Geotechnical Report Rifle Roundabouts Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado

Transcription

1 Geotechnical Report Rifle Roundabouts Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado Project No February 9, 2005 Prepared for: Schmueser Gordon Meyer, Inc. 118 West 6 th Street, Suite 200 Glenwood Springs, CO Attn: Jeff Simonson, P.E. Prepared by: Yeh and Associates, Inc Mel Ray Road Glenwood Springs, Colorado Phone: Fax:

2 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado TABLE OF CONTENTS PURPOSE AND SCOPE:... 1 PROPOSED CONSTRUCTION:... 1 SITE CONDITIONS:... 1 GEOLOGY:... 2 SUBSURFACE INVESTIGATION:... 3 SUBSURFACE CONDITIONS:... 3 LABORATORY TESTING... 4 PRELIMINARY PAVEMENT DESIGN:... 5 Subgrade Materials... 5 Pavement Recommendations... 6 Subgrade Preparation... 8 SURFACE DRAINAGE:... 9 LIMITATIONS:... 9 List of Figures Figure 1 Site Location Map Figures 2A & 2B Engineering Geology Sheets Appendices Appendix A Boring Logs Appendix B Laboratory Results Appendix C Pavement Thickness Design i

3 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado PURPOSE AND SCOPE: This report presents the results of our geotechnical study for the proposed construction of three roundabout intersections at Interstate 70 (I70) and Taughenbaugh Boulevard, Rifle, Colorado. The purpose of this study was to evaluate geotechnical characteristics of the onsite soils and to provide geotechnical recommendations for the pavement design for the proposed roundabouts. The study was conducted in accordance with our proposal dated September 9, A field exploration program consisting of geologic reconnaissance and exploratory drilling was conducted to obtain information on subsurface conditions. The drilling was observed by Yeh and Associates personnel on December 7 th and December 8 th, Material samples obtained during the field exploration were examined by the project personnel and representative samples were tested in the laboratory to determine the classification and engineering characteristics of the onsite material. Based on the information obtained, Yeh and Associates has completed an engineering analysis of the subsurface conditions. This report summarizes the data gathered, the results of our analysis, and our conclusions and preliminary recommendations based on the proposed construction, site reconnaissance, geotechnical subsurface investigation, and results of laboratory testing. PROPOSED CONSTRUCTION: The proposed three roundabout intersections are located at I70 and Taughenbaugh Boulevard in Rifle, Colorado. These intersections will replace the existing roadway configuration near the interstate exits. Approximately one mile of pavement/roadway will be improved under this project. SITE CONDITIONS: The topography along the proposed roadway is essentially flat with a regional slope direction toward the Colorado River to the north. The alignment of Taughenbaugh Boulevard runs approximately north to south, intersecting with east and west I70 as 1

4 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado shown in Figure 1. The site is at the location of the eastbound and westbound on and off ramps and overpass for I70. Commercial development is presently occurring on the south end of the proposed construction area. The Colorado River borders the north end of the project site. The drainage for the subject site is fair with the surface water being drained through culverts that are mainly located along the west side of the intersections and in some curb and gutter systems in the commercial district to the south. Although not observed at the time of our site reconnaissance or during our field investigation, surface water flow is intermittent with storm events, including snow melt. It also appears that no other surface water, springs or seeps occur within the study area except the areas east and west of the northernmost roundabout which are low areas that occasionally may have standing water. GEOLOGY: The geology of the site was investigated by reviewing published and unpublished geologic maps and reports, observing field conditions and drilling ten (10) test borings. Based on our investigation, the site consists of Quaternary alluvial deposits with varying thicknesses of clayey sand and sandy clay. The surficial material appears to consist of flood plain deposits resulting from changing stream levels of the Colorado River and cohesive deposits originating from the hillside to the south. The resulting material is typically a mixture of interbedded and discontinuous sand, silt, clay, gravel, cobbles and boulders. Bedrock is generally not exposed at the ground surface. It has been mapped by the U.S. Geological Survey (USGS) as being the Tertiary age Wasatch Formation. This formation is variegated in color as redbrown to redpurple, yellowbrown, tan and white conglomerate, sandstone, siltstone, mudstone and claystone. 2

