Attachment 1 - Specifications - 33 24 13 Amendment 0001.pdf

Amendment 0001

SECTION TABLE OF CONTENTS

DIVISION 33 - UTILITIES

SECTION 33 24 13

PIEZOMETERS

PART 1 GENERAL

1.1 UNIT PRICES

1.1.1 Piezometer Completion Aboveground

1.1.2 Piezometer or Test Hole Decommissioning/Abandonment

1.1.3 Site Cleanup

1.2 REFERENCES

1.3 SYSTEM DESCRIPTION

1.3.1 Installation Plan

1.4 SUBMITTALS

1.5 QUALITY ASSURANCE

1.5.1 Notification

1.5.2 Qualifications

1.6 DELIVERY, STORAGE, AND HANDLING

1.7 SITE CONDITIONS

PART 2 PRODUCTS

2.1 PIEZOMETER CASING

2.2 PIEZOMETER SCREEN

2.3 FILTER PACK

2.4 BENTONITE SEAL

2.5 CEMENT AND BENTONITE GROUT

2.6 CONCRETE COLLAR

2.7 PROTECTIVE POSTS

2.8 CONCRETE QUALITY

2.9 SAMPLE CONTAINERS

2.10 TRANSDUCER

PART 3 EXECUTION

3.1 DRILLING PROGRAM PLAN

3.2 PROTECTION OF EXISTING CONDITIONS

3.3 PREPARATION

3.3.1 Water Source

3.4 INSTALLATION

3.4.1 Drilling Method

3.4.2 Test Hole Requirements

3.4.3 Sampling

3.4.3.1 Sampling for Geotechnical Analysis

3.4.4 Borehole Diameter and Depth

3.4.5 Screen, Well Casing/Riser Pipe Placement

3.4.6 Filter Pack Placement

3.4.7 Bentonite Seal

3.4.8 Grout Placement

3.4.9 Concrete or Gravel Pad Placement

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3.4.10 Protective Casing or Vault Placement

3.4.10.1 Protective Concrete Collar

3.4.11 Piezometer Identification

3.4.12 Instrumentation

3.4.13 Falling Head Test

3.4.14 Drilling Waste Disposal

3.5 SURVEYS

3.6 BORING LOGS AND PIEZOMETER CONSTRUCTION DIAGRAMS

3.7 PIEZOMETER DECOMMISSIONING/ABANDONMENT

3.8 PIEZOMETER ACCEPTANCE

3.9 SITE CLEANUP

3.10 DOCUMENTATION AND QUALITY CONTROL REPORTS

3.10.1 Project Photographs

3.10.2 Survey Maps and Notes

3.10.3 Piezometer Construction Details

-- End of Section Table of Contents --

SECTION 33 24 13 Page 2

SECTION 33 24 13

PIEZOMETERS

PART 1 GENERAL

1.1 UNIT PRICES

Payment for each piezometer is made at the contract unit price (EACH) for that item. Payment includes full compensation for equipment, materials and labor for drilling; removal and disposal of temporary casing, cuttings, and drill fluid; preparation of borehole logs; and sample handling, containers, storage, and testing, and installation; casing/riser pipe, screen, filter pack, bentonite seal, concrete seal, surface completion, and equipment. Payment is not allowed for test holes or piezometers abandoned due to construction practices not in accordance with this specification, or for the convenience of the Contractor.

1.1.1 Piezometer Completion Aboveground

Payment includes compensation for protective covers, keyed-alike padlocks, locking caps, project photographs, concrete piezometer pads, gravel, and protective steel posts.

1.1.2 Piezometer or Test Hole Decommissioning/Abandonment

Permanent decommissioning/abandonment of piezometer or test holes is paid for only if it becomes necessary to abandon a piezometer or test hole as specified, and only for work completed and accepted as specified. Payment includes compensation for drilling, casing removal, piezometer or test hole sampling, materials, cement, mixing of cement, bentonite, and water, pumping of grout, equipment, removal of foreign objects, and transportation necessary to abandon the piezometer or test hole and for the required piezometer or test hole abandonment records.

