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Home My WebLink AboutMOUNTAIN'S EDGE (FORMERLY 2430 OVERLAND TRAIL - RESIDENTIAL) - PDP - PDP160045 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTPRELIMINARY GEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED SINGLE-FAMILY RESIDENTIAL DEVELOPMENT HERRING PROPERTY – 2430 SOUTH OVERLAND TRAIL FORT COLLINS, COLORADO SOILOGIC # 15-1132 June 11, 2015 Soilogic, Inc. 3050 67th Avenue, Suite 200 • Greeley, CO 80634 • (970) 535-6144 P.O. Box 1121 • Hayden, CO 81639 • (970) 276-2087 June 11, 2015 The Landhuis Company 212 North Wahsatch Avenue, Suite 301 Colorado Springs, Colorado 80903 Attn: Mr. Jeff Mark Re: Preliminary Geotechnical Subsurface Exploration Report Herring Property – 2430 South Overland Trail Fort Collins, Colorado Soilogic Project # 15-1132 Mr. Mark: Soilogic, Inc. (Soilogic) personnel have completed the preliminary geotechnical subsurface exploration for an approximate 18.5-acre parcel of land located at 2430 South Overland Trail in Fort Collins, Colorado. The results of our preliminary exploration and pertinent geotechnical engineering recommendations are included with this report. The subsurface materials encountered in the completed test borings consisted of a thin layer of vegetation and topsoil underlain by both brown/red-brown/rust/beige sandy lean clay and silty to clayey sand containing varying amounts of gravel and cobble. The silty/clayey sand and gravel extended to a depth of approximately 9 feet below ground surface at the location of boring B-1, where it was underlain by sandy lean clay. At the location of boring B-2, the silty/clayey sand extended to the full depth of exploration, approximately 15 feet below ground surface. Increasing clay content was observed in the near-surface soils encountered in borings B-3 through B-5, where sandy lean clay/clayey sand soils extended from just below the vegetative soil layer to the full depth of exploration in these borings. In general, the lean clay soils varied from medium stiff to hard in terms of consistency, while the silty, clayey sand varied from loose to very dense in terms of relative density. These soils generally exhibited low swell potential at in-situ moisture and density conditions; however, two samples of the lean clay soils obtained from boring B-5 at depths of approximately 9 and 14 feet below ground surface exhibited high to very high swell potential. Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 2 No groundwater was observed in any of the completed site borings at the time of drilling to the depth explored, 15 feet below existing site grades. Based on the subsurface conditions encountered in the completed site borings, results of field and laboratory testing and type of construction proposed, we expect a majority of the proposed lightly-loaded residential structures could be constructed with conventional footing foundations bearing directly on the site lean clay and silty/clayey sand overburden soils or properly placed and compacted fill soils with low volume change potential. Overexcavation/backfill procedures would be required where relatively dry deeper-lying lean clay exhibited high swell potential in laboratory testing, notably in the vicinity of boring B-5, drilled in the southeastern quarter of the property. Based on the depth of expansive soils encountered in this area, overexcavation/backfill procedures on the order of 10 feet below proposed basement bearing elevation would be anticipated. Drilled pier foundations systems used in conjunction with structural flooring systems could also be employed in areas where expansive soils are encountered. Deeper subsurface exploration would be required to define depth to bedrock in order to develop drilled pier foundation design criteria in these areas. The near-surface lean clay and silty/clayey sand soils encountered at this site typically exhibited low swell potential at in-situ moisture and density conditions, and in our opinion, appear suitable for direct support of floor slabs and exterior flatwork across a majority of the site, save for the previously outlined area in the vicinity of boring B-5. Similarly, we do not expect overexcavation/backfill procedures will be required to develop finish pavement subgrade levels. Based on the results of completed laboratory testing, the site lean clay and silty/clayey sand also generally appear suitable for use as low volume change (LVC) fill to develop the site. Other preliminary opinions and recommendations concerning design criteria and construction details for the proposed site improvements are included with this report. Preliminary pavement section design estimates are also included. Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 3 We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information or if we can be of further service to you in any way, please do not hesitate to contact us. Very Truly Yours, Soilogic, Inc. Reviewed by: Darrel DiCarlo, P.E. Wolf von Carlowitz, P.E. Senior Project Engineer Principal Engineer 44271 36746 PRELIMINARY GEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED SINGLE-FAMILY RESIDENTIAL DEVELOPMENT HERRING PROPERTY - 2430 SOUTH OVERLAND TRAIL FORT COLLINS, COLORADO SOILOGIC # 15-1132 June 11, 2015 INTRODUCTION This report contains the results of the preliminary geotechnical subsurface exploration completed for an approximate 18.5-acre parcel of land located at 2430 South Overland Trail in Fort Collins, Colorado. The purpose of our exploration was to describe the subsurface conditions encountered in the completed site borings and develop preliminary recommendations concerning design and construction of residence foundations and support of floor slabs, exterior flatwork and site pavements. Recommendations concerning the installation of site utilities and preliminary pavement section design estimates are also included. The conclusions and recommendations outlined in this report are based on results of the completed field and laboratory testing and our experience with subsurface conditions in this area. PROPOSED CONSTRUCTION The proposed development includes approximately 18.5 acres and will potentially be developed as single-family residential. We expect the residential structures will be lightly-loaded single story wood-frame structures constructed over full basements. Foundations loads for the structures are expected to be light, with continuous wall loads on the order of 3.5 kips per lineal foot and individual column loads less than 75 kips. Infrastructure improvements for the development will include utility installation and interior roadway construction. We expect the site roadway will be classified as local residential, utilized by low volumes of passenger vehicles and light trucks. Small grade changes are anticipated to develop finish site grades. SITE DESCRIPTION The site is currently developed with two, one to two-story, wood-frame single-family residences and several single-story wood-frame outbuildings. We anticipate the existing site residences and outbuildings will be razed prior to development. Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 2 At the time of our site exploration, the site was sparsely to moderately vegetated with native weeds and grasses. Mature, small to medium diameter deciduous trees and shrubs were also noted in the area surrounding the existing construction. Most of the site is relatively level, with the approximate northern portion of the property sloping slightly downward to the north and the southern portion of the property sloping toward a drainage swale. Site topography is characterized by a medium-sized drainage swale that runs from just south of the developed area to the approximate southeast corner of the property. This swale was not carrying water at the time of our exploration. A borrow pit was also noted on the south-central portion of the property. The maximum difference in ground surface elevation across the site estimated to be approximately 10 to 15 feet based on review of available USGS topographic maps. SITE EXPLORATION Field Exploration To develop subsurface information across the development parcel, a total of five (5) soil borings were extended to a depth of approximately 15 feet below present site grades. The boring locations were established in the field by Soilogic personnel by pacing and estimating angles and distances from identifiable site references. The boring locations should be considered accurate only to the degree implied by the methods used to make the field measurements. A diagram indicating the approximate boring locations is included with this report. Graphic logs of each of the auger borings are also included. The test holes were advanced using 4-inch diameter continuous-flight auger, powered by a truck-mounted CME-55 drill rig. Samples of the subsurface materials were obtained at regular intervals using California barrel sampling procedures in general accordance with ASTM specification D-1586. As part of the D-1586 sampling procedure, the standard sampling barrel is driven into the substrata using a 140 pound hammer falling a distance of 30 inches. The number of blows required to advance the sampler a distance of 12 inches is recorded and helpful in estimating the consistency, relative density or hardness of the soils or bedrock encountered. In the California barrel sampling procedure, relatively undisturbed samples are obtained in removable brass liners. Samples of the Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 3 subsurface materials obtained in the field were sealed and returned to the laboratory for further evaluation, classification and testing. Laboratory Testing The samples collected were tested in the laboratory to measure natural moisture content and visually and/or manually