GEOTECHNICAL ENGINEERING REPORT HARPER VALLEY SANITARY LIFT STATION AND FORCEMAIN KIRTLAND, NEW MEXICO. Submitted To:

Transcription

1 GEOTECHNICAL ENGINEERING REPORT HARPER VALLEY SANITARY LIFT STATION AND FORCEMAIN KIRTLAND, NEW MEXICO Submitted To: Wade Chacon, P.E. HDR Engineering, Inc. 255 Louisiana Boulevard NE, Suite 9500 Albuquerque, New Mexico 870 Submitted By: GEOMAT Inc. 95 Malta Avenue Farmington, New Mexico 8740 March 0, 206 GEOMAT Project Rev.

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3 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain TABLE OF CONTENTS Page No. INTRODUCTION... PROPOSED CONSTRUCTION... SITE EXPLORATION... 2 Field Exploration... 2 Laboratory Testing... 3 SITE CONDITIONS... 3 GEOLOGICAL SETTING...5 SUBSURFACE CONDITIONS... 6 Soil Conditions... 6 Groundwater Conditions... 7 Laboratory Test Result...8 OPINIONS AND RECOMMENDATIONS... 8 Lift Station Foundation... 9 Lateral Earth Pressures... 9 Corrosion and Cement Type... 0 Earthwork... General Considerations... Excavation... 2 Excavation Safety... 2 Dewatering Pipe Foundation... 3 Pipe Embedment... 3 Backfill Compliance PAVEMENT REPAIRS... 4 GENERAL COMMENTS... 5

4 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain APPENDIX A Site Plan Logs of Borings and Test Pits Unified Soil Classification APPENDIX B Laboratory Test Results Laboratory Test Procedures TABLE OF CONTENTS (continued) APPENDIX C Important Information About This Geotechnical Engineering Report (Taken From GBA)

5 GEOTECHNICAL ENGINEERING REPORT HARPER VALLEY SANITARY LIFT STATION AND FORCEMAIN KIRTLAND, NEW MEXICO GEOMAT PROJECT NO REV. INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed Harper Valley Sanitary Lift Station and Forcemain project in Kirtland, San Juan County, New Mexico, as shown on the Site Plan in Appendix A of this report. The purpose of these services is to provide information and geotechnical engineering recommendations about: subsurface soil conditions groundwater conditions lift station foundations excavation conditions pipeline backfill The opinions and recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, and experience with similar soil conditions, structures, and our understanding of the proposed project as stated below. PROPOSED CONSTRUCTION We understand that the project consists of the construction of a new sanitary lift station and approximately 6,300 lineal feet of forcemain pipeline. The proposed lift station will be located adjacent to an existing wastewater treatment plant near the south end of the Harper Valley Subdivision. The existing plant will be decommissioned and left in place. We also understand the new lift station will be either precast or cast-in-place concrete, and the bottom of the wet well will be approximately 5 to 8 feet below finished grade. The forcemain will consist of a 4 to 6-inch diameter HDPE pipeline, and will be placed from the new lift station to the existing LVMDWA Lift Station No. 3 located roughly 2,500 feet west of the intersection of Road 600 and the main entrance of the Harper Valley Subdivision. We understand the bury depth of the pipeline will be roughly 4 to 6 feet below grade. The forcemain alignment will run west from the new lift station to the southwest corner of the subdivision. It

6 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 2 will then run north along the western boundary of the subdivision to Road 600, then west along the south side of Road 600 to LVMDWD Lift Station No. 3. SITE EXPLORATION Our scope of services performed for this project included a site reconnaissance by a staff geologist, a subsurface exploration program, laboratory testing and engineering analyses. Field Exploration: Subsurface conditions along the forcemain alignment were explored on February 5, 206, by drilling nine exploratory borings at the approximate locations shown on the Site Plan in Appendix A. The borings, designated B- through B-9, were drilled at intervals of roughly 750 feet along the alignment using a CME-45 truck-mounted drill with continuous-flight, 7.25-inch O.D. hollow-stem auger. The borings were advanced to depths ranging from approximately 6 to feet. Soil samples were obtained from the borings using a standard 2-inch O.D. split spoon. The sampler was driven using a 40-pound hammer falling 30 inches. The standard penetration resistance was determined by recording the number of hammer blows required to advance the sampler in sixinch increments. Representative bulk samples of subsurface materials were also obtained. Soils were classified in accordance with the Unified Soil Classification System described in Appendix A. Boring logs were prepared and are presented in Appendix A. Groundwater evaluations were made in each boring at the time of drilling and approximately 24 hours later. A temporary piezometer was placed in each boring to facilitate the 24-hour water level measurements. Immediately after measuring the water levels, the piezometers were removed and the borings were backfilled with the auger cuttings. The groundwater levels observed during drilling and approximately 24 hours after drilling are presented on the Boring Logs in Appendix A. Subsurface conditions at the proposed lift station were explored on February 6, 206, by excavating one exploratory test pit at the approximate location shown on the Site Plan in Appendix A. The test pit, designated TP-, was excavated using a Hyundai 20 LC-7 trackhoe with a 48-inch wide bucket. The test pit was terminated at a depth of approximately 8 feet below existing ground surface (short of its planned depth of 25 feet) due to caving of the pit walls, infiltration of groundwater, and sloughing of the saturated soils. The borings and test pit were continuously monitored by a geologist from our office who examined and classified the subsurface materials encountered, obtained representative samples, observed groundwater conditions, and maintained a continuous log of each boring/test pit.