1.1.3 Site Cleanup

Separate payment is not made for cleanup of the site. Cleanup means restoring the site to its pre-construction condition, in accordance with paragraph 3.7, SITE CLEANUP. Cleanup is considered part of and incidental to the drilling, construction, and/or decommissioning of the piezometer.

1.2 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM A53/A53M (2018) Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless

ASTM A865/A865M (2006; R 2012) Standard Specification for

SECTION 33 24 13 Page 3

Threaded Couplings, Steel, Black or Zinc-Coated (Galvanized) Welded or Seamless, for Use in Steel Pipe Joints

ASTM C150/C150M (2012) Standard Specification for Portland Cement

ASTM C387/C387M (2011b) Standard Specification for Packaged, Dry, Combined Materials for Mortar and Concrete

ASTM D1586 (2011) Penetration Test and Split-Barrel Sampling of Soils

ASTM D2487 (2017) Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)

ASTM D2488 (2009a) Description and Identification of Soils (Visual-Manual Procedure)

ASTM D422 (1963; R 2007) Particle-Size Analysis of Soils

ASTM D4318 (2010; E 2014) Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM D5092 (2004; R 2010e1) Design and Installation of Ground Water Monitoring Wells in Aquifers

ASTM D5299 (1999; R 2012e1) Decommissioning of Ground Water Wells, Vadose Zone Monitoring Devices, Boreholes, and Other Devices for Environmental Activities

U.S. ARMY CORPS OF ENGINEERS (USACE)

ER 1110-1-1807 (2014) Drilling in Earth Embankment Dams and Levees

1.3 SYSTEM DESCRIPTION

Construct each piezometer to allow for the accurate measurement of ground water depths relative to the top of the piezometer riser, by use of electrical, wetted tape, or acoustical methods. The screened interval is that portion of a piezometer which is directly open to the host aquifer by way of openings in the piezometer screen and indirectly open to the aquifer by way of the filter pack (or other permeable material) extending continuously below and/or above the screen.

1.3.1 Installation Plan

Incorporate the following requirements into the Contractor's Piezometer Installation Plan and follow in the field.

a. Description of piezometer drilling methods, and installation procedures, including any temporary casing used, placement of filter

SECTION 33 24 13 Page 4 pack and seal materials, transducer installation, drill cuttings and fluids disposal, and soil sample disposition.

b. Description of piezometer construction materials, including piezometer screen, riser pipe, filter pack and filter pack gradation, transducer and associated materials, bentonite, drilling fluid additives (if used), drilling water, cement, and piezometer protective measures.

c. Description of quality control procedures to be used for placement of filter pack and seals in the boring, including depth measurements.

d. Description of protective cover surface completion procedures.

e. List of applicable publications, including state and local regulations and standards.

f. List of personnel assignments for this project, and personnel qualifications.

g. Description of piezometer decommissioning/abandonment procedures.

1.4 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Drilling Program Plan (Dpp); G

SD-02 Shop Drawings

SD-03 Product Data

Project Photographs; G Photographs taken before and after completion of the work, of each piezometer installation site.

Piezometers; G Catalog data for piezometer screens (to include the screen slot size), casing, riser pipe, filter pack material, bentonite, cement, piezometer vaults, locking caps, dedicated sampling equipment and chemical specifications on drill lubricants and tracers, if used. Include any information, written or otherwise, supplied by the manufacturers or suppliers of the above listed items.

Qualifications; G Personnel qualification documentation.

Permits; G A copy of all permits, licenses, or other requirements necessary for execution of the work. The piezometers should not be represented as wells to the regulatory agency as no withdrawals/testing shall be performed.

Installation Plan; G A plan, as specified in paragraph INSTALLATION PLAN, describing

SECTION 33 24 13 Page 5 the drilling methods, sampling, and piezometer construction piezometer 15 calendar days prior to beginning drilling operations.

