Loading...
HomeMy WebLinkAboutUNION PARK - PDP230005 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTPRELIMINARY GEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED ZIEGLER-CORBETT MIXED-USE DEVELOPMENT 4105 ZIEGLER ROAD, FORT COLLINS, COLORADO SOILOGIC # 22-1062 April 4, 2022 Soilogic, Inc. 3522 Draft Horse Court • Loveland, CO 80538 • (970) 535-6144 April 4, 2022 Landmark Homes 6341 Fairgrounds Avenue, Suite 100 Windsor, Colorado 80550 Attn: Mr. Andrew Quest Re: Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development Larimer County Parcel #’s 8732400010, 8732400009 and 8732000002 4105 Ziegler Road, Fort Collins, Colorado Soilogic Project # 22-1062 Mr. Quest: Soilogic, Inc. (Soilogic) personnel have completed the preliminary geotechnical subsurface exploration you requested for the proposed mixed-use development to be constructed on a combined property consisting of Larimer County Parcel Numbers 8732400010, 8732400009 and 8732000002, located at 4105 Ziegler Road in Fort Collins, Colorado. The results of our subsurface exploration and pertinent geotechnical engineering recommendations are included with this report. In summary, approximately 4 to 6 inches of vegetation and topsoil was encountered at the surface at the boring locations, underlain by brown/beige/rust lean clay with varying amounts of sand which varied to clayey sand in places. The apparently-natural lean clay/ clayey sand varied from soft to hard in terms of consistency or from very loose to medium dense in terms of relative density, typically exhibited no to low swell potential at in-situ moisture and density conditions (however one sample of sandy lean clay obtained from boring B-2 at a depth of about 9 feet below ground surface exhibited moderate swell potential) and extended to the bottom of each of the borings at a depth of approximately 15 feet below present site grades. Groundwater was not encountered in borings B-1, B-2, B-3 or B-5 to the depths explored (about 15 feet below ground surface), but was measured at a depth of about 15 feet below ground surface in boring B-4 when checked immediately after completion of drilling. When checked about five (5) days after drilling, borings B-1, B-2 and B-5 remained dry to the approximate depth explored, while groundwater was measured at a depth of about 14 Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 2 feet below ground surface at the locations of borings B-3 and B-4 at that time. Groundwater information is indicated in the upper right-hand corner of the attached boring logs. Based on the subsurface conditions encountered in the completed site borings, results of field and laboratory testing and type of construction anticipated, we expect relatively lightly-loaded commercial/retail and residential structures could be constructed with conventional footing foundations and floor slabs bearing on natural site lean clay/clayey sand with no to low swell potential or a suitable zone of properly moisture conditioned and compacted overexcavation/backfill (where deemed necessary). Overexcavation/backfill procedures are also recommended to develop low volume-change (LVC) floor slab and pavement support conditions where expansive soils are identified underlying these improvements. Moderately expansive lean clay/clayey sand soils were identified at the location of boring B-2 at a depth of approximately 9 feet below present site grade. Extending footing foundations through any expansive lean clay to bear on lean clay/clayey sand soils with low swell potential at greater depth could be considered (if/where feasible), however, overexcavation/backfill procedures would still be required beneath residence garage, basement and any other at-grade commercial/retail building floor slabs in areas where expansive lean clay soils are identified at the time of final, design-level explorations completed for each of the individual site structures. In addition to the presence of lean clay soils exhibiting moderate swell potential, comparatively soft, high moisture content clay soils exhibiting moderate compressibility were encountered at a depth of about 4 feet below ground surface in boring B-3, such that care will be needed to ensure footing foundations are supported on soils with suitable strength. Overexcavation/backfill procedures or other approved stabilization measures could be considered in areas of soft/compressible clay to reduce the potential for excessive post-construction settlement of the proposed structures. If raising the site through fill