classified in accordance with the Unified Soil Classification System (USCS). The USCS group symbols are indicated on the attached boring logs. An outline of the USCS classification system is included with this report. As part of the laboratory testing, a calibrated hand penetrometer (CHP) was used to estimate the unconfined compressive strength of essentially-cohesive specimens. The CHP also provides a more reliable estimate of soil consistency than tactual observation alone. Dry density, Atterberg limits, -200 wash and swell/consolidation tests were completed on selected samples to help establish specific soil characteristics. Atterberg limits tests are used to determine soil plasticity. The percent passing the #200 size sieve (-200 wash) test is used to determine the percentage of fine grained soils (clay and silt) in a sample. Swell/consolidation tests are performed to evaluate soil volume change potential with variation in moisture content. Results of the completed laboratory tests are outlined on the attached boring logs and swell/consolidation test summaries. SUBSURFACE CONDITIONS The subsurface materials encountered in the completed site borings can be summarized as follows. A thin layer of vegetation and topsoil was encountered at the surface at the boring locations. The vegetative soil layer was underlain by various sequences of brown/ red-brown/rust/beige sandy lean clay and silty to clayey sand containing varying amounts of gravel and cobble. The silty/clayey sand and gravel extended to a depth of approximately 9 feet below ground surface at the location of boring B-1, where it was underlain by sandy lean clay. At the location of boring B-2, the silty/clayey sand extended to the full depth of exploration, approximately 15 feet below ground surface. Increasing clay content was observed in the near-surface soils encountered in borings B-3 through B-5, where sandy lean clay/clayey sand soils extended from just below the vegetative soil layer to the full depth of exploration in these borings. In general, the lean Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 4 clay soils varied from medium stiff to hard in terms of consistency, while the silty, clayey sand varied from loose to very dense in terms of relative density. These soils generally exhibited low swell potential at in-situ moisture and density conditions; however, two samples of the lean clay soils obtained from boring B-5 at depths of approximately 9 and 14 feet below ground surface exhibited high to very high swell potential. The stratigraphy indicated on the included boring logs represents the approximate location of changes in soil types. Actual changes may be more gradual than those indicated. No groundwater was observed in any of the completed site borings at the time of drilling to the depth explored, 15 feet below existing site grades. Groundwater level information is indicated in the upper right-hand corner of the attached boring logs. Groundwater levels will vary seasonally and over time based on weather conditions, site development, irrigation practices and other hydrologic conditions. Site groundwater levels could be directly impacted by water levels in the medium-sized, unlined drainage swale which crosses the property from the just south of the developed area to the approximate southeast property corner. We anticipate this swale will be piped and backfilled during site development in order to reduce the potential for water surcharging overall groundwater levels in the localized area. Perched and/or trapped groundwater conditions may also be encountered at times throughout the year. Perched water is commonly encountered in soils overlying less permeable soil layers and/or bedrock. Trapped water is typically encountered within more permeable zones of layered soil and bedrock systems. The location and amount of perched/trapped water can also vary over time. ANALYSIS AND RECOMMENDATIONS General Based on the subsurface conditions encountered in the completed site borings, results of field and laboratory testing and type of construction proposed, we expect a majority of Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 5 the proposed lightly-loaded residential structures could be constructed with conventional footing foundations bearing directly on the silty/clayey sand and lean clay overburden soils or properly placed and compacted fill soils with low volume change potential. Overexcavation/backfill procedures would be required where deeper-lying lean clay soils exhibited high to very high swell potential in laboratory testing, notably in the vicinity of boring B-5, drilled in the approximate southeast quarter of the property. Based on the depth of expansive soils encountered in this area, overexcavation/backfill procedures on the order of 10 feet below proposed basement bearing elevation would be anticipated. Drilled pier foundations systems used in