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Home My WebLink AboutB14-0096 114017A (03-25-14) Geotech Study signed Ge Ptech G enw C d Sprn gsa Co orado 881601 Phone: 970-945-7988 HEPWORTH-PAWLAK GEOTECHNICAL Fax; 970-945-8454 Email: hpgeo@hpgeotech.com GEOT�CHNICAL STUDY PROPOSED DUPLEX LOT 15, BLOCK 9, VAIL INTERMOUNTAIN 27.54 SNOWB�RRY DRIVE VAIL, COLORADO JOB NO. 114 017A MARCH 25, 2014 PREPARED FOR: SLOPESIDE CONSTRUCTION, INC. ATTN: MIKE DANTAS 2121 N. FRONTAGE ROAD WEST PMB 206 VA1L, COLORADO 81657 mikedantas@comcast.net TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY............................................................................- 1 - BACKGROUND INFORMATION................................................................................- 1 - PROPOSED CONSTRUCTION.....................................................................................- 2 - SITECONDITIONS.......................................................................................................- 2 - GEOLOGICCONDITIONS...........................................................................................- 3 - FIELDEXPLORATION.................................................................................................- 3 - SUBSURFACE CONDITIONS......................................................................................- 4 - ENGINEERING ANALYSIS.........................................................................................- 5 - DESIGN RECOMMENDATIONS.................................................................................. 5 - FOUNDATIONS.........................................................................................................- 5 - FOUNDATION AND RETAINING WALLS............................................................- 6 - FLOORSLABS ..........................................................................................................- 8 - UNDERDRAIN SYSTEM..........................................................................................- 9 - SITEGRADING.........................................................................................................- 9 - SURFACEDRAINAGE...........................................................................................- 10 - LIMITATIONS .............................................................................................................- 11 - REFERENCES..............................................................................................................- 13 - FIGURE 1 - LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 - LOGS OF EXPLORATORY BORINGS FIGURE 3 - LEGEND AND NOTES FIGURES 4 - 7- SWELL-CONSOLIDATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS Job No. 114 017A �t� PURPOSE AND SCOPE OF STUDY This report presents the results of a geotechnical study far a proposed duplex to be located on Lot 15, Block 9, Vail Intermountain Subdivision, 2754 Snowberry Drive, Vail, Colorado. The project site is shown on Figure 1. The purpose of the study was to develop recommendations for the foundation design. The study was conducted in general accardance with our agreement for geotechnical engineering services to Slopeside Construction, Inc. dated January 21, 2014. A field exploration program consisting of exploratory borings was conducted to obtain information on the subsurface conditions. Samples of the subsoils and bedrock obtained during the field exploration were tested in the laboratory to determine their classification, compressibility or swell and other engineering chazacteristics. The results of the field exploration and laboratory testing were analyzed to develop geotechnical recommendations for the proposed building foundation and site grading designs. This report summarizes the data obtained during this study and presents our conclusions, design recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. BACKGROUND INFORMATION Hepworth-Pawlak Geotechnical previously performed a preliminary subsoil study for the water storage tank located on the adjacent Lot 14, submitting our findings in a report dated May 30, 2001, Job No. 101 311. We have been provided a copy of a geotechnical assessment for the Lot 14 water tank design prepared by Golder Associates, dated December 5, 2005, Job No. 053-2372. We have also been provided with a recent letter report regarding the excavation for the proposed duplex on Lot 15 and possible affects on the Lot 14 water tank by Michael West and Associates dated March 24, 2014. Information from these reports has been reviewed and