The URL can be used to link to this page

Home My WebLink AboutAVONDALE COTTAGES - FDP - FDP140018 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTSUBSURFACE EXPLORATION REPORT AVONDALE COTTAGES INFRASTRUCTURE RIDGEWOOD HILLS FIRST FILING – TRACT L FORT COLLINS, COLORADO EEC PROJECT NO. 1142014 Prepared for: Avondale Limited, LLC c/o LDE Consulting Group P.O. Box 271519 Fort Collins, Colorado 80527 Attn: Mr. Rod Arndt (rod.arndt@ldeconsulting.com) Prepared by: Earth Engineering Consultants, LLC 4396 Greenfield Drive Windsor, Colorado 80550 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 EARTH ENGINEERING CONSULTANTS, LLC April 2, 2014 Avondale Limited, LLC c/o LDE Consulting Group P.O. Box 271519 Fort Collins, Colorado 80527 Attn: Mr. Rod Arndt (rod.arndt@ldeconsulting.com) Re: Subsurface Exploration Report Avondale Cottages Infrastructure Ridgewood Hills First Filing – Tract L Fort Collins, Colorado EEC Project No. 1142014 Mr. Arndt: Earth Engineering Consultants, LLC (EEC) personnel have completed the geotechnical subsurface exploration you requested for the referenced project. Three (3) soil borings extending to depths of approximately 15 to 20 feet below present site grades were advanced in the proposed development area to obtain information on existing subsurface conditions. Auger borings were subsequently advanced at several locations on the site to help establish the approximate depth to the bedrock surface across the site. Additionally, six (6) shallow soil borings were advanced to depths of approximately 3 feet to allow field percolation testing of the in-situ soils. Individual boring logs and a site diagram indicating the approximate boring locations are included with this report. This exploration was completed in general accordance with our proposal dated February 7, 2014. Based on results of the field borings, the subsurface conditions at this site consist of a relatively thin mantle of moderately plastic cohesive soils overlying predominately sandstone bedrock. The dry, dense near surface cohesive soils exhibited high swell potential in laboratory testing. The higher swells of the subgrade soils would require mitigation for development of site infrastructure and will need to be addressed for the individual building construction. In the areas of the site where low swell potential sandstone is at essentially ground surface, mitigation for swell would likely not be needed. However, some difficulty may be encountered excavating the site bedrock. SUBSURFACE EXPLORATION REPORT AVONDALE COTTAGES INFRASTRUCTURE RIDGEWOOD HILLS FIRST FILING – TRACT L FORT COLLINS, COLORADO EEC PROJECT NO. 1142014 April 2, 2014 INTRODUCTION The geotechnical subsurface exploration for the proposed infrastructure development of Ridgewood Hills First Filing - Tract L, also known as Avondale Cottages, in Fort Collins, Colorado, has been completed. Three (3) test borings extending to depths of approximately 15 to 20 feet below current site grades were completed within the development area to obtain information on the existing subsurface conditions at the site. Eight (8) shallow auger borings were also completed to help establish the approximate depth to bedrock at other selected locations on the development site. Six (6) shallow soil borings were advanced near boring B-2 to depths of approximately 3 feet for percolation testing. Individual boring logs and a diagram indicating the approximate boring locations are included with this report. We understand this project involves the development of an approximate 1.5 acre property located immediately southeast of the intersection of Trilby Road and Avondale Road in Fort Collins. The approximate development parcel is outlined on the attached boring location diagram. The parcel will be developed as10 single-family residential cottages with separate garages and parking areas. We expect the site structures will have light foundation and floor loads. We expect small cuts and fills will be completed to develop site grades. Site pavements will be private access drives. The purpose of this report is to describe the subsurface conditions encountered in the borings, analyze and evaluate the test data and provide geotechnical evaluation of the property for proposed infrastructure development. General considerations for the proposed building construction are also provided within this report. Additional geotechnical explorations will be required to develop specific recommendations for the building(s) development. EXPLORATION AND TESTING PROCEDURES The test boring locations were established in the field by Earth Engineering Consultants, LLC (EEC) personnel by pacing and estimating angles from identifiable site features. The approximate boring locations are indicated on the attached boring location diagram. The locations of the test borings Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 2 should be considered accurate only to the degree implied by the methods used to make the field