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Terracon GeoTech Report 09292009.pdfI rerracan Consulting Engineers & Scientists To: Mr. Jerry Shuster, P.E. City of Edmonds From: James Georgis, L.E.G. /John Zipper, P.E. Date: September 29, 2009 Subject: Talbot Road/Perrinville Creek Drainage Improvements Geotechnical Considerations for Alternatives Evaluation (2 3t 00 Project No.: 81085157 We understand that Herrera Environmental Consultant's (Herrera) will be preparing an Alternatives Evaluation for the Talbot Road/Perrinville Creek Drainage Improvements project. We understand that the Alternatives Evaluation will consider two alignments alternatives and open -cut and trenchless construction methods with respect to constructability, cost, permitting, and private property disturbance and coordination. Terracon has prepared this memorandum to assist Herrera with geotechnical aspects of the Alternatives Evaluation. 2 SITE AND PROJECT DESCRIPTION The Talbot Road/Perrinville Creek Drainage Improvement Project includes stormwater alignment alternatives A and B. The stormwater alignment alternatives are intended to alleviate drainage problems along Talbot Road near Perrinville Creek. Alignment A includes the installation of a new storm drain pipe along the east side of the Robinson property (8307 Talbot Road) to the Perrinville Creek channel located within the BNSF right-of-way. Alignment B includes the installation of a new drain pipe along the north side of Talbot Road and the west side of the O'Hanley property (8229 Talbot Road). Alignment B will connect to the existing stormwater high flow bypass intake structure or the existing high flow bypass pipe located about 120 feet north of the intake structure. The preliminary locations of Alignments A and B are shown on the Site and- Exploration Plan, Figure 1. Preliminary information provided by Herrera for a 100 year storm event indicates that Alignment A would have a pipe diameter on the order of 27 inches, a slope of about 0.59 percent, and an invert depth ranging from about 3 to 4 feet below existing grade. We understand that portions of Alignment A would be roughly coincident with or in close proximity to an existing 12 -inch diameter concrete stormwater pipe. We understand that Alignment B may have a pipe diameter ranging from about 27 to 36 inches, a slope ranging from about 0.47 to 0.58 percent, and an invert depth ranging from about 5 to 20 feet below existing grade. We understand that these options are referred to as Alternatives 1 and 2, respectively. The site conditions for this study were evaluated in July of 2009. The regional geologic setting and surface and subsurface conditions are summarized below, while the exploration procedures and interpretive logs of the explorations are presented in Appendix A. Laboratory testing . procedures and results are presented in Appendix B. The approximate exploration locations, 21905 64!h Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304 Fax: 425-771-3549 Talbot Road/Perrinville Creek Drainage Improvements 1rerracon Geotechnical Considerations for Alternatives Evaluation Consulting Engineers & Scientists Project No.: 81085157 R September 29, age 2 I) existing topography, existing site improvements, and proposed alignment alternatives are shown on the Site and Exploration Plan, Figure 1. 3.1 REGIONAL GEOLOGIC SETTING The Preliminary Surficial Geologic Map of the Edmonds East and Edmonds West Quadrangles, Snohomish and King Counties, Washington (Washington Department of Natural Resources map GM -14, 1975) maps the site near the contact between Quaternary age Whidbey Formation deposits and Holocene age artificial fill. The Whidbey Formation is described as medium - bedded (2 to 4 feet) sand, silt, and clay. Artificial fill soils are compositionally highly variable and are not described in the publication. 3.2 SURFACE CONDITIONS Alignment A extends along the east side of the Robinson property (8307 Talbot Road) from Talbot Road, crosses under a portion of Perrinville Creek, then continues north to Perrinville Creek channel located in the BNSF right-of-way. The ground surface along the alignment slopes gently to the north with about 5 feet of relief. A wood -framed, single-family residence is located about 9.5 feet from the centerline of the alignment. The residence appears to be supported on conventional shallow foundations. Site improvements in close proximity to or above the proposed alignment include a paver driveway, mortared brick and natural stone walkways, a wooden deck, and a fort. A number of utilities are located in close proximity to the alignment including underground