AECOM tel 558 North Main Street fax Oshkosh, Wisconsin 54901

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1 tel 8 North Main Street fax Oshkosh, Wisconsin 4901 May 8, 2012 Mr. James Rabe P.E., CPESC Civil Engineer II City of Oshkosh 21 Church Avenue Oshkosh, WI 490 Subject: Subsurface Exploration and Engineering Services for the Sawyer Creek Dredging Project and Pipe Crossing in Oshkosh, Wisconsin Project No Dear Mr. Rabe, Technical Services, Inc. is pleased to provide you with this summary of the geotechnical activities completed for the above-referenced project. The field and laboratory services were performed in March and April, This report presents the results of the field and laboratory testing program. Background/Summary The primary focus of the project is the dredging and stream bank restoration extending from the Fox River to where Sawyer Creek meets North Koeller Street. Portions of the dredging are planned to be completed in the dry which will be facilitated by installing cofferdams. The remainder of the dredging will be performed via hydraulic methods. In addition, canoe access and fishing holes will be constructed at two locations. A new utility crossing below Sawyer Creek is also planned as part of the project. The existing sanitary sewer crossing at this location is pile supported. The new sewer crossing will be installed using trenchless methods. The purpose of this report is to provide geotechnical data to assist contractors in designing the cofferdams which will be required to facilitate the mechanical dredging which is proposed. In addition, deeper soil data is provided for the fishing hole excavation for the contractor s reference. Finally, soils data has been collected at the end of Dove Street and adjacent to the proposed sewer installation for the contractor s evaluation of construction methods. Subsurface Exploration A total of eight (8) soil borings, B-1 through B-8, were completed as part of the geotechnical exploration program conducted from March 28 to April 12, Borings ranged in depth from 17 to 29.6 feet. Possible bedrock or large boulders were encountered in five borings, B-1, B-2, B-, B- 4, and B-8 at depths of 21.0, 29., 28.2, 29.7, and 0., respectively. The locations of the borings were selected and located in the field by. The soil boring locations are shown on the Boring Location Diagram, Figure 1 in the attachments. The surface elevations of borings B-1 through B-7 are based on the water surface elevation in Sawyer Creek. The water surface is based on the United States Army Corps of Engineers Gauges on the Fox River. The surface elevation of Boring B-8 was interpolated from the ground surface data on Dove Street presented by Strand in their April 24 design drawings Sawyer Creek Geotechnical Report.docx

2 2 The soil borings B-1 through B-7 were performed by a three-person drill crew using a barge mounted Deidrich D2 drill rig using rotary wash drilling methods to advance the boreholes. The rig was set with approximately 1.7 feet between the rig and the water. The depth from the top of water to the bottom of the river floor ranged from 2 to. feet. Temporary four-inch steel casing was used to maintain an open borehole while drilling. Boring B-8 was performed by a two-person drill crew using a Deidrich D120 drill rig using continuous flight augers. Representative soil samples from the borings were obtained by means of split spoon sampling procedures in general conformance with ASTM Standard D-186. Soil sampling was generally performed at 2. foot intervals to a depth of 1 feet and at foot intervals thereafter. During the field operations, the drilling crew maintained a written log of the subsurface conditions including changes in the stratigraphy. Upon completion of the drilling operations, the boreholes were backfilled with a /8-inch bentonite chips to prevent groundwater migration and abandoned in general conformance with the Wisconsin Department of Natural Resources (WDNR) NR141. Samples obtained in the field were logged, labeled, sealed and brought to our Oshkosh, Wisconsin laboratory for further examination and testing. The laboratory testing program consisted of performing routine visual classification and moisture content testing on representative portions of each sample recovered. Calibrated penetrometer tests were performed on cohesive soil samples to estimate their unconfined compressive strengths. In the calibrated penetrometer test the unconfined compressive strength of a cohesive soil is estimated by measuring the resistance of the soil sample to penetration by a small spring calibrated cylinder. The results of the laboratory tests are shown on the individual soil boring logs included in the attachments. In conjunction with the laboratory testing program, each soil sample was visually classified on the basis of texture and plasticity in accordance with the Soil Classification System. The estimated group symbol included in parentheses following the soil descriptions on the boring logs is in general conformance with the Unified Soil Classification System, which serves as the basis of the Soil Classification System. A brief explanation of the classification of soil samples is included in the Laboratory Procedures in the attachments. Soil Profile The general soil profiles within the river consist of 2. to feet of black organic river sediment underlain by silty to sandy clay. Gravel, cobbles and boulders were encountered in borings B-4 and B-7 at depths ranging from 10. to 14 feet and 14.4 to 17. feet, respectively. The silty and sandy clay was generally stiff to hard in consistency. In borings B-1, B-2, B-4 and B-7, the silty and sandy clay were underlain by more granular layers consisting primarily of sand with varying amounts of silt and gravel. These granular layers were medium dense to extremely dense and were often very difficult to drill through. Borings B-1 through B-4 were terminated at depths of sampler of auger refusal. Based on our experience in Oshkosh, refusal occurred on large cobles and boulders which are generally encountered at the top of the weathered bedrock surface. The general soil profile at the end of Dove Street consisted of feet of clayey fill underlain by 1 feet of sandy to silty clay underlain by approximately 10 feet of silty sand. Gravel, cobbles and boulders were frequently encountered in the bottom 10 feet of the boring. We refer you to boring logs in the attachments to this report for additional detail on the soil profile encountered at the boring locations. K:\Projects\ \400_Technical_Information_and_Technical_Discipline_Files\404_Geotechnical\Report Attachments\ Sawyer Creek Geotechnical Report.docx