placement will be undertaken, areas of the site expected to receive fill depths greater than about 4 to 5 feet should be developed as early as possible during the development process and allowed to remain in place for several weeks in order to allow for consolidation of the underlying soils prior to construction of any overlying improvements. Based on the results of completed laboratory testing, the site lean clay/clayey sand appears suitable for use as fill and overexcavation/backfill to develop the site. Depending on the Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 3 04/04/2022 in-place moisture content of the pavement subgrade soils at the time of construction, stabilization of the lean clay/clayey sand subgrade soils may become necessary prior to surfacing in order to develop a suitable paving platform. Preliminary pavement section design estimates are included with this report. If public street improvements will be constructed as part of this project, a final pavement exploration will be required for these roadways after the sanitary sewer and water utilizes have been installed and the streets graded to approximate finish subgrade elevation in accordance with Larimer County Urban Area Street Standards (LCUASS). Other preliminary opinions and recommendations concerning design criteria and construction details for the proposed site improvements are also included. 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. Alec Kaljian, P.E. Senior Project Engineer Project Engineer 04/04/2022 PRELIMINARY GEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED ZIEGLER-CORBETT MIXED-USE DEVELOPMENT 4105 ZIEGLER ROAD, FORT COLLINS, COLORADO SOILOGIC # 22-1062 April 4, 2022 INTRODUCTION This report contains the results of the preliminary geotechnical subsurface exploration completed for the proposed mixed-use development to be constructed on a combined property consisting of Larimer County Parcel Numbers 8732400010, 8732400009 and 8732000002, located at 4105 Ziegler Road 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 the commercial/retail and residential structure foundations and support of floor slabs and site pavements. Recommendations concerning the installation of site utilities 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 We understand this project involves the development of combined parcels of land incorporating approximately 31 acres referenced as the Ziegler-Corbett properties, as residential and mixed-use. We expect the proposed single and multi-family residences and mixed-use buildings will be lightly-loaded one or two-story wood-frame structures constructed as slab-on-grade and/or over crawl spaces or full-depth basements if/where feasible. Foundation 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, public roadway and private site drive and parking area pavement construction. We expect the site pavements will be utilized by low volumes of automobiles and light trucks, with occasional trash, delivery and emergency truck traffic. Small grade changes are anticipated to develop finish site grades. Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 2 SITE DESCRIPTION The development parcels include 31 acres of land identified by the Larimer County Assessor’s Office as Parcel Numbers 8732400010, 8732400009 and 8732000002, located at 4105 Ziegler Road in Fort Collins, Colorado. At the time of our site exploration, a majority of the site was vacant/undeveloped and the ground surface contained a moderate growth of native grass and weed vegetation. The property was generally level, with a slight overall downward slope to the northeast. The maximum difference in ground surface elevation across the site is estimated to be on the order of 10 to 15 feet based upon provided survey information. Two (2) small, at-grade, single-story wood frame garage/barn structures were noted in the northeast corner of the development property. Other evidence of prior building construction was not observed on the development parcels by Soilogic Inc. (Soilogic) personnel at the time of our site exploration. SITE EXPLORATION Field Exploration To develop subsurface information across the development parcel, five (5) soil borings were extended to a depth of approximately 15 feet below present site grade across the combined property. The boring locations were selected by Soilogic personnel and established in the field by surveyors. A diagram indicating the approximate boring locations is included with this report. Graphic logs of each of the auger borings along with ground