7 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 3 Laboratory Testing: Samples retrieved during the field exploration were transported to our laboratory for further evaluation. At that time, the field descriptions were confirmed or modified as necessary, and laboratory tests were performed to evaluate the index properties of the subsurface materials. SITE CONDITIONS Forcemain Alignment: The southern portion of the forcemain follows an east-west alignment along the southern boundary of the Harper Hill subdivision and a north-south alignment along the western boundary of the subdivision. The ground surface along this portion of the alignment appeared to be relatively level and appeared to have been used as irrigated agricultural land in the past. At the time of our exploration, the southern portion of the alignment was vegetated by a thick growth of grasses and weeds. The following photograph depicts these conditions: View of Southern Portion of the Alignment from Road 600 View to the South The northern portion of the forcemain follows an east-west alignment along the southern edge of Road 600. Road 600 is paved and relatively level along this portion of the alignment. We understand the new pipeline will be installed off the edge of the asphalt on the roadway prism, except where it crosses the road to connect to the existing LVMDA Lift Station No. 3 on the north side of Road 600. Buried utilities, including gas, water, and communications, are known

8 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 4 to exist along the south side of Road 600 in close proximity to the proposed new forcemain. The following photograph depicts the site at the time of our exploration. Lift Station Site: Drill Rig at Boring B-2 View to the West The site of the proposed lift station is located approximately 50 feet south of the southern terminus of Road 6050, at the southern edge of the Harper Valley subdivision. An existing lift station structure is located roughly 20 feet east of the proposed new lift station. The ground surface appeared to be relatively level, and was vegetated by a thick growth of trees and brush at the time of our exploration. The San Juan River is located approximately 50 feet south of the lift station site. Buried utilities, including electric and communications, are known to exist in close proximity to the proposed lift station. The following photograph depicts the site at the time of our exploration.

9 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 5 GEOLOGICAL SETTING Test Pit TP- View to the Northeast The proposed project site is located in the north-central portion of the San Juan Basin. The San Juan Basin is described as a structural depression near the southeastern edge of the Colorado Plateau. Rocks in the San Juan Basin include thick sequences of marine, coastal, and terrestrial sediments deposited during late Paleozoic to early Tertiary time. In late Cretaceous and early Tertiary time, regional forces caused uplift of the Rocky Mountains to the north, along with subsidence of the San Juan Basin. Sediment derived from erosion of the mountains to the north continued to be deposited in the basin. These Tertiary sandstones, siltstones, and shales are the rocks presently exposed at the surface in the Four Corners area. The rocks are relatively undeformed and bedding is near-horizontal, except near the margins of the San Juan Basin, where uplift has deformed the rocks. An example of this deformation is the Hogback monocline near Fruitland. Ongoing erosion by wind and water has dissected these rocks into the mesas and washes that characterize the present landscape. Areas near the Animas, San Juan, and La Plata Rivers (including the project site) are characterized by alluvial river terrace deposits consisting of variable thicknesses of unconsolidated sand, gravel, cobbles, and boulders. These Quaternary alluvial deposits overlie the Tertiary shales and sandstones. The shales and sandstones are exposed in the hilly terrain immediately north of Road 600.