gas, power, communications, sewer, and stormwater. A number of trees are located along the alignment including a 10 -inch diameter maple, a cedar hedge, and scattered 4- to 10 -inch diameter mixed deciduous and evergreen trees. Alignment B extends along the north side of Talbot Road from an existing stormwater catch basin located near the southeast corner of the Robinson property, then along the west side of the O'Hanley property (8229 Talbot Road) to an existing stormwater high flow bypass intake structure located adjacent to Perrinville Creek. In general, the ground surface climbs from about elevation 17 feet near the existing catch basin to about elevation 33 feet near the southwest* corner of the O'Hanley property, then falls to about elevation 20 near the high flow bypass intake structure. A rockery wall and a wood -framed, single family residence (8333 Talbot Road) are located about 10 and 20 feet west of the alignment, respectively. The residence appears to be supported on conventional shallow foundations. Underground power. and communication lines are located near the alignment along the west side of the O'Hanley property, while water, gas, sewer, and communications lines are located near that Talbot Road portion of the alignment. Vegetation along the Talbot Road portion of the alignment primarily consists of grass and a row of 6- to 8 -inch diameter trees. That portion of the alignment located within the O'Hanley property is primarily vegetated with grass. 3.3 SUBSURFACE CONDITIONS The subsurface exploration consisted of advancing 4 borings (B-1 through B-4) at the approximate locations shown on Figure 1. The explorations ranged from about 16.5 to 26.5 feet below the ground surface. A generalized description of the subsurface conditions encountered at the exploration locations is presented below. Please refer to the exploration logs enclosed in Appendix A for a more detailed description of the subsurface conditions encountered at the exploration locations. 2190564 th Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304 Fax: 425-771-3549 Irerracon Consulting Engineers.& Scientists 3.3.1 SOIL CONDITIONS Talbot Road/Perrinville Creek Drainage Improvements Geotechnical Considerations for Alternatives Evaluation Project No.: 81085157 September 29, 2009 AAPage 3 The soil conditions disclosed at the exploration locations were relatively consistent with respect to soil type and density. In general, the explorations encountered fill soils over soils interpreted as Whidbey Formation deposits. Undocumented fill soils were encountered in borings B-1, B-3, and B-4 to depths of approximately 4.5, 3.5, and 5 feet below the ground surface, respectively. In general, the fill consisted of loose silty sand with trace gravel and sand with silt and trace gravel. Soils interpreted as Whidbey Formation deposits were encountered below the fill soils in borings B-1, B-3, and B-4, and at the ground surface in boring B-2. The Whidbey formation soils extended to the total depth explored at approximately 26.5 feet below the ground surface. In general, the Whidbey Formation deposits consisted of medium dense to dense sand with gravel and silt to gravelly sand with silt. 3.3.2 GROUNDWATER CONDITIONS Groundwater was observed in all four borings at the time of exploration. Groundwater observations are presented below in Table 1. Site groundwater levels should be expected to fluctuate with seasonal variations in precipitation, site utilization, and other factors. 4 GEOTECHNICAL CONSIDERATIONS FOR ALTERNATIVES EVALUATION Terracon completed a preliminary geotechnical evaluation of the surface conditions observed along Alignments A and B and the subsurface conditions encountered in borings B-1 through B- 4 relative to conventional open cut installation and the following trenchless construction installation methods. ® Pipe Bursting ® Auger Bore ® Pipe Jacking ® Pipe Ramming ® Pilot Tube ® Microtunnelling 21905 64th Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304 Fax: 425-771-3549 TABLE 1 GROUNDWATER OBSERVATION AT TIME OF EXPLORATION Exploration Approximate Ground Surface Elevation (ft) Approximate Groundwater Depth (ft) Approximate Groundwater Elevation (ft) B-1 22 3.5 18.5 B-2 31 17 14 B-3 16 4 12 B-4 17 5 12 Site groundwater levels should be expected to fluctuate with seasonal variations in precipitation, site utilization, and other factors. 