surface elevations recorded by surveyors are also included. The test holes were advanced using 4-inch diameter continuous-flight auger, powered by a truck-mounted CME-45 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 or relative density of the soils encountered. In the California barrel sampling procedure, lesser disturbed samples are obtained in removable brass liners. Samples of the subsurface materials obtained in the Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 3 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 materials (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. As part of laboratory testing, water soluble sulfate (WSS) tests are currently being completed on two (2) selected samples of the lean clay/clayey sand soils to help evaluate corrosive soil characteristics with respect to buried concrete and results will be provided under separate cover when they become available. SUBSURFACE CONDITIONS The subsurface materials encountered in the completed site borings can be summarized as follows. Approximately 4 to 6 inches of vegetation and topsoil was encountered at the surface at the boring locations, underlain by brown/beige/rust lean clay with varying amounts of sand which varied to clayey sand in places. The apparently-natural lean clay/ clayey sand varied from soft to hard in terms of consistency or from very loose to medium dense in terms of relative density, typically exhibited no to low swell potential at in-situ moisture and density conditions (however one sample of sandy lean clay obtained Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 4 from boring B-2 at a depth of about 9 feet below ground surface exhibited moderate swell potential) and extended to the bottom of each of the borings at a depth of approximately 15 feet below present site grades. 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. Groundwater was not encountered in borings B-1, B-2, B-3 or B-5 to the depths explored (about 15 feet below ground surface), but was measured at a depth of about 15 feet below ground surface in boring B-4 when checked immediately after completion of drilling. When checked about five (5) days after drilling, borings B-1, B-2 and B-5 remained dry to the approximate depth explored, while groundwater was measured at a depth of about 14 feet below ground surface at the locations of borings B-3 and B-4 at that time. Groundwater 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. 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 anticipated, we expect relatively lightly-loaded commercial/retail and residential structures could be constructed with conventional footing foundations and floor slabs bearing on natural site lean clay/clayey sand with no to low swell potential or a suitable zone of properly moisture conditioned Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 5 and compacted overexcavation/backfill (if/where deemed necessary). Overexcavation/ backfill procedures would also be recommended to develop low volume-change (LVC) floor slab and pavement support conditions where expansive soils are identified underlying these improvements. Moderately expansive lean clay/clayey sand soils were identified at the location of boring B-2 at a depth of approximately 9 feet below present site grade. Extending footing foundations through any expansive lean clay to bear on lean clay/clayey sand soils with low swell potential at greater depth could be considered (if/where feasible), however, overexcavation/backfill procedures would still be required beneath residence garage, basement and any other at-grade commercial/retail building floor slabs in areas where expansive lean clay soils are identified. The comparatively soft, high moisture content clay soils encountered in the area of boring B-3 would be subject to consolidation under additionally imposed fill loads. Areas of the site expected to receive fill depths greater than 4 to 5 feet should be developed as early as possible in the construction process. We recommend the fill materials in these areas be placed and allowed to remain in place for several weeks prior to the installation of site utilities and construction of any overlying improvements in order to allow for consolidation of underlying soils. Final subsurface explorations should be performed after the site has been graded to approximate finish grade and building location, size and type of construction (at-grade, crawl space or basement) have been determined to define subsurface conditions and provide design-level