measurements. The field borings were completed using a CME-55 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch nominal diameter continuous flight augers and samples of the subsurface materials encountered were obtained using split barrel and California barrel sampling procedures in general accordance with ASTM Specifications D1586 and D3550, respectively. In the split barrel and California barrel sampling procedures, standard sampling spoons are driven into the ground by means of a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the split barrel and California barrel samplers is recorded and is used to estimate the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. In the California barrel sampling procedure, relatively undisturbed samples are obtained in removable brass liners. All samples obtained in the field were sealed and returned to our laboratory for further examination, classification, and testing. The permeability of the near surface site soils was evaluated within six (6) shallow soil percolation borings drilled to approximate depths of 3 feet below site grades. Soil percolation tests were conducted in general accordance with Larimer County requirements. Results of those tests are provided on the attached summary sheet. Laboratory moisture content and visual classifications were completed on each of the recovered samples. Appropriate samples were tested for unconfined strength using a calibrated hand penetrometer. Dry density tests were completed on selected samples. Washed sieve analysis and Atterberg limits tests were completed to evaluate the quantity and plasticity of the fines in the subgrade materials. Swell/consolidation tests were performed on selected samples to evaluate the tendency of the subgrade materials to change volume with variation in moisture content at current moisture and density conditions. Results of the outlined tests are indicated on the attached boring logs and summary sheets. As part of the testing program, all samples were examined in the laboratory and classified in accordance with the attached General Notes and the Unified Soil Classification System, based on the Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 3 soils’ texture and plasticity. The estimated group symbol for the Unified Soil Classification System is indicated on the boring logs and a brief description of that classification system is included with this report. Classification of the bedrock was based on visual and tactual evaluation of disturbed samples and auger cuttings. Coring and/or petrographic analysis may reveal other rock types. SITE AND SUBSURFACE CONDITIONS The proposed development parcel is located immediately southeast of the intersection of Trilby Road and Avondale Road in Fort Collins, Colorado. The development parcel encompasses approximately 1.5 acres which is presently covered by a small parking area, trees, and landscaped vegetation. Evidence of prior building construction was not observed on the development site at the time of our field exploration. The development parcel has relatively flat surface with approximately 5 feet of elevation difference over the site. Based on results of field borings and laboratory testing, subsurface conditions can be generalized as follows. Vegetation and topsoil were encountered at the ground surface of the boring locations. The topsoil/vegetation was generally underlain by brown sandy lean clay. The overburden cohesive soils were relatively dry and hard at the time of our exploration, exhibited high swell potential at current moisture and density conditions. The overburden soils were underlain by highly weathered to weathered bedrock consisting of predominately sandstone with some interbedded siltstone. The bedrock was generally poorly- cemented/moderately hard becoming more well-cemented and harder with depth. Cemented lenses were observed at shallower depths in boring B-1. Depth to bedrock as observed in the test borings and subsequent auger borings ranged from approximately 2 to 6½ feet below ground surface. The approximate depth to the soil/bedrock waterline is denoted on the attached boring location diagram. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil and bedrock types; in-situ, the transition of materials may be gradual and indistinct. Percolation testing performed at the site showed that the subsoils and relatively shallow bedrock do not allow water to percolate into the subgrades. Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 4 GROUNDWATER OBSERVATIONS Observations were made while drilling and after completion of the borings to detect the presence and depth to hydrostatic groundwater. Free water was not observed in any of the test borings at the time of our exploration. Zones of perched and/or trapped water may be encountered in the subgrade soils and the underlying bedrock at times throughout the year. Perched water is commonly encountered in more permeable soils overlying lower permeability bedrock. The location and amount of perched/trapped water may vary over time depending on variations in hydrologic conditions, and other conditions not apparent the time of this report. The water level observations outlined represent the observed water levels at the boring locations at the time of the field exploration. Water levels can vary at locations away from the test borings and at varying times. ANALYSIS AND RECOMMENDATIONS Swell/Consolidation Test Results Swell/consolidation testing is performed to evaluate the swell or collapse potential of soil or bedrock to assist in determining/evaluating foundation, floor slab and/or pavement design criteria. In the swell/consolidation test, relatively undisturbed samples obtained directly from the California barrel sampler are placed in a laboratory apparatus and inundated with water under a pre-established load. The swell-index is the resulting amount of swell or collapse under the initial loading condition expressed as a percent of the sample’s initial thickness. After the inundation period, additional incremental loads are applied to evaluate swell pressure and/or consolidation. As a part of our laboratory testing, we conducted three (3) swell/consolidation tests on samples of the subgrade materials. The swell index value for the one (1) cohesive soil sample analyzed revealed high swell characteristics when inundated with water and pre-loaded at 150 psf. The two (2) swell/consolidation tests performed on the sandstone bedrock exhibited low swell characteristics when inundated with water and pre-loaded at 500 psf. Results of the laboratory swell tests are indicated the table below, on the attached boring logs, and on the enclosed summary sheets. Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 5 Swell Consolidation Test Results Boring No. Depth, ft. Material Type In-Situ Moisture Content, % Dry Density, pcf Inundation Pressure, psf Swell Index, (+/-) % B-1 9 Sandstone with Interbedded Siltstone 5.1 110.0 500 (-) 0.7 B-2 2 Sandy Lean Clay 12.2 119.6 150 (+) 11.7 B-2 9 Sandstone with Interbedded Siltstone 9.2 110.7 500 (-) 0.9 The Colorado Association of Geotechnical Engineers (CAGE) uses the following information to provide uniformity in terminology between geotechnical engineers to provide a relative correlation risk performance to measured swell. “The representative percent swell values are not necessarily measured values; rather, they are a judgment of the swell of the soil and/or bedrock profile likely to influence slab performance.” Geotechnical engineers use this information to also evaluate the swell potential risks for foundation performance based on the risk categories. Recommended Representative Swell Potential Descriptions and Corresponding Slab Performance Risk Categories Slab Performance Risk Category Representative Percent Swell (500 psf Surcharge) Representative Percent Swell (1000 psf Surcharge) Low 0 to < 3 0 < 2 Moderate 3 to < 5 2 to < 4 High 5 to < 8 4 to < 6 Very High > 8 > 6 Based on the laboratory test results, the samples of overburden subsoils and the underlying bedrock formation analyzed were within the high to low risk range, respectively. General Site Preparation – Infrastructure Areas All existing vegetation and/or topsoil should be removed from beneath site roadways and/or site fill areas. In addition, the dry, hard near surface cohesive soils should be removed from the pavement areas to a depth of at least 2 feet from the top of subgrade elevation. After stripping and completing all cuts and prior to placement of any fill, to develop site grades the exposed surfaces should be scarified to a minimum depth of 9 inches, adjusted in moisture content Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 6 and compacted to at least 95% of the material's maximum dry density as determined in accordance with ASTM Specification D698, the standard Proctor procedure. The moisture content of the scarified materials should be adjusted to be within a range of 2% of standard Proctor optimum moisture at the time of compaction. In general, fill materials required to develop the site subgrades should consist of approved, low- volume change materials which are free from organic matter and debris. The on-site, near surface sandy lean clay soils could be used within the pavement areas with careful moisture/density control. The cohesive soils would need to be maintained at the increased moisture levels until the overlying pavements are placed to maintain low swell potential. Cohesive fill soils allowed to dry would reestablish higher swell potential. Excavated sandstone bedrock could generally be used as site fill, but may require additional processing to create a consistent fill material. Processing well cemented zones observed at some locations might require measures beyond reworking with site grading equipment. Fill soils to support site pavement/flatwork improvements should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted to at least 95% of the material’s maximum