considered in the prepazation of this report. Job No. 114 017A C£�tGCh -z - PROPOSED CONSTRUCTION The proposed duplex will be a four-story structure cut into the steep hillside of the Lot. There will be a one story master bedroom in the rear of the residence at the fourth floor level. The uphill side of the residence will retain an approximately 34 feet high cut with the cut daylighting on the north side near the adjacent Snowberry Drive. It is planned to shore the uphill side cuts for the building excavation with a permanent soil nail wall. It is planned to backfill the foundation with the on-site soils. There will be several low(4 to 5 feet high) boulder retaining walls along the east and west sides of the building. Ground floors will be slab-on-grade. We assume relatively light to moderate foundation loadings, typical of the proposed type of construction. There will also be some grading (up to about 4 feet maximum cut) on the uphill side of the nearby access road to the water storage tank to reduce the slope grade. If building loadings, location or grading plans change significantly from those described above, we should be notified to re-evaluate the recommendations contained in this report. SITE CONDITIONS The lot is vacant and located on steep northwesterly facing mountainside terrain above Snowberry Lane. Slope grades range from about 35 to 40%, becoming steeper (on the order of 50%) on the downhill side of the lot below the proposed building. The steeper grades along the downhill side of the lot are probably from cuts for construction of Snowberry Drive. The site was covered with about 4 feet of snow at the time of our field exploration which limited our observations. We expect most of the ground surface on the lot is natural except for the Snowberry Lane road cut. Elevation difference across the proposed building location is about 38 feet. Elevation difference across the lot is about 120 feet. Vegetation below the snow probably consists of grass and weeds. There are scattered evergreen trees on the lot. Job No. 114 017A �t��„� - 3 - The water storage tank on Lot 14 to the east is an above ground steel structure. The tenain at the tank also slopes down to the northwest. The tank site was graded by cut at the uphill, southern side and fill at the downhill, northern side. The tank is located about 145 feet east of the proposed duplex and about 30 feet higher in elevation. A previous (smaller) water tank on the site has been removed. GEOLOGIC CONDITIONS The site is not located within potential geologic hazard areas for rockfall, debris flow and avalanche according to the Town of Vail mapping. (Town of Vai12000a, 2000b, and 2000c). The hillside area to the southeast of the tank has been noted as an ancient landslide by Golder Associates in their report. We do not believe the subject Lot 15 is within the ancient landslide complex. The soils appear to consist of colluvium and alluvial deposits. The underlying bedrock is the Minturn Formation. There is a risk of construction induced slope instability on the subject lot due the planned relatively deep cuts. The risk of construction induced slope instability should be low provided the uphill sides of the planned excavation are retained with a permanent soil nail wall system as planned. Recommendations for the site grading and soil nail wall designs are discussed in the"Site Grading" section of this report. FIELD EXPLORATION The field exploration for the project was conducted between February 26 through 28, 2014. Three explaratory borings were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions. The borings were advanced with 4 inch diameter continuous flight augers powered by a track-mounted CME 45 drill rig. Snow removal by the client was needed to access the boring locations. The borings were logged by a representative of Hepworth-Pawlak Geotechnical, Inc. lob No. 114 017A C�tCCh - 4 - Samples of the subsoils and bedrock were taken with a 2 inch I.D. spoon sampler. The sampler was driven into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM Method D-1586. The penetration resistance values are an indication of the relative density or consistency of the subsoils and hardness of the bedrock. Depths at which the samples were taken and the penetration resistance values are shown on the Logs of Exploratory Borings, Figure 2. The samples were returned to our laboratory for review by the project engineer and testing. Slotted PVC pipe was installed in the borings to allow monitoring of the groundwater levels. Depths at which the pipe was installed in