conjunction with structural flooring systems could also be employed in areas where expansive soils are encountered. Deeper subsurface exploration would be required to define depth to bedrock in order to develop drilled pier foundation design criteria in these areas. The near-surface lean clay and silty/clayey sand soils encountered at this site typically exhibited low swell potential at in-situ moisture and density conditions, and in our opinion, could be used for direct support of floor slabs and exterior flatwork across a majority of the site. Similarly, we do not expect overexcavation/backfill procedures will be required to develop finish pavement subgrade levels. Based on the results of completed laboratory testing, the site lean clay and silty/clayey sand also generally appear suitable for use as low volume change (LVC) fill to develop the site. Demolition and Site Development All existing topsoil and vegetation should be removed from proposed fill and pavement areas. In addition, any existing site improvements, including foundation and floor slab concrete associated with the existing site residences and outbuildings should be completely removed. Care will be needed to ensure all soft/loose zones of in-place fill and backfill material associated with the existing site improvements is also completely removed. In addition, all tree root systems and dry and desiccated soils associated with the tree root systems should be completely removed from proposed improvement areas. The excavated/removed materials should be replaced with controlled and compacted fill developed as outlined below. Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 6 After completing all cuts and any removal procedures and prior to placement of any fill or overexcavation/backfill, we recommend the exposed subgrade soils be scarified to a depth of 9 inches, adjusted in moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. The moisture content of the scarified soils should be adjusted to within ±2% of standard Proctor optimum moisture content at the time of compaction. Fill soils required to develop the site should consist of approved low volume change (LVC) soils free from organic matter, debris and other objectionable materials. Based on the results of the completed laboratory testing, it is our opinion the site lean clay and silty/clayey sand could be used as fill to develop the site. Cobbles greater than 3 inches in any dimension should not be used as fill within the top 18 inches of subgrade in floor slab, exterior flatwork and pavement areas. If it is necessary to import fill material to the site, those materials should have low potential for volume change and be relatively impervious. Fill soils should be approved prior to use. Typically soils with a liquid limit less than 40 and plasticity index less than 18 could be used as low volume change fill. We recommend the site lean clay and silty/clayey sand or approved import LVC soils be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted as recommended for the scarified materials above. Footing Foundations Based on the materials encountered in the completed site borings and results of laboratory testing, we expect a majority of the site structures could be constructed with conventional spread footing foundations bearing on the natural sandy lean clay and/or silty/clayey sand and gravel with low volume change potential or suitable fill soils placed and compacted as outlined above. Overexcavation/backfill procedures would be required where deeper-lying lean clay soils exhibited high to very high swell potential in laboratory testing, notably in the vicinity of boring B-5, drilled in the approximate southeast quarter of the property. Based on the depth of expansive soils encountered in this area, overexcavation/backfill procedures on the order of 10 feet below proposed basement bearing elevation would be anticipated. Developing adequate separation distance between foundations and expansive soils through fill placement could also be considered. Drilled pier foundations systems used in conjunction with structural flooring Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 7 systems could also be employed in areas where expansive soils are encountered. Deeper subsurface exploration would be required to define depth to bedrock in order to develop drilled pier foundation design criteria in these areas. It may be possible to recondition the highly to very highly expansive lean clay soils in the area of boring B-5 at the time of overlot grading, potentially precluding the need for any future overexcavation/backfill procedures that may become warranted if the materials were allowed to remain in place prior to fill placement. Further exploration would be required prior to grading to fully define the depth and lateral extent of these soils. For design of footing foundations bearing on natural, undisturbed sandy lean