10 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 6 The project area is generally considered tectonically stable. A review of a fault and fold database (U.S. Geological Survey and New Mexico Bureau of Mines and Mineral Resources, 2006, Quaternary fault and fold database for the United States, accessed 2/7/206, from USGS web site: http//earthquakes.usgs.gov/regional/qfaults) indicates that the nearest mapped faults are roughly 00 miles to the southeast near Cuba, New Mexico, 00 miles to the north near Montrose, Colorado, and 200 miles to the west near Page, Arizona. These faults are considered to be sources of magnitude M>6 earthquakes during the Quaternary (the past.6 million years). Based on a review of an earthquake probability map (U.S. Geological Survey, 2002 Earthquake Probability Mapping, accessed 2/7/206, from USGS web site: the probability of an earthquake with a magnitude of M 5.0, which is considered to be felt by everyone and capable of causing significant property damage, within a 50 km radius of the project site, within a 500 year period, is 4 to 6 percent. SUBSURFACE CONDITIONS Soil Conditions: As presented on Boring Logs B- through B-4 in Appendix A, we encountered generally loose sandy soils and/or gravel to the depths explored along the northern portion of the forcemain alignment (along Road 600). Sandy soils were encountered to the full depth explored in B-3 and B-4. In B- and B-2, we encountered gravel and cobbles below the surficial sandy soils. The sandy soils were generally loose and damp, and the gravelly soils were dense and damp. Auger refusal on cobbles was encountered at depths of approximately 8 and 6 feet in B- and B-2, respectively. As shown on Boring Logs B-5 through B-9, we encountered fine-grained sandy, silty, and/or clayey soils overlying gravel along the southern portion of the forcemain alignment. These finegrained soils were encountered to the full depth explored in B-5 and B-6. In B-7, B-8, and B-9, we encountered gravel below the surficial fine-grained soils. Although gravel was not encountered to the depth explored in B-5 and B-6, it is likely present at variable depths along much of the alignment. The fine-grained soils along the southern portion of the alignment were generally damp to wet, and loose to very soft. The gravelly soils were generally damp to wet, and medium dense to dense. The gravelly soils along the southern portion of the alignment contained relatively few cobbles, and it was possible to drill to the planned depth with moderate difficulty. As shown on Test Pit Log TP-, we encountered damp fine-grained sandy soils overlying gravel at the site of the proposed lift station. The gravelly soils extended to the total depth of exploration, and were generally damp to wet. The gravelly soils contained sand and relatively few cobbles. The test pit was terminated at a depth of approximately 8 feet due to caving of the

11 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 7 pit walls, infiltration of groundwater, and sloughing of the saturated soils as shown in the following photograph: Test Pit TP- Excavation with Caving and Groundwater View to the Northeast Groundwater Conditions: Groundwater was not encountered to the depths explored in borings B- through B-4 (along Road 600). Groundwater was encountered in all of the borings along the southern portion of the alignment (B-5 through B-9). Free groundwater and/or saturated soils were encountered during drilling at depths of approximately 5 to 6 feet below existing ground surface. Water levels measured approximately 24 hours after drilling ranged from approximately 6 to 9 feet below existing ground surface. It should be realized that the 24-hour water level measurements do not necessarily represent the stabilized, or static, groundwater level. Multiple measurements over a greater time period would be necessary to determine the static water level. Groundwater was encountered in the test pit at a depth of approximately 7 feet below existing ground surface. Groundwater was observed flowing into the excavation at a moderate rate. It was not possible to advance the excavation beyond a depth of approximately 9 feet due to

12 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 8 infiltration of groundwater. The remainder of the excavation was penetrated by probing the excavator bucket into the groundwater to a depth of approximately 8 feet. Groundwater elevations can fluctuate over time depending upon precipitation, irrigation, runoff/infiltration of surface water, and the level of water in the San Juan River. We do not have any information regarding the historical fluctuation of the groundwater level in this vicinity. Laboratory Test Results: Laboratory analyses of representative samples indicate the fine-grained soils have fines contents (silt- and/or clay-sized particles passing the U.S. No. 200 sieve) ranging from approximately 27 to 82 percent. Plasticity indices of the soils ranged from non-plastic (NP) to 6. In-situ moisture contents of samples tested ranged from approximately 6 to 28 percent. Results of all laboratory tests are presented in Appendix B. OPINIONS AND RECOMMENDATIONS Construction of the proposed lift station and forcemain is considered feasible based on the geotechnical conditions encountered and tested for this report. If there are any significant deviations from the assumed alignment or invert elevations noted at the beginning of this report, the opinions and recommendations of this report should be reviewed and confirmed/modified as necessary to reflect the final planned design conditions. Due to the presence of groundwater at relatively shallow depths at the site of the proposed lift station and along the southern portion of the forcemain alignment, along with the soil conditions encountered, we anticipate that sloping, shoring or bracing, and/or dewatering techniques will be required to extend excavations to the required depths in these areas. Gravels and cobbles were encountered at relatively shallow depths along the northern portion of the forcemain alignment. Excavations in these dense, coarse-grained soils could necessitate the use of heavy-duty equipment. Caving and sloughing of the gravelly soils should be expected. Sloping, shoring, or bracing will likely be required to facilitate safe and effective excavation. Buried utilities, including gas, electric, water, and communications, are known to exist in close proximity to the proposed new lift station, as well as, along the northern portion of the forcemain alignment. All earthwork and pipe installation should be in accordance with the 2006 Edition of the New Mexico Standard Specifications for Public Works Construction (NMSSPWC).

