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HomeMy WebLinkAboutKECHTER TOWNHOMES - PDP200010 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT400 North Link Lane | Fort Collins, Colorado 80524 Telephone: 970-206-9455 Fax: 970-206-9441 GEOLOGIC AND PRELIMINARY GEOTECHNICAL INVESTIGATION 3620 EAST KECHTER ROAD FORT COLLINS, COLORADO Prepared For: TWG Development, LLC 333 North Pennsylvania Street, Suite 100 Indianapolis, Indiana 46204 Attention: Ryan Kelly Project No. FC08892-115 June 14, 2019 i TABLE OF CONTENTS SCOPE ....................................................................................................................... 1 SUMMARY OF CONCLUSIONS ............................................................................... 1 SITE DESCRIPTION AND PROPOSED DEVELOPMENT ...................................... 2 SITE GEOLOGY ........................................................................................................ 2 GEOLOGIC HAZARDS .............................................................................................. 3 Expansive Soils and Bedrock................................................................................. 3 Seismicity................................................................................................................ 3 Radioactivity ........................................................................................................... 4 FIELD AND LABORATORY INVESTIGATIONS ....................................................... 5 SUBSURFACE CONDITIONS ................................................................................... 5 DEVELOPMENT RECOMMENDATIONS ................................................................. 6 Over-Excavation ..................................................................................................... 6 Site Grading ............................................................................................................ 6 Permanent Cut and Fill Slopes .............................................................................. 7 Utility Construction .................................................................................................. 7 PRELIMINARY PAVEMENT RECOMMENDATIONS ............................................... 9 Subgrade Preparation ............................................................................................ 9 Preliminary Pavement Thickness Design .............................................................. 9 PRELIMINARY RECOMMENDATIONS FOR STRUCTURES ................................. 9 Foundations .......................................................................................................... 10 Slabs-on-Grade and Basement Floor Construction ............................................. 10 Below-Grade Construction ................................................................................... 10 Surface Drainage ................................................................................................. 11 General Design Considerations ........................................................................... 11 WATER SOLUBLE SULFATES .............................................................................. 12 RECOMMENDED FUTURE INVESTIGATIONS ..................................................... 13 LIMITATIONS ........................................................................................................... 13 FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 – SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX A – LABORATORY TEST RESULTS APPENDIX B – GUIDELINE SITE GRADING SPECIFICATIONS TWG DEVELOPMENT, LLC 1 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 SCOPE This report presents the results of our Geologic and Preliminary Geotechnical Investigation for 3620 Kechter Road in Fort Collins, Colorado. The purpose of our investigation was to identify geologic hazards that may exist at the site and to evaluate the subsurface conditions to assist in planning and budgeting for the proposed development. The report includes descriptions of site geology, our analysis of the impact of geologic conditions on site development, a description of subsoil and groundwater conditions found in our exploratory borings, and discussions of site development as influenced by geotechnical considerations. The scope was described in our Service Agreement (CTL Project No. FC-17-0179) dated April 30, 2019. This report was prepared based upon our understanding of the development plans. The recommendations are considered preliminary and can be used as guidelines for further planning of development and design of grading. We should review final development and grading plans to determine if additional investigation is merited, or if we need to revise our recommendations. Additional investigations will be required to design building foundations and pavements. A summary of our findings and recommendations is presented below. More detailed discussions of the data, analysis and recommendations are presented in the report. SUMMARY OF CONCLUSIONS 1. The site contains geologic hazards that should be mitigated during planning and development. No geologic or geotechnical conditions were identified which would preclude development of this site. Expansive soils, and regional issues of seismicity and radioactivity are the primary geologic concerns pertaining to the development of the site. 2. The subsurface conditions encountered in