Figure 1: Project Location Map

Figure 2: Site Location Map

N

2.0 GEOLOGY AND SEISMICITY

2.1 Regional and Local Geology

The project is located in the California Coast Ranges Section of the Pacific Border Province. The region is underlain by a series of complexly folded, faulted, and metamorphosed rocks of the Salinian, Franciscan, and Great Valley Complexes. The site is mapped as underlain by unnamed (Ku) and undifferentiated strata (Km) of the Salinian Complex, and Serpentinite (Jsp) of the Coast Range Ophiolite of the Great Valley Complex (Graymer et al., 2014) and unnamed marine sandstone (Kss) and Granodiorite-quartz diorite of Bear Mountain (Kgdb), quartzofeldspathic (MzPzqf), and Coast Ridge belt (MzPzc) members of the Salinian Complex (Rosenberg and Wills, 2016). A map of the regional geology is presented in Figure 3.

These units include sheared and metamorphosed units that are known to be highly variable over relatively short distances. Weathering and alteration of these units is also known to be highly variable.

Figure 3(a) and (b): Mapped Geology in the Nacimiento-Fergusson Road project area.

2.2 Seismicity

Several known seismic source faults are mapped within approximately 40 miles of the project area and are summarized in Table 1 below (CalTrans, 2022, U.S. Geological Survey, 2022a,b).

The American Association of State Highway and Transportation Officials (AASHTO) criteria for recommended seismic response parameters are based on the AASHTO LRFD Bridge Design Specifications, 9th Edition, 2020, and represents horizontal peak ground acceleration (PGA) with a 7 percent probability of exceedance in 75 years (approximate 1,000-year return period). The 1,000-year return period uniform hazard spectrum for the approximate center of the Nacimiento- Fergusson Road project (36.011232° N latitude and 121.454826° W longitude) was obtained in accordance with the AASHTO ground motion maps. The site was classified as “Class C” according to site class definitions specified in Table 3.10.3.1-1 of AASHTO and soil profile assumptions based on identification of shallow bedrock throughout most of the project site. The recommended spectral acceleration coefficient values for probabilistic design are summarized on Table 2.

Table 1: Summary of Nearby Seismic Source Faults

FAULT OR FAULT ZONE

DISTANCE

FROM

CENTER OF

PROJECT

FAULT

PARALLEL

SLIP RATE

FAULT

LENGTH AGE

(miles) (inch/year) (miles) (years) Hosgri Fault 7.12 0.55 60.27 < 15,000

Rinconada Fault Zone 17.03 0.39 75.81 < 130,000

San Gregorio Fault Zone 18.33 0.53 149.75 < 15,000

Monterey Bay-Tularcitos Fault Zone 23.59 0.20 52.20 < 15,000

Oceanic-West Huasna Fault Zone 26.51 - - < 130,000

San Andreas Fault Zone 36.28 8.66 672.32 < 15,000

Calaveras South - Paicines Extension 38.7 5.51 96.93 < 15,000

- Data not included in USGS Quaternary Faults Database.

Table 2: Summary of Seismic Parameters Corrected for Site Class C

Peak Seismic Ground Acceleration Coefficient (As) 0.39

Horizontal Response Spectral Acceleration at Period of 0.2 sec (SDS) 0.92

Horizontal Response Spectral Acceleration at Period of 1.0 sec (SD1) 0.43

Site Factor at Zero-Period of Acceleration Spectrum (FPGA) 1.043

Site Factor at Short-Period of Acceleration Spectrum (Fa) 1.069

Site Factor at Long-Period Range of Acceleration Spectrum (Fv) 1.492

Based on the long acceleration coefficient SD1 value of 0.43, the site is assigned to Seismic Hazard Zone 3, in accordance with Table 3.10.6-1 of AASHTO.

3.0 FIELD EVALUATION

To evaluate the field conditions, a CFLHD team visited the project site and conducted limited field measurements and observations on September 8 and 9, 2021. This team included Lorell Dutiel (ERFO Coordinator), Thomas McCrary (Roadway Design Engineer), Aaron Estep (Hydraulics Engineer), Timberley Belish (Environmental Protection Specialist), and James Arthurs (Geotechnical Engineer). The CFLHD team met with representatives of the U.S. Forest Service and Los Padres National Forest.

Field observations by the Geotechnical Engineer focused on evaluating the existing roadway conditions and soil properties. Evaluations and recommendations presented in this memorandum are based on visual observations and the limited measurements taken during the site visit. Due to ERFO project time and budget constraints to expedite project delivery and reestablish roadway access, no subsurface investigations were conducted. Samples of the overburden soil material were collected from the project area by James Arthurs and shipped to the CFLHD lab for testing. All samples were collected from the surface using hand tools. Samples at MP 15.02 and 18.53 were collected from the existing cut slope. The sample at MP 9.31 was collected from stockpiled debris materials that had previously been removed from the roadway by USFS maintenance personnel.

Results of the testing are presented in Table 3 and Table 4 below. Detailed lab results are attached to this memorandum. Design analyses were based on the lab testing results and presumptive properties and experience from similar repairs.

Table 3: Classification Testing Results

MILEPOST1 OFFSET PERCENT

SAND

PERCENT

PASSING 200 LL PI USCS AASHTO

9.31 LT 66 11 NV NP SP-SM A-1-b(0)

15.02 RT 52 2.4 NV NP SP A-1-a(0)

18.53 RT 40 1.9 NV NP GW A-1-a(0)

1 Estimated milepost is based on MP 0.0 at intersection of Nacimiento-Fergusson Road and Mission Road

Table 4: Engineering and Chemical Properties Testing Results

MILEPOST1 OFFSET

MAXIMUM

DRY DENSITY2

(pcf)

OPTIMUM MOISTURE

CONTENT2

LA

ABRASION

(% loss) pH

RESISTIVITY

(ohm-cm)

9.31 LT 126.1 8.6 - 7.1 5,040

15.02 RT - - 44 6.9 7,960

18.53 RT 122.5 11.6 75 6.8 8,620

1 Estimated milepost is based on MP 0.0 at intersection of Nacimiento-Fergusson Road and Mission Road 2 Samples contained a high percentage of oversize particles. Reported results are for material passing the No. 4 sieve.