5 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado SUBSURFACE INVESTIGATION: Representatives from our firm explored the subsurface conditions along the proposed roadway on December 7 th and December 8 th, Our investigation included drilling, sampling, and logging of ten exploratory borings to depths ranging from 5.1 to 11.5 feet at the approximate locations shown on Figures 2A and 2B. Test holes were drilled with a Dietrich 53 truck mounted drill rig utilizing 4inch diameter, solid stem augers. Soil samples were collected at selected intervals in each of the borings utilizing a California sampler and/or a standard split spoon sampler. Disturbed drive samples were obtained from the standard split spoon samples in accordance with ASTM D 1586 and blow counts were recorded for Standard Penetration Tests (SPT). Relatively undisturbed samples were obtained from the California sampler and blow counts were recorded for Penetration Tests (PT). The PT and SPT when properly evaluated are indicators of the consistency or relative density of the material tested. The results are shown on the Boring Logs, Appendix A. All boreholes were backfilled using the excavated material and additional sand as needed. Borings excavated in the asphalt road surface were also covered with 6 to 8 inches of asphaltic cold patch. The proposed boring locations were surveyed by Schmueser Gordon Meyer of Glenwood Springs, Colorado and placed on a base map. The actual borings were located on a base map using hand survey methods. SUBSURFACE CONDITIONS: The exploratory borings were drilled to obtain the current subgrade conditions and to determine the design criteria for the proposed alignment. The locations of the borings are presented on the Engineering Geology Sheets, which are found in Figures 2A and 2B. Graphical boring logs of the conditions encountered are presented in Appendix A. Borings 1, 810 and 1315 encountered thin layers of granular road base or fill on thick deposits of native alluvial soils. Borings 7, 11 and 12 encountered only deposits of alluvial soils. Borings 26 were not drilled due to weather restrictions placed on the 3

6 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado drilling by the Colorado Department of Transportation (CDOT). The alluvial soils are generally sands or gravels containing silts, clays and cobbles. Characteristics of this material are typically nonplastic to low plasticity with occasional medium plastic clay lenses, dense to very dense, dry to damp, brown to dark brown in color, and contains subangular to rounded polygenetic clasts. Boring 12 encountered significantly thicker lenses of clay with higher plasticity than found in the other borings. Undocumented fill material may be encountered during construction. Natural onsite materials and imported material may have been reworked during the original construction of I70 and during subsequent construction along the highway. These materials are characteristically loose and may require recompaction or removal during construction. Free groundwater was not encountered in any of the test holes during drilling. Variations in groundwater conditions may occur seasonally. The magnitude of the variation will be largely dependent upon the amount of spring snowmelt, duration and intensity of precipitation, local landscape irrigation practices, site grading changes, and the surface and subsurface drainage characteristics of the surrounding area. Perched water tables may be present, but were not encountered in these borings. LABORATORY TESTING Laboratory testing was conducted to study the engineering characteristics of the materials obtained in the exploratory borings. Samples obtained from the borings were examined and visually classified. Laboratory testing was performed on selected samples to determine their classification, gradation, Atterberg limits, moisture contents, moisturevolume change characteristics, and RValues. Results of the laboratory testing are shown in the Summary of Laboratory Test Results found in Appendix B. The testing was conducted in general accordance with recognized test procedures, primarily those of the American Society for Testing and Materials (ASTM) or American Association of State Highway Transportation Officials (AASHTO). 4

7 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado PRELIMINARY PAVEMENT DESIGN: A pavement section is a layered structure designed to disperse dynamic traffic loads to the subgrade. The performance of the pavement structure depends on the traffic loadings and physical properties of the subgrade materials. As described below, soils are represented for flexible pavement design purposes by means of a soil support value that is empirically related to strength. Subgrade Materials Based on the results of our field exploration and laboratory testing the pavement subgrade materials were natural interbedded and discontinuous deposits of gravelly sand with silts and clays. These soils were generally classified as A4, A6. and A26 4 in accordance with the American Association of State Highway and Transportation Officials (AASHTO) and SC, SM CLML and CL in accordance with the Unified Soil Classification System (USCS). Road base and fill material was generally classified as silty to clayey sand with gravel (A1a and A26, SC, SM). Swell/Consolidation tests were conducted in accordance with ASTM D4546 Procedure B to determine the swell or collapse potential of selected samples of the subgrade materials upon the addition of water. The test results indicate that the subgrade soils tested possess a slight consolidation potential of 0.1%. Two Hveem Rvalue tests (ASTM 2844) were performed on samples of the composite subgrade materials. The results indicate overall values of 13 through 19 at an exudation pressure of 300 psi. For this pavement design, an Rvalue of 10 was used to calculate a resilient modulus (Mr) of 3562 psi using equation 2.2 in the 2005 CDOT Pavement Design Manual. Traffic loading information was provided by Schmueser Gordon Meyer of Glenwood Springs. The 20year design 18kip Equivalent Single Axle Loads (ESALs) for the flexible pavement on SH 13 was calculated to be 1,938,917 based on 2002 Average Daily Traffic (ADT) and projected 2025 ADT values. 5