SD-06 Test Reports

Water Source; G

Filter Pack; G

Drilling Fluid Additive; G Manufacturer's data, if available, including analytical test results of the additive, if not a part of the manufacturer's data.

Falling Head Test Report; G

1.5 QUALITY ASSURANCE

1.5.1 Notification

Notify the Contracting Officer 10 days prior to drilling. Piezometers shall not be installed until after completion of all earthwork operations adjacent to the drilling site.

1.5.2 Qualifications

Provide a driller licensed in the state of Illinois, according to the state requirements. Furnish Contractor documentation proving a minimum of 5 years of drilling and piezometer installation experience, and appropriate health and safety personnel on staff.

1.6 DELIVERY, STORAGE, AND HANDLING

Store and maintain piezometer materials in a clean, uncontaminated condition throughout the course of the project.

1.7 SITE CONDITIONS

Access to each piezometer site, including any utility clearance, permits, licenses, or other requirements and the payment thereof necessary for execution of the work is the responsibility of the Contractor. Obtaining other rights-of-entry is the responsibility of the Contractor. Visit each proposed piezometer location to observe any condition that may hamper transporting equipment or personnel to the site.

PART 2 PRODUCTS

2.1 PIEZOMETER CASING

Provide new piezometer casing/riser as shown on the plans. Piezometer risers shall be 2 inch nominal internal diameter, galvanized steel pipe and fittings, meeting the requirements of ASTM A53/A53M Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless and ASTM A865/A865M for threaded couplings, steel, black or Zinc-coated (galvanized)welded or seamless, for use in steel pipe joints.

Provide 2 inch galvanized steel pipe cap with 1/8 inch diameter hole in top. Do not use pop rivets or screws. Provide a galvanized steel locking cap that threads onto the top of the piezometer casing.

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2.2 PIEZOMETER SCREEN

Provide piezometer screen, designed and constructed in accordance with paragraph SYSTEM DESCRIPTION and as shown on the plans. Well screens to be set in sands shall be 2 inch nominal internal diameter type 304 stainless steel with No. 10 slots. Seal the bottom section of the screen watertight by means of a flush threaded end cap of the same material as the piezometer screen, within 6 inches of the open portion of the screen.

2.3 FILTER PACK

Provide filter pack consisting of clean, washed, rounded to sub-rounded siliceous material free from calcareous grains or material. Organic matter, soft, friable, thin, or elongated particles are not permissible.

The filter shall be graded uniformly between the U.S. standard No. 20 and No. 40 sieves, shall have an effective size of at least 0.15 mm, and not more than 3% shall be finer than the No. 40 sieve.

2.4 BENTONITE SEAL

Provide a minimum five (5) foot thick bentonite seal, intended to keep grout from entering the filter pack, consisting of pelletized, sodium montmorillonite furnished in sacks or buckets from a commercial source, free of impurities which adversely impact the water quality. If the bentonite seal is located above any borehole fluid levels, place a layer of fine sand at the top of the bentonite seal, to provide an additional barrier to any downward migration of grout.

2.5 CEMENT AND BENTONITE GROUT

Provide cement grout with a mixture of a maximum of 6 gallons of approved water per 94 lb bag of portland cement, conforming to ASTM C150/C150M, Type I. Add no more than 5 percent by weight of bentonite powder to reduce shrinkage, hold the cement in suspension prior to the grout set.

Use sodium bentonite powder and/or granules for high-solids bentonite grout. Mix water from an approved source with these powders or granules to form a thick bentonite slurry, consisting of a mixture of bentonite and the manufacturer's recommended volume of water to achieve an optimal seal. The slurry shall contain at least 20 percent solids by weight and have a density of 9.4 lb per gallon of water or greater.

2.6 CONCRETE COLLAR

Construct a 12-inch diameter concrete collar around the riser from 4 feet below the ground surface to 2 feet above ground surface. The riser should extend up for 1 foot above the concrete collar. Install a lockable protective piezometer cap. Provide weather resistant padlocks which use the same key (keyed-alike) on the lockable caps for all piezometers. Cap any piezometer that is to be temporarily removed from service or left incomplete due to delay in construction with a watertight cap and equipped with a vandal resistant cover.