our borings were variable across the site. In general, the soils encountered in our borings consisted of sandy clay to the depths explored, with occasional sand and/or gravel layers of 1 to 7 feet in thickness at depths of 13 to 23 TWG DEVELOPMENT, LLC 2 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 feet below the existing ground surface. No bedrock was encountered in this investigation. Groundwater was encountered at depths ranging from 11 to 17 feet below the existing ground surface. One boring had caved at a depth of 12 feet, prior to secondary measurement. Groundwater levels will not likely affect planned development at this site. 3. Expansive soils were encountered in the upper 10 feet of our borings. We anticipate footing foundations can be used if they extend through the expansive soils or an over-excavation is performed. We anticipate a minimum over-excavation depth of 3 to 4 feet below foundations. The over-excavation can be performed after the development of the site. Slab-on-grade basement floors can also be used, but may also require a 3 to 4 foot over-excavation. 4. Pavement sections of5 to 6 inches of hot mix asphalt (HMA) over 6 inches of aggregate base course (ABC) are anticipated for preliminary planning purposes. An over-excavation of 1 to 2 feet may be recommended to mitigate the expansive soils. SITE DESCRIPTION AND PROPOSED DEVELOPMENT The site is located north of Kechter Road, between Lady Moon Drive and Jupiter Drive in southeast Fort Collins, Colorado. The site is generally in a plains area and is primarily vegetated with natural grasses and weeds. At the time of our exploration the site contained an existing residence, livestock pens and associated outbuildings. The site had gentle slopes to the north in the northern portion, west in the western portion and south in the southern portion. An existing pond was located less than 100 feet west of the site. We understand the parcel is planned for development of multifamily residences. We assume the residences will be 1 to 2- story, wood-framed structures. SITE GEOLOGY The geology of the site was investigated through review of mapping by Roger B. Colton (Geologic Map of the Boulder-Fort Collins-Greeley Area, Front Range Urban Corridor, Colorado 1978). Based on the referenced mapping, the site lays within an area of Eolian deposition. This unit is wind-deposited and typically consists TWG DEVELOPMENT, LLC 3 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 of silt, clay and medium to fine sand of varying fractions. Based on our visual review of the samples and laboratory test results, the mapping is consistent with the conditions at the site. GEOLOGIC HAZARDS Our investigation identified several geologic hazards that must be considered during the planning and development phases of this project. None of the geologic hazards identified will preclude development of the property. Development plans are preliminary. Planning should consider the geologic hazards discussed below. The hazards require mitigation which could include avoidance, non-conflicting use or engineered design and construction during site development. Geologic hazards at the site that need to be addressed include expansive soils and regional issues of seismicity and radioactivity. The following sections discuss each of these geologic hazards and associated development concerns. Mitigation concepts are discussed below and in the DEVELOPMENT RECOMMENDATIONS section of the report. Expansive Soils and Bedrock The soils at this site include low to high swelling sandy clay. Problems associated with the existence of expansive materials are typically mitigated through currently utilized foundation and floor slab techniques like over-excavation. Individual soils and foundation investigations conducted for specific sites should address procedures for mitigating problems associated with expansive soils. Seismicity This area, like most of central Colorado, is subject to a low degree of seismic risk. No indications of recent movements of any of the faults in the Larimer County area have been reported in the available geologic literature. As in most areas of recognized low seismicity, the record of the past earthquake activity in Colorado is somewhat incomplete. TWG DEVELOPMENT, LLC 4 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 Based on the subsurface conditions encountered in our borings and our understanding of the geology, the site classifies as a Seismic Site Class D (2015 International Building Code). Only minor damage to relatively new, properly designed and built buildings would be expected. Wind loads, not seismic considerations, typically govern dynamic structural design in this area. Radioactivity It is normal in the Front Range of Colorado and nearby eastern plains to measure radon gas in poorly ventilated spaces in contact with soil or bedrock. Radon 222 gas is considered a health hazard and is one of several radioactive products in the chain of the natural decay of uranium into stable lead. Radioactive nuclides are common in the soils and sedimentary rocks underlying the subject site. Because these sources exist on most sites, there is potential for radon gas accumulation in poorly ventilated spaces. The amount of soil gas that can accumulate is a function of many factors, including the radio-nuclide activity of the soil and bedrock, construction methods and materials, pathways for soil gas and existence of poorly-ventilated accumulation areas. It is difficult