the borings are shown on the Figure 2 boring logs. SUBSURFACE CONDITIONS Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. The subsoils encountered, below about '/z foot of organic topsoil, consisted of clayey to occasionally very clayey silty sand that was typically gravelly and contained scattered cobbles. The sand soils were medium dense to dense with depth and extended down to depths from about 51 to 79 feet where hard sandstone/siltstone bedrock was encountered. Drilling in the hard bedrock with auger equipment was generally difficult. Laboratory testing performed on samples obtained from the borings included natural moisture content and density,percent finer than sand size gradation analyses, Atterberg limits, and unconfined compressive strength. Results of swell-consolidation testing performed on relatively undisturbed drive samples of the sand soils,presented on Figures 4 through 7, indicate low to moderate compressibility under conditions of loading and wetting. The liquid and plastic limits testing indicate the fine portion of the sand soils have low plasticity. The unconfined compressive strength testing indicates the more clayey sand soils to be stiff to very stif£ The laboratory testing is summarized in Table 1. Job No. 114 017A G�tECh - 5 - Free water was encountered in the borings at the time of drilling near the surface of the bedrock at depths from about 51 to 79 feet. When checked 22 to 24 days following drilling, the free water levels were from about 49 to 81'/z feet. The snow depth around the boring locations made accurate measurement of the water levels difficult. It appears the groundwater is generally perched on the bedrock surface. The subsoils and bedrock were generally moist. ENGINEERING ANALYSIS The project will be difficult to constnxct due to the steep hillside terrain and the extensive grading planned. Permanently retaining the uphill side cuts of the excavation will be needed to reduce the potential for construction induced slope instability. It appears that the planned project, if properly designed and constructed, will not adversely impact the water storage tank on the adjacent Lot 14. Lightly to moderately loaded spread footings beazing on the natural granular soils should be suitable for foundation support of the building with a relatively low risk of settlement. We do not expect groundwater level will be encountered in the building excavation. Shallow seasonal seepage is typical and the shoring should intercept and drain these layers. Drilled piers or driven piles down into bedrock aze feasible foundation alternatives to spread footings, and provide a low risk of foundation movement and could be used to help resist lateral loadings. Provided below are recommendations for a spread footing foundation. If recommendations for drilled piers or driven piles are desired, we should be contacted. DESIGN RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratory borings and the nature of the proposed construction, we recommend the building be founded with spread footings bearing on the natural granular soils. Job No. ll 4 017A Ger+U�tECh - 6 - The design and construction criteria presented below should be observed for a spread footing foundation system. 1) Footings placed on the undisturbed natural granular soils should be designed for an allowable bearing pressure of 2,500 psf. Based on experience, we expect settlement of footings designed and constructed as discussed in this section will be up to about 1 to 1'/z inches. We should review the settlement potential when foundation loadings are known. 2) The footings should have a minimum width of 18 inches for continuous walls and 2 feet for isolated pads. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Placement of foundations at least 48 inches below exterior grade is typically used in this area. 4) Continuous foundation walls should be well reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least 12 feet. Foundation walls acting as retaining structures should also be designed to resist lateral earth pressures as discussed in the "Foundation and Retaining Walls" section of this report. 5) The topsoil and any loose or disturbed soils should be removed and the footing bearing level extended down to the relatively dense, natural granular soils. The exposed soils in footing area should then be moisture adjusted to near optimum and compacted. If water seepage is encountered, the footing areas should be dewatered before concrete placement. 