2.7 PROTECTIVE POSTS

Provide and place 3 inch diameter, schedule 40 carbon steel, 6-foot, 6-inchlong, primed and painted, protective bollards around the piezometer.

Protective bollard shall be constructed of standard weight steel pipe Type B conforming to ASTM A53/A53M. All pipe shall be hot-dipped galvanized.

Posts shall be painted yellow unless a different color is approved by the

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Government. The first coat shall be SSPC Paint 25 - Type I, second and third coats shall be MPI 9.

2.8 CONCRETE QUALITY

Specified compressive strength f'c shall be a minimum of 4000 pounds per square inch at 28 days. The mix shall contain a minimum of 500 pounds of cementitious material per yard, and possess a maximum water-cement ratio of 0.45. The maximum nominal size coarse aggregate shall be 1 inch. The air content shall be 6.0 plus or minus 1.5 percent. The slump shall not vary more than plus or minus 1 1/2 inch from 3 1/2 inches.

2.9 SAMPLE CONTAINERS

a. Place cuttings, and driven samples for geotechnical purposes, in Contractor furnished containers consisting of air-tight pint size plastic or glass wide mouth jars secured with moisture proof lids and labeled with the project name, date of sample, piezometer number and depth at which the sample was taken.

b. Label both the container and lid in permanent indelible ink. Place jars in partitioned cardboard Contractor furnished boxes. Label boxes with project number, piezometer number, depths and jar numbers. Do not mix jars from piezometers, only samples from one piezometer should be in a box.

2.10 TRANSDUCER

Approved Transducer shall be:

a. Solinst Level Logger Edge Model 3001, non-vented (see Attached Cut Sheet)

b. The transducer shall hang from a stainless steel wireline.

c. For programming and reading the transducers, and serve as interface to a computer, an optical reader will be required.

d. One Barologger 3001 is needed for each of the levee systems.

e. The pressure sensor shall be based on the F65 sensor for bidding purpose however final determination of sensor will be made per location during construction.

f. Landside toe piezometers shall have caps that meet the specs AND can resist up to 15 psi of 'blowout' pressure.

PART 3 EXECUTION

3.1 DRILLING PROGRAM PLAN

Drilling Requirements: By Engineering Regulation (ER) 1110-1-1807, all drilling in Levees must have an approved Drilling Program Plan (DPP) prior to any drilling, sampling, grouting, or any other invasive in-situ testing or exploration. A DPP is required for the work associated with the piezometers. This DPP must be approved and signed by the St. Louis District Levee Safety Program Manager AND then subsequently approved by USACE's Geotechnical and Materials Community of Practice Standing Committee on Drilling and Instrumentation, which is a nationwide

SECTION 33 24 13 Page 8 committee. The Contractor's plan must be fully compliant with ER 1110-1-1807 . The Contractor shall allow at least 60 days for approval of this DPP. If the Contractor's DDP does not meet the requirements of ER 1110-1-1807 , additional time will be needed to secure the approval of the DPP; this additional time shall not result in additional cost to the government or project delay. All drilling programs in dams and levees should be designed to minimize the need for any drilling fluid such as air, gas, water, mud, polymers, slurries or any other drilling fluid that could pressurize the borehole soils. Drilling shall be performed by an approved drill rig operator and overseen by an approved drilling inspector. These professionals shall be approved in advance of work by submittal. Alternates should be approved in advance, last-minute approvals cannot be performed.

3.2 PROTECTION OF EXISTING CONDITIONS

Maintain all existing survey monuments, relief wells, piezometers, and any other structure, and protect them from damage from equipment and vehicular traffic. Immediately report and repair any items damaged by the Contractor. Re-install piezometers requiring replacement due to Contractor negligence according to these specifications. Protect piezometers scheduled for abandonment from damage so that abandonment may be performed according to these specifications. Prior to excavation, obtain written approval from the local utility companies to drill at each site, to avoid disturbing buried utilities.