to predict the concentration of radon gas in finished construction. During our investigation, we did not detect any radiation levels above normal background levels for the area. We recommend testing to evaluate radon levels after construction is completed. If required, typical mitigation methods for residential construction may consist of sealing soil gas entry areas and periodic ventilation of below-grade spaces and perimeter drain systems. It is relatively economical to provide for ventilation of perimeter drain systems or underslab gravel layers at the time of construction, compared to retrofitting a structure after construction. Radon rarely accumulates to significant levels in above-grade, heated and ventilated spaces. TWG DEVELOPMENT, LLC 5 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 FIELD AND LABORATORY INVESTIGATIONS Subsurface conditions were further investigated by drilling six exploratory borings at the approximate locations shown on Figure 1. The borings were drilled using a truck-mounted drill rig and with 4-inch diameter, continuous-flight auger. Our field representative observed drilling, logged the soils found in the borings and obtained samples. Summary logs of the soils found in the borings and field penetration resistance values are presented on Figure 2. Samples of soils were obtained during drilling by driving a modified California-type sampler (2.5 inch O.D.) into the soil using a 140-pound hammer falling 30 inches. Samples recovered from the borings were returned to our laboratory and visually classified by the geotechnical engineer. Laboratory testing included determination of moisture content and dry density, swell-consolidation characteristics, Atterberg limits, particle-size analysis and water soluble sulfate content. Laboratory test results are presented in Appendix A. SUBSURFACE CONDITIONS Subsurface conditions encountered in the borings consisted of sandy clay with sand and gravel interlayers at depths of 13 feet or more. Bedrock was not encountered to the depths explored. The sandy clay soils exhibited 0.2 to 7.3 percent swell after wetting under approximate overburden pressures. Samples typically showed greater expansion potential near the existing ground surface. Samples from borings TH-1 and TH-3 exhibited the greatest expansion potential. Groundwater was encountered at depths ranging from 11 to 17 feet below the existing ground surface. Groundwater levels will not likely affect planned development at this site but may be encountered in utility excavations if planned near or below the measured water table. A more detailed description of the subsurface conditions is presented in our boring logs and laboratory testing. TWG DEVELOPMENT, LLC 6 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 DEVELOPMENT RECOMMENDATIONS Over-Excavation Over-excavation consists of removal of fill, expansive soils and reworking these soils as engineered fill compacted in a controlled manner. Areas of expansive soils should be further delineated during design level investigations after development. Excavation observations and density testing are commonly recommended for sites such as this in addition to a design level geotechnical investigation. Site Grading At the time of this investigation, site grading plans were not available for review in conjunction with this subsurface exploration program. It is important that deep fills (if planned) be constructed as far in advance of surface construction as possible. It is our experience that fill compacted in accordance with the compaction recommendations in this report may settle about 1 percent of its height under its own weight. Most of this settlement usually occurs during and soon after construction. Some additional settlement is possible after development and landscape irrigation increases soil moisture. We recommend delaying the construction of buildings underlain by deep fills as long as possible to allow for this settlement to occur. Delaying construction of structures up to one year where located on deep fills is recommended. The existing on-site soils are suitable for re-use as fill material provided debris or deleterious organic materials are removed. If import material is used, it should be tested and approved as acceptable fill by CTL|Thompson. In general, import fill should meet or exceed the engineering qualities of the onsite soils. Prior to fill placement, all trash and debris should be removed from fill areas and properly disposed. The ground surface in areas to be filled should be stripped of vegetation, TWG DEVELOPMENT, LLC 7 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 topsoil and other deleterious materials, scarified to a depth of at least 8 inches, moisture conditioned and compacted as recommended below. The depth of any topsoil is not anticipated to be more than 6 inches in most areas. Site grading fill should be placed in thin, loose lifts, moisture conditioned and compacted. In areas of deep fill, we recommend higher compaction criteria to help reduce settlement of the fill. Compaction and moisture requirements are presented in Appendix B. The placement and compaction of fill should be observed and density tested during construction. Guideline site grading specifications are presented in Appendix B. Permanent Cut and Fill Slopes We recommend permanent cut and fill slopes be designed with a maximum inclination of 3:1 (horizontal to vertical). Structures should be setback from the top or bottom of cut and