8 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado Pavement Recommendations Only asphalt pavement sections were designed for this report. Both full depth and composite asphalt pavement sections using a combination of asphalt concrete and aggregate base course (ABC), and pit run subbase (ABC, Class 2 or Class 3 with an R value > 60) are presented in the table below. Pavement section thicknesses were calculated using the Darwin computer program following the 2005 CDOT Pavement Design Manual. The design parameters for pavement design in accordance with CDOT Standards are shown in the following table. Asphalt Pavement Design Parameters Initial Serviceability 4.5 Reliability Level, % 95 Terminal Serviceability 2.5 Overall Standard Deviation.44 Construction Stage 1 Resilient Modulus, psi Year Design ESALs 1,938,917 HBP Str. Layer Coefficient 0.44 ABC Str. Layer Coefficient 0.12 Subbase Str.Layer Coefficient 0.10 The Darwin Program outputs of the pavement thickness designs are shown in Appendix C and are summarized below. Design Life Thickness Section Pavement Type (years) (inches) Full Depth HBP SH13 HBP + ABC (Class 6) HBP + ABC + Subbase As can be seen in the above table, there are a number of ways to construct a pavement which will satisify the design criteria for the anticipated traffic loads over the next 20 years. 6

9 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado Full depth asphalt is fairly fast and causes the least traffic disruption of the three options since the least amount of removal (if any) will be required. HBP is the most expensive of the materials used in this pavement, so the construction cost of this option might be the highest. The HBP and ABC combination requires an intermediate amount of removal of existing embankment. In addition, the ABC will be better able to carry traffic in a temporary application without pavement than the third option. The third option is to use a larger depth of subbase (pit run Class 2 or Class 3 base) and may be the most economical option from the construction cost standpoint. That cost needs to be weighed against the cost of traffic control and disruption. We recommend the HBP, ABC, and subbase option if traffic can be handled during construction without cutting off the use of SH 13 between Rifle and the businesses south of I 70. For the asphalt mix, we recommend that the asphalt mix meet Grading SX (100) criteria in accordance with the current CDOT Specifications. The SuperPave Gyratory Revolutions (N des ) for the asphalt mix should be 100. A performance graded binder meeting the requirements of PG 5828 is recommended for the SX(100) mix. This binder provides a 96% reliability against rutting and 98% reliability against low temperature thermal cracking. As an option to improve the longterm performance of the pavement, the top 2 inch lift of the asphalt pavement could be made using a polymer modified binder meeting the requirements for Performance Grade PG The PG 7628 is recommended to prevent rutting because of the turning movements and the slow moving nature of the anticipated traffic. This binder has performed well in applications of heavy, slow moving traffic such as roundabouts and intersections. Along with the increased rut resistance, PG 7628 still provides the low temperature properties needed to reduce low 7

10 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado temperature cracking and has been shown to increase performance life 10 or more percent. Regardless of the pavement chosen, the asphalt mix for asphalt pavement should be placed in 2 to 3 inch lifts. We recommend that the total asphalt pavement thickness be a minimum of 5 inches to prevent tearing by turning traffic on the roundabouts, and also if construction is delayed for winter, the lower 3 inch lift could carry traffic over the winter and the final lift could be placed in the following spring. Aggregates for hot plant mix bituminous pavement should be of uniform quality, composed of clean, hard, durable particles of crushed stone, gravel, or slag. Excess of fine material should be wasted before crushing. The specifications of gradation for the Grading SX are shown below: Grading SX Sieve Size Percent Passing by Weight, % 3 / / /8 * #4 * # #30 * # *See details in CDOT Standard Specifications. Subgrade Preparation Prior to placing subbase or aggregate base course and asphalt pavement, the entire subgrade area should be scarified to a depth of 12 inches and recompacted to the specified relative compaction with a moisture content in accordance with the CDOT 8