See attached lab results for details.

The Nacimiento-Fergusson Road appears to have been constructed using conventional cut and sidecast fill techniques as shown on Figure 4 and Figure 5. Cut slopes for the roadway vary between 1V:1H for rock and 1V:1.5H to 1V:2:H for soil. Native slopes in the area are typically

Figure 4: Typical Roadway Section near MP 9.34 vegetated with deciduous trees and brush or undergrowth, while cut and fill slopes are grassy with

Figure 6: Typical Roadway Section near MP 18.53

Figure 5: Highly weathered rock near MP 18.37 isolated bushes. Areas of exposed bedrock are generally bare and unvegetated. Undisturbed areas were generally mantled in a layer of residual soil, with local bedrock outcrops. Local instability or raveling was noted in the existing bedrock cut slopes, but appeared to be limited to a maintenance level issue. This raveling is limited to small (less than 6-inch maximum dimension) particles that do not pose a significant safety hazard. Bedrock exposed in cut slopes was varied from slightly to highly weathered. Where less weathered, the intact rock was moderately strong to very strong.

Where highly weathered, open, soil-filled joints dominate the rock-mass properties (Figure 6).

Site observations and repair recommendations are summarized in Table 5. Photos of the sites are attached to this memorandum.

Table 5: Site Observations and Repair Recommendations

Site1,2 MP3 Site Description Proposed Repair

BA 7 9.31

Approximately 20% of material is boulders 12" or larger, 40% is material greater than 6".

Potentially to be used for gabion or MSE facing fill. Total 450 CY of debris.

1 9.34 Deposition point for debris flows from canyon. Not ERFO eligible.

BA 6 10.52

Approximately 20% of material is boulders 12" or larger, likely about 10 CY of larger rocks. Rock is hard and chips under hammer point (R5-R6).

2 13.29 Culvert over-topped and eroded embankment, 100' long erosion. Replace embankment.

3 14.38 Culvert over-topped and eroded embankment.

Replace culvert, RSS to limit channel constriction

4 14.58 Culvert over-topped, water scoured embankment, 4' high scarp, 30' long. Rock in cut slope.

MSE Wall

5 14.74 Combine Sites 5 and 6. Debris flow in large channel with 5' of debris deposited on roadway. Material collected for potential borrow source. Scour and failure of embankment, 115' long.

Conventional embankment, replace culvert.

6 14.75 7 14.77 No roadway damage, not ERFO eligible.

8 14.83 Embankment failure, 4’ high scarp, 60’ long. MSE Wall

Site1,2 MP3 Site Description Proposed Repair

8b 14.87 Buried culvert, maintenance issue, not ERFO eligible.

8a 15 Not ERFO eligible, 6' high, 100' long scarp.

Hard rock in cut slope.

BA 5 15.02 -

9 15.08 Not ERFO eligible, erosion of soil in front of dry stack rock wall.

10 15.28 Erosion around culvert, 6' high, 350' long scarp. MSE Wall

11 15.73 Embankment failure, 3' high scarp, 50' wide.

Located near water tank. Highly weather rock in adjacent cut slope.

Reconstruct embankment, RSS to limit channel impacts

12 16.66 Embankment failure / culvert overtopping. Fill slope eroded.

Add/Replace culvert, reconstruct embankment.

13 16.94 Embankment failure, 5' high scarp, 30' long.

Silty sand and gravel. Bedrock in adjacent cut slope.

MSE Wall

14 17.13 Embankment failure, 10' high scarp, 30' wide.

Slope below failure is about 1:1.5. MSE Wall

14a 17.29 Not ERFO eligible. Erosion of outboard slope. Small RSS or Deep Patch.

15 17.49 Embankment failure, 11' high scarp, 25' wide.

Rock visible below roadway. MSE Wall

BA 4 17.68 Weathered metamorphic rock BA 3 18.26 Weathered metamorphic rock BA 2 18.37 Weathered metamorphic rock

BA 1 18.53 20' high slope, weathered metamorphic rock, vehicle pullout on outboard side

16 18.59 Embankment failure, 8' high scarp, 75' wide. MSE Wall 1 BA indicates potential borrow area, subject to environmental clearance.

2 Observations included for non-ERFO eligible sites for information only; no design performed for these sites.

3 Estimated milepost is based on MP 0.0 at intersection of Nacimiento-Fergusson Road and Mission Road

4.0 ANALYSIS

4.1 Slope Stability

Slope stability analysis was completed for the failed embankments at Site 4, 8, 10, 13, 14, 15, and

16. Back calculation analyses for slope conditions at failure were first conducted using the Slide

7.0 computer program developed by RocScience. Slide 7.0 uses limit equilibrium methods to determine the factors of safety for slope stability. The back-analyzed soil parameters were then used for retaining wall design calculations.

Presumptive soil properties at each location were estimated based on laboratory testing, visual classification, and experience with similar soil materials for initial input in the back analysis. Based on the recent fire activity and heavy precipitation events leading to the roadway embankment damage, groundwater levels were assumed to be relatively shallow at the time of failure. An incipient static factor of safety of unity was used to refine the estimated soil parameters.

Conservative, presumptive properties for existing embankment materials were assigned based on visual classification and experience with similar materials.

Bedrock was observed both in the existing roadway cut slopes and in the native slopes below the embankment. Global stability analysis of the sites therefore included bedrock at various depths below the road surface depending on observations at each site. The depth to bedrock is a conservative assumption for slope stability analysis and does not necessarily reflect the actual subsurface profile. Difficult excavation conditions may be expected. Recommendations regarding excavation in bedrock are presented in Section 5, below.