3 Construction Considerations Cofferdams will be required to facilitate the mechanical dredging at four locations along the project alignment. Cofferdams could include earthen embankments, driven piling or other commercially available temporary water diversion systems. All commercially available systems should be installed in accordance with the manufacturer s recommendations. If an earthen embankment is utilized, consideration should be given to the foundation of the cofferdam. The existing river bottom sediments are low strength, compressible and relatively permeable. The cofferdam embankment should be sized appropriately to resist sliding and provide an adequate factor of safety for global stability for the dredged and dewatered condition which will exist. Earthen embankments can be designed and constructed in such a way as to create a mud wave which will displace the majority of the soft sediments below the cofferdams. The mud wave will be effective in removing the majority of the sediment thickness; however, a think soft layer could still be present which could affect the global stability of the cofferdam. Seepage at the base of the cofferdam should be carefully monitored. If any signs of piping appear, remedial actions should be taken immediately. If driven piling is utilized, hard driving conditions including hard and dense soils, gravel and cobbles, will be encountered below the soft and loose sediments. Piling and pile driving equipment should be selected and sized appropriately for the conditions which will be encountered. Trenchless construction will be utilized for the installation of the sanitary sewer which crosses below Sawyer Creek at Dove Street. The invert of the proposed sewer will be at an approximate elevation of 729 feet below the creek channel and will tie into manholes at approximate elevations of 741. feet to 742 feet. Boring B-7 was performed adjacent to the proposed sewer alignment in Sawyer Creek. Hard drilling and zones of gravel were encountered in this boring in the zone where the sewer will be installed. Trenchless installation equipment should be selected which can accommodate these expected gravelly soil conditions. General Qualifications The scope of this letter report is limited to this project and the locations described herein. The information supplied in this letter report is based on subsurface conditions as revealed in the data collected by, the subsurface conditions existing at the time of field work, and our professional interpretation of this information. Variations between boring locations can and do occur. This report should be used only for the purpose intended, and no other warranty, either expressed or implied, is made. If you have any questions or comments with regard to this information, please do not hesitate to contact us. Respectfully, Shannon R. Kyle Assistant Project Engineer Jeremy M. Thomas, P.E. Project Engineer Paul A. Tarvin, P.E. Principal Engineer Attachments K:\Projects\ \400_Technical_Information_and_Technical_Discipline_Files\404_Geotechnical\Report Attachments\ Sawyer Creek Geotechnical Report.docx