4 GEOTECHNICAL CONSIDERATIONS FOR ALTERNATIVES EVALUATION Terracon completed a preliminary geotechnical evaluation of the surface conditions observed along Alignments A and B and the subsurface conditions encountered in borings B-1 through B- 4 relative to conventional open cut installation and the following trenchless construction installation methods. ® Pipe Bursting ® Auger Bore ® Pipe Jacking ® Pipe Ramming ® Pilot Tube ® Microtunnelling 21905 64th Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304 Fax: 425-771-3549 Ifierr6con Consulting Engineers & Scientists ® Horizontal Directional, Drilling Talbot Road/Perrinville Creek Drainage Improvements Geotechnical Considerations for Alternatives Evaluation Project No.: 81085157 v If September 2 P 09 g0e 4 L] nr L The following sections provide a discussion regarding geotechnical design and construction considerations for open -cut and trenchless construction methods along Alignments A and B. 4.1 ALIGNMENT A Preliminary information provided by Herrera for a 100 year storm event indicates that Alignment A would have a pipe diameter on the order of 27 inches, a slope of about 0.29 percent, and an invert depth ranging from about 3 to 4 feet below existing grade. We understand that portions of Alignment A would be roughly coincident with or in close proximity to an existing 12 -inch diameter concrete stormwater pipe. Fill soils consisting of loose sand with silt and trace gravel and silty sand with trace gravel were encountered to depths of 3.5 to 5 feet below existing grade. The fill soils were underlain by Whidbey formation soils primarily consisting of medium dense to dense sand with silt and gravel. Groundwater was observed near to slightly below anticipated invert depths at the time of exploration. Based on the site conditions, it is our opinion that open cut is the preferred installation method from a geotechnical perspective. A summary of open cut and trenchless construction geotechnical considerations is presented. below. 4.1.1 OPEN CUT INSTALLATION Based on our review of the site conditions, conventional open cut installation appears feasible from a geotechnical perspective. Cut depths appear to be relatively shallow and temporary shoring, if needed, would likely be limited to that portion of the trench located adjacent to the residence at 8307 Talbot Road. Groundwater was encountered near to slightly below the proposed invert depth and dewatering, if required, would likely be minimal provided that earthwork was completed during the dry season. Open cut installation would likely require a temporary stream diversion and restoration of existing site improvements. 4.1.2 TRENCHLESS INSTALLATION In general, trenchless installation methods do not appear well suited to Alignment A from a geotechnical perspective due to the following primary factors. Trenchless construction methods (including drilled and bored installations and upsized pipe busting) typically utilize a pipe cover of at least 2 to 3 pipe diameters to reduce the potential for settlements and/or heave associated with the installation methods and damage to at grade improvements. In our opinion, the use of trenchless methods at the shallow depths proposed would likely result in settlement and/or heave of at grade improvements located near the alignment. The existing concrete pipe may be reinforced. Bursting of RCP pipe is extremely difficult and typically avoided if at all possible. Wood associated with the existing tree root systems would likely have a significant adverse impact on drilled or bored trenchless installation methods. 2190564 th Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304 Fax: 425-771-3549 Talbot Road/Perrinville Creek Drainage Improvements Irerracon Geotechnical Considerations for Alternatives Evaluation Consulting Engineers & Scientists Project No.: 81085957 ! September 29, 2009 :_R_ : f Page 5 Trenchless methods with adequate grade control would likely be limited to pipe jacking, microtunnelling, and pilot tube installation. Conventional auger bore or pipe ramming would likely require a significantly oversized casing 'to correct for potential misalignment. Pipe ramming is loud and results in significant ground vibration. These considerations often preclude its use in residential areas or in close proximity to sensitive structures. Horizontal directional drilling requires extensive staging and pull back areas and has environmental considerations such as inadvertent releases of drilling fluid. It also has poor line and grade control relative -to gravity installations. Preliminary information provided by Herrera for a 100 year storm event indicates that Alignment B may have a pipe diameter ranging from about 27 to 36 inches, a slope ranging from about 0.47 to 0.58 percent, and an invert depth ranging from about 5 to 20 feet below existing grade. Fill soils consisting of loose sand with silt and silty sand with trace gravel were encountered to depths of 4.5 feet below existing grade. The fill soils were underlain by Whidbey formation soils primarily consisting of medium dense to dense sand with silt'and gravel. Groundwater was observed above anticipated invert depths at the time of exploration. Based on the site conditions, it appears that open cut and several trenchless installation methods are feasible from a geotechnical perspective. We anticipate that open cut and pilot tube installation methods may be the preferred methods for Alignment B when considering other factors. A summary of open cut and trenchless construction geotechnical considerations is presented below. 