13 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 9 LIFT STATION FOUNDATION: The lift station could be supported directly on compacted native gravel/cobble soils. If necessary, a leveling course of flowable fill or ⅜-inch pea gravel could be placed below the bottom of the structure to reduce the potential for damage from protruding cobbles. The lift station should be designed to resist the uplift and horizontal forces resulting from the groundwater table in the area. Total and differential settlements resulting from the assumed structural loads are estimated to be on the order of ½ inch or less. Lateral Earth Pressures: For soils above any free water surface - Recommended equivalent fluid pressures for unrestrained foundation elements are presented in the following table: Active: Granular soil backfill (on-site sand)...35 psf/ft Undisturbed subsoil...30 psf/ft Passive: Foundation walls psf/ft Coefficient of base friction: The coefficient of base friction should be reduced to 0.30 when used in conjunction with passive pressure. Where the design includes restrained elements, the following equivalent fluid pressures are recommended: At rest: Granular soil backfill (on-site sand) psf/ft Undisturbed subsoil psf/ft Soils in Submerged Condition - Hydrostatic forces should be added to the following, as appropriate.

14 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 0 Active: Granular soil backfill (on-site sand)...5 psf/ft Undisturbed subsoil...5 psf/ft Passive: Foundation walls psf/ft Coefficient of base friction: The coefficient of base friction should be reduced to 0.5 when used in conjunction with passive pressure. Where the design includes restrained elements, the following equivalent fluid pressures are recommended: At rest: Undisturbed Soil psf/ft Fill against the walls of the vault should be compacted to a minimum of 90 percent of the maximum dry density as determined by ASTM D 557. Medium to high plasticity clay soils should not be used as backfill against the vault walls. Compaction of each lift adjacent to walls should be accomplished with hand-operated tampers or other lightweight compactors. Over compaction may cause excessive lateral earth pressures that could result in wall movement. CORROSION AND CEMENT TYPE: Two representative soil samples obtained from the borings along the forcemain alignment, and one sample from the test pit at the lift station site, were tested to evaluate the potential for the onsite soils to corrode buried metal and/or concrete. The samples were tested for ph, electrical resistivity, and soluble sulfates and chlorides. Results of these tests are presented in the following table. Results of Corrosivity Testing Sample No. Boring/Test Sample Resistivity Sulfates Chlorides ph Pit Depth (ft) (ohm-cm) (ppm) (ppm) 3723 B , ND 3727 B , TP

15 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain Corrosion of Concrete: The soluble sulfate contents of the samples tested ranged from 89.4 ppm to 563 ppm, which is characterized as slight to moderate sulfate exposure according to American Concrete Institute Building Code 38, Table For moderate levels of sulfate exposure, ACI 38 recommends the use of Type II cement and a maximum water-cementitious material ratio of In addition, ACI recommends the use of concrete with a minimum 28-day compressive strength of 4,000 psi. All concrete should be designed, mixed, placed, finished, and cured in accordance with the guidelines presented by the American Concrete Institute (ACI). Corrosion of Metals: Corrosion of buried ferrous metals can occur when electrical current flows from the metal into the soil. As the resistivity of the soil decreases, the flow of electrical current increases, increasing the potential for corrosion. A commonly accepted correlation between soil resistivity and corrosion of ferrous metals is shown in the following table. Resistivity (ohm-cm) Corrosivity 0 to,000 Severely Corrosive,000 to 2,000 Corrosive 2,000 to 0,000 Moderately Corrosive >0,000 Mildly Corrosive The samples tested had resistivities ranging from 600 ohm-cm to 3,220 ohm-cm. Based on these laboratory results and the table above, the on-site soils would be characterized as moderately to severely corrosive toward ferrous metals. The potential for corrosion should be taken into account during the design process. EARTHWORK: General Considerations: The opinions contained in this report for the proposed construction are contingent upon compliance with recommendations presented in this section. The presence of underground utilities, including gas, electric, water, and communication lines, should be expected at the lift station site and along Road 600.

16 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 2 Excavation: We present the following general comments regarding our opinion of the excavation conditions for the designers information with the understanding that they are opinions based on our boring data. Our borings were advanced using 7.25-inch O.D. continuous-flight auger, and the test pit was excavated with a Hyundai 20 LC-7 trackhoe with a 48-inch wide bucket. The relative ease or difficulty of excavation may be significantly different using other types of equipment and techniques. More accurate information regarding the excavation conditions should be evaluated by contractors or other interested parties from test excavations using the equipment that will be used during construction. Based on our subsurface evaluation it appears that excavations in the sandy, clayey, and gravelly soils along the alignment will be possible using standard excavation equipment. Significant caving and sloughing was noted in our exploratory test pit, TP-. Excavations deeper than a few feet are likely to experience caving or sloughing, especially near the water table. Sloping, shoring, or bracing of excavation walls, along with dewatering techniques, are likely to be necessary to maintain safe, stable excavations. Excavation Safety: Construction of stable temporary excavations is the responsibility of the contractor. Temporary slopes and excavations should be designed and constructed in accordance with the Department of Labor Occupational Safety and Health Administration 29 CFR Part 926, Subpart P, Occupational Safety and Health Standards Excavations ( OSHA Construction Standards for Excavations ). According to OSHA Construction Standards for Excavations, all excavations greater than four feet in depth must be sloped, shored, or braced. Spoils must be placed at least two feet from the edge of the excavation to reduce the potential for sidewall failure due to excessive lateral pressures. Other details regarding excavation safety, as described in Subpart P, shall be followed. Conditions affecting stability of slopes and excavations can change over time depending on variables such as weather, vibration or surcharges due to nearby equipment, etc. The contractor s designated Competent Person (as defined in subpart P) shall monitor and assess conditions affecting soil stability during construction.