Slope geometry was based on roadway design cross-sections prepared from topographic survey collected by CFLHD, dated July 5, 2022.

The back-analyzed and assumed soil and rock parameters were used in further analyses to examine the effectiveness of repair options and are summarized in Table 6 below. Results of the slope stability analyses are attached to this memorandum.

Table 6: Material Properties Used in Wall Design.

SOIL TYPE

UNIT WEIGHT FRICTION

ANGLE COHESION

(pcf) (degrees) (psf) All Sites

Select Granular Backfill 125 34 0 RSS Backfill 125 32 0

Sites 3, 4, 8, 10, 16 On-Site Soil / Fill 120 32 100

SOIL TYPE

UNIT WEIGHT FRICTION

ANGLE COHESION

(pcf) (degrees) (psf) Weathered Bedrock 130 32 200

Bedrock 140 32 500 Site 13

On-Site Soil / Fill 120 36 100 Weathered Bedrock 130 36 200

Bedrock 140 36 500 Site 14

On-Site Soil / Fill 120 33 100 Weathered Bedrock 130 32 200

Bedrock 140 32 500 Site 15

On-Site Soil / Fill 120 32 50 Weathered Bedrock 130 32 200

Bedrock 130 32 500

4.2 Mechanically Stabilized Earth Wall Design Analyses

MSE walls are earth retaining structures constructed of soil reinforcing elements (either steel or geosynthetic) placed in a high quality backfill material. These structures rely on the soil reinforcement to create a coherent mass to resist the lateral pressures imposed by materials behind the reinforced fill. MSE walls have been utilized on many projects as context sensitive solutions preserving scenic, aesthetic, historic, and environmental resources.

4.2.1 Analysis Procedures

Based on the observed conditions and to comply with the ERFO objectives to restore the roadway to acceptable and safe conditions within budget, a Mechanically Stabilized Earth (MSE) retaining wall was analyzed as the preferred repair alternative for Sites 4, 8, 10, 13, 14, 15, and 16. A near vertical retaining wall system is expected to best meet the project requirements based on the existing site conditions, steep existing slopes, and the proposed roadway widths. An MSE system is likely the most cost-effective retaining wall system for the proposed application.

The MSE walls were designed as gravity retaining walls based on the proposed typical roadway section and cross sections prepared by the CFLHD Roadway Engineer. Table 7 presents a summary of the analyzed wall geometries. The MSEW software package published by ADAMA Engineering was used to check external (sliding, overturning, and bearing resistance) stability for the walls. Slide2, published by RocScience, was used to check global stability. Global stability analyses in Slide2 used the Morgenstern-Price method to calculate overall factors of safety for slope or retaining wall stability.

Table 7: Wall Geometries Analyzed in MSEW

MAXIMUM

DESIGN HEIGHT

MINIMUM

REINFORCEMENT LENGTH

FOR EXTERNAL STABILITY

REINFORCEMENT

TYPES

(FP-14, 714.04)1

6 ft 8.0 ft (3) Type II 8 ft 9.5 ft (4) Type II

10 ft 11.0 ft (5) Type II 12 ft 12.5 ft (6) Type II

14 ft 14.0 ft (5) Type II

(2) Type III

16 ft 16.0 ft (5) Type II

(3) Type III

18 ft 17.5 ft

(4) Type II

(3) Type III

(2) Type IV

1Reinforcement types provided for information only. Internal stability analysis to be performed by contractor according to Section 257.

Preliminary external design including global stability, bearing resistance, sliding, overturning, and eccentricity was performed to evaluate the proposed wall geometry. The final MSE wall internal stability will be designed and submitted by the contractor. The walls were designed in general accordance with the AASHTO LRFD Bridge Design Specifications 9th Edition including interim revisions, and FHWA Publication NHI-10-024 and NHI-10-025, Volumes 1 and 2, respectively, entitled “Design and Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes” dated November 2009. Acceptance criteria used for preliminary design are shown in Table 8.

The capacity to demand ratios (CDR) for bearing resistance and sliding are used to quantify the ratio of the factored resistance to the factored load. Resistance factors of 0.65 and 1.00 were used in preliminary design for bearing and sliding, respectively. Load factors for bearing, sliding, and eccentricity are shown in Tables 4-1 and 4-2 of FHWA (2009). Seismic stability was considered in the preliminary analyses using 50% of As for the horizontal acceleration.

Table 8: MSE Wall Design Minimum Acceptance Criteria

STABILITY MODE MINIMUM ACCEPTANCE

CRITERIA

Global Stability *FS = 1.30 (static) 1.10 (seismic) Bearing Resistance CDR = 1.0

Sliding CDR = 1.0 Limiting Eccentricity emax = L/4

Notes: FS = Factor of Safety, CDR = Capacity to Demand Ratio, Eccentricity (emax) for soil foundations.

*See discussion in following this table

In general, the existing slopes at the project site are very steep (between 1V:1H and 1V:1.5H) and interpreted to be quasi-stable under static conditions and unstable under the design seismic loading.

Depth to bedrock below the roadway is not certain and has a high impact on the calculated factors of safety. Analysis of global stability for the MSE walls therefore evaluated both the reinforcing length required to meet the minimum acceptable global factor of safety, and the AASHTO defined minimum reinforcement length (8 feet or 70% of wall height, whichever is greater). Due to the quasi-stable nature of the slopes, a minimum global static factor of safety of 1.3 was not considered as the primary acceptance criteria. Instead, we evaluated the change in static and seismic factors of safety between the backanalysis case and the proposed wall geometry. Improvement in the static factor of safety and a reduction of less than 0.05 in the seismic factor of safety were considered acceptable.

4.2.2 Analysis Results

Calculated capacity-demand ratios for external stability at the maximum design heights are presented in Table 9. Results of the MSE wall design calculations are attached to this memo.