fill slopes. If site constraints (property boundaries and streets) do not permit construction with recommended slopes, we should be contacted to evaluate the subsurface soils and steeper slopes. Utility Construction We believe excavations for utility installation in the overburden soils can be performed with conventional heavy-duty trenchers or large backhoes. Depending on the depths of planned utilities, groundwater may be encountered in excavations. If groundwater is encountered during construction, dewatering may be accomplished by sloping excavations to occasional sumps where water can be removed by pumping. Utility trenches should be sloped or shored to meet local, State and federal safety regulations. Based on our investigation, we believe the sand and gravel classifies as Type C soil, and the clay as Type B soil based on OSHA standards. TWG DEVELOPMENT, LLC 8 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 Excavation slopes specified by OSHA are dependent upon soil types and groundwater conditions encountered. Seepage and groundwater conditions in trenches may downgrade the soil type. Contractors should identify the soils encountered in the excavation and refer to OSHA standards to determine appropriate slopes. Excavations deeper than 20 feet should be designed by a professional engineer. The width of the top of an excavation may be limited in some areas. Bracing or “trench box” construction may be necessary. Bracing systems include sheet piling, braced sheeting and others. Lateral loads on bracing depend on the depth of excavation, slope of excavation above the bracing, surface loads, hydrostatic pressures, and allowable movement. For trench boxes and bracing allowed to move enough to mobilize the strength of the soils, with associated cracking of the ground surface, the “active” earth pressure conditions are appropriate for design. If movement is not tolerable, the “at rest” earth pressures are appropriate. We suggest an equivalent fluid density of 40 pcf for the “active” earth pressure condition and 55 pcf for the “at rest” earth pressure condition, assuming level backfill. These pressures do not include allowances for surcharge loading or for hydrostatic conditions. We are available to assist further with bracing design if desired. Water and sewer lines are usually constructed beneath paved roads. Compaction of trench backfill can have significant effect on the life and serviceability of pavements. We believe trench backfill should be placed in thin, loose lifts, and moisture conditioned to between optimum and 3 percent above optimum content for clay soils and within 2 percent of optimum moisture content for sand. Trench backfill should be compacted to at least 95 percent of maximum dry density (ASTM D 698). The placement and compaction of fill and backfill should be observed and tested by our firm during construction. If deep excavations are necessary for planned utilities, the compaction requirements provided in Table A should be considered. TWG DEVELOPMENT, LLC 9 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 PRELIMINARY PAVEMENT RECOMMENDATIONS Subgrade Preparation Based on the borings, the near surface soils on this site will consist of expansive sandy clay. Over-excavation of the subgrade may be recommended to mitigate swelling soils under roadways. We anticipate over-excavation depths of 1 to 2 feet. Preliminary Pavement Thickness Design Preliminary guidelines for pavement systems on this site are provided. Final pavement sections should be determined based a design level geotechnical investigation and anticipated frequency of load applications on the pavement during the desired design life. Flexible hot mixed asphalt (HMA) or rigid Portland cement concrete (PCC) pavements can be used at this site for automobile and light truck traffic use. Rigid pavements are recommended in any areas subject to heavy truck traffic. We anticipate pavement sections will be on the order of 5 to 6 inches of HMA over 6 inches of aggregate base course (ABC) or 6 inches of PCC. PCC pavements in this area are typically reinforced due to the underlying active clays. Properly designed control joints and other joints systems are required to control cracking and allow pavement movement. PRELIMINARY RECOMMENDATIONS FOR STRUCTURES The property is currently planned for residential construction. Our field and laboratory data indicate the soil conditions vary across the site. The following discussions are preliminary and are not intended for design or construction. After grading is completed, a detailed soils and foundation investigation should be performed. TWG DEVELOPMENT, LLC 10 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 Foundations Our investigation for this site indicates structures may be founded on shallow foundations if extended through the upper expansive soils or placed on a shallow over-excavation. We anticipate a minimum excavation depth of 3 to 4 feet below foundations. A design level geotechnical investigation may identify potential hazards for specified areas not indicated by our borings which may suggest the need for a deeper foundation system. Slabs-on-Grade and Basement Floor Construction Slab-on-grade floors can be used for unfinished basements. Over- excavation may be recommended in areas where expansive soils are encountered at the basement elevation. Structurally supported floor systems should be planned in all non-basement finished living areas and in basements where slab risk