4.2.1 OPEN CUT INSTALLATION Based on our review of the site conditions, conventional open cut installation appears feasible from a geotechnical perspective. Cut depths may approach 20 feet and the need for temporary shoring is anticipated. Groundwater was encountered above the anticipated invert depth and dewatering would likely be required. Open cut installation would require restoration of existing site improvements. A trench box is one type of support system which might be used. The zone between the trench box and the excavation face should be backfilled as necessary to limit ground movements. As an alternate, braced or unbraced shoring of various types could be considered. 4.2.2 TRENCHLESS INSTALLATION In general, trenchless installation methods appear better suited to Alignment B due to its increased depth and cover. However, groundwater was observed above the anticipated invert depth and the gravity alignment has a relatively flat slope. Geotechnical considerations for trenchless installation methods are summarized below. ® Microtunnelling appears feasible due to good line and grade control and the ability to work below the water table. However, limited dewatering may be needed at the access pits. Slurry type microtunnelling requires relatively large staging areas for equipment and pipe. Microtunnelling does not allow for access to the face of the excavation if an 2190564 th Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304. Fax: 425-771-3549 Talbot Road/Perrinville Creek Drainage Improvements Geotnhnjcal Considerations for Alternatives Evaluation IrerraconConsulting Engineers & Scientists (� 0 E.� Project No.: 81085157 i" j September 29, 2009 Page 6 obstruction is encountered. Obstructions require a shaft to remove the machine or the obstruction. Microtunnelling is one of the more costly trenchless installation methods. ® Pipe ramming is feasible below the water table provided that the access pits are adequately dewatered. However, pipe ramming has no line and grade control and would likely require a significantly oversized steel casing to accommodate potential installation misalignments. Pipe ramming methods produces significant noise and ground vibration. Pilot tube methods have relatively good line and grade control and can be used to install conveyance pipe.(such as vitrified clay) without the need for casing.. Pilot tube methods require relatively small access pits and can often be completed from within 6.5 to 8 -foot diameter shafts or manholes. The use of a pilot tube appears feasible given the ground conditions and alignment lengths, provided the alignment is dewatered. It should be noted that the upper limit of pilot tube equipment appears to be about 48 inches. ® Conventional auger bore and. pipe jacking have poor to moderate line and grade control, respectively. Both methods would likely require the use of oversized casing -to allow for corrections in potential misalignment. Both methods would require dewatering of the alignment. Both methods would require moderate to large sending pits. ® Horizontal directional drilling requires extensive staging and pull back areas and has environmental considerations such as inadvertent releases of drilling fluid. It also has poor line and grade control relative to gravity installations. We trust that this memorandum meets your current needs. Please contact us should you have any questions. Enclosure: Figure 1 — Site and Exploration Plan Appendix A — Field Exploration Procedures and Logs Appendix B -- Laboratory Test Procedures and Results CC: Mr. Andy Behnke, P.E. Herrera Environmental Consultant's 2200 Sixth Avenue, Suite 1100 Seattle, WA 98121 2190564 'h Avenue West, Suite 100, Mountlake Terrace, WA 98043 425-771-3304 Fax: 425-771-3549 T °r c ALIGNMENTB ALTERNATIVE ,s fir., f +t ALIGNMENTA i PLAN VIEW LEGEND: N ®B-1 BORING NUMBER AND APPROXIMATE LOCATION 6.6 aFFwrr_u4n: s;aery Fir Basemap DWG file provided by Hertel and modined by TERRACON. RFA DATE I sr I