3.3 PREPARATION

In areas shown on the plans to require decontamination:

3.3.1 Water Source

Piezometer drilling/installation requires the use of potable water. Prior to its use at the site, obtain approval for the potable water from the Contracting Officer's Representative. The Contractor is responsible for locating the source, obtaining the water from the source, transporting it to, and storing it at the site.

3.4 INSTALLATION

3.4.1 Drilling Method

a. Use a drilling method which prevents the collapse of formation material against the piezometer screen and casing during installation of the piezometer. Bentonite drilling mud should not be used in drilling the holes. Drilling mud should be "Revert" or equal. Make the inside diameter of any temporary casing used sufficient to allow accurate placement of the screen, riser, centralizer(s), filter pack, seal and grout.

b. The use of drilling aids such as bentonite, other clay-based agents, or any other foreign matter capable of affecting the characteristics of the ground water is prohibited in potentially contaminated areas.

Any drilling fluid additive used shall be inorganic in nature. Grease or oil on drill rods, casing, or auger joints are not permitted in potentially contaminated areas; however, PTFE tape or vegetable oil (in solid phase form) are acceptable.

c. Provide a drill rig free from leaks of fuel, hydraulic fluid, and oil

SECTION 33 24 13 Page 9 which may contaminate the borehole, ground surface or drill tools.

During construction of the piezometer, use precautions to prevent tampering with the piezometer entrance of foreign material, and prevent runoff from entering the piezometer during construction. If there is an interruption in work, such as overnight shutdown or inclement weather, close the piezometer opening with a watertight uncontaminated cover. Secure the cover in place or weighted down so that it cannot be removed except with the aid of the drilling equipment or through the use of drill tools.

3.4.2 Test Hole Requirements

Drill one test hole for every piezometer installed. The test hole may be converted to the permanent piezometer.

3.4.3 Sampling

3.4.3.1 Sampling for Geotechnical Analysis

a. Take samples of all materials penetrated by each drilled piezometer /test hole. Perform soil sampling with a stainless steel split tube sampler using standard sampling techniques in accordance with ASTM D1586. Extract samples from their in-situ environment in as near an intact, minimally disturbed condition as technically practical.

Retrieve samples according to ASTM D1586 at least every 2.5 feet from each test hole. Obtain samples continuously through the area expected to be screened. Place drive-sampled materials in airtight containers and label as specified in paragraph SAMPLE CONTAINERS, and deliver to the Government-designated facility.

b. Classify all samples in lab in accordance with ASTM D2487. Perform ASTM D422 sieve analysis on all sand samples and ASTM D4318 on all fine-grained soil samples.

c. The contractor shall address coordination with the Contracting Officer's Representative in the Piezometer Installation Plan to avoid any delays associated with the analysis of test hole samples. Through proper coordination, decisions regarding final installation depths can be made in real time.

3.4.4 Borehole Diameter and Depth

Provide sufficient diameter in borings for piezometer installation to permit at least 2 inches of annular space between the boring wall and all sides of the centered riser pipe and screen. Determine depths of individual borings as specified in the approved Piezometer Installation Plan or as indicated on the drawings.

3.4.5 Screen, Well Casing/Riser Pipe Placement

a. Provide the piezometer screen to length and depth as specified on the drawings, with specified bottom cap securely attached, set to the appropriate depth.

b. Place the bottom of the piezometer screen as directed by the GEOTECHNICAL ENGINEER. Place the well screen in the appropriate location in the borehole so that the completed piezometer functions in accordance with paragraphs SYSTEM DESCRIPTION and PIEZOMETER

ACCEPTANCE.

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c. Place the piezometer screen as specified on the drawings. Join the screen and piezometer casing/riser pipe sections with approved joints, with the piezometer casing/riser pipe extending upward from the screen to an elevation appropriate for the surface completion described in paragraph Protective Casing Placement. Do not allow the piezometer screen and riser pipe to drop or fall uncontrolled into the borehole.