foundation, floor slab and pavement thickness design recommendations and to develop suitable overexcavation/backfill procedures (if/where deemed appropriate). Preliminary pavement section design estimates for private site drives and parking areas are included with this report. Final pavement section design alternatives can be provided as part of design-level geotechnical subsurface explorations to be completed once development plans have been finalized and the site developed to approximate finish grade. If public City of Fort Collins streets will be constructed as part of this project, a final pavement exploration will be required for these roadways after utilities have been installed and streets graded to approximate finish subgrade elevation in accordance with Larimer County Urban Area Street Standards (LCUASS). Depending on the in-place Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 6 moisture content of the subgrade soils at the time of construction, stabilization of the pavement subgrade soils may become necessary after grading and/or overexcavation/ backfill have been performed and prior to surfacing in order to develop a suitable paving platform. Site Development All existing vegetation and topsoil should be completely removed from the building, pavement and any proposed fill areas. Existing undocumented fill (if/where encountered) should also be removed at this time. After stripping and completing any cuts and removal procedures and prior to placement of any new fill or overlying improvements, 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 be within the range of -1 to +3% 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 results of the completed laboratory testing, it is our opinion the site lean clay/clayey sand could be used as fill to develop the site provided the proper moisture content is developed in those materials at the time of placement and compaction. If it is necessary to import fill material to the site, those materials should have low potential for volume change and be relatively impervious. Import materials (if required) should be approved prior to use and should have a maximum liquid limit of 40, maximum plasticity index of 18 and should contain a minimum of 25% fines in order to reduce the ability of those materials to pond and transmit water. Suitable fill soils should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted as recommended for the scarified soils above. At the high end of the above-recommended moisture content range, some pumping of the fill and overexcavation/backfill soils may be observed and would be expected. Slopes steeper than 4:1 (H:V) expected to receive fill should be continuously and horizontally benched level during fill placement in order to reduce the potential for development of a shear plane between the natural site soils and overlying fill. Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 7 Care should be taken to maintain the proper moisture content in the prepared subgrade soils prior to foundation and floor slab concrete placement and/or paving. The prepared structural mat should not be left exposed for extended periods of time. In the event that the reconditioned soils are allowed to dry out or if rain, snowmelt or water from any source is allowed to infiltrate the bearing/subgrade soils, reworking of those materials or removal/replacement procedures may be required. Footing Foundations Based on the materials encountered in the completed site borings and results of laboratory testing, we expect the site structures could be constructed with conventional spread footing foundations bearing on natural, undisturbed site lean clay/clayey sand with no to low swell potential and/or properly placed and compacted fill or overexcavation/ backfill (where deemed necessary). For design of footing foundations bearing on soft to hard/loose to medium dense lean clay/clayey sand and/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 with minimum dead-load pressures on the order of 500 psf appear suitable. Final subsurface explorations should be performed after the site has been graded to approximate finish grade and building location, size and type of construction (at-grade, crawl space or basement) have been determined to help better define subsurface conditions at the specific building locations and determine if/where overexcavation/ backfill procedures might be warranted. Floor Slabs Based on the type of construction proposed and results of the completed field and laboratory testing, we expect lightly-loaded commercial/retail building and residential garage and basement floor slabs could be supported on reconditioned natural site soils with no to low swell potential or properly placed and compacted fill and/or overexcavation/backfill (where deemed necessary). Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 8 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. Below-Grade Construction We recommend perimeter drain systems be installed around all below-grade areas (including crawl spaces, if any) to help reduce the potential for development of hydrostatic pressures behind below-grade walls and surface water infiltration into the below-grade 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 levels at the high points of the systems, run around the interior or exterior perimeters of crawl space areas and exterior perimeters of basement 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 and or project underdrain system (if available). 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/clayey sand could be used as backfill in these areas. The site lean clay/clayey sand soils should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted as previously outlined in the “Site Development” section of this report. 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. Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 9 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/clayey sand could be used as pipeline backfill. Lean clay/ clayey sand pipeline backfill should be placed in maximum 9-inch loose lifts, adjusted in moisture content and compacted as previously outlined in the “Site Development” section of this report. 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/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 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. When checked about five (5) days after drilling, borings B-1, B-2 and B-5 remained dry to the approximate depth explored (about 15 feet below ground surface), while groundwater was measured at a depth of about 14 feet below ground surface at the locations of borings B-3 and B-4 at that time. 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 Roadways We expect overexcavation/backfill procedures may be required to develop LVC potential site pavement subgrades in some areas of the site where expansive lean clay/clayey sand soils are identified underlying pavements to any appreciable degree. Site pavements could be supported directly on reconditioned natural site soils with no to low swell Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 10 potential and/or properly placed and compacted overexcavation/backfill soils (if/where deemed necessary). A final subgrade evaluation and pavement section design report will be required for public street improvements once overlot grading and utility installation has been completed and roadways are developed to approximate finish grade in accordance with the Larimer County Urban Area Street Standards (LCUASS). For preliminary design estimates, a composite pavement section consisting of 4 to 5 inches of hot bituminous pavement overlying 6 to 8 inches of aggregate base course and Portland cement concrete section in the range of 5 to 6 inches could be used for local residential roadways. A composite pavement section consisting of 5 to 6 inches of hot bituminous pavement overlying 6 to 8 inches of aggregate base course could be used for preliminary estimates for streets designated residential collector. The site lean clay/clayey sand would be particularly susceptible to strength loss and instability when elevated in moisture content with a tendency to rut and pump when wetted. Depending on the time of year when construction occurs and other hydrologic conditions, stabilization of site pavement subgrades may become necessary to develop a suitable paving platform. If required, we recommend consideration be given to stabilization of the pavement subgrades with Class C fly ash or Portland cement (pending results of water-soluble sulfate testing). Chemical stabilization can also eliminate some of the uncertainty associated with attempting to pave during periods of inclement weather. In addition, it may be possible to reduce the required thicknesses of asphaltic concrete and aggregate base course with the increase in subgrade strength developed through the chemical stabilization procedures. 