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5 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B-1 UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY SURFACE ELEVATION Air DESCRIPTION OF MATERIAL UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water Organic sandy clay - little gravel and wood - brown - very loose - saturated (OL) Sandy clay - trace gravel and grass - brown - very soft (CL) A Clayey silt - trace fine sand and gravel - gray - stiff (ML) Sandy clay - trace gravel - brown - very stiff (CL) Silty clay - trace sand and gravel - gray - stiff (CL) Fine to medium gravelly sand - little silt and clay - gray - dense to extremely dense (SW) Possible bedrock End of Boring Boring backfilled with /8 inch bentonite chips. Standard penetration tests performed with safety hammer Calibrated Penetrometer 0/0" LOG GPJ FS_DATATEMPLATE.GDT /7/12 The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. NORTHING BORING STARTED OFFICE /28/12 Oshkosh, Wisconsin EASTING BORING COMPLETED ENTERED BY SHEET NO. OF /28/12 CAH 1 1 WL RIG/FOREMAN APP'D BY JOB NO. D- Barge/BZ PFT

6 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B-2 UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY DESCRIPTION OF MATERIAL SURFACE ELEVATION Air UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water Fine sandy silt - little gravel and clay - trace roots - brown - very loose - saturated (ML) WT. OF HAMMER Silty clay - trace sand and gravel - brown - stiff to very stiff (CL) Medium sandy clay - trace gravel - grayish brown - stiff to soft (CL) A 2. Silty sand - little clay and gravel - gray - dense (SM) 9 24/6" LOG GPJ FS_DATATEMPLATE.GDT /7/ NORTHING EASTING WL 29. Possible boulder or bedrock End of Boring Boring backfilled with /8 inch bentonite chips. Standard penetration tests performed with safety hammer The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. BORING STARTED /28/12 BORING COMPLETED /29/12 RIG/FOREMAN D- Barge/BZ OFFICE ENTERED BY CAH APP'D BY PFT Calibrated Penetrometer Oshkosh, Wisconsin SHEET NO. OF 1 1 JOB NO

7 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B- UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY DESCRIPTION OF MATERIAL SURFACE ELEVATION Air UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water Organic silty sand - trace roots - black - very loose - saturated (OL) WT. OF ROD Silty clay - trace sand and gravel - brown - very stiff to stiff (CL) Driller's Note: Gavel and cobbles encountered while drilling below a depth of 1 feet WT. OF ROD LOG GPJ FS_DATATEMPLATE.GDT /7/ NORTHING EASTING WL 7 7A 28.2 Possible boulder or bedrock End of Boring Boring backfilled with /8 inch bentonite chips. Standard penetration tests performed with safety hammer The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. BORING STARTED /29/12 BORING COMPLETED /29/12 RIG/FOREMAN D- Barge/BZ OFFICE ENTERED BY CAH APP'D BY PFT 6 26 Calibrated Penetrometer Oshkosh, Wisconsin SHEET NO. OF 1 1 JOB NO

8 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B-4 UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY DESCRIPTION OF MATERIAL SURFACE ELEVATION Air UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water Organic silty sand - trace roots - black - very soft (OL) WT. OF ROD Sandy clay - trace silt and gravel - brown - medium to soft (CL) Sample driven on gravel 6/9" Sandy clay - trace silt and gravel - brown - very stiff to hard (CL) Silty sand - little gravel and trace clay - gray - extremely dense - wet (SM) /11" LOG GPJ FS_DATATEMPLATE.GDT /7/ NORTHING EASTING WL End of Boring Boring advanced to 29.6 feet with solid-stem auger. Boring backfilled with /8 inch bentonite chips. The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. BORING STARTED /29/12 BORING COMPLETED /29/12 RIG/FOREMAN D- Barge/BZ OFFICE ENTERED BY CAH APP'D BY PFT Calibrated Penetrometer Oshkosh, Wisconsin SHEET NO. OF 1 1 JOB NO /1"

9 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B- UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY SURFACE ELEVATION Air DESCRIPTION OF MATERIAL UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water Silty clay - trace gravel, sand, and roots - brown - soft (CL) Silty clay - trace gravel and sand - brown - very stiff to hard (CL) Hard drilling noted at 12. feet End of Boring Boring backfilled with /8 inch bentonite chips. Standard penetration tests performed with safety hammer Calibrated Penetrometer LOG GPJ FS_DATATEMPLATE.GDT /7/12 The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. NORTHING BORING STARTED OFFICE 4/2/12 Oshkosh, Wisconsin EASTING BORING COMPLETED ENTERED BY SHEET NO. OF 4/2/12 CAH 1 1 WL RIG/FOREMAN APP'D BY JOB NO. D-2/JD PFT