SITE AND EXPLORATION PLAN FIGURE Her racon Talbot Road/Perrinville Creek Drainage Improvements Consulting Engineers and Scientists Edmonds, Washington 2vns:hA,v,,v, s.a,ro uas Tera$ra?;Ji9 Prepared for:. Herrera Environmental Consultants _ r PH (425)191M FAX (425j nl3549 29ABAIDIMA 1 APPENDIX A FIELD F Our field exploration included 14 borings completed in July 2009. The approximate exploration locations are shown on the Site and Exploration Plan, Figure 1. The exploration locations were determined by measuring distances from existing site features'with a fiberglass tape relative to a topographic site plan provided by Herrera Environmental Consultants. As such, the exploration locations should be considered accurate only to the degree implied by the measurement method. Ground surface elevations at the exploration locations were extrapolated from topographic information presented on the topographic site plan. Descriptive logs of the explorations are enclosed in this appendix. The following sections describe our procedures associated with the exploration. Borings The 4 borings were advanced by an independent drilling company working under subcontract to Terracon. The borings were advanced with a hollow stem auger using a track -mounted drill rig. A geologist from our firm continuously observed the borings, logged the subsurface conditions encountered, and obtained representative soil samples. All samples were stored in moisture -tight containers and transported to our laboratory for further visual classification. After each boring was completed, the borehole was backfilled with bentonite. Throughout the drilling operation, soil samples were obtained at 2.5- to 5 -foot depth intervals by means of the Standard Penetration Test (ASTM: D-1586). This testing and sampling procedure consists of driving a standard 2 -inch outside diameter steel split spoon sampler 18 inches into the soil with a 140 -pound hammer free falling 30 inches. The number of blows required to drive the sampler through each 6 -inch interval is recorded, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or "blow count" (N value). If a total of 50 blows is struck within any 6 -inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular sails and the relative consistency of cohesive soils. The enclosed boring logs describe the vertical sequence of soils and materials encountered in each boring, based primarily upon our field classifications. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring. If groundwater was encountered in a borehole, the approximate groundwater depths, and date of observation, are depicted on the log. GENERAL NOTE DRILLING & SAMPLING SYMBOLS: SS: Split Spoon -1-3/8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin -Walled Tube - 2" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger DB: Diamond Bit Coring - 4P, N, B RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2 -inch O.D. split -spoon sampler (SS) the last 12 inches of the total 18 -inch penetration with a 140 -pound hammer failing 30 inches is considered the "Standard Penetration" or "N -value". WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling N/E: Not Encountered WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the Indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System, Coarse Grained Soils have more than.50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non -plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their In-place relative density and fine-grained soils on the basis of their consistency. CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS Standard Penetration or N -value (SS) Blows/Ft. 0-3 4-9 10-29 30-49 > 50 Relative Densitv Very Loose Loose Medium Dense Dense Very Dense RELATIVE PROPORTIONS OF SAND AND GRAVEL Standard Descriptive Term(s) of other Unconfined Penetration or constituents Compressive N -value (SS) Trace Strength, Qu, psf Blows/Ft. Consistency < 500 0-1 Very Soft 500 — 1,000 2-4 Soft 1,000 — 2,000 4-8 Medium Stiff 2,000 — 4,000 B-15 Stiff 4,000 — 8,000 15-30 Very Stiff 8,000+ > 30 Hard RELATIVE DENSITY OF COARSE-GRAINED SOILS Standard Penetration or N -value (SS) Blows/Ft. 0-3 4-9 10-29 30-49 > 50 Relative Densitv Very Loose Loose Medium Dense Dense Very Dense RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Term(s) of other Percent of Maior Component , constituents DryWeight of Sample Particle Size Trace <15 Boulders Over 12 in. (300mm) With 15-29 Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) . Sand #4 to #200 sieve (4.75mm to 0.075mm) RELATIVE PROPORTIONS OF FINES Silt or Clay Passing #200 Sieve (0.075mm) Descriptive Term(s) of other Percent of