clay and/or silty/clayey sand and gravel with low volume change potential or properly placed and compacted fill or overexcavation/backfill, maximum net allowable soil bearing pressures in the range of 1,000 to 2,000 psf appear suitable, with minimum dead-load pressures in the range of 500 to 650 psf. Individual site explorations should be completed for each of the proposed residences to help better define subsurface conditions at the specific residence locations and ensure the proposed improvements will be supported on like materials with suitable strength and low volume change potential. Drilled Pier Foundations Where highly to very highly expansive clay is encountered near proposed foundation bearing elevation at the time of site-specific subsurface exploration, it is our opinion drilled pier foundations used in conjunction with structural flooring systems would offer the most reliable method for mitigating damage to the residences and residence floor slabs as a result of expansive clay uplift forces. We expect drilled pier and structural flooring systems would be required across less than 25% of the site, if at all. Drilled piers would develop support capacity through a combination of end bearing and skin friction along the drilled shaft extended into bedrock underlying the site or be designed as friction piers and terminated in the overburden lean clay soils. Uplift forces developed on the drilled piers by expansive lean clays would be resisted by anchoring the piers into deeper-lying bedrock or lean clays less likely to experience moisture-induced volume Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 8 change subsequent to construction. Deeper subsurface exploration would be required to define depth to bedrock in order to develop drilled pier foundation design criteria in these areas. Floor Slabs Based on the type of construction proposed and results of the completed field and laboratory testing, we expect a majority of the lightly-loaded residential floor slabs could be supported on natural, undisturbed site lean clay and/or silty/clayey sand with low swell potential or properly placed and compacted fill or overexcavation/backfill (where required). Care should be taken to avoid disturbing floor slab subgrades prior to concrete placement. Subgrade soils expected to receive floor slab concrete should be evaluated closely prior to surfacing. If areas of disturbed, wet and softened, or dry subgrade soils develop during construction, those materials should be removed and replaced or reworked in place prior to placement of the overlying improvements. Basement Construction We recommend perimeter drain systems be installed around all below-grade areas to help reduce the potential for development of hydrostatic pressures behind below-grade walls and surface water infiltration into the basement areas. Perimeter drain systems should consist of a 4-inch diameter, perforated drain pipe surrounded by a minimum of six (6) inches of free-draining gravel. A filter fabric should be considered around the free- draining gravel or perforated pipe to reduce the potential for an influx of fine-grained soils into the systems. The drain pipes should be placed at approximate foundation bearing level at the high point of the systems, run around the exterior or interior perimeters of the below-grade areas with a minimum slope of ⅛-inch per foot to facilitate efficient water removal and be designed to discharge to sump pit and pump systems, underdrain system or free outfalls. If free outfalls will be considered, measures to help reduce the potential for reverse flow and animal access into the systems should be considered. Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 9 Backfill placed adjacent to the below grade walls should consist of LVC potential and relatively impervious soils which are free from organic matter, debris and other objectionable materials. The site lean clay and silty/clayey sand with gravel could be used as backfill in these areas. Cobbles greater than 3 inches in any dimension should be screened and removed prior to use as wall backfill to reduce the potential for point loads on the foundation walls. The site lean clay and silty/clayey sand backfill soils should be placed in loose lifts not to exceed 9 inches thick, adjusted to be within ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. Excessive lateral stress can be imposed on below-grade walls when using heavier mechanical compaction equipment. We recommend compaction of unbalanced basement wall backfill be completed using light mechanical or hand compaction equipment. Utility Installation Bedding around utility pipelines should be placed in accordance with recommendations from the pipeline designer. Backfill soils placed above pipelines should consist of approved materials which are free from organic matter, debris and other objectionable materials. The on-site lean