6) A representative of the geotechnical engineer should observe all footing excavations prior to concrete placement to evaluate bearing conditions. FOUNDATION AND RETAINING WALLS Foundation walls and retaining structures up to 15 feet in height which are laterally supported and can be expected to undergo only a slight amount of deflection should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit lob No. 114 017A ��„� - � - weight of at least 50 pcf for backfill consisting of the on-site granular soils. Foundation walls and retaining structures greater than 15 feet in height which are laterally supported and can be expected to undergo only a slight amount of deflection should be designed for a uniform lateral earth pressure of 25H in psf where H is the wall height in feet for backfill consisting of the on-site granular soils. Cantilevered retaining sh•uctures up to 15 feet in height which are separate from the main building and can be expected to deflect sufficiently to mobilize the full active earth pressure condition should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 45 pcf for backfill consisting of the on-site granular soils. Cantilevered retaining structures taller than 15 feet in height which are separate from the main building and can be expected to deflect sufficiently to mobilize the full active earth pressure condition should be designed for a uniform lateral earth pressure of 22.SH in psf where H is the wall height in feet for backfill consisting of the on-site granular soil. The backfill should not contain topsoil or oversized rocks and be compacted as recommended below. It should be feasible to reduce the lateral earth pressure load on the uphill building wall provided the excavation cut slope is retained with a permanent soil nail wall structure. For about a 35 feet high foundation wall with a permanent soil nail wall located 5 feet from the wall we estimate a uniform lateral earth pressure on the wa11 of 13H in psf where H is the wall height in feet. We should review our lateral earth pressure recommendation when the grading and soil nail wa11 plans have been developed. All foundation and retaining structures should be designed for appropriate hydrostatic and surcharge pressures such as adjacent footings,traffic, construction materials and equipment. The pressures recommended above assume drained conditions behind the walls and a horizontal backfill surface. The buildup of water behind a wall or an upward sloping backfill surface will increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain should be provided to prevent hydrostatic pressure buildup behind walls. Backfill should be placed in uniform lifts and compacted to at least 90% of the masimum standard Proctor density at a moisture content near optimum. Backfill in pavement and Job No. 114 017A �Hg�C�„� - 8 - walkway areas should be compacted to at least 95% of the maacimum standard Proctor density. Care should be taken not to overcompact the backfill or use large equipment near the wall, since this could cause excessive lateral pressure on the wall. Some settlement of deep foundation wall backfill should be expected, even if the material is placed correcfly, and could result in distress to facilities constructed on the backfill. We estimate settlement of the onsite soils compacted to at least 95% standard Proctor density will be about 1% of the fill depth. Use of a select granular, import material such as road base and increasing compaction to at least 98% standard Proctor density could be done to reduce the settlement potential. The lateral resistance of foundation or retaining wall footings will be a combination of the sliding resistance of the footing on the foundation materials and passive earth pressure against the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated based on a coefficient of friction of 0.40. Passive pressure of compacted backfill against the sides of the footings can be calculated using an equivalent fluid unit weight of 400 pcf. The coefficient of friction and passive pressure values recommended above assume ultimate soil strength. Suitable factors of safety should be included in the design to limit the strain which will occux at the ultimate strength,particularly in the case of passive resistance. Fill placed against the sides of the footings to resist lateral loads should be a suitable granular material compacted to at least 95% of the maximum standard Proctor density at a moisture content near optimum. FLOOR SLABS The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded slab- on-grade construction. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minimum 6 inch layer of free-draining gravel should be placed beneath basement level slabs to facilitate drainage. This material should consist of minus 2 inch Job No. 114 017A �t��„i - 9 - aggregate with at least 50%retained on the No. 4 sieve and less than 2%passing the No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 95%of maYimum standard Proctor density at a moisture content near optimum. Required fill can consist of the on-site granular soils devoid of vegetation,topsoil and oversized rock. UNDERDRAIN SYSTEM Although free water was encountered below planned excavation depths during our exploration, it has been our experience in mountainous areas and where clayey soils are present that local perched groundwater can develop during times of heavy precipitation ar seasonal runof£ Frozen ground during spring runoff can also create a perched condition. We recommend below-grade construction, such as retaining walls, crawlspace and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain system. The drains should consist of drainpipe placed in the bottom of the wall backfill surrounded above the invert level with free-draining granular material. The drain should be placed at each level of excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1%to a suitable gravity outlet. Free-draining granular material used in the underdrain system should contain less than 2%passing the No. 200 sieve, less than 50%passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at least 2 feet deep and extend to above any groundwater seepage encountered in the excavation cut face. The drain gravel should be separated from the on-site soil backfill by a filter fabric such as Mirafi 140N. SITE GRADING The risk of construction-induced slope instability at the site appears low provided the uphill cuts for the building are retained with a permanent type soil nail wall system. We understand the soil nail wall will be up to about 35 feet tall. The wall should be properly designed and constructed to act as a permanent structure including epoxy coated Job No. 114 017A �t� - 10 - reinforcement bars and a relatively thick reinforced shot-crete facing, and adequate overall slope stability. We suggest the following soil parameters for the soil nail wall design: angle of internal friction of 30 to 32 degrees, cohesion of 50 to 100 psf, and moist unit weight of 125 to 130 pcf. There should be at least 20% drainage coverage behind the wall connected to a drain pipe and gravel system at the bottom of the wall that flows to gravity outlet. The soil nail wall should be designed for both internal and global stability. The wall should be designed by an engineer with considerable experience in the area. We should review the soil nail wall design prior to construction. Unretained cut and fill depths should be limited to one level, about 8 to 10 feet, and graded at a stable slope. Permanent unretained cut and fill slopes should be graded at 2 horizontal to 1 vertical or flatter and protected against erosion by revegetation or other means. Embankment fills should be compacted to at least 95% of the masimum standard Proctor density near optimum moisture content. Prior to fill placement, the subgrade should be carefully prepared by removing all vegetation and topsoil and compacting to at least 95% of the maximum standard Proctor density. The fill should be benched horizontally into the hillside. The risk of slope instability will be increased if seepage is encountered in cuts and flatter slopes may be necessary. If seepage is encountered in cuts, an investigation should be conducted to determine if the seepage will adversely affect the cut stability. For the re-grading of the lower portion of the tank road, the cuts should be limited to about 4 to 5 feet and graded no steeper than 2 (H) to 1(V) as discussed above, or retained such as with a stacked boulder wall or other means. There will be stacked boulder retaining walls located along the east and west sides of the residence. The boulder retaining walls should be limited to about 6 feet in height and designed as gravity retaining structures. Underdrains should be provided behind the boulder retaining walls. We can design the boulder retaining walls if desired. SURFACE DRAINAGE There could be considerable surface water runoff from the mountainside above the site, especially during spring and early suimner runoff. The following drainage precautions Job No. 114 017A C_'-�PteCh - 11 - should be observed during construction and maintained at all times after the duplex has been completed: 1) Inundation of the foundation excavations and underslab areas should be avoided during construction. 