PLASTICITY DESCRIPTION constituents Dry Weight Term Plasticity Index Trace < 5 Non -plastic 0 With 5-12 Low • 1-10 Modifiers >12 Medium 11-30 High > 30 ABased on the material passing the 3 -in. (75 -mm) sieve alf field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. °Gravels with 5 to 12% fines require dual symbols: GW -GM well -graded �igravel with silt, GW -GC well -graded gravel with clay, GP -GM poorly graded gravel with silt, GP -GC poorly graded gravel with clay. °Sands with 5 to 12% fines require dual symbols: SW -SM well -graded sand with silt, SW -SC well -graded sand with clay, SP -SM poorly graded sand with silt, SP -SC poorly graded sand with clay ECu = Doo/Dto Cc = D3o)2 Dto x Doo F If soil contains >_ 15% sand, add "with sand" to group name. 91f fines classify as CL -ML, use dual symbol GC -GM, or SC -SM. 60 50 n. W 40 O z }^ 30 U 1-- 20 a. 10 7 4 0 0 Hit fines are organic, add "with organic fines" to group name. 1 If soil contains z 15% gravel, add "with gravel" to group name. J if Atterberg limits plot in shaded area, soil is a CL -ML, silty clay. Klf soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel," whichever is predominant, L If soil contains z 30% plus No. 200 predominantly sand, add "sandy" to group name. M if soil contains >_ 30% plus No, 200, predominantly gravel, add "gravelly" to group name, NPI >- 4 and plots on or above "A" line. o PI <4 or plots below "A" line. PPI plots on or above "A" line. Q PI plots below "A" line. For classification of fine-grained ' � soils and fine-grained fraction UNIFIED SOIL CLASSIFICATION SYSTEM �� j� �, Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests" of coarse-grained soils Soil Classification Group J ,' �P Symbol Group Name" Coarse Grained Soils Gravels Clean Gravels Cu Z 4 and 1 5 C,,g 3E GW Well -graded gravel' More than 50% retained More than 50% of coarse Less than 5% fines' Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravel' O�° 1Z fraction retained on then PI=0.9 (LL -8) on No. 200 sieve No; 4 sieve Gravels with Fines Fines classify as ML or MH GM Silty gravel'-'-" More than 12% fines° Fines classify as CL or CH GC Clayey gravel',"-" Sands Clean Sands Cu z 6 and 1 5 Cc 5 3E SW Well -graded sand' 50% or more of coarse Less than 5% fines' Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sand' fraction passes • MH or OH No. 4 sieve Sands with Fines Fines classify as ML or MH SM Silty sand"Na More than 12% fines° Fines Classify as CL or CH SC Clayey sand"",' Fine -Grained Soils Slits and Clays inorganic PI > 7 and plots on or above "A" line' CL -Lean clayK`,"" 50% or more passes the Liquid limit less than 50 PI <4 or plots below "A" line' ML Silty,-" No. 200 sieve organic Liquid limit - oven dried Organic clay"""" < 0,75 Liquid limit - not dried OL Organic siitK"�° Silts and Clays inorganic PI plots on or above "A" line CH Fat clay""" Liquid limit 50 or more PI plots below "A" line MH Elastic Silty"I" organic Liquid limit - oven dried < 0.75 OH Organic clayy'-µP Liquid limit - not dried Organic siltK"�° Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat ABased on the material passing the 3 -in. (75 -mm) sieve alf field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. °Gravels with 5 to 12% fines require dual symbols: GW -GM well -graded �igravel with silt, GW -GC well -graded gravel with clay, GP -GM poorly graded gravel with silt, GP -GC poorly graded gravel with clay. °Sands with 5 to 12% fines require dual symbols: SW -SM well -graded sand with silt, SW -SC well -graded sand with clay, SP -SM poorly graded sand with silt, SP -SC poorly graded sand with clay ECu = Doo/Dto Cc = D3o)2 Dto x Doo F If soil contains >_ 15% sand, add "with sand" to group name. 91f fines classify as CL -ML, use dual symbol GC -GM, or SC -SM. 60 50 n. W 40 O z }^ 30 U 1-- 20 a. 10 7 4 0 0 Hit fines are organic, add "with organic fines" to group name. 1 If soil contains z 15% gravel, add "with gravel" to group name. J if Atterberg limits plot in shaded area, soil is a CL -ML, silty clay. Klf soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel," whichever is predominant, L If soil contains z 30% plus No. 200 predominantly sand, add "sandy" to group name. M if soil contains >_ 30% plus No, 200, predominantly gravel, add "gravelly" to group name, NPI >- 4 and plots on or above "A" line. o PI <4 or plots below "A" line. PPI plots on or above "A" line. Q PI plots below "A" line. For classification of fine-grained ' soils and fine-grained fraction of coarse-grained soils Equation of "A" - line J ,' �P Horizontal at PI=4 to LL=25.6. ' then Pi=0.73 (LL -20) Q ' t Equation of "U" - line �.' Vertical at LL=16 to