is judged high or very high. Slab performance risk should be more thoroughly defined during the design level soils and foundation investigation. Below-Grade Construction Groundwater was encountered during this investigation. With long-term development and associated landscaping, a “perched” water table may develop on relatively impermeable soil layers. To reduce the risk of hydrostatic pressure developing on foundation walls, foundation drains will be necessary around all below-grade areas. The drains should drain to sumps where water can be removed by pumping. Foundation walls and grade beams should be designed to withstand lateral earth pressures. The design pressure should be established during design- level soils investigations. TWG DEVELOPMENT, LLC 11 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 Surface Drainage The performance of foundations will be influenced by surface drainage. The ground surface around proposed residences should be shaped to provide runoff of surface water away from the structure and off of pavements. We generally recommend slopes of at least 12 inches in the first 10 feet where practical in the landscaping areas surrounding residences. There are practical limitations on achieving these slopes. Irrigation should be minimized to control wetting. Roof downspouts should discharge beyond the limits of backfill. Water should not be allowed to pond on or adjacent to pavements. Proper control of surface runoff is also important to limit the erosion of surface soils. Sheet flow should not be directed over unprotected slopes. Water should not be allowed to pond at the crest of slopes. Permanent slopes should be re-vegetated to reduce erosion. Water can follow poorly compacted fill behind curb and gutter and in utility trenches. This water can soften fill and undermine the performance of the roadways, flatwork and foundations. We recommend compactive effort be used in placement of all fill. General Design Considerations Exterior sidewalks and pavements supported above the on site clays are subject to post construction movement. Flat grades should be avoided to prevent possible ponding, particularly next to the building due to soil movement. Positive grades away from the buildings should be used for sidewalks and flatwork around the perimeter of the buildings in order to reduce the possibility of lifting of this flatwork, resulting in ponding next to the structures. Where movement of the flatwork is objectionable, procedures recommended for on-grade floor slabs should be considered. TWG DEVELOPMENT, LLC 12 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 Joints next to buildings should be thoroughly sealed to prevent the infiltration of surface water. Where concrete pavement is used, joints should also be sealed to reduce the infiltration of water. Since some post construction movement of pavement and flatwork may occur, joints around the buildings should be periodically observed and resealed where necessary. Roof drains should be discharged well away from the structures, preferably by closed pipe systems. Where roof drains are allowed to discharge on concrete flatwork or pavement areas next to the structures, care should be taken to insure the area is as water tight as practical to eliminate the infiltration of this water next to the buildings. WATER SOLUBLE SULFATES Concrete that comes into contact with soils can be subject to sulfate attack. We measured water-soluble sulfate concentrations in one sample from this site. Additional tests should be performed during design-level investigations. The concentration measured in this sample was 0.02 percent. Sulfate concentrations less than 0.1 percent indicate Class 0 exposure to sulfate attack for concrete that comes into contact with the subsoils, according to the American Concrete Institute (ACI). For this level of sulfate concentration, ACI indicates any type of cement can be used for concrete that comes into contact with the subsoils. In our experience, superficial damage may occur to the exposed surfaces of highly permeable concrete, even though sulfate levels are relatively low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious material ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drainage or high water tables. Concrete should be air entrained. TWG DEVELOPMENT, LLC 13 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 RECOMMENDED FUTURE INVESTIGATIONS Based on the results of this investigation and the proposed development, we recommend the following investigations be performed: 1. Review of final site grading plans by our firm; 2. Construction testing and observation for site development; 3. Subgrade investigation and pavement design after site grading is complete; 4. Design-level soils and foundation investigations after grading; 5. Construction testing and observation for residential building construction and paving. LIMITATIONS Our exploratory borings were located to obtain preliminary subsoil data indicative of conditions on this site. Although our borings were spaced to obtain a reasonably accurate picture of subsurface conditions, variations in the subsoils not indicated in our borings are always possible. We believe this investigation was conducted in a manner consistent with that level of skill and care ordinarily used by members of the profession currently practicing under similar conditions in the locality of this project. No warranty, express or implied, is made. This report was prepared from data