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95% of the masimum standard Proctor density in pavement and slab areas and to at least 90% of the maximum standard Proctar density in landscape areas. Settlement of deeper backfill areas should be expected and the backfill grading design should take this into consideration. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in paved areas. Free-draining wall backfill should be capped with filter fabric such as Mirafi 140N and about 2 feet of the on-site soils to reduce surface water infiltration. 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. 5) Landscaping which requires regular heavy irrigation should be located at least 5 feet from foundation walls. LIMITATIONS This study has been conducted in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either express or implied. The conclusions and recommendations submitted in this report are based upon the data obtained from the exploratory barings drilled at the locations indicated on Figure 1,the proposed type of construction and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then a professional in this special field of practice should be Job No. 114 017A �t��„ _ 12 _ consulted. Our findings include interpolation and extrapolation o'Pthe subsurface conditions idenYified at the exploratory borings and variations in the subsurface conditions may not become evident until excavation is performed. IFconditions encountered durit�g construction appear different from those described in this report, we should be ilotified so that re-evaluation of the recommendations may be made. Tl�is report has been prepared for the exclusive use by our client for design purposes. We are not responsible far technical inteipretations by others of our informatio�t. As the project evolves, we should provide continued consultation and field seivices during construction to review and monitor the implementation of our recommendations, and to verify that tlte recommendations have been appropriately interpreted. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recoinmend on-site observation of excavations and foundation bearing strata and testing of structural fill by a representative of the geotechnical engineer. Respectfully Submitted, HEPWORTH - PA LAK GE,��p1 r�j;CAL, INC. +! ,e � ��i = ,C`{ � g ° David A. Young, P.E. _�y� -216 � � s'�s� 3 2� '� �t/�a Reviewed by: y�''��N��`�� ,�_.;:x`�,__ � .�' r � . . --.,�� ,--, - � ��f.��,�� Steven L. Pawlak, P.E. DAY/ksw cc: Inteiltion Architecture - Seth Bossung (seth(c�,intentionarchitecture.com) KRM Consultauts—Joe O'Malley (joena,krmconsultants.com) HTM Construction— Chris Todd (Chris.Todd(a�htmconstruction.com) .lob No. 114 017A �t�h - 13 - REFERENCES Town of Vail, 2000a. Official Rockfall Hazard Map, Town of Vail. Prepared by the Town of Vail,Vail, Colorado (Adopted by the Town Council on October 17, 2000). Town of Vail, 2000b. Official Debris Flow Hazard Map, Town of Vail. Prepared by the Town of Vail, Vail, Colorado (Adopted by the Town Council on October 17, 2000). Town of Vail, 2000c. Official Avalanche Hazard Map, Town of Vail. Prepared by the Town of Vail, Vail, Colorado (Adopted by the Town Council on October 17, 2000). Job No. 114 017A ��h APPROXIMATE SCALE _ g1g0 1" = 50' � — �p a�gp� ��. � 81"f 0 i / i ,�60 / / 0 \ / � / � � 8150 m��/ I �/ //� ` /� � �i a�RO � � / /� � g13� 8�?� � / / � / 8160 � � �/ � � / i — �\ \ I � � �/ � �PREVIOUS �I � � / �� / I� OCATIONNK� � // I l � � � — — 8�i� \\ _ �� 1 �� / � I I /� � � � � - - EXISTING i WATER TANK � � � LOT 15 / � B�'16 a11� Golder Associates gt5o ' � I 2734�OWBER�Y DRI�E � � � � 12-05-05 Report I_ _ _ � � � � , � LOT 16 Job No. 053-2373 — i � // ' / g1�� I / � � i � _. � ' � / � � — � I �i� / � _ � BORING 1 i� /� I � / i � 1 � � � / a�AO � � / � � � � � J� � � BORING2 �/ ,�g0- - � _ � � � � LOTi � � � � I i� � / i — PR OSED I a 0 $ � � DU EX i � � p9 / � � � � � _ IX /I i � � i — � ' � � � � � i 8�,zp— � � � v � � / � i � � i � � � i � i g110 - - - - - � � � � � � � � �� / � _ _ � � 6��3 / � � � � � g100- - � � � � � � � � $�$p � � �� i g0 SNOWBERRY DRIVE 114 017A � C�7Q I'1 LOCATION OF EXPLORATORY BORINGS Figure 1 HEPWORTH-PAWLAK GEOTECHNICAL BORING 1 BORING 2 BORING 3 ELEV.= 8828' ELEV.= 8802' ELEV.