The use of factory-sealed (plastic wrapped) screen, free from painted markings, does not waive requirements for pre-installation cleaning.

e. Verify the alignment of the piezometer by passing a 5 foot long section of rigid pipe 1/4 inch smaller in diameter than the inside diameter of the casing through the entire piezometer. If the pipe does not pass freely, the piezometer will not be accepted. Thoroughly clean the pipe section with high pressure hot water prior to each test. Use temporary casing, hollow stem augers or other measures, as necessary, to prevent collapse of the boring against the piezometer screen and piezometer casing/riser pipe prior to placement of the filter pack and sealing materials. Install a cap on the top of the riser pipe, either vented, or a telescopic fit, constructed to preclude binding to the piezometer casing caused by tightness of fit, unclean surfaces, or weather conditions. Make cap secure enough to preclude the introduction of foreign material into the piezometer, yet allow pressure equalization between the piezometer and the atmosphere.

3.4.6 Filter Pack Placement

a. After the screen and piezometer casing have been concentrically placed in the hole, construct the approved filter pack around the screen by filling the entire space between the screen and the wall of the hole over the selected screened interval. Place the lowermost 1-foot of filter pack in the boring prior to installation of the piezometer screen, serving as a base on which to place the screen. Lower a tremie pipe having an inside nominal diameter of not less than 1 inch, to the bottom of the annulus between the hole and piezometer. Arrange the tremie pipe so that water and filter pack material fed at uniform rates are discharged as the filter pack material fills the hole from the bottom up. Raise the tremie pipe at a rate that will keep the bottom of the pipe no more than 5 feet above the top of the surface of the filter pack level, and no more than 2 feet below the surface of the filter pack level at all times.

b. Dumping filter pack material from the surface of the ground and agitating the piezometer in an effort to settle the filter material is not allowed. Install the filter pack continuously and without interruption until the filter pack has been placed to a minimum of 3 feet above the top of the screen in the piezometer. Directly measure the depth to the top of the filter pack and record.

c. Protect filter pack material from contamination prior to placement by either storing it in plastic lined bags, or in a location protected from the weather and contamination on plastic sheeting. Transport filter pack material to the piezometer site in a manner which prevents contamination by other soils, oils, grease, and other chemicals.

Remove temporary drill casing, if installed, or auger simultaneously with the above operation. Minimize lifting of the riser pipe when withdrawing the temporary casing/auger. Place filter pack material in lifts no greater than 3 foot prior to retraction of the temporary casing/auger. Leave a minimum of 6 inches of filter pack in the

SECTION 33 24 13 Page 11 temporary casing/auger at all times during filter pack installation.

Take frequent measurements inside the annulus during retraction to ensure that the filter pack is properly placed.

3.4.7 Bentonite Seal

Place a minimum 5 foot thick hydrated bentonite seal on top of the filter pack in a manner which prevents bridging of the bentonite in the annulus, such that the bottom of the bentonite seal is a minimum of 3 feet above the top of the screen. Directly measure the depth to the top of the bentonite seal and record immediately after placement, without allowance for swelling. If the bentonite seal is located above any borehole fluid levels, place a 1 foot layer of fine sand at the top of the bentonite seal.

3.4.8 Grout Placement

Mechanically mix a non-shrinking cement, in accordance with paragraph CEMENT AND BENTONITE GROUT, and placed in one continuous operation into the annulus above the bentonite seal to within 2 feet of the ground surface.

Make grout injection in accordance with ASTM D5092. Construct the bottom of the tremie pipe to direct the discharge to the sides rather than downward, keeping the discharge end of the tremie pipe submerged at all times. Add additional grout from the surface to maintain the level of the grout at the land surface as settlement occurs. Work is not permitted in the piezometer within 24 hours after cement grouting. Verify the alignment of the well by passing a 5 foot long section of rigid PVC or stainless steel 1/4 inch smaller in diameter than the inside diameter of the casing through the entire piezometer. If the pipe does not pass freely, the piezometer will not be accepted. Thoroughly clean the pipe section with high pressure hot water/steam prior to each test.