developed during our field exploration, laboratory testing, engineering analysis and experience with similar conditions. The recommendations contained in this report were based upon our understanding of the planned construction. If plans change or differ from the assumptions presented herein, we should be contacted to review our recommendations. TH-1 TBM TH-2 TH-3 TH-4 TH-5 TH-6 Kechter Road LADY MOON DR. STRAUSS CABIN RD. KECHTER RD. SITE ROCK CREEK DR. LEGEND: INDICATES APPROXIMATE LOCATION OF EXPLORATORY BORING INDICATES APPROXIMATE LOCATION OF TEMPORARY BENCHMARK; BACK OF WALK (ELEVATION 100') TH-1 TBM TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL I T PROJECT NO. FC08892-115 FIGURE 1 Locations of Exploratory Borings VICINITY MAP (FORT COLLINS, COLORADO) NOT TO SCALE 40' 80' APPROXIMATE SCALE: 1" = 80' 0' 60 65 70 75 80 85 90 95 100 105 60 65 70 75 80 85 90 95 100 105 39/12 41/12 21/12 16/12 10/12 WC=12.4 DD=117 SW=7.3 SS=0.020 WC=17.1 DD=113 SW=4.5 WC=6.7 -200=17 WC=12.4 DD=117 SW=7.3 SS=0.020 WC=17.1 DD=113 SW=4.5 WC=6.7 -200=17 TH-1 El. 103.5 10/12 19/12 10/12 9/12 7/12 WC=11.1 DD=97 SW=0.4 WC=12.5 DD=123 SW=1.6 WC=18.0 DD=114 SW=0.4 WC=22.6 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 117 PCF From TH - 1 AT 4 FEET MOISTURE CONTENT= 12.4 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-1 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 113 PCF From TH - 1 AT 9 FEET MOISTURE CONTENT= 17.1 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-2 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 97 PCF From TH - 2 AT 4 FEET MOISTURE CONTENT= 11.1 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-3 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 123 PCF From TH - 2 AT 9 FEET MOISTURE CONTENT= 12.5 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-4 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 114 PCF From TH - 2 AT 14 FEET MOISTURE CONTENT= 18.0 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-5 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 108 PCF From TH - 2 AT 19 FEET MOISTURE CONTENT= 22.6 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-6 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 101 PCF From TH - 2 AT 24 FEET MOISTURE CONTENT= 26.0 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-7 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 NO MOVEMENT DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 117 PCF From TH - 3 AT 4 FEET MOISTURE CONTENT= 10.9 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-8 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 118 PCF From TH - 3 AT 9 FEET MOISTURE CONTENT= 13.2 % Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 120 PCF From TH - 3 AT 14 FEET MOISTURE CONTENT= 15.9 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-9 COMPRESSION % EXPANSION -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING -4 -3 -2 -1 0 1 2 3 ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 111 PCF From TH - 4 AT 9 FEET MOISTURE CONTENT= 13.3 % Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 112 PCF From TH - 4 AT 14 FEET MOISTURE CONTENT= 13.5 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-10 COMPRESSION % EXPANSION -4 -3 -2 -1 0 1 2 3 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING -4 -3 -2 -1 0 1 2 3 NO MOVEMENT DUE TO WETTING 0.1 1.0 10 100 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 113 PCF From TH - 5 AT 4 FEET MOISTURE CONTENT= 17.1 % Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 116 PCF From TH - 5 AT 9 FEET MOISTURE CONTENT= 16.6 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-11 COMPRESSION % EXPANSION -4 -3 -2 -1 0 1 2 3 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING -4 -3 -2 -1 0 1 2 3 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 117 PCF From TH - 6 AT 9 FEET MOISTURE CONTENT= 15.8 % Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 118 PCF From TH - 6 AT 14 FEET MOISTURE CONTENT= 14.3 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-12 COMPRESSION % EXPANSION -4 -3 -2 -1 0 1 2 3 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING -4 -3 -2 -1 0 1 2 3 ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 0.1 1.0 10 100 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 112 PCF From TH - 6 AT 19 FEET MOISTURE CONTENT= 19.5 % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-13 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 NO MOVEMENT DUE TO WETTING 0.1 1.0 10 100 Sample of SAND, CLAYEY, GRAVELLY (SC) GRAVEL 11 % SAND 72 % From TH - 1 AT 14 FEET SILT & CLAY 17 % LIQUID LIMIT % PLASTICITY INDEX % Sample of SAND, CLAYEY, GRAVELLY (SC) GRAVEL 8 % SAND 73 % From TH - 3 AT 19 FEET SILT & CLAY 19 % LIQUID LIMIT % PLASTICITY INDEX % TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115 FIGURE A-14 Gradation Test Results 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. PASSING WATER- MOISTURE DRY LIQUID PLASTICITY APPLIED SWELL NO. 200 SOLUBLE DEPTH CONTENT DENSITY LIMIT INDEX SWELL* PRESSURE PRESSURE SIEVE SULFATES BORING (FEET) (%) (PCF) (%) (PSF) (PSF) (%) (%) DESCRIPTION TH-1 4 12.4 117 7.3 500 0.02 CLAY, SANDY (CL) TH-1 9 17.1 113 4.5 1,100 CLAY, SANDY (CL) TH-1 14 6.7 17 SAND, CLAYEY, GRAVELLY (SC) TH-2 4 11.1 97 0.4 500 800 CLAY, SANDY (CL) TH-2 9 12.5 123 1.6 1,100 4,900 CLAY, SANDY (CL) TH-2 14 18.0 114 0.4 500 1,100 CLAY, SANDY (CL) TH-2 19 22.6 108 -0.2 2,400 CLAY, SANDY (CL) TH-2 24 26.0 101 0.0 3,000 CLAY, SANDY (CL) TH-3 4 10.9 117 3.8 500 5,500 CLAY, SANDY (CL) TH-3 9 