clay and silty/clayey sand could be used as pipeline backfill. Pipeline backfill should be placed in maximum 9-inch loose lifts, adjusted to within ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. At current moisture contents, we expect the site soils will require the addition of water to achieve proper moisture content prior to placement as utility backfill. Care will be needed to ensure utilities are not placed on or above disturbed or sloughed materials. Utility excavations will likely expose the overburden lean clay and silty/clayey sand. Care will also be needed to develop stable side slopes in pipeline trenches. As such, we expect temporary shoring, bracing, or cutting of shallow slopes may be necessary in deeper excavations. Excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards. As a safety measure, it is recommended that Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 10 vehicles and soil stockpiles be kept to a minimum lateral distance from the crest of the slope equal to no less than the slope height. Groundwater was not encountered in the site borings to a depth of 15 feet below present site grade, however perched/trapped water may be encountered at times during the year. Cuts below groundwater elevation will require dewatering to facilitate proper construction. We expect a majority of the dewatering procedures could be completed through open pumping procedures in sumps fed from ditches or sloped trench excavations. Site Pavements We expect the pavement subgrades will consist of lean clay and silty/clayey sand with low swell potential. Pavement subgrades should be developed as outlined in the “Site Development” portion of this report. At current moisture levels, and provided streets are constructed at or near present site grades, we do not expect overexcavation/backfill procedures would be required for development of the roadway subgrade soils. Structure pavement design is based, in part, on subgrade support as established by the Hveem R-value test. The site lean clay would be subject to low remolded strength. An R-value test of the subgrade soils will be required at the time of final pavement design. Drilling for final pavement design can be completed once the roadway system is developed to approximate finish grade and water and sewer utilities installed in accordance with Larimer County Urban Area Street Standards (LCUASS). The development streets are anticipated to be classified as local residential, with expected low volumes of passenger vehicle traffic. For preliminary estimates, a composite pavement section consisting of 4 to 5 inches of hot bituminous pavement overlying 6 to 8 inches of aggregate base course could be used. Drainage Positive drainage is imperative for satisfactory long-term performance of the proposed site structures and associated site improvements. We recommend positive drainage be developed away from all site structures and pavement areas to reduce the potential for Preliminary Geotechnical Subsurface Exploration Report Herring Property - 2430 South Overland Trail Fort Collins, Colorado Soilogic # 15-1132 11 wetting of the subgrade and bearing materials. Water which is allowed to pond adjacent to site improvements can result in unsatisfactory performance of those improvements over time. Water which is allowed to pond adjacent to site roadways can result in a loss of subgrade support and premature failure of the roadway pavement sections. LIMITATIONS This report was prepared based upon the data obtained from the completed site exploration, laboratory testing, engineering analysis and any other information discussed. The completed borings provide an indication of subsurface conditions at the boring locations only. Variations in subsurface conditions can occur in relatively short distances away from the borings. This report does not reflect any variations which may occur across the site or away from the borings. If variations in the subsurface conditions anticipated become evident, the geotechnical engineer should be notified immediately so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any biological or environmental assessment of the site or identification or prevention of pollutants or hazardous materials or conditions. Other studies should be completed if concerns over the potential of such contamination or pollution exist. The geotechnical engineer should be retained to review the plans and specifications so that comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. The geotechnical engineer should also be retained to provide testing and observation services during construction to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with the generally accepted standard of care for the profession. No warranties express or implied, are made. The conclusions and recommendations contained in this report should not be considered valid in the event that any changes in the