dry density as determined in accordance with the standard Proctor procedure. The moisture content of predominately cohesive fill materials should be adjusted to be within the range of ± 2% of optimum moisture content at the time of placement. Imported ganular fill material, if used, could typically be adjusted to a workable moisture content. Care should be taken after preparation of the subgrades to avoid disturbing the subgrade materials. Positive drainage should be developed away from structures and across and away from pavement edges to avoid wetting of subgrade materials. Subgrade materials allowed to become wetted subsequent to construction of the site improvements can result in unacceptable performance of those improvements. Building Foundation Systems - Preliminary We understand the site buildings will likely be constructed with crawl spaces with footing foundations extending to bear on the underlying sandstone bedrock. The site appears amenable for that type of building construction based on the results of our field exploration. The relatively thin zone of near-surface cohesive soils, which were generally dry and dense at the time of our exploration, will Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 7 require particular attention in the design and construction of the driveway and garage floor systems to reduce the amount of movement should the subsoils become subjected to elevated moisture contents. The swell potential of the subgrade soils will need to be addressed during the design and construction of any improvements supported directly on or above the expansive materials. Groundwater was not encountered during the exploration, but percolation testing showed the site soils to be relatively impermeable and a perched water table could develop seasonally with increased water used for landscaping. Pavement Subgrades/Pavements As indicated under site development section of this report, overexcavation and backfill procedures should be implemented to remove a portion the dry, hard cohesive soils to reduce the potential for post-construction heaving of the exterior flatwork and pavements. Where the subgrades would extend to the sandstone bedrock or where the sandstone was used to develop the subgrades, overexcavation procedures would not be needed. The pavement subgrades should be prepared as suggested under the “Site Preparation” section of this report. After completion of the pavement subgrades, care should be taken to prevent disturbance of those materials prior to placement of the overlying pavements. Soils which are disturbed by construction activities should be reworked in-place or, if necessary, removed and replaced prior to placement of overlying fill or pavements. In areas of overexcavation and backfill with moisture-conditioned lean clay, subgrade stabilization with Class C fly ash may be needed. Depending on placement procedures, use of Portland cement concrete (PCC) pavements may represent reduced potential for the need to stabilize the subgrades. We estimate 12% Class C fly ash would be required to stabilize the top 12 inches of the pavement subgrades. We expect overexcavation depths in the range of 2 feet would be required to help reduce the swell potential of the subgrades immediately beneath the pavements. Even with those mitigation procedures, some movement of the pavements would be expected. In areas above flexible pavements will be supported on a stabilized subgrade, we recommend the overlying pavement section include 4 inches of hot bituminous pavement (HBP) over 4 inches of aggregate base course (ABC). In areas of PCC pavements, those pavements could consist of at least Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 8 5 inches of non-reinforced PCC. The HBP, ABC and PCC should be consistent with the requirements outlined in the Larimer County Urban Area Street Standards. Depending on final site grading and/or weather conditions at the time of pavement construction, stabilization of a portion of the site pavement subgrades may be required to develop a paving platform. The site clayey soils could be subject to instability, at higher moisture contents. Stabilization could also be considered as part of the pavement design, although prior to finalizing those sections, a stabilization mix design would be required. Based on the results of the percolation testing, the site is not appropriate for a permeable pavement. Other Considerations and Recommendations Although evidence of fills or underground facilities such as septic tanks, cesspools, basements, and utilities was not observed during the site reconnaissance, such features could be encountered during construction. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. Near surface sandstone bedrock was observed over most of the site. The site bedrock showed varying degrees of cementation with occasional well cemented zones observed. Excavating the sandstone may require alternative methods and/or equipment although we do not expect blasting would be necessary (although may be considered). Use of the sandstone bedrock for site fill material should be possible although some processing of more well cemented zones may be needed. GENERAL COMMENTS The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations, which may occur between borings or across the site. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical Earth Engineering Consultants, LLC EEC Project No. 1142014 April 2, 2014 Page 9 engineer be retained for testing and observations during earthwork and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of LDE Consulting Group for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. In the event that any changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by the geotechnical engineer. Earth Engineering Consultants, LLC DRILLING AND EXPLORATION DRILLING & SAMPLING SYMBOLS: SS: Split Spoon ‐ 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample ST: Thin‐Walled Tube ‐ 2" O.D., unless otherwise noted WS: Wash Sample R: Ring Barrel Sampler ‐ 2.42" I.D., 3" O.D. unless otherwise noted PA: Power Auger FT: Fish Tail Bit HA: Hand Auger RB: Rock Bit DB: Diamond Bit = 4", N, B BS: Bulk Sample AS: Auger Sample PM: Pressure Meter HS: Hollow Stem Auger WB: Wash Bore Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2‐inch O.D. split spoon, except where noted. WATER LEVEL MEASUREMENT SYMBOLS: WL : Water Level WS : While Sampling WCI: Wet Cave in WD : While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB : After Boring ACR: After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D‐2488. Coarse Grained Soils have move than 50% of their dry weight retained on a #200 sieve; they are described as: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are 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 relative in‐ place density and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium dense (SM). CONSISTENCY OF FINE‐GRAINED SOILS Unconfined Compressive Strength, Qu, psf Consistency < 500 Very Soft 500 ‐ 1,000 Soft 1,001 ‐ 2,000 Medium 2,001 ‐ 4,000 Stiff 4,001 ‐ 8,000 Very Stiff 8,001 ‐ 16,000 Very Hard RELATIVE DENSITY OF COARSE‐GRAINED SOILS: N‐Blows/ft Relative Density 0‐3 Very Loose 4‐9 Loose 10‐29 Medium Dense 30‐49 Dense 50‐80 Very Dense 80 + Extremely Dense PHYSICAL PROPERTIES OF BEDROCK DEGREE OF WEATHERING: Slight Slight decomposition of parent material on joints. May be color change. Moderate Some decomposition and color change throughout. High Rock highly decomposed, may be extremely broken. Group Symbol Group Name Cu≥4 and <Cc≤3 E GW Well‐graded gravel F Cu<4 and/or 1>Cc>3 E GP Poorly‐graded gravel F Fines classify as ML or MH GM Silty gravel, G,H Fines Classify as CL or CH GC Clayey Gravel F,G,H Cu≥6 and 1<Cc≤3 E SW Well‐graded sand 1 Cu<6 and/or 1>Cc>3 E SP Poorly‐graded sand 1 Fines classify as ML or MH SM Silty sand G,H,I Fines classify as CL or CH SC Clayey sand G,H,I inorganic PI>7 and plots on or above "A" Line CL Lean clay K,L,M PI<4 or plots below "A" Line ML Silt K,L,M organic Liquid Limit ‐ oven dried Organic clay K,L,M,N Liquid Limit ‐ not dried Organic silt K,L,M,O inorganic PI plots on or above "A" Line CH Fat clay K,L,M PI plots below "A" Line MH Elastic Silt K,L,M organic Liquid Limit ‐ oven dried Organic clay K,L,M,P Liquid Limit ‐ not dried Organic silt K,L,M,O Highly organic soils PT Peat (D30) D x D GW‐GM well graded gravel with silt NPI≥4 and plots on or above "A" line. GW‐GC well‐graded gravel with clay OPI≤4 or plots below "A" line. GP‐GM poorly‐graded gravel with silt PPI plots on or above "A" line. GP‐GC poorly‐graded gravel with clay QPI plots below "A" line. 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 Earth Engineering Consultants, LLC IIf soil contains >15% gravel, add "with gravel" to group name JIf Atterberg limits plots shaded area, soil is a CL‐ ML, Silty clay Gravels with Fines more than 12% fines Clean Sands Less than 5% fines Sands with Fines RIDGEWOOD HILLS FIRST FILING - TRACT L FORT COLLINS, COLORADO EEC PROJECT NO. 1142014 FEBRUARY 2014 DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF TOPSOIL & VEGETATION _ _ SANDY LEAN CLAY (CL) 1 brown _ _ 2 _ _ SANDSTONE CS 3 50/3" -- 9.8 99.0 brown / rust _ _ some interbedded siltstone 4 _ _ SS 5 50/2" 2000 11.2 _ _ cemented lenses - 4.5 to 8.5' 6 _ _ 7 _ _ 8 _ _ 9 _ _ brown / grey / rust CS 10 50/3" 9000+ 5.1 107.0 23 10 57.2 <500 psf None _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 50/1" 9000+ 13.4 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ CS 20 50/3" 9000 11.2 109.8 BOTTOM OF BORING 20.0' _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC RIDGEWOOD HILLS FIRST FILING - TRACT L DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 SANDY LEAN CLAY (CL) _ _ dark brown 2 hard to very stiff _ _ %@ 150 psf CS 3 41 9000+ 12.2 118.5 42 26 65.3 8000 psf 11.7% _ _ 4 _ _ SS 5 22 9000+ 12.2 _ _ 6 _ _ 7 SANDSTONE _ _ brown / rust / grey 8 some interbedded siltstone _ _ 9 _ _ CS 10 50/4" 9000+ 9.2 