PI=7, �' O�° 1Z then PI=0.9 (LL -8) • MH or OH ' Mt. or OL Form 111--6/98 10 16 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT (LL) l� LOG OF BORING NO. -1 Page I of I CLIENT City of Edmonds SITE PROJECT Edmonds, WA Talbot Road/Perrinville Creek Drainage Improvement SAMPLES TESTS U ° DESCRIPTION O c o t� z W n a o U � W > Ztn o'W Uzi Z � Z u� o D m z W m ¢Z >- Ua Q. n m� Approx. Surface Elev.: 22 ft U) U o c~n 2" Grass Sod Over SP S1 SS 6 7 23 SAND, with silt, brown, loose, moist SM (Probable Fill) 2.519.5 ___ __19.5 Siity SANtrace gravel and fine SM S2 SS 9 5 29 organics, dark brown, loose, wet (Possible 14,5 Fill) — — — — — — — — — — — — — — 17.5 SAND, with gravel and silt, gray, loose to 5 S3 SS 5 39 22 dense, wet to saturated SW SM SW Sieve S4 SS 18 9 19 SM Analysis 10 SW S5 SS 18 11 SM ., SW S6 SS 18 10 n SM H z U ;� 15 S7 SS 14 25 W SW SM a r' 16.5 5,5 o J BOTTOM OF BORING N O Q O 1- O m The stratification lines represent the approbmate boundary lines *fathead 140H SPT hammer between soil and rock types: In-situ, the transition may be gradual. **SPT-N Blows might be overstated due to presence of gravel and cobbles WATER LEVEL OBSERVATIONS, ft V 3,5 WD -Y -7 I rerracon BORING STARTED 7-2-09 W WL BORING COMPLETED 7-2-09 o WL RIG HSA DRILLER Boretec o WL m LOGGED JPG JOB # 81095047 rrnjll LOG OF BORING NO. B-2 Page t of 2 CLIENT City of Edmonds SITE PROJECT Edmonds, WA 'Talbot Road/Perrinville Creek Drainage improvement SAMPLES TESTS 0 DESCRIPTION JC o V5 W n z !Y _ _ } W w > zcn z o!Wuj W Zz 0. (D o Z) z U) 1— Q a o g Approx. Surface Elev.: 31 ft cc) 2" Grass Sod Over SAND, with gravel and silt, gray-brown, medium dense, moist SP S1 SS 10 24 4 SM 5 SP S2 SS 4 13 SM Sieve SP S3 SS 8 19 5 SM Analysis 10 SP S4 SS 8 16 SM m'. SP S5 SS 12 20 5 SM o v 15 SP S6 SS 10 29 w SM o � a _ SP S7 SS 8 20 14 F; 3 ; SM o' 0 •., 20 — —---------- ----- ____ _____ 11 20 o Continued Next Page m F The stratification lines represent the appropmate boundary lines *fathead 140H SPT hammer 6 between a soil and rock types: in-situ, the transition may be gradual. **SPT-N Blows might be overstated due to presence of gravel and cobbles WATER LEVEL. OBSERVATIONS, ft V- 17 WD T BORING STARTED 7-2-09 WL BORING COMPLETED 7-2-09 W T Irerracon, RIG HSA DRILLER Boretec WL o ME WL LOGGED JPG JOB # 81095047 ( jfi I � lljj}1f p�j L111 LI U t LOG OF BORING NO.. -2 Page 2 of 2 CLIENT City of Edmonds SITE PROJECT Edmonds, WA Talbot Road/Perrinville Creek Drainage Improvement SAMPLES TESTS DESCRIPTION °�° c F— w a U 3' _ Z LL aQ,�UO ¢ 0 Ur Q D Z �m Q o. jN �H Gravelly SAND, with silt, gray -brown, SW S8 SS 12 18 12 Sieve medium dense to dense, wet to saturated SM Analysis SW 99 SS 5 31 SM 25 SW S10 SS 6 14 SM 26.5 4.5 BOTTOM OF BORING m 0 t; H Z 2O K F�- 'a O ai U' • WO t - Q 3 ' 0 0 0 rThe stratification lines represent the appro)dmate boundary lines *fathead 140H SPT hammer o between soil and rock types: in-situ, the transition may be gradual. **SPT -N Blows might be overstated due to presence of gravel and cobbles WATER LEVEL OBSERVATIONS, ft V 17 WD -T BORING STARTED 7-2-09 WL BORING COMPLETED 7-2-09 T Irerracon RIG HSA DRILLER Boretee o WL o WL m LOGGED JPG JOB## 81095047 ", N Uii1j, Y -14 LOG OF BORING NO. -3 Page 9 of 1 CLIENT City of Edmonds SITE PROJECT Edmonds, WA Talbot Road/Perrinville Creek Drainage Improvement SAMPLES TESTS CD U DESCRIPTION 0 � c t= z w o a � ~ T s ° w > z° o'w a zz o CL CL b U m 0 w° a ° t -O wF r z Q° W16 OW °o: Z °u�u11 (9 Approx. Surface Elev.: 16 ft o co n z � m ° o ii r~n - 3" Crushed Rock Over SAND, with silt, trace gravel, gray -brown, medium dense, moist to wet (Fill) (Blow count overstated, on possible root) SW S1 SS 3 35 7 3.5.—.---------------------- 12.5 SM SAND, with gravel and silt, gray, medium dense to dense, wet to saturated 5 SW S2 SS 12 16 20 SM SW S3 SS 12 18 16 SM 10 SW S4 SS 18 15 SM N .• SW S5 SS 18 32 SM 0 0 z o •; SW S6 SS 14 17 ;:15 ,• SM a � •• vi 16.5 -0.5 o BOTTOM OF BORING a 0 N 6 O K F- O ro r The stratification lines represent the appropmate boundary lines 'fathead 140H SPT hammer o between sal and rock types: in-situ, the transition may be gradual. "SPT=N Blows might be overstated due to presence of gravel and cobbles WATER LEVEL OBSERVATIONS, ft Q 4 WD I 3z Irerracon BORING STARTED 7-2-09 m WL BORING COMPLETED 7-2-09 o WL 7 RIG HSA DRILLER Boretec o WL m LOGGED JPG JOB # 81095047 [D) OF BORING NO. -4. Page I of 1 FLOG CLIENT City of Edmonds SITE PROJECT Talbot Road/Perrinville Creek Drainage Improvement Edmonds, WA SAMPLES TESTS O o CL uj o o DESCRIPTION k02 z u' zF a co m w o z� Wf_ o� o'jj 16 0W z Approx. Surface Elev.: 17 ft n Z W U) m n:3 g~ Silty