3.4.9 Concrete or Gravel Pad Placement

Construct a concrete pad with a minimum radius of 2 feet from the protective casing and 6 inch thick, sloped away from the piezometer around the piezometer casing at the final ground level elevation. Furnish pre-packaged, dry, combined concrete materials for the well pads conforming to ASTM C387/C387M normal weight, normal strength concrete.

Combine the dry materials with potable water and mix in an approved mixer or container until uniform in consistency and color. Limit water to the minimum amount possible.

3.4.10 Protective Casing or Vault Placement

Provide all piezometers with a lockable cap with keyed-alike locks on the caps for all piezometers.

3.4.10.1 Protective Concrete Collar

a. Construct a concrete collar from the top of grout to approximately 3 feet above the ground surface. The concrete collar shall encapsulate the riser to 6 inches below the top of riser. The collar shall be a minimum 12 inches in diameter and formed with sonotube.

b. Install three protective steel posts equally spaced around the concrete pad. Fill the steel posts with cement. Do not install the posts in the concrete pad, but a 0.5-1.0 foot radial distance from the outer edge of the concrete pad. Set the posts in concrete, and extending a minimum of 3 feet above the ground surface, with at least

SECTION 33 24 13 Page 12 one third of the posts' total length below ground surface.

3.4.11 Piezometer Identification

Affix a corrosion resistant metal tag to the exterior and interior of the cap. Provide the metal tag stamped with the piezometer identification number. Use identification numbers for the piezometer as indicated on the drawings.

The concrete collar shall be painted yellow unless a different color is approved by the Government. The collar shall also be marked with the piezometer I.D.

3.4.12 Instrumentation

Install transducer to center of the water column in the piezometers. Fix transducer by means of a stainless steel suspension wire to the top of the cap of the piezometer as recommended by the transducer manufacturer.

3.4.13 Falling Head Test

Upon completion of the drilling and installation of the piezometer piping, and prior to concrete finishing, a falling head test shall be performed to confirm the functionality of the piezometer. The Contractor shall use form WES 798, following this specification, for recording the installation and falling head test. The Falling Head Test Report shall be submitted to the Government for approval. The piezometer shall be filled to the top with clear water, and the rate at which the water falls in the riser pipe observed and recorded. The depth to the water shall be recorded every minute for the first five minutes, and at five-minute intervals thereafter, for a maximum of 30 additional minutes, and a final reading, approximately 24 hours following the start of the falling head test. If the piezometer has been properly installed, the time required for the water in the riser pipe to fall 50 percent of the total fall to the groundwater table should not be appreciably greater, if any, than that listed below:

Type of Material Piezometer Screen Set In Period of Observation Approx Time for 50% fall Sandy silt 30 minutes 30 minutes Silty Sand 10 minutes 5 minutes

3.4.14 Drilling Waste Disposal

Properly dispose of slurry, drill cuttings, other solid or liquid material bailed, pumped, or otherwise removed from the borehole during drilling, installation, and completion as approved by the Government.

3.5 SURVEYS

Establish coordinates and elevations for each piezometer/test hole.

Determine horizontal coordinates to the closest 1.0 foot and referenced to the State Plane Coordinate System. Obtain a ground elevation to the closest 0.1 foot at each piezometer. The highest point on the top of the riser pipe serves as a measurement point; reference this elevation and survey to the nearest 0.01 foot using the National Geodetic Vertical Datum 1988. Plot the location, identification, coordinates, and elevations of the piezometer and monuments on maps with a scale large enough to show their location with reference to other structures.

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3.6 BORING LOGS AND PIEZOMETER CONSTRUCTION DIAGRAMS

Samples shall be classified in the field in accordance with ASTM D2488.