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 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 pavements can result in a loss of subgrade support and premature failure of the overlying pavement sections. Preliminary Geotechnical Subsurface Exploration Report Proposed Ziegler-Corbett Mixed-Use Development 4105 Ziegler Road, Fort Collins, Colorado Soilogic # 22-1062 11 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 45 4" CFA Automatic JJ / BM Estimated Swell % Passing SOIL DESCRIPTION Depth "N"MC DD qu % Swell @ Pressure # 200 Sieve (ft)(%)(pcf)(psf)500 psf (psf)LL PI (%) 4-6" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 25 8.4 102.3 9000+2.7%2300 --- - 4 - 5 CS 18 8.1 98.1 9000+None <500 --- - CL LEAN CLAY with varying amounts 6 to SC of SAND, varies to CLAYEY SAND - brown, beige, rust 7 stiff to very stiff / loose to medium dense - trace to minor GRAVEL 8 - 9 - 10 CS 17 11.3 114.7 9000+----- - 11 - 12 - 13 - 14 - 15 CS 12 21.6 104.2 6000 ----- BOTTOM OF BORING @ 15.0'- 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 ZIEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATION FORT COLLINS, COLORADO Project # 22-1062 April 2022 Sheet Drilling Rig:Water Depth Information Start Date 3/23/2022 Auger Type:During Drilling None Finish Date 3/23/2022 Hammer Type:After Drilling None USCSSamplerAtterberg Limits Surface Elev.4935.2'Field Personnel:5 Days After Drilling None LOG OF BORING B-2 1/1 CME 45 4" CFA Automatic JJ / BM Estimated Swell % Passing SOIL DESCRIPTION Depth "N"MC DD qu % Swell @ Pressure # 200 Sieve (ft)(%)(pcf)(psf)500 psf (psf)LL PI (%) 4-6" VEGETATION & TOPSOIL - 1 - 2 - 3 - 4 - 5 CS 21 8.6 103.8 9000+2.1%2900 --- - CL LEAN CLAY with varying amounts 6 to SC of SAND, varies to CLAYEY SAND - brown, beige, rust 7 stiff to hard / loose to medium dense - trace to minor GRAVEL 8 - 9 - 10 CS 45 10.1 119.0 9000+3.5%5000 --38.9% - 11 - 12 - 13 - 14 - 15 CS 13 20.9 104.3 6000 ----- BOTTOM OF BORING @ 15.0'- 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 5 Days After Drilling None USCSSamplerAtterberg Limits Start Date 3/23/2022 Auger Type:During Drilling None Finish Date 3/23/2022 Hammer Type:After Drilling None Surface Elev.4926.4'Field Personnel: Sheet Drilling Rig:Water Depth Information ZIEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATION FORT COLLINS, COLORADO Project # 22-1062 April 2022 LOG OF BORING B-3 1/1 CME 45 4" CFA Automatic JJ / BM Estimated Swell % Passing SOIL DESCRIPTION Depth "N"MC DD qu % Swell @ Pressure # 200 Sieve (ft)(%)(pcf)(psf)500 psf (psf)LL PI (%) 4-6" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 16 18.5 101.7 9000+None <500 --- - 4 - 5 CS 4 18.3 100.3 5000 None <500 --- - CL LEAN CLAY with varying amounts 6 to SC of SAND, varies to CLAYEY SAND - brown, beige, rust 7 soft to stiff / very loose to medium dense - trace to minor GRAVEL 8 - 9 - 10 CS 11 18.9 106.4 5000 None <500 --- - 11 - 12 - 13 - 14 - 15 CS 16 18.8 106.7 9000 ----- BOTTOM OF BORING @ 15.0'- 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 5 Days After Drilling 14.0'USCSSamplerAtterberg Limits Start Date 3/23/2022 Auger Type:During Drilling None Finish Date 3/23/2022 Hammer Type:After Drilling None Surface Elev.4929.7'Field Personnel: Sheet Drilling Rig:Water Depth Information ZIEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATION FORT COLLINS, COLORADO Project # 22-1062 April 2022 LOG OF BORING B-4 1/1 CME 45 4" CFA Automatic JJ / BM Estimated Swell % Passing SOIL DESCRIPTION Depth "N"MC DD qu % Swell @ Pressure # 200 Sieve (ft)(%)(pcf)(psf)500 psf (psf)LL PI (%) 4-6" VEGETATION & TOPSOIL - 1 - 2 - 3 - 4 - 5 CS 10 9.9 94.1 6000 0.1%600 --- - CL LEAN CLAY with varying amounts 6 to SC of SAND, varies to CLAYEY SAND - brown, beige, rust 7 medium stiff to stiff /- loose to medium dense 8 trace to minor GRAVEL - 9 - 10 CS 17 15.2 109.9 9000+0.4%800 --- - 11 - 12 - 13 - 14 - 15 CS 13 17.7 109.2 4000 ----- BOTTOM OF BORING @ 15.0'- 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 5 Days After Drilling 14.0'USCSSamplerAtterberg Limits Start Date 3/23/2022 Auger Type:During Drilling 15.0' Finish Date 3/23/2022 Hammer Type:After Drilling 15.0' Surface Elev.4938.3'Field Personnel: Sheet Drilling Rig:Water Depth Information ZIEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATION FORT COLLINS, COLORADO Project # 22-1062 April 2022 LOG OF BORING B-5 1/1 CME 45 4" CFA Automatic JJ / BM Estimated Swell % Passing SOIL DESCRIPTION Depth "N"MC DD qu % Swell @ Pressure # 200 Sieve (ft)(%)(pcf)(psf)500 psf (psf)LL PI (%) 4-6" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 9 18.2 101.0 7000 0.5%1000 --- - 4 - 5 CS 10 17.1 109.5 6000 None <500 33 16 45.6% - CL LEAN CLAY with varying