10 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B-6 UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY SURFACE ELEVATION Air DESCRIPTION OF MATERIAL UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water.0 1. Silty clay - little sand - trace gravel and roots - brown - very stiff to hard (CL) End of Boring Boring backfilled with /8 inch bentonite chips. Standard penetration tests performed with safety hammer 0 20 Calibrated Penetrometer 70 LOG GPJ FS_DATATEMPLATE.GDT /7/12 The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. NORTHING BORING STARTED OFFICE 4/2/12 Oshkosh, Wisconsin EASTING BORING COMPLETED ENTERED BY SHEET NO. OF 4/2/12 CAH 1 1 WL RIG/FOREMAN APP'D BY JOB NO. D-2/JD PFT

11 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B-7 UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. SAMPLE TYPE SAMPLE DISTANCE RECOVERY SURFACE ELEVATION Air DESCRIPTION OF MATERIAL UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % LIQUID STANDARD PENETRATION BLOWS/(FT) Water Organic sandy clay - little silt and gravel - black - medium dense (OL) Silty clay - trace gravel and sand - brown - very stiff (CL) Sample 2 disturbed by gravel 4 Gravelly clay - trace silt and sand - brown - medium dense to very dense (GC) LOG GPJ FS_DATATEMPLATE.GDT /7/ NORTHING EASTING WL Silty clay - trace gravel - stiff (CL) Clayey silt - trace sand - gray - medium dense (ML) End of Boring Boring backfilled with /8 inch bentonite chips. Standard penetration tests performed with safety The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. BORING STARTED 4/2/12 BORING COMPLETED 4//12 RIG/FOREMAN D-2/JD OFFICE ENTERED BY CAH APP'D BY PFT 18 2 Calibrated Penetrometer Oshkosh, Wisconsin SHEET NO. OF 1 1 JOB NO

12 SITE LOCATION CLIENT City of Oshkosh PROJECT NAME Sawyer Creek Dredging Sawyer Creek, Oshkosh, WI LOG OF BORING NUMBER ARCHITECT-ENGINEER B-8 UNCONFINED COMPREIVE STRENGTH TONS/FT DEPTH(FT) ELEVATION(FT) SAMPLE NO. 1 SAMPLE TYPE SAMPLE DISTANCE RECOVERY DESCRIPTION OF MATERIAL SURFACE ELEVATION Fill: Fine sandy clay, trace silt, gravel, and wood - brown - very stiff (Fill: CL) UNIT DRY WT. LBS./FT. PLASTIC WATER CONTENT % STANDARD PENETRATION BLOWS/(FT) LIQUID PA PA 2..0 Fill: Silty clay - trace sand and roots - gray - stiff (Fill: CL) Silty clay - trace gravel and sand - reddish brown - very stiff to hard (CL) Silty sand - trace gravel - gray - dense to extremely dense- moist (SM) Gravel noted 2 to 0 feet 4 LOG GPJ FS_DATATEMPLATE.GDT /7/ NORTHING EASTING WL End of Boring Boring advanced to 0. feet with solid-stem auger. Boring backfilled with /8 inch bentonite chips. The stratification lines represent the approximate boundary lines between soil types: in situ, the transition may be gradual. BORING STARTED 4/12/12 BORING COMPLETED 4/12/12 RIG/FOREMAN 120/JD OFFICE ENTERED BY CAH APP'D BY PFT Calibrated Penetrometer Oshkosh, Wisconsin SHEET NO. OF 1 1 JOB NO /"