17 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 3 Dewatering: In areas where groundwater is encountered during excavation, dewatering may be required in order to facilitate the entry of personnel and/or equipment into the excavation. Water should be removed from the excavation using pumps, well points, or similar techniques, and either contained or discharged to a lower point. According to the NMSSPWC specification, the groundwater should be lowered to at least six inches below pipe grades before laying pipes in trenches. Pipe Foundation: Pipes should be bedded on a stable subgrade which is free of water. Any areas where pumping soils or otherwise unstable subgrade conditions are encountered must be stabilized before laying pipe. If such conditions are encountered during construction, GEOMAT should be contacted to provide specific recommendations for stabilization. Pipe Embedment: As required in the NMSSPWC specifications, a minimum thickness of eight (8.0) inches of embedment (bedding) material should be placed on top of the subgrade to support and protect the pipe. Once the pipe has been placed and aligned, shading material should be placed to a minimum of eight (8.0) inches above the top of the pipe. Hand tamping or similar techniques should be employed to ensure that the bedding material completely supports the haunch of the pipe. Embedment material below the pipe should be compacted to a minimum density of 95 percent of the ASTM D557 maximum dry density. To avoid damage to the pipe, mechanical compaction equipment should not be used over the pipe in the embedment zone. Embedment material should be a granular soil such as sand, silty/clayey sand, or fine-grained gravel. It should be free of coarse-grained gravel particles or cobbles. Silt, clay, or organic soils are not suitable for use as embedment material. Soils used for embedment should have a fines content (percentage of silt and/or clay-sized particles passing the U.S. No. 200 sieve) of less than 50 percent. Alternatively, flowable fill could be used as embedment material. The use of flowable fill could be appropriate in situations where placing personnel and/or compaction equipment in excavations is impractical due to closely-spaced adjacent utilities or unstable excavations.

18 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 4 Backfill: Excavations should be backfilled to the planned finished grades using native or imported soils that are free of debris, rubble, frozen soil, organic material, or other deleterious material. Fill material should be free of cobbles or boulders greater than six inches in diameter. Additionally, backfill material should conform to any specifications provided by the pipe manufacturer. Backfill material should be compacted to a minimum of 90 percent of the maximum dry density as determined by ASTM D557. Soils should be compacted at moisture contents near optimum. Material should be placed in horizontal lifts in thicknesses that permit compaction to the required densities with the equipment being used. The existing soils along much of the alignment are predominantly fine-grained, and as such, are expected to be moisture sensitive. The fine-grained native soils may pump or become unstable or unworkable at high water contents. Workability may be improved by scarifying and drying. Over-excavation of wet zones and replacement with granular materials may be necessary. Lightweight excavation equipment may be required to reduce pumping. Compliance: The recommendations in this report depend upon compliance with Earthwork recommendations. To assess compliance, observation and testing should be performed by GEOMAT. PAVEMENT REPAIRS: Existing bituminous pavement removed in connection with construction shall be cut with a saw or other suitable tool. Care shall be taken to assure that the edge of removed pavement does not vary from a straight line more than two inches for any given section of removed pavement. Patching of removed pavement shall conform to the following detail, as well as, applicable NMSSPWC specifications.

19 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 5 No edge of a pavement patch shall be in a wheel path; the edge shall be either between wheel paths or on the centerline of the road. If the outer edge of the paved surface is damaged, the paving shall be replaced to between the wheel paths of the lane damaged. If the damage extends beyond the outer wheel, the paving shall be replaced to the centerline of the road. Trench backfill under pavements, and within 5 feet of the edge of the pavement, should be compacted to a minimum of 90 percent of the ASTM D557 maximum dry density. For trenching that will be within 5 feet of the edge of the pavement, the backfill should be compacted to a density of not less than 90 percent of the maximum dry density, as determined by ASTM D557. GENERAL COMMENTS It is recommended that GEOMAT be retained to provide a general review of final design plans and specifications in order to confirm that earthwork recommendations in this report have been interpreted and implemented. In the event that any changes of the proposed project are planned, the opinions and recommendations contained in this report should be reviewed and the report modified or supplemented as necessary. GEOMAT should also be retained to provide services during the construction phase of the project. Construction testing, including field and laboratory evaluation of fill and/or backfill materials, should be performed to determine whether applicable project requirements have been met. The analyses and recommendations in this report are based in part upon data obtained from the field exploration. The nature and extent of variations beyond the location of test excavations may not become evident until construction. If variations then appear evident, it may be necessary to re-evaluate the recommendations of this report.