amounts 6 to SC of SAND, varies to CLAYEY SAND - brown, beige, rust 7 medium stiff to stiff /- loose to medium dense 8 trace to minor GRAVEL - 9 - 10 CS 14 18.2 109.6 9000+1.6%1900 --- - 11 - 12 - 13 - 14 - 15 CS 9 9.1 113.3 7000 ----- BOTTOM OF BORING @ 15.0'- 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 5 Days After Drilling None USCSSamplerAtterberg Limits Start Date 3/23/2022 Auger Type:During Drilling None Finish Date 3/23/2022 Hammer Type:After Drilling None Surface Elev.4927.3'Field Personnel: Sheet Drilling Rig:Water Depth Information ZIEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATION FORT COLLINS, COLORADO Project # 22-1062 April 2022 Liquid Limit - Plasticity Index - % Passing #200 - Dry Density (pcf)102.3 IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 SWELL/CONSOLIDATION TEST SUMMARY Sample ID: B-1 @ 2 Initial Moisture 8.4% Sample Description: Light Brown Sandy Lean Clay (CL), silty 500 Final Moisture 23.9% % Swell @ 500 psf 2.7% Swell Pressure (psf)2,300 -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 (pcf)98.1 500 Final Moisture 23.6% % Swell @ 500 psf None Swell Pressure (psf)<500 Initial Moisture 8.1% Sample ID: B-1 @ 4 Sample Description: Light Brown Sandy Lean Clay (CL) (Swell Only - Disturbed Sample) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)103.8 500 Final Moisture 18.3% % Swell @ 500 psf 2.1% Swell Pressure (psf)2,900 Initial Moisture 8.6% Sample ID: B-2 @ 4 Sample Description: Brown/Rust Sandy Lean Clay to Clayey Sand (CL-SC), trace Gravel SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 38.9% Dry Density (pcf)119.0 500 Final Moisture 16.9% % Swell @ 500 psf 3.5% Swell Pressure (psf)5,000 Initial Moisture 10.1% Sample ID: B-2 @ 9 Sample Description: Brown/Rust Sandy Lean Clay (CL), slightly calcareous SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)101.7 500 Final Moisture 21.9% % Swell @ 500 psf None Swell Pressure (psf)<500 Initial Moisture 18.5% Sample ID: B-3 @ 2 Sample Description: Brown Lean Clay with Sand (CL) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)100.3 500 Final Moisture 25.2% % Swell @ 500 psf None Swell Pressure (psf)<500 Initial Moisture 18.3% Sample ID: B-3 @ 4 Sample Description: Brown/Rust Sandy Lean Clay (CL) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)106.4 500 Final Moisture 21.3% % Swell @ 500 psf None Swell Pressure (psf)<500 Initial Moisture 18.9% Sample ID: B-3 @ 9 Sample Description: Brown/Beige Lean Clay with Sand (CL) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)94.1 500 Final Moisture 26.4% % Swell @ 500 psf 0.1% Swell Pressure (psf)600 Initial Moisture 9.9% Sample ID: B-4 @ 4 Sample Description: Light Brown Sandy Lean Clay to Clayey Sand (CL-SC) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)109.9 500 Final Moisture 18.7% % Swell @ 500 psf 0.4% Swell Pressure (psf)800 Initial Moisture 15.2% Sample ID: B-4 @ 9 Sample Description: Brown/Beige/Rust Sandy Lean Clay (CL), trace Gravel SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)101.0 500 Final Moisture 22.4% % Swell @ 500 psf 0.5% Swell Pressure (psf)1,000 Initial Moisture 18.2% Sample ID: B-5 @ 2 Sample Description: Brown Sandy Lean Clay (CL) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit 33 Plasticity Index 16 % Passing #200 45.6% Dry Density (pcf)109.5 500 Final Moisture 20.7% % Swell @ 500 psf None Swell Pressure (psf)<500 Initial Moisture 17.1% Sample ID: B-5 @ 4 Sample Description: Brown/Rust Sandy Lean Clay to Clayey Sand (CL-SC) SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 (pcf)109.6 500 Final Moisture 21.1% % Swell @ 500 psf 1.6% Swell Pressure (psf)1,900 Initial Moisture 18.2% Sample ID: B-5 @ 9 Sample Description: Brown/Beige/Rust Lean Clay with Sand (CL), calcareous, trace Gravel SWELL/CONSOLIDATION TEST SUMMARY IEGLER-CORBETT MIXED-USE DEVELOPMENT PRELIMINARY EXPLORATIO FORT COLLINS, COLORADO Project # 22-1062 April 2022 -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 Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF Clean Gravels 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 Cu ! 6 and 1 " Cc " 3E SW Well graded sandI Clean Sands 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 PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Silts and Clays 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 Liquid limit - oven dried Organic clayK,L,M,P Organic 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 = 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. 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+