11 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado Standard Specification for Road and Bridge Construction. In locations where the inplace subgrade contains more than 40% minus 200 material, a separator fabric conforming to CDOT Separator Geotextile Class B should be installed prior to placing the subbase. Imported fill material should be compacted in thin lifts to optimum moisture plus or minus two percent of optimum moisture content in accordance AASHTO T 99 or T 180. As noted above, the subbase material should have a minimum Rvalue of 60, and the ABC should have a minimum Rvalue of 77. For all layers, drainage needs to be addressed during construction to prevent ponding of water and provide for ease of construction. The pavement subgrade and each layer ABC should be proof rolled with a heavily loaded pneumatictire vehicle. Areas which deform more than 0.5 inch under heavy wheel loads should be removed, replaced if necessary and reworked to achieve a stable subgrade prior to paving. We recommend that proof rolling and compaction tests be performed under the direct supervision of a representative of the geotechnical engineer. SURFACE DRAINAGE: The collection and diversion of surface drainage away from paved areas is extremely important to the satisfactory performance of pavement. Proper design of drainage should include prevention of ponding of water on or immediately adjacent to pavement areas. All landscape sprinkler heads adjacent to pavement areas should be frequently checked for leaks and maintained in good working order. Overspray from sprinklers should be minimized. Slopes and other stripped areas should be protected against erosion by revegetation or other methods. LIMITATIONS: This study has been conducted in accordance with generally accepted geotechnical engineering practices in this area for use by the client for design purposes. The conclusions and recommendations submitted in this report are based upon the data obtained from exploratory borings, a preliminary field reconnaissance and the proposed type of construction. The nature and extent of subsurface variations across the site may not become evident until excavation is performed. If during construction, fill, soil, 9

12 Rifle Roundabouts Project NO Interstate 70 and Taughenbaugh Boulevard Rifle, Colorado or water conditions appear to be different from those described herein, this office should be advised at once so reevaluation of the recommendations may be made. We recommend onsite observation of excavations and foundation bearing strata by a representative of the geotechnical engineer. Respectfully Submitted, YEH AND ASSOCIATES, INC. Robert LaForce, P.E. Reviewed by ShanTai Yeh, P.E. 10

13 References Shroba, R.R., Green, M.W., and Fairer, G.M., 1995, Preliminary geologic map of the Rifle quadrangle, Garfield County, Colorado, OpenFile Report 9552, U.S. Geological Survey.

14 COLORADO SITE LOCATION Interstate 70 Taughenbaugh h Boulevard Rifle Roundabouts City of Rifle, Colorado Pavement Design Report FIGURE 1 SITE MAP 0170 Mel Ray Road Glenwood Springs, CO Phone: (970) Fax: (970)

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17 APPENDIX A BORING LOGS

18 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH01 Project Number: Date: Sheet 1 of 1 Boring Began: 12/8/2004 Drilling Method: SolidStem Auger Completed: 12/8/2004 Drill Bit: Casing: Drill: Dietrich 53 Truck mount Weather: Cloudy, cold,~30f Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Inclination: Vertical Date Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in N Lithology Material Description Total Depth: 11.5 ft Ground Elevation: Location: Corner Lions Pk Cir & Hwy 13 Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND with clay, SC, brown, dry to damp, dense, subangular to subrounded, (road base). Start drill 9:30 am 5 R R R R ft. gravelly SAND with trace silt and clay; few cobbles up to 6inches (~10%), SM, brown, dry to damp, dense to very dense, subrounded to rounded, nonto low plasticity, (alluvium). Bulk sample collected while light snow fall may affect moisture content MC= 7 % #200= 23 % LL= 28 PL= 17 PI= 11 AASHTO: A27 USCS: SC Auger grinding on cobbles; slower drilling; SPT 50 for 0 in. Bulk sample collected 2.58 ft SPT 50 for 1 in ft. sandy SILT with trace clay, CLML, brown, damp, hard, nonto low plasticity; fine to med grained sand, (alluvium). Drill speed faster in sand BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/ /16/16 32 Bottom of Hole at 11.5 ft. MC= 13 % #200= 65 % USCS: CLML Hole backfilled with commercial play sand mixture and native material; patched with heated asphalt. Hole complete 11:00 am

19 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH07 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: Sunny, p cloudy,cold,~30f N Lithology Material Description Total Depth: 5.1 ft Ground Elevation: Location: L turn lane Taugh to W. I70 Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, dry, dense to very dense, subrounded to rounded, Nonplastic, (alluvium). Start drill 3:15 p.m. MC= 2 % #200= 14 % USCS: SM 5 R R Bottom of Hole at 5.1 ft. SPT 50 for 0 in. Backfilled hole and patched with asphalt; finish drill 3:40 p.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