nature, design or location of the project as outlined in this report are planned, unless those changes are reviewed and the conclusions of this report modified and verified in writing by the geotechnical engineer. LOG OF BORING B-1 1/1 CME 55 4" CFA Manual BMc Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 8" VEGETATION & TOPSOIL - 1 - 2 - 3 - SC-SM SILTY to CLAYEY SAND 4 w/G with GRAVEL & COBBLES - brown, rust 5 CS 50/2" 7.7 97.1 N/A - - - - - very dense - 6 - 7 - 8 - 9 - 10 CS 19 17.4 110.7 9000+ None <500 - - - - 11 CL SANDY LEAN CLAY - light brown/beige 12 very stiff - trace to minor GRAVEL 13 - 14 - 15 CS 27 15.1 115.0 9000+ None @ 1000 <1000 - - - BOTTOM OF BORING @ 15.0' - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO LOG OF BORING B-2 1/1 CME 55 4" CFA Manual BMc Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 6" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 34 3.3 110.8 N/A - - - - - - 4 - 5 CS 29 6.7 113.9 N/A - - - - - - 6 - SC-SM SILTY to CLAYEY SAND with 7 varying amouts of GRAVEL - brown, red-brown, rust 8 medium dense - contains SANDY LEAN CLAY lenses 9 - 10 CS 30 6.8 121.7 9000+ None <500 - - - - 11 - 12 - 13 - 14 - 15 CS 24 4.5 131.6 9000+ - - - - - BOTTOM OF BORING @ 15.0' - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 HERRING PROPERTY PRELIMINARY EXPLORATION Atterberg Limits LOG OF BORING B-3 1/1 CME 55 4" CFA Manual BMc Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 4" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 11 14.9 111.6 9000 None <500 28 13 45.8% - 4 - CL-SC SANDY LEAN CLAY to CLAYEY SAND 5 CS 16 12.1 113.5 7000 None <500 - - - varies - brown, red-brown, beige, rust 6 stiff to very stiff / loose to medium dense - trace to minor GRAVEL 7 - 8 - 9 increasing GRAVEL content - below 9' depth 10 CS 26 2.8 125.0 9000+ - - - - - - 11 - 12 - 13 - 14 - 15 CS 24 3.5 128.5 9000+ - - - - - BOTTOM OF BORING @ 15.0' - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO LOG OF BORING B-4 1/1 CME 55 4" CFA Manual BMc Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 6" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 9 15.7 109.4 8000 None <500 - - - - 4 - 5 CS 12 13.5 105.1 5500 - - - - - - 6 - CL SANDY LEAN CLAY 7 dark brown to brown, beige, rust - medium stiff to very stiff 8 silty, minor GRAVEL - 9 - 10 CS 23 4.7 111.3 9000+ None <500 - - - - 11 - 12 CL-SC possibly varies to CLAYEY SAND - with varying amounts of GRAVEL 13 with depth - loose 14 - 15 CS 12 5.7 88.9 N/A - - - - - BOTTOM OF BORING @ 15.0' - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO LOG OF BORING B-5 1/1 CME 55 4" CFA Manual BMc Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 6" VEGETATION & TOPSOIL - 1 - 2 - CL-SC SANDY LEAN CLAY to CLAYEY SAND 3 varies - brown, rust 4 medium stiff / loose - 5 CS 8 10.8 109.3 9000+ - - - - - - 6 - 7 - 8 - 9 - 10 CS 25 9.7 126.0 9000+ 7.4% 9000 - - - CL SANDY LEAN CLAY - brown, olive, gray, beige, rust 11 very stiff to hard - trace to minor GRAVEL 12 - 13 - 14 - 15 CS 41 11.9 125.2 9000+ 6.3% @ 1000 12000 - - - BOTTOM OF BORING @ 15.0' - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 110.7 pcf Sample Description: Brown/Rust/Beige Sandy Lean Clay (CL) with Gravel Sample ID: B-1 @ 9' HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY None <500 psf Initial Moisture Final Moisture % Swell @ 500 psf Swell Pressure 17.4% 15.3% -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 115.0 pcf Final Moisture 16.5% % Swell @ 1,000 psf None Swell Pressure <500 paf Sample ID: B-1 @ 14' Sample Description: Brown/Rust/Beige Sandy Lean Clay (CL) with Gravel Initial Moisture 15.1% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 121.7 pcf Final Moisture 11.1% % Swell @ 500 psf None Swell Pressure <500 psf Sample ID: B-2 @ 9' Sample Description: Brown/Red-Brown/Rust Clayey Sand (SC) with Gravel Initial Moisture 6.8% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit 28 Plasticity Index 13 % Passing #200 45.8% Dry Density 111.6 pcf Final Moisture 18.3% % Swell @ 500 psf None Swell Pressure <500 psf Sample ID: B-3 @ 2' Sample Description: Brown/Rust Clayey Sand (SC) with Gravel Initial Moisture 14.9% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 113.5 pcf Final Moisture 15.9% % Swell @ 500 psf None Swell Pressure <500 psf Sample ID: B-3 @ 4' Sample Description: Red-Brown Sandy Lean Clay to Clayey Sand (CL-SC) with Gravel Initial Moisture 12.1% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 109.4 pcf Final Moisture 17.6% % Swell @ 500 psf None Swell Pressure <500 psf Sample ID: B-4 @ 2' Sample Description: Dark Brown Sandy Lean Clay (CL), silty Initial Moisture 15.7% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 111.3 pcf Final Moisture 16.7% % Swell @ 500 psf None Swell Pressure <500 psf Sample ID: B-4 @ 9' Sample Description: Beige/Rust Sandy Lean Clay (CL) with Gravel Initial Moisture 4.7% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 