13.2 118 1.1 1,100 CLAY, SANDY (CL) TH-3 14 15.9 120 -0.1 1,800 CLAY, SANDY (CL) TH-3 19 11.9 113 19 SAND, CLAYEY, GRAVELLY (SC) TH-4 9 13.3 111 1.2 1,100 CLAY, SANDY (CL) TH-4 14 13.5 112 0.0 1,800 CLAY, SANDY (CL) TH-5 4 17.1 113 1.2 500 CLAY, SANDY (CL) TH-5 9 16.6 116 0.2 1,100 CLAY, SANDY (CL) TH-6 4 11.2 108 41 22 69 CLAY, SANDY (CL) TH-6 9 15.8 117 0.2 1,100 CLAY, SANDY (CL) TH-6 14 14.3 118 -0.2 1,800 CLAY, SANDY (CL) TH-6 19 19.5 112 0.0 2,400 CLAY, SANDY (CL) SWELL TEST RESULTS* TABLE A-I SUMMARY OF LABORATORY TESTING ATTERBERG LIMITS Page 1 of 1 * NEGATIVE VALUE INDICATES COMPRESSION. TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL|T PROJECT NO. FC08892-115 APPENDIX A LABORATORY TEST RESULTS TABLE A-I: SUMMARY OF LABORATORY TEST RESULTS APPENDIX B GUIDELINE SITE GRADING SPECIFICATIONS TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTLT PROJECT NO. FC08892-115 B-1 GUIDELINE SITE GRADING SPECIFICATIONS 1. DESCRIPTION This item shall consist of the excavation, transportation, placement and compaction of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve preliminary street and overlot elevations. These specifications shall also apply to compaction of excess cut materials that may be placed outside of the development boundaries. 2. GENERAL The Soils Engineer shall be the Owner's representative. The Soils Engineer shall approve fill materials, method of placement, moisture contents and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE The Contractor shall remove all vegetation and debris before excavation or fill placement is begun. The Contractor shall dispose of the cleared material to provide the Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill or where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed from the ground surface upon which fill is to be placed. The surface shall then be plowed or scarified until the surface is free from ruts, hummocks or other uneven features, which would prevent uniform compaction. 5. COMPACTING AREA TO BE FILLED After the foundation for the fill has been cleared and scarified, it shall be disked or bladed until it is free from large clods, brought to the proper moisture content (0 to 3 percent above optimum moisture content for clays and within 2 percent of optimum moisture content for sands) and compacted to not less than 95 percent of maximum dry density as determined in accordance with ASTM D698. 6. FILL MATERIALS Fill soils shall be free from organics, debris or other deleterious substances, and shall not contain rocks or lumps having a diameter greater than six (6) TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTLT PROJECT NO. FC08892-115 B-2 inches. Fill materials shall be obtained from cut areas shown on the plans or staked in the field by the Engineer. On-site materials classifying as CL, CH, SC, SM, SW, SP, GP, GC and GM are acceptable. Concrete, asphalt, organic matter and other deleterious materials or debris shall not be used as fill. 7. MOISTURE CONTENT AND DENSITY Fill material shall be moisture conditioned and compacted to the criteria in the table, below. Maximum density and optimum moisture content shall be determined from the appropriate Proctor compaction tests. Sufficient laboratory compaction tests shall be made to determine the optimum moisture content for the various soils encountered in borrow areas. FILL COMPACTION AND MOISTURE REQUIREMENTS Soil Type Depth from Final Grade (feet) Moisture Requirement (% from optimum) Density Requirement Clay 0 to 15 feet 0 to +3 95% of ASTM D 698 Sand -2 to +2 95% of ASTM D 698 Clay Greater than 15 feet -2 to +1 98% of ASTM D 698 Sand -2 to +1 95% of ASTM D 1557 The Contractor may be required to add moisture to the excavation materials in the borrow area if, in the opinion of the Soils Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. The Contractor may be required to rake or disc the fill soils to provide uniform moisture content through the soils. The application of water to embankment materials shall be made with any type of watering equipment approved by the Soils Engineer, which will give the desired results. Water jets from the spreader shall not be directed at the embankment with such force that fill materials are washed out. Should too much water be added to any part of the fill, such that the material is too wet to permit the desired compaction from being obtained, rolling and all work on that section of the fill shall be delayed until the material has been TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTLT PROJECT NO. FC08892-115 B-3 allowed to dry to the required moisture content. The Contractor will be permitted to rework wet material in an approved manner to hasten its drying. 8. COMPACTION OF FILL AREAS Selected fill material shall be placed and mixed in evenly spread layers. After each fill layer has been placed, it shall be uniformly compacted to not less than the specified percentage of maximum density. Fill shall be compacted to the criteria above. At the option of the Soils Engineer, soils classifying as SW, GP, GC, or GM may be compacted to 95 percent of maximum density as determined in accordance with ASTM D 1557 or 70 percent relative density for cohesionless sand soils. Fill materials shall be placed such that the thickness of loose materials does not exceed 12 inches and the compacted lift thickness does not exceed 6 inches. Compaction as specified above, shall be obtained by the use of sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other equipment approved by the Engineer for soils classifying as CL, CH, or SC. Granular fill shall be compacted using vibratory equipment or other equipment approved by the Soils Engineer. Compaction shall be accomplished while the fill material is at the specified moisture content. Compaction of each layer shall be continuous over the entire area. Compaction equipment shall make sufficient trips to ensure that the required density is obtained. 