Results of the global stability analyses are summarized in Table 10 and attached to this memo.

These are greater than the typical value of 70 percent of the design height due to the steepness of existing slopes below the walls and potential for elevation water levels.

Table 9:- Calculated Capacity-Demand Ratios at Maximum Design Height

MODE OF

FAILURE

CRD

Static Seismic

Base Sliding 2.08 1.02 Bearing 4.09 2.13

Overturning 4.22 1.68

Results of the global stability modelling are also attached and are summarized in Table 10. This table also presents recommended minimum reinforcement lengths to meet acceptable performance criteria for global stability for the walls. As previously discussed, the acceptable performance criteria for walls on this project is lower than the AASHTO defined minimums due to site conditions specific to this project. Table 11 presents a summary of recommended reinforcement lengths based on anticipated maximum wall heights at each site.

Table 10: Calculated Global Stability Factors of Safety

SITE

BACKANALYSIS FS for AASHTO min. RL1 RL for FS ≥1.3 in Static

Case Minimum RL for Global Stability

Static Seismic Static Seismic % of H Seismic FS % of H

4 1.32 0.99 1.28 0.97 95% 0.98 95%

8 1.21 0.91 1.22 0.91 91% 0.96 91%

10 1.28 0.92 1.2 0.89 106% 0.94 106%

13 1.02 0.75 1.22 0.92 114% 0.98 70%

14 1.01 0.83 1.25 0.93 95% 0.96 70%

15 1.03 0.76 1.41 1.04 70% 1.04 70%

16 1.04 0.77 1.2 0.9 94% 0.97 70%

1 FS = Factor of Safety, RL = Reinforcement Length, H = Wall Height

If stable bedrock is encountered in the wall excavations, the CFLHD Contract Officer (CO), the CFLHD Geotechnical Engineer, and the Wall Designer should be notified immediately to provide guidance on revision of reinforcement lengths. We anticipate that reinforcement lengths can be truncated to reduce or eliminate excavation of bedrock.

Table 11: Recommended Minimum Reinforcement Lengths for MSE Walls

SITE

H

MAX.1

RL

MIN.1 SITE

H

MAX.1

RL

MIN.1

(ft) (ft) (ft) (ft)

10 11

18 17.5 8 9.5 16 16 6 8 14 14

16 16 12 12.5 14 14 10 11 12 12.5 8 9.5 10 11 6 8 8 9.5

10 11

6 8 8 9.5

16 16 6 8 14 14

16 16 12 12.5 14 14 10 11 12 12.5 8 9.5 10 11 6 8 8 9.5

14 14 6 8 12 12.5 10 11 8 9.5 6 8

1RL = Reinforcement Length, H = Wall Height

4.3 Reinforced Soil Slopes

Based on the observed conditions and to comply with the ERFO objectives to restore the roadway to acceptable and safe conditions within budget, a Reinforced Soil Slope (RSS) was analyzed as a potential repair alternative for Sites 3 and 11 during preliminary development of the project design.

At these sites, proposed embankment construction will potentially constrict drainage channels.

Preliminary analysis of the RSS was conducted using Slide2. Final internal and external stability of the RSS was not completed. At this time, RSS are not anticipated for incorporation into the project. The preliminary analysis performed indicates that RSS are feasible but does not provide full engineering design. If RSS are selected for inclusion in the project, additional design analyses by the CFLHD Geotechnical Engineer will be required.

5.0 RECOMMENDATIONS AND CONSTRUCTION CONSIDERATIONS

Bedrock is likely to be encountered during excavation for the MSE walls. Based on bedrock outcrops observed along the Nacimiento-Fergusson Road, we interpret that the upper foot or more of bedrock are weathered in most locations. Relatively fresh, hard bedrock was observed in isolated cutslopes along the project alignment. Hard bedrock was not observed in the erosion or slide scars. Therefore, relatively fresh, hard, and intact bedrock may be encountered in excavations for the project and is likely to be encountered in excavations where bedrock is exposed in the adjacent cutslopes. A twelve-inch layer of Foundation Fill should be placed between the excavated bedrock and the bottom of wall, as shown in the plans. Some general information on rock rippability and excavation characteristics is attached to this memorandum for informational purposes. Determination of rippability is the responsibility of the contractor.

The contractor should document the location of bedrock encountered during the retaining wall excavation for review by the CFLHD CO, the CFLHD Geotechnical Engineer, and the Wall Designer. If hard, intact bedrock is encountered, revision of the MSE wall design may be required and desirable to limit excavations in rock and minimize required shoring areas. The Contractor should work with CFLHD to document the bedrock locations early in the construction process, so that design revision may be completed in a timely manner. This design revision may include truncation of reinforcements in the lower portion of the MSE wall.

Shoring is anticipated at the retaining wall locations to maintain the required temporary roadway width. Design of shoring and excavation safety is the responsibility of the contractor. As an alternative to shoring, access ramps that allow passenger and emergency response vehicles to pass through the wall excavations may also be considered.

Retaining wall design and construction should conform to the FP-14 and project Special Contract Requirements (SCR), Sections 257 and 255, respectively.

6.0 DISCLAIMERS/LIMITATIONS CLAUSE

Subsurface exploration was not performed as a part of this scope of work. Interpretation of surface and subsurface conditions is based on limited field reconnaissance and surface mapping of soil and rock outcrops. The Recommendations section of this report includes 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 judgement of the Contractor.

Attachments (4)

A - Lab Testing Results

B - Site Photos

C - Excavation Characteristics of Rocks and Rippability Charts

D - Slope Stability and MSE Wall Design Analyses

Prepared by:

James Arthurs

Acting Lead Geotechnical Engineer, CFLHD

Reviewed by:

Evan Garich

Geotechnical Engineer, WFLHD

Approved by:

James Arthurs, Ph.D., P.E.