20 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH08 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: P. cloudy, cold,~2530f N Lithology Material Description Total Depth: 10.1 ft Ground Elevation: Location: L turn lane Taugh to E. I70 Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND, SP, dark brown, dry, dense, subangular to subrounded, (road base) ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, dry, dense to very dense, subrounded to rounded, (alluvium). Start drill 12:35 p.m. Bulk sample from 15 ft 5 R R SPT 50 for 4 in ft. sandy SILT with trace clay and gravel, ML, dark brown, damp, nonto low plasticity, (alluvium) ft. gravelly SAND with silt and trace clay, SWSM, dark brown, damp, dense, subrounded, nonplastic, (alluvium). BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10 R R ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, damp, dense to very dense, subrounded to rounded, (alluvium). Bottom of Hole at 10.1 ft. SPT 50 for 0 in. Backfilled hole and patched with asphalt; finish drill 2:30 p.m.

21 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH09 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Completed: 12/7/2004 Drill Bit: Casing: Drill: Dietrich 53 Truck mount Weather: P. cloudy, cold, ~25F Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Inclination: Vertical Date Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in N Lithology Material Description Total Depth: 5.1 ft Ground Elevation: Location: E bound off ramp I70 Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND, SP, brown, dry, dense, subangular to subrounded, (road base). Start drill 3:50 p.m ft. clayey SAND with some gravel and trace silt; few cobbles up to 6inches (~10%), SC, brown, dry, dense to very dense, subrounded to rounded, (alluvium). MC= 4 % #200= 26 % AASHTO: A27 USCS: SC 5 R R Bottom of Hole at 5.1 ft. SPT 50 for 0 in. Backfilled hole and patched with asphalt; finish drill 4:15 p.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

22 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH10 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: P. cloudy, cold,~2530f N Lithology Material Description Total Depth: 6.0 ft Ground Elevation: Location: E bound on ramp I70 Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND, SP, brown, dry, dense, subangular to subrounded, (road base). Start drill 2:45 p.m ft. clayey SAND with some gravel and trace silt; few cobbles up to 6inches (~10%), SC, brown, dry, dense to very dense, subrounded to rounded, nonto low plasticity, (alluvium). 5 29/ ft. sandy SILT with trace clay and trace gravel, CLML, brown, dry to damp, hard, nonto low plasticity, (alluvium). Bottom of Hole at 6.0 ft. Backfilled hole and patched with asphalt; finish drll 3:00 p.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

23 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH11 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: Sunny, p cloudy,cold,~30f N Lithology Material Description Total Depth: 6.0 ft Ground Elevation: Location: N of inter Taugh. & S. 7th Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, dry to damp, dense to very dense, subangular to rounded, (alluvium). Start drill 12:00 noon 5 30/R R SPT 3050 for 6 in. Bottom of Hole at 6.0 ft. Hole backfilled and patched with asphalt; finish drill 12:30 p.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

24 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH12 Project Number: Date: Sheet 1 of 1 Boring Began: 12/8/2004 Drilling Method: SolidStem Auger Completed: 12/8/2004 Drill Bit: Casing: Drill: Dietrich 53 Truck mount Weather: Cloudy, cold,~30f Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: Water at 9 ft Final By: S. White Depth 9.0 ft Inclination: Vertical Date 12/8/04 Time 12:30 pm Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in N Lithology Material Description Total Depth: 10.2 ft Ground Elevation: Location: NW Rifle Bus Park Bldg Coordinates: N: E: Field Notes and Lab Tests ft. silty CLAY with trace sand, CLML, brown, moist, stiff to very stiff, low to med plasticity, (alluvium). Drilling started 11:30 a.m. 8/ ft. sandy GRAVEL with some cobbles (~10%) and trace clay, GPGC, brown, moist, dense to very dense, subrounded to rounded, (alluvium) ft. silty CLAY with trace sand, CLML, brown, moist, stiff to very stiff, low to med plasticity, (alluvium). Auger grinding on cobbles; 6inch gravel and cobble layer Bulk sample collected from 16 ft 5 8/ ft. gravelly SAND with trace silt and clay; few cobbles up to 6inches (~10%), SC, brown, moist to wet, dense to very dense, subrounded to rounded, (alluvium). MC= 25 % #200= 89 % LL= 36 PL= 24 PI= 12 USCS: CL MC= 28 % DD= 95.0 pcf S/C= 0.1 % BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10 R R Bottom of Hole at 10.2 ft. Moisture content wet at 9 ft; encountered groundwater SPT 50 for 2 in. Hole filled with native material. Hole completed 12:30 p.m.