20 Geotechnical Engineering Report GEOMAT Project No Rev. Harper Valley Lift Station and Forcemain 6 Our professional services were performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical engineers practicing in this or similar localities at the same time. No warranty, express or implied, is intended or made. We prepared the report as an aid in design of the proposed project. This report is not a bidding document. Any contractor reviewing this report must draw his own conclusions regarding site conditions and specific construction equipment and techniques to be used on this project. This report is for the exclusive purpose of providing geotechnical engineering and/or testing information and recommendations. The scope of services for this project does not include, either specifically or by implication, any environmental assessment of the site or identification of contaminated or hazardous materials or conditions. If the owner is concerned about the potential for such contamination, other studies should be undertaken. This report has also not addressed any geologic hazards that may exist on or near the site. This report may be used only by the Client and only for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both on and off site), or other factors may change over time and additional work may be required with the passage of time. Any party, other than the Client, who wishes to use this report, shall notify GEOMAT in writing of such intended use. Based on the intended use of the report, GEOMAT may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements, by the Client or anyone else, will release GEOMAT from any liability resulting from the use of this report by an unauthorized party.

21 Appendix A

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23 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B- Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: None Encountered Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SILTY SAND, brown to tan, fine-grained, loose, damp 2 3 SM SS GP GRAVEL with sand and cobbles, brown to gray, fine- to coarse-grained, dense, damp Boring terminated at 8½ feet due to auger refusal on cobbles Total Depth 8½ feet GEOMAT GPJ GEOMAT.GDT 3/2/ A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

24 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-2 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: None Encountered Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SILTY SAND, brown to tan, fine-grained, loose, damp 2 27 NP SM 3 4 with gravel SS 8 5 GP GRAVEL with sand and cobbles, brown to gray, fine- to coarse-grained, dense, damp Boring terminated at 6½ feet due to auger refusal on cobbles Total Depth 6½ feet 9 0 GEOMAT GPJ GEOMAT.GDT 3/2/ A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

25 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-3 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: None Encountered Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SILTY SAND with trace gravel, brown to tan, fine-grained, loose, damp GRAB SS 8 5 SM GEOMAT GPJ GEOMAT.GDT 3/2/ SS Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

26 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-4 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: None Encountered Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SILTY SAND with gravel, brown to tan, fine-grained, medium dense, damp 2 33 NP SS 8 5 tan SM GEOMAT GPJ GEOMAT.GDT 3/2/ SS 8 0 loose 2 Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

27 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-5 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: 9.0 ft after 24 hours Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description CLAYEY SAND, brown to tan, fine-grained, loose, moist SC 2 82 NP GRAB SS SILT with sand, brown, very soft, moist sampler advances 8 inches under weight of hammer ML 6 7 wet soils during drilling - no free water at time of drililng 8 GEOMAT GPJ GEOMAT.GDT 3/2/ SS 8 SM SILTY SAND, brown, fine-grained, very loose, wet sampler advances 8 inches under Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

28 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-6 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: 8.4 ft after 24 hours Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SANDY LEAN CLAY, tan, soft, damp GRAB SS 8 CL 5 6 very soft - sampler advances 8 inches under weight of hammer wet soils during drilling - no free water at time of drililng GEOMAT GPJ GEOMAT.GDT 3/2/ SS Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

29 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-7 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: 8.4 ft after 24 hours Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SANDY LEAN CLAY, brown to tan, soft, moist 66 6 GRAB CL 2 3 damp SS 8 5 very soft wet soils during drilling - no free water at time of drilling 6 SAND, tan, fine- to medium-grained, poorly graded, loose, wet 7 SP 8 9 GEOMAT GPJ GEOMAT.GDT 3/2/ SS 8 GP GRAVEL with sand and occasional cobbles, brown to gray, fine- to coarse-grained, dense, wet Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

30 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-8 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: 6.5 ft after 24 hours Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description CLAYEY SAND, brown, fine-grained, loose, moist GRAB 2 SC SS GRAVEL with sand and occasional cobbles, brown to gray, fine- to coarse-grained, loose, damp wet at time of drililng - free water in boring 8 GP 9 GEOMAT GPJ GEOMAT.GDT 3/2/ SS 8 0 able to drill into gravel with moderate difficulty 2 Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