Acting Lead Geotechnical Engineer, CFLHD

7.0 REFERENCES

American Association of State Highway and Transportation Officials (AASHTO). “AASHTO LRFD Bridge Design Specifications.” Ninth Edition, 2020.

California Department of Transportation (CalTrans). (2022). “ARS Online v.2.3.09”.

<http://dap3.dot.ca.gov/ARS_Online/index.php>

Graymer, R.W., Langenheim, V.E., Roberts, M.A., and McDougall, K. 2014. “Geologic and Geophysical Maps of the Eastern Three-Fourths of the Cambria 30’ x 60’ Quadrangle, Central California Coast Ranges.” 1:100,000. U.S. Geological Survey, Scientific Investigation Map 3287.

Rosenberg, L.I. and Wills, C.J. 2016. “Preliminary Geologic Map of the Point Sur 30’ x 60’ Quadrangle.” 1:100,000. California Geologic Survey.

U.S. Department of Transportation, Federal Highway Administration (FHWA). (2014). “Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects, FP-14.”

Publication No. FHWA-FLH-14-001.

U.S. Department of Transportation, Federal Highway Administration (FHWA). (2009). “Design and Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes.”

Publication No. FHWA-NHI-10-024.

U.S. Geological Survey (2022a). “Quaternary Fault and Fold Database of the United States.”

USGS Earthquake Hazards Program, <http://earthquake.usgs.gov/hazards/qfaults/>

U.S. Geologic Survey (2022b). “U.S. Seismic Design Maps.” USGS Earthquake Hazards Program, <http://earthquake.usgs.gov/designmaps/us/application.php>

CA ERFO FS LSPDR 2021-1(1)

Nacimiento-Fergusson Road

A – Lab Results

B - Photos

Site 2

Photo 1: Eroded embankment

Photo 2: Plugged culvert

Site 3

Photo 3: Embankment erosion

Photo 4: Upstream view of drainage

Photo 5: Cut slope above roadway

Site 4

Photo 6: Embankment erosion

Sites 5 and 6

Photo 7: Overall site with debris piled on shoulders, embankment erosion below red vehicle

Photo 8: Debris piles on shoulders and upstream channel, culvert outlet buried under debris

Photo 9: Debris in upstream channel

Photo 10: Embankment failure due to scour and erosion of toe

Site 8

Photo 11: Embankment failure looking up station

Photo 12: Embankment failure looking downstation

Site 10

Photo 13: Embankment failure around culvert

Photo 14: Bedrock in cut slope adjacent to embankment failure

Site 11

Photo 15: Embankment damage

Photo 16: Embankment failure due to scour and erosion in channel

Site 13

Photo 17: Embankment failure

Photo 18: Bedrock in cut slope above failure

Site 14

Photo 19: Embankment failure

Site 15

Photo 20: Embankment failure

Site 16

Photo 21: Embankment failure / erosion

Photo 22: Culvert adjacent to embankment failure

Potential Borrow Areas

Photo 23: Borrow Area 1

Photo 24: Borrow Area 2

Photo 25: Borrow Area 6

Photo 26: Borrow Area 7

C – Excavation Characteristics of Rocks

And Rippability Charts

Table C.1: Rock Hardness and Excavation Characteristics1

Rock Hardness

Description

Identification Criteria

Unconfined Compressive Strength

Seismic Compression (P-Wave) Velocity Excavation

Characteristics MPa psi m/s f/s

Very Soft Rock

Material crumbles under firm blows with sharp end of geological pick; can be peeled with a knife; too hard to cut a triaxial sample by hand. SPT will refuse. Pieces up to 3-c, thick can be broken by finger pressure.

1.7-3.0 246-435 450-1,200 1,475- 3,935 Easy Ripping

Soft Rock

Can just be scraped with a knife;

indentations 1-mm to 3-mm show in specimen with firm blows of the pick point; has dull sound under hammer.

3.0-10.0 435-1,450 1,200- 1,500

3,935- 4,920 Hard Ripping

Hard Rock

Cannot be scraped with a knife; hand specimen can be broken with a pick with a single firm blow; rock rings under hammer.

10.0-20.0 1,450- 2,900

1,500- 1,850

4,920- 6,070

Very Hard Ripping

Very Hard Rock

Hand specimen breaks with a pick after more than one blow; rock rings under hammer.

20.0-70.0 2,900- 10,150

1,850- 2,150

6,070- 7,050

Extremely Hard Ripping or Blasting

Extremely Hard Rock

Specimen require many blows with geological pick to break through intact material; rock rings under hammer.

> 70.0 > 10,150 > 2,150 >7,050 Blasting

1Table from Weaver (1975).

Table C.2: Excavation Characteristics of Rock2

Classification Elements

Class I Class II Class III Very hard ripping to blasting Hard ripping Easy ripping

Rock material requires drilling and explosives or impact procedures for excavation may classify as rock excavation (NRCS Construction

Spec. 21). Must fulfill all conditions below:

Rock material requires ripping techniques for excavation may classify as rock excavation (NRCS Construction Spec.

21). Must fulfill all conditions below:

Rock material can be excavated as common material by earth-moving or ripping equipment may classify as common excavation (NRCS

Construction Spec. 21).

Must fulfill all conditions below:

Headcut erodibility index, kh (NEH628.52) kh ≥ 100 10 < kh < 100 kh ≤ 10

Seismic velocity, approximate (ASTM

D5777 and Caterpillar Handbook of Ripping, 1997)

> 2,450 m/s (> 8,000 ft/s)

2,150-2,450 m/s (7,000-8,000 ft/s)

< 2,150 m/s (< 7,000 ft/s)

Minimum equipment size (flywheel power) required to excavate rock. All machines assumed to be heavy-duty, track-type backhoes or tractors equipped with a single tine, rear-mounted ripper.