13 General Notes Drilling and Sampling Symbols: : Split Spoon - 1-/8" I.D. 2" O.D. (Unless otherwise noted) HS : Hollow Stem Auger ST : Shelby Tube-2" O.D. (Unless otherwise noted) WS : Wash Sample PA : Power Auger FT : Fish Tail DB : Diamond Bit-NX, BX, AX : Rock Bit AS : Auger Sample BS : Bulk Sample JS : Jar Sample PM : Pressuremeter Test VS : Vane Shear GS : Giddings Sampler OS : Osterberg Sampler Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 0 inches on a 2 inch O.D. split spoon sampler, except where otherwise noted. Water Level Measurement Symbols: WL : Water Level WS : While Sampling WD : While Drilling AB : After Boring WCI : Wet Cave In DCI : Dry Cave In BCR : Before Casing Removal ACR : After Casing Removal Water levels indicated on the boring logs are the levels measured in the boring at the time indicated. In pervious soils, the indicated elevations are considered reliable groundwater levels. In impervious soils, the accurate determination of groundwater elevations may not be possible, even after several days of observations; additional evidence of groundwater elevations must be sought. Gradation Description and Terminology: Coarse grained or granular soils have more than 0% of their dry weight retained on a #200 sieve; they are described as boulders, cobbles, gravel or sand. Fine grained soils have less than 0% of their dry weight retained on a #200 sieve; they are described as clay or clayey silt if they are cohesive and silt if they are non-cohesive. In addition to gradation, granular soils are defined on the basis of their relative in-place density and fine grained soils on the basis of their strength or consistency and their plasticity. Major Component of Sample Size Range Description of Other Components Present in Sample Percent Dry Weight Boulders Over 8 in. (200 mm) Trace 1-9 Cobbles 8 inches to inches (200 mm to 7 mm) Little Gravel inches to #4 sieve (7 mm to 4.76 mm) Some 20-4 Sand #4 to #200 sieve (4.76 mm to mm) And -0 Silt Passing #200 sieve (0.074 mm to 0.00 mm) Clay Smaller than 0.00 mm Consistency of Cohesive Soils: Relative Density of Granular Soils: Unconfined Compressive Strength, Qu, tsf Consistency N-Blows per foot Relative Density <0.2 Very Soft 0 - Very Loose Soft 4-9 Loose Medium (firm) Medium Dense Stiff 0-49 Dense Very Stiff 0-80 Very Dense Hard >80 Extremely Dense >8.00 Very Hard

14 Field and Laboratory Procedures Field Sampling Procedures Auger Sampling (AS) In this procedure, soil samples are collected from cuttings off of the auger flights as they are removed from the ground. Such samples provide a general indication of subsurface conditions; however, they do not provide undisturbed samples, nor do they provide samples from discrete depths. Split-Barrel Sampling () - (ASTM Standard D ) In the split-barrel sampling procedure, a 2-inch O.D. split barrel sampler is driven into the soil a distance of 18 inches by means of a 140-pound hammer falling 0 inches. The value of the Standard Penetration Resistance is obtained by counting the number of blows of the hammer over the final 12 inches of driving. This value provides a qualitative indication of the in-place relative density of cohesionless soils. The indication is qualitative only, however, since many factors can significantly affect the Standard Penetration Resistance Value, and direct correlation of results obtained by drill crews using different rigs, drilling procedures, and hammer-rod-spoon assemblies should not be made. A portion of the recovered sample is placed in a sample jar and returned to the laboratory for further analysis and testing. Shelby Tube Sampling Procedure (ST) - ASTM Standard D In the Shelby tube sampling procedure, a thin-walled steel seamless tube with a sharp cutting edge is pushed hydraulically into the soil and a relatively undisturbed sample is obtained. This procedure is generally employed in cohesive soils. The tubes are identified, sealed and carefully handled in the field to avoid excessive disturbance and are returned to the laboratory for extrusion and further analysis and testing. Giddings Sampler (GS) This type of sampling device consists of -foot sections of thin-wall tubing which are capable of retrieving continuous columns of soil in -foot maximum increments. Because of a continuous slot in the sampling tubes, the sampler allows field determination of stratification boundaries and containerization of soil samples from any sampling depth within the -foot interval.