31 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Borehole B-9 Page of Project Name: Harper Valley Lift Station & ForcemainDate Drilled: 2/5/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: CME-45 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: 6. ft after 24 hours Sampling Method: Hand and Split spoon samples Logged By: DB Hammer Weight: 40 lbs Remarks: None Hammer Fall: 30 inches Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Blows per 6" Sample Type & Length (in) Recovery USCS Soil Symbol Depth (ft) Soil Description SILTY SAND, brown, fine-grained, loose, moist 2 42 NP GRAB 3 SM SS 8 5 very loose SANDY LEAN CLAY, brown to tan, soft to medium stiff, wet wet soils during drilling - no free water at time of drilling CL 9 GEOMAT GPJ GEOMAT.GDT 3/2/ SS 8 GP GRAVEL with sand and occasional cobbles, gray, fine- to coarse-grained, medium dense, wet Total Depth ½ feet A = Auger Cuttings MC = Modified California (Ring Sample) SS = Split Spoon CS = 5 ft Continuous Barrel Sampler bgs = below ground surface

32 95 Malta Avenue Farmington, NM 8740 Tel (505) Fax (505) Test Pit TP- Page of Project Name: Harper Valley Lift Station & ForcemainDate Excavated: 2/6/206 Project Number: Latitude: Client: HDR Engineering, Inc. Longitude: Site Location: Kirtland, New Mexico Elevation: Rig Type: Hyundai 20 LC-7 Test Pit Location: See Site Plan Excavation Method: 48-inch Bucket Groundwater Depth: Approx. 7 ft during excavation Sampling Method: Hand sample Logged By: DB Hammer Weight: N/A Remarks: None Hammer Fall: N/A Laboratory Results Dry Density (pcf) % Passing #200 Sieve Plasticity Index Moisture Content (%) Field Dry Density (pcf) Field Moisture Content (%) Sample Type USCS Soil Symbol Depth (ft) Soil Description TEST PIT GPJ 2/22/6 45 NP GRAB SM GP SILTY SAND with gravel, brown, fine-grained, damp GRAVEL with sand and occasional cobbles, brown, damp estimated 5% cobbles by volume moist - severe caving below 5 feet tree roots to 4" diameter visible to 6 foot depth wet at 7 feet - moderate groundwater infiltration unable to advance excavation below 9 feet due to caving and flowing of saturated soils slurry-like soils flow back into hole with each scoop trackhoe bucket extending to depth of approximately 8 feet (i.e., below water surface) Total depth penetrated by trackhoe bucket approximately 8 feet Test pit terminated due to caving and sloughing Total Depth 8 feet G = Grab Sample MC = Modified California (Ring Sample) SS = Split Spoon ND = Nuclear Densometer D = Disturbed Bulk Sample

33

34 TEST DRILLING EQUIPMENT & PROCEDURES Description of Subsurface Exploration Methods Drilling Equipment Truck-mounted drill rigs powered with gasoline or diesel engines are used in advancing test borings. Drilling through soil or softer rock is performed with hollowstem auger or continuous flight auger. Carbide insert teeth are normally used on bits to penetrate soft rock or very strongly cemented soils which require blasting or very heavy equipment for excavation. Where refusal is experienced in auger drilling, the holes are sometimes advanced with tricone gear bits and NX rods using water or air as a drilling fluid. Sampling Procedures - Dynamically driven tube samples are usually obtained at selected intervals in the borings by the ASTM D586 test procedure. In most cases, 2 outside diameter, 3/8 inside diameter, samplers are used to obtain the standard penetration resistance. Undisturbed samples of firmer soils are often obtained with 3 outside diameter samplers lined with 2.42 inside diameter brass rings. The driving energy is generally recorded as the number of blows of a 40-pound, 30-inch free fall drop hammer required to advance the samplers in 6- inch increments. These values are expressed in blows per foot on the boring logs. However, in stratified soils, driving resistance is sometimes recorded in 2- or 3-inch increments so that soil changes and the presence of scattered gravel or cemented layers can be readily detected and the realistic penetration values obtained for consideration in design. Undisturbed sampling of softer soils is sometimes performed with thin-walled Shelby tubes (ASTM D587). Tube samples are labeled and placed in watertight containers to maintain field moisture contents for testing. When necessary for testing, larger bulk samples are taken from auger cuttings. Where samples of rock are required, they are obtained by NX diamond core drilling (ASTM D23). Boring Records - Drilling operations are directed by our field engineer or geologist who examines soil recovery and prepares boring logs. Soils are visually classified in accordance with the Unified Soil Classification System (ASTM D2487), with appropriate group symbols being shown on the logs.