126.0 pcf Final Moisture 13.1% % Swell @ 500 psf 7.4% Swell Pressure 9,000 psf Sample ID: B-5 @ 9' Sample Description: Gray-Brown/Beige/Rust Sandy Lean Clay (CL) with Gravel Initial Moisture 9.7% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density 125.2 pcf Final Moisture 13.9% % Swell @ 1,000 psf 6.3% Swell Pressure 12,000 psf Sample ID: B-5 @ 14' Sample Description: Gray-Brown/Olive/Brown Sandy Lean Clay (CL), minor Gravel Initial Moisture 11.9% HERRING PROPERTY PRELIMINARY EXPLORATION 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Clean Gravels Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF Fines classify as ML or MH GM Silty gravelF,G, H Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H Clean Sands Cu ! 6 and 1 " Cc " 3E SW Well graded sandI Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI Fines classify as ML or MH SM Silty sandG,H,I Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines More than 12% finesD Fines classify as CL or CH SC Clayey sandG,H,I Silts and Clays PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Liquid limit less than 50 Inorganic PI < 4 or plots below “A” lineJ ML SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,N Fine-Grained Soils 50% or more passes the No. 200 sieve Organic Liquid limit - not dried < 0.75 OL Organic siltK,L,M,O Inorganic PI plots on or above “A” line CH Fat clayK,L,M Silts and Clays Liquid limit 50 or more PI plots below “A” line MH Elastic siltK,L,M Organic Liquid limit - oven dried Organic clayK,L,M,P Liquid limit - not dried < 0.75 OH Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well graded gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D 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 E Cu = D60/D10 Cc = GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1⅜" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube – 2.5" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger CS: California Barrel - 1.92" I.D., 2.5" O.D., unless otherwise noted 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 falling 30 inches is considered the “Standard Penetration” or “N-value”. For 2.5” O.D. California Barrel samplers (CB) the penetration value is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer falling 30 inches, reported as “blows per inch,” and is not considered equivalent to the “Standard Penetration” or “N-value”. 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 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. FINE-GRAINED SOILS COARSE-GRAINED SOILS BEDROCK (CB) Blows/Ft. (SS) Blows/Ft. Consistency (CB) Blows/Ft. (SS) Blows/Ft. Relative Density (CB) Blows/Ft. (SS) Blows/Ft. Consistency < 3 0-2 Very Soft 0-5 < 3 Very Loose < 24 < 20 Weathered 3-5 3-4 Soft 6-14 4-9 Loose 24-35 20-29 Firm 6-10 5-8 Medium Stiff 15-46 10-29 Medium Dense 36-60 30-49 Medium Hard 11-18 9-15 Stiff 47-79 30-50 Dense 61-96 50-79 Hard 19-36 16-30 Very Stiff > 79 > 50 Very Dense > 96 > 79 Very Hard > 36 > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Terms of Other Constituents Percent of Dry Weight Major Component 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 Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Terms of Other Constituents Percent of Dry Weight Term Plasticity Index Trace With Modifiers < 5 5 – 12 > 12 Non-plastic Low Medium High 0 1-10 11-30 30+ F If soil contains ! 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains ! 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ! 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. N PI ! 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. Project # 15-1132 June 2015 Sheet Drilling Rig: Water Depth Information Start Date 5/28/2015 Auger Type: During Drilling None Finish Date 5/28/2015 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 24 Hours After Drilling - USCS Sampler Atterberg Limits Project # 15-1132 June 2015 Sheet Drilling Rig: Water Depth Information Start Date 5/28/2015 Auger Type: During Drilling None Finish Date 5/28/2015 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 24 Hours After Drilling - USCS Sampler Atterberg Limits Project # 15-1132 June 2015 Sheet Drilling Rig: Water Depth Information Start Date 5/28/2015 Auger Type: During Drilling None Finish Date 5/28/2015 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 24 Hours After Drilling - USCS Sampler Atterberg Limits - During Drilling After Drilling Sheet Start Date Finish Date 24 Hours After Drilling Water Depth Information 5/28/2015 None 2430 S. OVERLAND TRAIL, FORT COLLINS, COLORADO Project # 15-1132 June 2015 Sampler USCS Surface Elev. None Auger Type: Drilling Rig: Hammer Type: Field Personnel: 5/28/2015 - Project # 15-1132 June 2015 Sheet Drilling Rig: Water Depth Information Start Date 5/28/2015 Auger Type: During Drilling None Finish Date 5/28/2015 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 24 Hours After Drilling - USCS Sampler Atterberg Limits