SAND, trace gravel, brown, loose, moist (Probable Fill) SM S1 SS 14 7 23 5-- — — ------s-- 92 _ SAND, with gravel and silt, gray-brown, 5 Sieve Analysis SW S2 SS 10 21 14 medium dense, wet to saturated SM Grades to gray. SW S3 SS 18 17 23 SM 10—SW S4 SS 18 13 SM SW S5 SS 18 16 SM F 0 .o U •: :: 15 SW S6 SS 18 15 SM • 0.5 N :• 16.5 o BOTTOM OF BORING J K Q N O Q O ff H O m The stratification lines represent the approAmate boundary lines **SPT-N Blows might be overstated due to *fathead presence 140H of gravel SPT hammer and cobbles a between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft BORING STARTED 7-2-09 BORING COMPLETED _ 7-2-09 m WL SZ 5 WD HSA DRILLER Boretec o WL 17 - IrerracRIG LOGGED JPG JOB # 81095047 LU WL m ou ['� M V y APPENDIX B A series of laboratory tests were performed during the course of this study to evaluate the index and geotechnical engineering properties of the subsurface soils. Descriptions of the types of tests performed are given below. Visual Classification Samples recovered from the exploration locations were visually classified in the field during the exploration program. Representative portions of the samples were carefully packaged in moisture tight containers and transported to our laboratory where the field classifications were verified or modified as required. Visual classification of soil was generally done in accordance with the Unified Soil Classification system. Visual soil classification includes evaluation of color, relative moisture content, soil type based upon grain size, and accessory soil types included in the sample. Soil classifications are presented on the exploration logs in Appendix A. Moisture Content Determination Moisture content determinations were performed on representative samples obtained from the exploration in order to aid in identification and correlation of soil types. The determinations were made in general accordance with the test procedures described in ASTM: D-2216. The results are shown on the exploration logs in Appendix A. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses were performed on representative samples in general accordance with ASTM: D-422. The results of the grain size determinations were used in classification of the soils, and are presented in this appendix. 100 - No 80- i- 70 - m_ W 60- z M- Z 50 U. - W 40- (. 0611 20- 10 - GRAIN SIZE ANALYSIS Test Results Summary ALM D 422 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Sample Coarse NINE Coarse Medium oil Slit Clay BOULDERS COBBLES GRAVEL 111111 11 milillill 111 111 11011 --11 111111 1 1 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Exploration Sample Coarse Fine Coarse Medium Fine Slit Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-1 S-4 7.5 19 9.4 SAND with gravel and Silt JOB NO: 81095047 PROJECT NAME: Irerracon DATE OF TESTING: 7/10/2009 Talbot Road Stormwater Geotechnical and Environmental Consulting Improvements 100• 90- X 80 U W 70 W 60- z u. Z 50 LU V W40 - CL 30- 20- 10- 0- SIZE 020100 GIN SIZE ANALYSIS Test Results Summary AS M D 422 SIZE OF OPENING IN INCHES 36" 12" 6" 3" 1112" 314" 3/6" U.S. STANUAKU SItVt SIGt 4 _ 10 20 40 60 140 200 n r Limuiwc i cr< ' Fine Coarse Medium Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED I 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Exploration Sample Coarse Fine Coarse Medium Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Exploration Sample Depth (feet) Moisture (%) Fines {%) Description B-2 S-3 7.5 5 5.0 SAND with gravel and silt JOB NO: 81095047 PROJECT NAME: Irerralcon DATE OF TESTING: 7/10/2009 Talbot Road Stormwater Geotechnical and Environmental Consulting Improvements 10C 9C F- = 8C U W 7C i- W 6C •Z 5C W U W 4C 0. 3C 2( 1( C 1000.000 GRAIN SIZE ANALYSIS Test Results Summary `� F i ASTM D 422 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Comments: Exploration Sample Coarse FineCoarse Fines (%) Medium Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) 'Description B-2 S-8 20.0 12 5.8 gravelly SAND with silt JOB NO: 81095047 PROJECT NAME: Irerracon DATE OF TESTING: 7/10/2009 Talbot Road Stormwater Geotechnical and Environmental Consulting Improvements 10( 91 8( (`J LLt 7( m W 6( Z u. Z 5( W C� LU 4( 0. 3( 2( 1( 1000.000 D) ��_ � � GRAIN SIZE ANALYSIS ITest Results Summary ' ' � (j ASTM D 422 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Exploration Sample Coarse Fine Coarse Medium Fine Slit Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-4 S-2 5.01 14 9.1 SAND with gravel and silt JOB NO: 81095047 PROJECT NAME: Herracon DATE OF TESTING: 7/10/2009 Talbot Road Stormwater Geotechnical and Environmental Consulting Improvements