35 Appendix B

36 Silty SAND (SM) Silty SAND (SM) SILT with sand (ML) Silty SAND (SM) Silty SAND (SM) NLL = No Liquid Limit NPL = No Plastic Limit NP = Non-Plastic CLASSIFICATION Sandy Lean CLAY (CL) LAB NO. BORING/ TEST PIT SAMPLE DEPTH (ft) SIEVE ANALYSIS, CUMULATIVE PERCENT PASSING ATTERBERG LIMITS 3/4" /2" 3/8" No. 4 No. 8 No. 0 No. 6 No. 30 No. 40 No. 50 No. 00 No. 200 LL PL PI IN-SITU MOISTURE (%) 3724 B NLL NPL NP B NLL NPL NP B NLL NPL NP B B NLL NPL NP TP NLL NPL NP 0.3 Project Harper Valley Lift Station and Forcemain SUMMARY OF SOIL TESTS Job No Location Kirtland, New Mexico Date Drilled February 5-6, 206

37 LABORATORY TESTING PROCEDURES Consolidation Tests: One-dimensional consolidation tests are performed using Floating-ring type consolidometers. The test samples are approximately 2.5 inches in diameter and.0 inch high and are usually obtained from test borings using the dynamically-driven ring samplers. Test procedures are generally as outlined in ASTM D2435. Loads are applied in several increments to the upper surface of the test specimen and the resulting deformations are recorded at selected time intervals for each increment. Samples are normally loaded in the in-situ moisture conditions to loads which approximate the stresses which will be experienced by the soils after the project is completed. Samples are usually then submerged to determine the effect of increased moisture contents on the soils. Each load increment is applied until compression/expansion of the sample is essentially complete (normally movements of less than inches/hour). Porous stones are placed on the top and bottom surfaces of the samples to facilitate introduction of the moisture. Expansion Tests: Tests are performed on either undisturbed or recompacted samples to evaluate the expansive potential of the soils. The test samples are approximately 2.5 inches in diameter and.0 inch high. Recompacted samples are typically remolded to densities and moisture contents that will simulate field compaction conditions. Surcharge loads normally simulate those which will be experienced by the soils in the field. Surcharge loads are maintained until the expansion is essentially complete. Atterberg Limits/Maximum Density/Optimum Moisture Tests: These tests are performed in accordance with the prescribed ASTM test procedures.

38 Appendix C

39 Important Information about This Geotechnical-Engineering Report Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. Geotechnical Services Are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a civil engineer may not fulfill the needs of a constructor a construction contractor or even another civil engineer. Because each geotechnical- engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. No one except you should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one not even you should apply this report for any purpose or project except the one originally contemplated. Read the Full Report Serious problems have occurred because those relying on a geotechnical-engineering report did not read it all. Do not rely on an executive summary. Do not read selected elements only. Geotechnical Engineers Base Each Report on a Unique Set of Project-Specific Factors Geotechnical engineers consider many unique, project-specific factors when establishing the scope of a study. Typical factors include: the client s goals, objectives, and risk-management preferences; the general nature of the structure involved, its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless the geotechnical engineer who conducted the study specifically indicates otherwise, do not rely on a geotechnical-engineering report that was: not prepared for you; not prepared for your project; not prepared for the specific site explored; or completed before important project changes were made. Typical changes that can erode the reliability of an existing geotechnical-engineering report include those that affect: the function of the proposed structure, as when it s changed from a parking garage to an office building, or from a lightindustrial plant to a refrigerated warehouse; the elevation, configuration, location, orientation, or weight of the proposed structure; the composition of the design team; or project ownership. As a general rule, always inform your geotechnical engineer of project changes even minor ones and request an assessment of their impact. Geotechnical engineers cannot accept responsibility or liability for problems that occur because their reports do not consider developments of which they were not informed. Subsurface Conditions Can Change A geotechnical-engineering report is based on conditions that existed at the time the geotechnical engineer performed the study. Do not rely on a geotechnical-engineering report whose adequacy may have been affected by: the passage of time; man-made events, such as construction on or adjacent to the site; or natural events, such as floods, droughts, earthquakes, or groundwater fluctuations. Contact the geotechnical engineer before applying this report to determine if it is still reliable. A minor amount of additional testing or analysis could prevent major problems. Most Geotechnical Findings Are Professional Opinions Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. Geotechnical engineers review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ sometimes significantly from those indicated in your report. Retaining the geotechnical engineer who developed your report to provide geotechnical-construction observation is the most effective method of managing the risks associated with unanticipated conditions. A Report s Recommendations Are Not Final Do not overrely on the confirmation-dependent recommendations included in your report. Confirmationdependent recommendations are not final, because geotechnical engineers develop them principally from judgment and opinion. Geotechnical engineers can finalize their recommendations only by observing actual subsurface conditions revealed during construction. The geotechnical engineer who developed your report cannot assume responsibility or liability for the report s confirmation-dependent recommendations if that engineer does not perform the geotechnical-construction observation required to confirm the recommendations applicability. A Geotechnical-Engineering Report Is Subject to Misinterpretation Other design-team members misinterpretation of geotechnical-engineering reports has resulted in costly