9. COMPACTION OF SLOPES Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but not too dense for planting, and there is not appreciable amount of loose soils on the slopes. Compaction of slopes may be done progressively in increments of three to five feet (3' to 5') in height or after the fill is brought to its total height. Permanent fill slopes shall not exceed 3:1 (horizontal to vertical). 10. PLACEMENT OF FILL ON NATURAL SLOPES Where natural slopes are steeper than 20 percent in grade and the placement of fill is required, benches shall be cut at the rate of one bench for each 5 feet in height (minimum of two benches). Benches shall be at least 10 feet in width. Larger bench widths may be required by the Engineer. Fill shall be placed on completed benches as outlined within this specification. TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTLT PROJECT NO. FC08892-115 B-4 11. DENSITY TESTS Field density tests shall be made by the Soils Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density tests shall be taken in compacted material below the disturbed surface. When density tests indicate that the density or moisture content of any layer of fill or portion thereof is not within specification, the particular layer or portion shall be reworked until the required density or moisture content has been achieved. 12. SEASONAL LIMITS No fill material shall be placed, spread or rolled while it is frozen, thawing, or during unfavorable weather conditions. When work is interrupted by heavy precipitation, fill operations shall not be resumed until the Soils Engineer indicates that the moisture content and density of previously placed materials are as specified. 13. NOTICE REGARDING START OF GRADING The Contractor shall submit notification to the Soils Engineer and Owner advising them of the start of grading operations at least three (3) days in advance of the starting date. Notification shall also be submitted at least 3 days in advance of any resumption dates when grading operations have been stopped for any reason other than adverse weather conditions. 14. REPORTING OF FIELD DENSITY TESTS Density tests made by the Soils Engineer, as specified under "Density Tests" above, shall be submitted progressively to the Owner. Dry density, moisture content, and percentage compaction shall be reported for each test taken. 15. DECLARATION REGARDING COMPLETED FILL The Soils Engineer shall provide a written declaration stating that the site was filled with acceptable materials and was placed in general accordance with the specifications. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC) SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING 0 10 20 30 50 60 70 80 90 100 PERCENT RETAINED 40 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC) SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING PERCENT RETAINED 0 10 20 30 40 50 60 70 80 90 100 DD=108 SW=-0.2 WC=26.0 DD=101 SW=0.0 WC=11.1 DD=97 SW=0.4 WC=12.5 DD=123 SW=1.6 WC=18.0 DD=114 SW=0.4 WC=22.6 DD=108 SW=-0.2 WC=26.0 DD=101 SW=0.0 TH-2 El. 103.5 12/12 16/12 13/12 19/12 8/12 WC=10.9 DD=117 SW=3.8 WC=13.2 DD=118 SW=1.1 WC=15.9 DD=120 SW=-0.1 WC=11.9 DD=113 -200=19 WC=10.9 DD=117 SW=3.8 WC=13.2 DD=118 SW=1.1 WC=15.9 DD=120 SW=-0.1 WC=11.9 DD=113 -200=19 TH-3 El. 104.0 15/12 14/12 16/12 10/12 10/12 WC=13.3 DD=111 SW=1.2 WC=13.5 DD=112 SW=0.0 WC=13.3 DD=111 SW=1.2 WC=13.5 DD=112 SW=0.0 TH-4 El. 103.5 13/12 10/12 27/12 9/12 8/12 WC=17.1 DD=113 SW=1.2 WC=16.6 DD=116 SW=0.2 WC=17.1 DD=113 SW=1.2 WC=16.6 DD=116 SW=0.2 TH-5 El. 98.5 13/12 13/12 8/12 11/12 22/12 WC=11.2 DD=108 LL=41 PI=22 -200=69 WC=15.8 DD=117 SW=0.2 WC=14.3 DD=118 SW=-0.2 WC=19.5 DD=112 SW=0.0 WC=11.2 DD=108 LL=41 PI=22 -200=69 WC=15.8 DD=117 SW=0.2 WC=14.3 DD=118 SW=-0.2 WC=19.5 DD=112 SW=0.0 TH-6 El. 103.5 ELEVATION - FEET FIGURE 2 DRIVE SAMPLE. THE SYMBOL 39/12 INDICATES 39 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. ELEVATION - FEET WATER LEVEL MEASURED SEVERAL DAYS AFTER DRILLING. SAND, CLEAN TO CLAYEY, WET, MEDIUM DENSE, BROWN, REDDISH BROWN (SP, SC) 2. 3. CLAY, SANDY, MOIST, STIFF TO VERY STIFF, BROWN, OLIVE (CL) THE BORINGS WERE DRILLED ON MAY 10 AND 16, 2019 USING 4-INCH DIAMETER CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG. 1. LEGEND: NOTES: SAND AND GRAVEL, SLIGHTLY CLAYEY, WET, MEDIUM DENSE, BROWN, REDDISH BROWN (SP, GP) WATER LEVEL MEASURED AT TIME OF DRILLING. BORING ELEVATIONS WERE SURVEYED BY A REPRESENTATIVE OF OUR FIRM REFERENCING THE TEMPORARY BENCHMARK SHOWN ON FIGURE 1. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. 4. Summary Logs of Exploratory Borings WC DD SW -200 LL PI UC SS - - - - - - - - INDICATES DEPTH WHERE HOLE CAVED. INDICATES MOISTURE CONTENT (%). INDICATES DRY DENSITY (PCF). INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%). INDICATES PASSING NO. 200 SIEVE (%). INDICATES LIQUID LIMIT. INDICATES PLASTICITY INDEX. INDICATES UNCONFINED COMPRESSIVE STRENGTH (PSF). INDICATES SOLUBLE SULFATE CONTENT (%). TWG DEVELOPMENT, LLC 3620 EAST KECHTER ROAD CTL | T PROJECT NO. FC08892-115