260 kW (350 hp), for kh < 1,000

375 kW (500 hp), for kh < 10,000

Blasting, for kh > 10,000

185 kW (250 hp) 110 kW (150 hp)

1The classification is a general guide and does not prescribe the actual contract payment method to be used, nor supersedes NRCS contract documents. The classification is for engineering design purposes only.

2Table from USDA (2012).

USE OF SEISMIC VELOCITY CHARTS1

The charts of ripper performance estimated by seismic wave velocities have been developed from field tests conducted in a variety of materials. Considering the extreme variations among materials and even among rocks of a specific classification, the charts must be recognized as being at best only one indicator of rippability.

Accordingly, consider the following precautions when evaluating the feasibility of ripping a given formation:

Tooth penetration is often the key to ripping success, regardless of seismic velocity. This is particularly true in homogeneous materials such as mudstones and claystones and the fine-grained caliches. It is also true in tightly cemented formations such as conglomerates, some glacial tills and caliches containing rock fragments.

Low seismic velocities of sedimentaries can indicate probable rippability. However, if the fractures and bedding joints do not allow tooth penetration, the material may not be ripped effectively.

Pre-blasting or “popping” may induce sufficient fracturing to permit tooth entry, particularly in the caliches, conglomerates and some other rocks; but the economics should be checked carefully when considering popping in the higher grades of sandstones, limestones and granites.

Ripping is still more art than science, and much will depend on operator skill and experience.

Ripping for scraper loading may call for different techniques than if the same material is to be dozed away. Cross-ripping requires a change in approach. The number of shanks used, length and depth of shank, tooth angle, direction, throttle position all must be adjusted according to field conditions. Ripping success may well depend on the operator finding the proper combination for those conditions.

1Text and the following tables from Hawthorne Cat (2018).

Ripper Performance

● D8R/D8T

19-76

Rippers

D8R/D8T

● Multi- or Single Shank No. 8 Ripper

● Estimated by Seismic Wave Velocities

11111 51 61 2 3 4 7 8 9 10 11 12 13 14 15

2 3 410

TOPSOIL

CLAY

GLACIAL TILL

IGNEOUS ROCKS

GRANITE

BASALT

TRAP ROCK

SEDIMENTARY ROCKS

SHALE

SANDSTONE

SILTSTONE

CLAYSTONE

CONGLOMERATE

BRECCIA

CALICHE

LIMESTONE

METAMORPHIC ROCKS

SCHIST

SLATE

MINERALS and ORES

COAL

IRON ORE

Seismic Velocity Meters Per Second × 1000

Feet Per Second × 1000

RIPPABLE MARGINAL NON-RIPPABLE

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 76PHB-Sec19-TTT-4-Rippers(pg59-82).indd 76 6/21/18 3:33 PM6/21/18 3:33 PM

19-77

RippersRipper Performance

● D9R/D9T

D9R/D9T

● Multi- or Single Shank No. 9 Ripper

● Estimated by Seismic Wave Velocities

11111 51 61 2 3 4 7 8 9 10 11 12 13 14 15

2 3 410

TOPSOIL

CLAY

GLACIAL TILL

IGNEOUS ROCKS

GRANITE

BASALT

TRAP ROCK

SEDIMENTARY ROCKS

SHALE

SANDSTONE

SILTSTONE

CLAYSTONE

CONGLOMERATE

BRECCIA

CALICHE

LIMESTONE

METAMORPHIC ROCKS

SCHIST

SLATE

MINERALS and ORES

COAL

IRON ORE

RIPPABLE MARGINAL NON-RIPPABLE

Seismic Velocity Meters Per Second × 1000

Feet Per Second × 1000

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 77PHB-Sec19-TTT-4-Rippers(pg59-82).indd 77 6/21/18 3:33 PM6/21/18 3:33 PM

19-78

Rippers Ripper Performance

● D10T2

D10T2

● Multi- or Single Shank No. 10 Ripper

● Estimated by Seismic Wave Velocities

11111 51 61 2 3 4 7 8 9 10 11 12 13 14 15

2 3 410

TOPSOIL

CLAY

GLACIAL TILL

IGNEOUS ROCKS

GRANITE

BASALT

TRAP ROCK

SEDIMENTARY ROCKS

SHALE

SANDSTONE

SILTSTONE

CLAYSTONE

CONGLOMERATE

BRECCIA

CALICHE

LIMESTONE

METAMORPHIC ROCKS

SCHIST

SLATE

MINERALS and ORES

COAL

IRON ORE

Seismic Velocity Meters Per Second × 1000

Feet Per Second × 1000

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 78PHB-Sec19-TTT-4-Rippers(pg59-82).indd 78 6/21/18 3:33 PM6/21/18 3:33 PM

19-79

RippersRipper Performance

● D11T

D11T

● Multi- or Single Shank No. 11 Ripper

● Estimated by Seismic Wave Velocities

11111 51 61 2 3 4 7 8 9 10 11 12 13 14 15

2 3 410

GLACIAL TILL

IGNEOUS ROCKS

GRANITE

BASALT

TRAP ROCK

SEDIMENTARY

SHALE

SANDSTONE

SILTSTONE

CLAYSTONE

CONGLOMERATE

BRECCIA

CALICHE

LIMESTONE

METAMORPHIC

SCHIST

SLATE

MINERALS and ORES

COAL

IRON ORE

Seismic Velocity Meters Per Second × 1000

Feet Per Second × 1000

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 79PHB-Sec19-TTT-4-Rippers(pg59-82).indd 79 6/21/18 3:33 PM6/21/18 3:33 PM

19-80

Rippers Ripper Performance

● D11T CD

D11T CD

● Single Shank No. 11 Ripper

● Estimated by Seismic Wave Velocities

11111 51 61 2 3 4 7 8 9 10 11 12 13 14 15

2 3 410

GLACIAL TILL

IGNEOUS ROCKS

GRANITE

BASALT

TRAP ROCK

SEDIMENTARY

SHALE

SANDSTONE

SILTSTONE

CLAYSTONE

CONGLOMERATE

BRECCIA

CALICHE

LIMESTONE

METAMORPHIC

SCHIST

SLATE

MINERALS and ORES

COAL

IRON ORE

Seismic Velocity Meters Per Second × 1000

Feet Per Second × 1000

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 80PHB-Sec19-TTT-4-Rippers(pg59-82).indd 80 6/21/18 3:33 PM6/21/18 3:33 PM

19-81

RippersEstimated Ripper Production Graphs

● D8R/D8T ● D9R/D9T

CONSIDERATIONS FOR USING

PRODUCTION ESTIMATED GRAPHS:

● Machine rips full-time — no dozing.