15 Field and Laboratory Procedures Subsurface Exploration Procedures Hand-Auger Drilling (HA) In this procedure, a sampling device is driven into the soil by repeated blows of a sledge hammer or a drop hammer. When the sampler is driven to the desired sample depth, the soil sample is retrieved. The hole is then advanced by manually turning the hand auger until the next sampling depth increment is reached. The hand auger drilling between sampling intervals also helps to clean and enlarge the borehole in preparation for obtaining the next sample. Power Auger Drilling (PA) In this type of drilling procedure, continuous flight augers are used to advance the boreholes. They are turned and hydraulically advanced by a truck, trailer or track-mounted unit as site accessibility dictates. In auger drilling, casing and drilling mud are not required to maintain open boreholes. Hollow Stem Auger Drilling (HS) In this drilling procedure, continuous flight augers having open stems are used to advance the boreholes. The open stem allows the sampling tool to be used without removing the augers from the borehole. Hollow stem augers thus provide support to the sides of the borehole during the sampling operations. Rotary Drilling () In employing rotary drilling methods, various cutting bits are used to advance the boreholes. In this process, surface casing and/or drilling fluids are used to maintain open boreholes. Diamond Core Drilling (DB) Diamond core drilling is used to sample cemented formations. In this procedure, a double tube (or triple tube) core barrel with a diamond bit cuts an annular space around a cylindrical prism of the material sampled. The sample is retrieved by a catcher just above the bit. Samples recovered by this procedure are placed in sturdy containers in sequential order.

16 Laboratory Procedures Water Content (Wc) The water content of a soil is the ratio of the weight of water in a given soil mass to the weight of the dry soil. Water content is generally expressed as a percentage. Hand Penetrometer (Qp) In the hand penetrometer test, the unconfined compressive strength of a soil is determined, to a maximum value of 4. tons per square foot (tsf) or 7.0 tsf depending on the testing device utilized, by measuring the resistance of the soil sample to penetration by a small, spring-calibrated cylinder. The hand penetrometer test has been carefully correlated with unconfined compressive strength tests, and thereby provides a useful and a relatively simple testing procedure in which soil strength can be quickly and easily estimated. Unconfined Compression Tests (Qu) In the unconfined compression strength test, an undisturbed prism of soil is loaded axially until failure or until 20% strain has been reached, whichever occurs first. Dry Density (γd) The dry density is a measure of the amount of solids in a unit volume of soil. Use of this value is often made when measuring the degree of compaction of a soil. Classification of Samples In conjunction with the sample testing program, all soil samples are examined in our laboratory and visually classified on the basis of their texture and plasticity in accordance with the Soil Classification System which is described on a separate sheet. The soil descriptions on the boring logs are derived from this system as well as the component gradation terminology, consistency of cohesive soils and relative density of granular soils as described on a separate sheet entitled " General Notes". The estimated group symbols included in parentheses following the soil descriptions on the boring logs are in general conformance with the Unified Soil Classification System (USCS) which serves as the basis of the Soil Classification System.

17 Standard Boring Log Procedures In the process of obtaining and testing samples and preparing this report, standard procedures are followed regarding field logs, laboratory data sheets and samples. Field logs are prepared during performance of the drilling and sampling operations and are intended to essentially portray field occurrences, sampling locations and procedures. Samples obtained in the field are frequently subjected to additional testing and reclassification in the laboratory by experienced geotechnical engineers, and as such, differences between the field logs and the final logs may exist. The engineer preparing the report reviews the field logs, laboratory test data and classifications, and using judgment and experience in interpreting this data, may make further changes. It is common practice in the geotechnical engineering profession not to include field logs and laboratory data sheets in engineering reports, because they do not represent the engineer's final opinions as to appropriate descriptions for conditions encountered in the exploration and testing work. Results of laboratory tests are generally shown on the boring logs or are described in the text of the report, as appropriate. Samples taken in the field, some of which are later subjected to laboratory tests, are retained in our laboratory for sixty days and are then discarded unless special disposition is requested by our client. Samples retained over a long period of time, even in sealed jars, are subject to moisture loss which changes the apparent strength of cohesive soil, generally increasing the strength from what was originally encountered in the field. Since they are then no longer representative of the moisture conditions initially encountered, observers of these samples should recognize this factor.

18 Soil Classification System (1) 1. See General Notes for component gradation terminology, consistency of cohesive soils and relative density of granular soils. 2. Reference: Unified Soil Classification Systems. Borderline classifications, used for soils possessing characteristics of two groups, are designated by combinations of group symbols. For example: GW-GC, well-graded gravel-sand mixture with clay binder.