101.6 20.0 <500 psf None _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 50/2" 9000 11.8 _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC RIDGEWOOD HILLS FIRST FILING - TRACT L DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 SANDY LEAN CLAY (CL) _ _ dark brown 2 _ _ SS 3 34 9000+ 12.5 130.8 _ _ SANDSTONE 4 brown / grey / rust _ _ some interbedded siltstone CS 5 50/5" 9000 5.6 _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 50/3" 5000 10.1 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ CS 15 50/1" 9000+ 9.5 13.4 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 50/3" 9000+ 14.9 _ _ BOTTOM OF BORING DEPTH 20.5' 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC RIDGEWOOD HILLS FIRST FILING - TRACT L Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Grey / Rust Sandstone with Interbedded Siltstone Sample Location: Boring 1, Sample 3, Depth 9' Liquid Limit: 23 Plasticity Index: 10 % Passing #200: 57.2% Beginning Moisture: 5.1% Dry Density: 110 pcf Ending Moisture: 14.8% Swell Pressure: <500 psf % Swell @ 500: None Ridgewood Hills First Filing - Tract L Fort Collins, Colorado 1142014 February 2014 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: Ridgewood Hills First Filing - Tract L Fort Collins, Colorado 1142014 February 2014 Beginning Moisture: 12.2% Dry Density: 119.6 pcf Ending Moisture: 16.8% Swell Pressure: 8000 psf % Swell @ 150: 11.7% Sample Location: Boring 2, Sample 1, Depth 2' Liquid Limit: 42 Plasticity Index: 26 % Passing #200: 65.3% SWELL / CONSOLIDATION TEST RESULTS Material Description: Dark Brown Sandy Lean Clay (CL) -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: Ridgewood Hills First Filing - Tract L Fort Collins, Colorado 1142014 February 2014 Beginning Moisture: 9.2% Dry Density: 101.6 pcf Ending Moisture: 20.9% Swell Pressure: <500 psf % Swell @ 500: None Sample Location: Boring 2, Sample 3, Depth 9' Liquid Limit: - - Plasticity Index: - - % Passing #200: 20.0% SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Rust / Grey Sandstone -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added FORT COLLINS, COLORADO PROJECT NO: 1142014 LOG OF BORING B-3 FEBRUARY 2014 SHEET 1 OF 1 WATER DEPTH START DATE 2/26/2014 WHILE DRILLING None SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 2/26/2014 AFTER DRILLING N/A A-LIMITS SWELL FORT COLLINS, COLORADO PROJECT NO: 1142014 LOG OF BORING B-2 FEBRUARY 2014 SHEET 1 OF 1 WATER DEPTH START DATE 2/26/2014 WHILE DRILLING None SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 2/26/2014 AFTER DRILLING N/A A-LIMITS SWELL FORT COLLINS, COLORADO PROJECT NO: 1142014 LOG OF BORING B-1 FEBRUARY 2014 SHEET 1 OF 1 WATER DEPTH START DATE 2/26/2014 WHILE DRILLING None SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 2/26/2014 AFTER DRILLING N/A A-LIMITS SWELL more than 12% fines HIf fines are organic, add "with organic fines" to group name LIf soil contains ≥ 30% plus No. 200 predominantly sand, add "sandy" to group name. MIf soil contains ≥30% plus No. 200 predominantly CGravels with 5 to 12% fines required dual symbols: gravel, add "gravelly" to group name. UNIFIED SOIL CLASSIFICATION SYSTEM Soil Classification Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Sands 50% or more coarse fraction passes No. 4 sieve Fine‐Grained Soils 50% or more passes the No. 200 sieve <0.75 Kif soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel", whichever is predominant. OL <0.75 OH Primarily organic matter, dark in color, and organic odor ABased on the material passing the 3‐in. (75‐mm) sieve ECu=D60/D1 Cc= Silts and Clays Liquid Limit less than 50 Silts and Clays Liquid Limit 50 or more Clean Gravels Less than 5% fines Gravels more than 50% of coarse fraction retained on No. 4 sieve Coarse ‐ Grained Soils more than 50% retained on No. 200 sieve DSands with 5 to 12% fines require dual symbols: BIf field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. FIf soil contains ≥15% sand, add "with sand" to GIf fines classify as CL‐ML, use dual symbol GC‐ CM, or SC‐SM. 0 10 20 30 40 50 60 0102030405060708090100110 PLASTICITY INDEX (PI) LIQUID LIMIT (LL) ML OR OL MH OR OH For Classification of fine‐grained soils and fine‐grained fraction of coarse‐grained soils. Equation of "A"‐line Horizontal at PI=4 to LL=25.5 then PI‐0.73 (LL‐20) Equation of "U"‐line Vertical at LL=16 to PI‐7, then PI=0.9 (LL‐8) CL‐ML HARDNESS AND DEGREE OF CEMENTATION: Limestone and Dolomite: Hard Difficult to scratch with knife. Moderately Can be scratched easily with knife. Hard Cannot be scratched with fingernail. Soft Can be scratched with fingernail. Shale, Siltstone and Claystone: Hard Can be scratched easily with knife, cannot be scratched with fingernail. Moderately Can be scratched with fingernail. Hard Soft Can be easily dented but not molded with fingers. Sandstone and Conglomerate: Well Capable of scratching a knife blade. Cemented Cemented Can be scratched with knife. Poorly Can be broken apart easily with fingers. Cemented