● Power shift tractors with single shank rippers.

● 100% efficiency (60 min hour).

● Charts are for all classes of material.

● In igneous rock with seismic velocity of 8000 fps

(2450 mps) or higher for the D11T, and 6000 fps (1830 mps) or higher for the D10T2, D9R/D9T and D8R/D8T, the production figures shown should be reduced by 25%.

● Upper limit of charts reflect ripping under ideal con-di tions only. If conditions such as thick lamination, vertical lamination or any factor which would adversely affect production are present, the lower limit should be used.

B

A

2 3 4 5 6 7 8

1 2

B

2 3 4 5 6 7 8

1 2

A

SEISMIC VELOCITY (in meters per second x 1000)

KEY

A — IDEAL

B — ADVERSE

SEISMIC VELOCITY (in feet per second x 1000)

D9R/D9T WITH SINGLE SHANK

P R

O D

U C

T

IO

N

B C

Y /h o u r)

P R

O D

U C

T

IO

N

B m

3 / h o u r)

SEISMIC VELOCITY (in meters per second x 1000)

SEISMIC VELOCITY (in feet per second x 1000)

D8R/D8T WITH SINGLE SHANK

P R

O D

U C

T

IO

N

B C

Y /h o u r)

P R

O D

U C

T

IO

N

B m

3 / h o u r)

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 81PHB-Sec19-TTT-4-Rippers(pg59-82).indd 81 6/21/18 3:33 PM6/21/18 3:33 PM

19-82

Rippers Estimated Ripper Production Graphs

● D10T2 ● D11T ● D11T CD

B

A

2 3 4 5 6 7 98

1 2

SEISMIC VELOCITY (in meters per second x 1000)

SEISMIC VELOCITY (in feet per second x 1000)

D10T2 WITH SINGLE SHANK

P R

O D

U C

T

IO

N

B C

Y /h o u r)

P R

O D

U C

T

IO

N

B m

3 / h o u r)

A

B

2 3 6 7 1094 85

1 2 3

SEISMIC VELOCITY (in meters per second x 1000)

SEISMIC VELOCITY (in feet per second x 1000)

D11T WITH SINGLE SHANK

P R

O D

U C

T

IO

N

B C

Y /h o u r)

P R

O D

U C

T

IO

N

B m

3 / h o u r)

KEY

A — IDEAL

B — ADVERSEA

B

2 3 6 7 1094 85

1 2 3

SEISMIC VELOCITY (in meters per second x 1000)

SEISMIC VELOCITY (in feet per second x 1000)

D11T CD WITH SINGLE SHANK

P R

O D

U C

T

IO

N

B C

Y /h o u r)

P R

O D

U C

T

IO

N

B m

3 / h o u r)

PHB-Sec19-TTT-4-Rippers(pg59-82).indd 82PHB-Sec19-TTT-4-Rippers(pg59-82).indd 82 6/21/18 3:33 PM6/21/18 3:33 PM

D - Calculations

Prepared by: James Arthurs Date: 8/17/22

Checked by: Evan Garich Date: 9/7/22

Global Stability (Slide2)

Site 4

1.321.32

250.00 lbs/ft2

1.321.32

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

32200140Weathered Bedrock

32500145Bedrock

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-20 0 20 40 60 80

Scenario StaticGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 4.slmdDate 8/9/2022, 3:00:25 PM

Project

CA ERFO FS LSPDR 2021-1(1) Nacimiento-Fergusson Rd

SLIDEINTERPRET 9.019

0.9940.9940.9940.994

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

32200140Weathered Bedrock

32500145Bedrock

0.195

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-40 -30 -20 -10 0 10 20 30 40 50 60 70 80

Scenario SeismicGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 4.slmdDate 8/9/2022, 3:00:25 PM

Project

1.281.28

1.281.28

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ ft3) ColorMaterial

Name

32100120On‐Site Soil / Fill

340125 Select

Granular Backfill

32200140Weathered Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1000100Slope FaceGeosynthetic Reinforcement Geogrid, Type

7.0 ft

10.0 ft

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100

Scenario StaticGroup MSE Walls - RL=8' Company FHWA-CFLDrawn By JMA File Name Site 4.slmdDate 8/9/2022, 3:00:25 PM

Project

0.970.970.970.97

(deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

340125 Select

Granular Backfill

32200140Weathered Bedrock

32500145Bedrock

Allowable Tensile

Strength (lbs/ ft)

Strip Coverage

AnchorageTypeColorSupport Name

1000100Slope FaceGeosynthetic Reinforcement Geogrid, Type

10.0 ft

7.0 ft

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-30 -20 -10 0 10 20 30 40 50 60 70 80 90

Scenario SeismicGroup MSE Walls - RL=8' Company FHWA-CFLDrawn By JMA File Name Site 4.slmdDate 8/9/2022, 3:00:25 PM

Project

1.311.31

1.311.31

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

340125 Select

Granular Backfill

32200140Weathered Bedrock

32500145Bedrock

10.0 ft

9.5 ft Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1000100Slope FaceGeosynthetic Reinforcement Geogrid, Type

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-30 -20 -10 0 10 20 30 40 50 60 70 80