25 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH13 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: Sunny, p cloudy,cold,~30f N Lithology Material Description Total Depth: 6.5 ft Ground Elevation: Location: S 7th St across from Rifle Bus Ctr Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND, SP, brown, dry, dense, subangular to subrounded, (road base). Start drill 11:25 a.m. 6/ ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, dry, dense to very dense, subrounded to rounded, alluvium as fill?, (alluvium) ft. clayey SILT with trace sand, CLML, brown, damp to moist, stiff, low plasticity, (alluvium). MC= 20 % #200= 93 % LL= 22 PL= 16 PI= 6 USCS: CLML MC= 19 % DD= pcf S/C= 0.1 % 5 3/3/3 6 Bottom of Hole at 6.5 ft. Backfilled hole and patched with asphalt; finsh drill 11:50 a.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

26 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH14 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: Sunny, p cloudy,cold,~30f N Lithology Material Description Total Depth: 6.0 ft Ground Elevation: Location: S 7th St across from CDOT Coordinates: N: E: Field Notes and Lab Tests 16/8/ ft. (asphalt) ft. gravelly SAND, SP, brown, dry, dense, subangular to subrounded, (road base) ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, dry, dense to very dense, subrounded to rounded, alluvium as fill?, (alluvium) ft. clayey SILT with trace sand, CLML, brown, moist, very stiff, low plasticity, (alluvium). Start drill 10:15 a.m. 5 4/4 8 Bottom of Hole at 6.0 ft. Hole backfilled and patched with asphalt; finish drill 10:30 a.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

27 YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS Project: Rifle Roundabouts Boring: TH15 Project Number: Date: Sheet 1 of 1 Boring Began: 12/7/2004 Drilling Method: SolidStem Auger Drill: Dietrich 53 Truck mount Driller: Dakota DrillingDale and Sean Logged By: S. White Ground Water Notes: None encountered Final By: S. White Depth Date Inclination: Vertical Time Elevation (feet) Depth (feet) Run / Sample Type Recovery (%) Rock RQD Soil Samples Blows per 6 in Completed: 12/7/2004 Drill Bit: Casing: Weather: Sunny, p cloudy,cold,~30f N Lithology Material Description Total Depth: 6.5 ft Ground Elevation: Location: south Taughenbaugh Blvd Coordinates: N: E: Field Notes and Lab Tests ft. (asphalt) ft. gravelly SAND, SP, brown, dry, dense, subangular to subrounded, (road base). Start drill 10:45 a.m ft. gravelly SAND with trace silt and few cobbles up to 6inches (~10%), SW, brown, moist, dense to very dense, subrounded to subangular, alluvium as fill?, (alluvium). 6/ ft. sandy SILT with trace clay, CLML, brown, moist, stiff, nonto low plasticity, (alluvium). MC= 16 % #200= 64 % LL= 24 PL= 22 PI= 2 USCS: CLML 5 4/4/5 9 Bottom of Hole at 6.5 ft. Hole backfilled and patched with asphalt; finish drill 11:15 a.m. BORING LOG 24129_JAN_26_05.GPJ YEH ASSOCIATES.GDT 1/2/13 10

28 APPENDIX B LABORATORY RESULTS

29 YEH & ASSOCIATES, INC Summary of Laboratory Test Results Project No: Project Name: Rifle Roundabouts Date: 1/25/2005 Sample Location Natural Gradation Atterberg Water Unconf. Natural Dry % Swell (+) / Moisture Gravel Fines < Soluble Comp. Boring Sample Density Sand ph Consoli Depth (ft) Content > #4 #200 LL PL PI Sulfate Strength NO. Type (pcf) (%) dation () () (%) (%) (%) % (psf) RVALUE CLASSIFICATION AASHTO USCS TH Bulk A26 SC TH Bulk 19.0 SM TH SPT A6 CLML TH Bulk NP A1a SM TH Bulk A26 SC TH Bulk CLML TH SPT A6 CL TH CA CL TH SPT A4 CLML TH CA CLML TH SPT A4 CLML Rev 2 8/02 Page 1 of 1

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37 APPENDIX C PAVEMENT THICKNESS DESIGN

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