= 8788' � 12/72 � 24/12 18/12 WC=10.4 16/12 24/12 DD=124 WC=15.5 WC=71.5 -200=38 DD=111 10 DD=123 LL=23 �� -200=30 PI=7 18/12 WC=13.5 20/12 17/12 DD=117 WC=11.1 WC=12.0 18/12 DD=721 DD=119 -200=40 LL=29 20 P1=17 50/9 UC=2,250 20 16/12 WC=15A 23/12 DD=116 WC=10.3 26��2 DD=122 30 30 23/72 WC=17.8 50/9 DD=120 WC=9.1 43/12 -200=36 DD=130 WC=9.5 � � -200=34 DD=126 a�i 40 LL=23 -200=26 40 �' r P�=� � � 4O/12 UC=S,9OO L a p WC=62 31/12 � DD=126 50/10 24 50 0 50 40/12 — 50/6 WC=10J 50/5 DD=125 WC=9.3 DD=131 60 -zoo=si 60 70/5 0 LL=22 — PI=7 22 = 60/6 �� 70 50/5 0 80 = 80 24 so/s wc=a.s DD=130 Note: Explanation of symbols is shown on Figure 3. BOTTOM OF BORING AT 83 1/2 FEET H 114 017A C�"� LOGS OF EXPLORATORY BORINGS Figure 2 HEPWORTH�PAWLAKGEOTECHNICAL LEGEND: � TOPSOIL; organic sandy silty clay, moist, black. � SAND (SC); clayey to occasionally very clay, silty, typically gravelly, scattered cobbles, medium dense to dense with depth, moist, mixed brown, to medium low plastic fines. � SANDSTONE/SILTSTONE BEDROCK; hard, moist, mixed brown, non-plastic. Minturn Formation. � Relatively undisturbed drive sample; 2-inch I.D. California liner sample. 24�12 Drive sample blow count; indicates that 24 blows of a 140 pound hammer falling 30 inches were required to drive the California sampler 12 inches. � Free water level in boring and number of days following drilling measurement was taken. � Indicates slotted PVC pipe installed in boring to depth shown. NOTES: 1. Exploratory borings were drilled between February 26 and 28, 2014 with 4-inch diameter continuous flight power auger. 2. Locations of exploratory borings were measured approximately by pacing from features shown on the site plan provided. 3. Elevations of exploratory borings were obtained by interpolation between contours shown on the site plan provided. Boring logs are drawn to depth. 4. The exploratory boring locations and elevations should be considered accurate only to the degree implied by the method used. 5. The lines between materials shown on the exploratory boring logs represent the approximate boundaries between material types and transitions may be gradual. 6. Water level readings shown on the logs were made at the time and under the conditions indicated. Fluctuations in water level may occur with time. 7. LaboratoryTesting Results: WC = Water Content (%) DD = Dry Density (pc� -200 = Percent passing No. 200 sieve LL = Liquid Limit(%) PI = Plasticity Index (%) UC = Unconfined Compressive Strength (ps� 114 017A �'�Ch LEGEND AND NOTES Figure 3 HEPWORTH-PAWLAK GEOTECHNICAL Moisture Content = 15.0 percent Dry Density = 116 pcf Sample of: Clayey Silty Sand with Gravel From: Boring 1 at 22 Y Feet 0 1 0 No movement o upon � 2 wetting � a E 0 c� 3 4 0.1 1.0 10 100 APPLIED PRESSURE- ksf Moisture Content = 11.8 percent Dry Density = 120 pcf Sample of: Clayey Silty Sand with Gravel From: Boring 1 at 32 Y Feet 0 1 ° No movement o upon � 2 wetting � a E 0 U 3 4 0.1 1.0 10 100 APPLIED PRESSURE-ksf I—I 114 017A �� t�C�''� SWELL-CONSOLIDATION TEST RESULTS Figure 4 HEPWORTH-PAWLAK GEOTECHNICAL Moisture Content = 6.2 percent Dry Density = 126 pcf Sample of: Clayey Silty Sand with Gravel From: Boring 1 at 42 Y Feet 0 1 0 No movement a upon 'N 2 wetting � Q E 0 c.> 3 4 0.1 1.0 10 100 APPLIED PRESSURE- ksf Moisture Content = 12.0 percent Dry Density = 119 pcf Sample of: Clayey Silty Sand From: Boring 2 at 14 Feet 0 1 � Compression o upon N 2 wetting m Q E 0 U 3 4 5 0.1 1.0 10 100 APPLIED PRESSURE-ksf 114 017A �eCh SWELL-CONSOLIDATION TEST RESULTS Figure 5 HEPWORTH-PAWLAK GEOTECHNICAL Moisture Content = 10.3 percent Dry Density = 122 pcf Sample of: Clayey Silty Sand with Gravel From: Boring 2 at 24 Feet 0 o � o No movement ��, upon � 2 wetting a E 0 U 3 4 0.1 1.0 10 100 APPLIED PRESSURE- ksf Moisture Content = 10.7 percent Dry Density = 125 pcf Sample of: Sandstone/Siltstone Bedrock From: Boring 2 at 54 Feet 0 a 1 � No movement 4 upon � 2 wetting a E 0 U 3 4 0.1 1.0 10 100 APPLIED PRESSURE- ksf 114 017A �eC�"� SWELL-CONSOLIDATION TEST RESULTS Figure 6 HEPWORTH-PAWLAKGEOTECHNICAL Moisture Content = 15.5 percent Dry Density = 111 pcf Sample of: Clayey Silty Sand From: Boring 3 at 6 Feet 0 0 1 � No movement �° upon � 2 wetting Q E 0 U 3 4 5 6 0.1 1.0 10 100 APPLIED PRESSURE- ksf Moisture Content = 13.5 percent Dry Density = 117 pcf Sample of: Clayey Silty Sand with Gravel From: Boring 3 at 11 Feet 0 � 1 � No movement o upon � p wetting a E 0 U 3 4 0.1 1.0 10 100 APPLIED PRESSURE- ksf 114 017A �L1@Ch SWELL-CONSOLIDATION TEST RESULTS Figure 7 HEPWORTH�PAWL4K GEOTECHNICAL � 0 � � � � � � � b d a 3 �3 �3 ,� �3 �3 ,� �3 � Z b b b b � b b b b � b❑ bp �, b b � O Y N� � c�a cCa � c�C c�C c�a cCa � cd cd � c�a cCd � U (/l C/] V1 V] � C/� C/� V] V] .-"-'. 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