Scenario StaticGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 4.slmdDate 8/9/2022, 3:00:25 PM

Project

0.980.980.980.98

(deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

340125 Select

Granular Backfill

32200140Weathered Bedrock

32500145Bedrock

10.0 ft

9.5 ft Allowable Tensile

Strength (lbs/ ft)

Strip Coverage

AnchorageTypeColorSupport Name

1000100Slope FaceGeosynthetic Reinforcement Geogrid, Type

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-20 0 20 40 60 80

Scenario SeismicGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 4.slmdDate 8/9/2022, 3:00:25 PM

Project

Site 8

1.211.21

1.211.21

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

32200130Weathered Bedrock

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100

Scenario StaticGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 8.slmdDate 8/10/2022, 12:35:01 PM

Project

0.910.910.910.91

(deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

32200130Weathered Bedrock

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100

Scenario SeismicGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 8.slmdDate 8/10/2022, 12:35:01 PM

Project

1.221.22

1.221.22

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200130Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcement Geogrid, Type 2

11.0 ft

16.0 ft

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100 120

Scenario StaticGroup MSE Wall - RL=70% Company FHWA-CFLDrawn By JMA File Name Site 8.slmdDate 8/10/2022, 12:35:01 PM

Project

0.910.910.910.91

(deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200130Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcement Geogrid, Type 2

11.0 ft

16.0 ft

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100 120 140 160

Scenario SeismicGroup MSE Wall - RL=70% Company FHWA-CFLDrawn By JMA File Name Site 8.slmdDate 8/10/2022, 12:35:01 PM

Project

1.321.32

1.321.32

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200130Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcement Geogrid, Type 2

16.0 ft

14.5 ft

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100 120 140

Scenario StaticGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 8.slmdDate 8/10/2022, 12:35:01 PM

Project

0.960.960.960.96

(deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200130Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcement Geogrid, Type 2

16.0 ft

14.5 ft

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-40 -20 0 20 40 60 80 100 120 140

Scenario SeismicGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 8.slmdDate 8/10/2022, 12:35:01 PM

Project

Site 10

1.2431.243

1.2431.243

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

32200140Weathered Bedrock

32500140Bedrock

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-20 -10 0 10 20 30 40 50 60 70 80 90 100

Scenario StaticGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 10.slmdDate 8/10/2022, 12:35:01 PM

Project

0.920.920.920.92

(deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

32100120On‐Site Soil / Fill

32200140Weathered Bedrock

32500140Bedrock

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-20 0 20 40 60 80 100 120 140 160

Scenario SeismicGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 10.slmdDate 8/10/2022, 12:35:01 PM

Project

1.301.30

1.301.30

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200140Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcing Geogrid, Type 2

17.0 ft

16.0 ft

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-20 0 20 40 60 80 100 120 140 160

Scenario StaticGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 10.slmdDate 8/10/2022, 12:35:01 PM

Project

0.940.940.940.94

(deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200140Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosynthetic Reinforcing Geogrid, Type

16.0 ft

17.0 ft

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-20 0 20 40 60 80 100 120 140 160 180

Scenario SeismicGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 10.slmdDate 8/10/2022, 12:35:01 PM

Project

1.1971.197

1.1971.197

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200140Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcing Geogrid, Type 2

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-20 0 20 40 60 80 100 120 140

Scenario StaticGroup MSE Wall - RL=70% Company FHWA-CFLDrawn By JMA File Name Site 10.slmdDate 8/10/2022, 12:35:01 PM

Project

0.8930.8930.8930.893

(deg)

Cohesion (psf)

Unit Weight (lbs/ ft3)ColorMaterial Name

32100120On‐Site Soil / Fill

340125Select Granular Backfill

32200140Weathered Bedrock

32500140Bedrock

Allowable Tensile Strength (lbs/ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosyntheticReinforcing Geogrid, Type 2

0.195

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-20 0 20 40 60 80 100 120 140 160

Scenario SeismicGroup MSE Wall - RL=70% Company FHWA-CFLDrawn By JMA File Name Site 10.slmdDate 8/10/2022, 12:35:01 PM

Project

Site 13

1.021.02

1.021.02

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

36100120On‐Site Soil / Fill

36200130Weathered Bedrock

36500140Intact Bedrock

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-160 -140 -120 -100 -80 -60 -40 -20 0 20

Scenario StaticGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 13.slmdDate 8/10/2022, 12:35:01 PM

Project

0.750.750.750.75

(deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial

Name

36100120On‐Site Soil / Fill

36200130Weathered Bedrock

36500140Intact Bedrock

0.195

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-160 -140 -120 -100 -80 -60 -40 -20 0 20

Scenario SeismicGroup Backanalysis Company FHWA-CFLDrawn By JMA File Name Site 13.slmdDate 8/10/2022, 12:35:01 PM

Project

1.311.31

1.311.31

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial Name

36100120On‐Site Soil / Fill

340125Select Granular Backfill

36200130Weathered Bedrock

36500140Intact Bedrock

Allowable Tensile

Strength (lbs/ ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slope FaceGeosynthetic Reinforcement Geogrid, Type

16.0 ft

14.0 ft

Safety Factor 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 6.00+

-160 -140 -120 -100 -80 -60 -40 -20 0 20

Scenario StaticGroup MSE Wall - FS=1.3 Company FHWA-CFLDrawn By JMA File Name Site 13.slmdDate 8/10/2022, 12:35:01 PM

Project

0.980.980.980.98

16.0 ft

14.0 ft

Phi (deg)

Cohesion (psf)

Unit Weight (lbs/ft3)ColorMaterial Name

36100120On‐Site Soil / Fill

340125Select Granular Backfill

36200130Weathered Bedrock

36500140Intact Bedrock

Allowable Tensile

Strength (lbs/ ft)

Strip Coverage

AnchorageTypeColorSupport Name

1500100Slo…