The Contractor shall keep accurate hand-written (paper) logs and records of all work accomplished under this contract. All such records shall be preserved in good condition and order by the Contractor until they are delivered and accepted, and the Government shall have the right to examine such records at any time prior to their delivery. Separate logs shall be made for each hole. All drill logs shall subscribe to the following requirements:

a. Logs shall be prepared in the field, as borings are drilled, by a qualified, experienced geologist or geotechnical engineer. Each log shall be signed by the preparer.

b. All log entries shall be printed. Photo reproductions shall be clear and legible. Illegible or incomplete logs will not be accepted. One legible copy of each field log shall be completed and sent to the Government within 24 hours of completion of field work. A PDA field data collection instrument shall also be used, with data export to Open Ground Cloud software. The boring will not be accepted by the Government before the drilling logs are received and approved.

c. Borehole depth information shall be from direct measurements accurate to one tenth of a foot.

d. Boring logs shall be prepared on the USACE ENG 1836 Drilling Log form that will be furnished under separate cover. Final logs shall be furnished electronically as Open Ground Cloud files and shall indicate all laboratory test results. Final logs shall be checked by a qualified geotechnical technician, engineer, or geologist.

e. All relevant information blanks in the log heading and log body shall be completed. If surveyed horizontal control is not available at the time of drilling, location sketches referenced by measured distances from prominent surface features, shall be shown on, or attached to the log.

f. Each and every material type encountered shall be described in column c of the log form. (Material types are to be logged directly from samples and indirectly interpolated using professional judgment, drill cuttings, drill action, etc., between sampling intervals.)

g. Unconsolidated materials shall be described as outlined below and in the following sequence:

1. Descriptive USCS classification in accordance with ASTM D2488

2. Consistency of cohesive materials or apparent density of non-cohesive materials

3. Moisture content assessment, e.g., moist, wet, saturated, etc.

4. Color

5. Other descriptive features (bedding characteristics, organic materials, macrostructure of fine-grained soils e.g., root holes, fractures, etc.)

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h. Stratigraphic/lithologic changes shall be identified in column c by a solid horizontal line at the appropriate scale depth on the log which corresponds to measured borehole depths at which changes occur, measured and recorded to the nearest one-tenth of a foot. Gradational transitions, changes identified from cuttings or methods other than direct observation and measurement shall be identified by a horizontal dashed line at the appropriate scale depth based on the logger's best judgment. All lines shall be drawn with a straight edge.

i. Logs shall clearly show in columns e and f, the depth intervals from which all samples are retained.

j. Logs shall identify the depth at which water is first encountered, the depth to water at the completion of drilling and the stabilized depth to water. The absence of water in borings shall be indicated.

Water level data shall include time and date of all water level readings and time allowed for levels to stabilize. The reference point for all water level depth measurements shall be clearly indicated on the log (e.g., existing ground surface, top of piezometer riser, etc).

k. Logs shall show borehole and sample diameters and depths at which drilling or sampling methods or equipment change.

l. Logs shall show total depth of penetration and sampling. The bottom of the hole shall be clearly identified on the log with the notation "Bottom of Hole."

m. Logs shall identify any drilling fluid losses including depths at which they occur, rate of loss and total volume lost.

n. Logs shall show drilling fluids used including, as appropriate:

1. Source of make-up water

2. Drill fluid additives by brand, product name and mixture proportions

o. Logs shall show depths and types of any temporary casing used.

p. Logs shall identify any intervals of hole instability.

q. Intervals of soil sampling attempts shall be shown in column e, including depths from which attempts were made and length of sample recovered from each attempt.

r. Any special drilling or sampling problems shall be recorded on logs, including descriptions of problems resolved.

3.7 PIEZOMETER DECOMMISSIONING/ABANDONMENT

Any piezometer disapproved by the Contracting Officer, or any piezometer decommissioned/abandoned by the Contractor for any reason shall be decommissioned/abandoned according to the requirements of the State of Illinois, ASTM D5299, and the requirements of these specifications. Grout test holes decommissioned/abandoned for any reason from the bottom to the top or to within 1 foot of the top of the ground surface, as directed by the Government according to the protocol for grout/bentonite placement established in paragraph Grout Placement, using the grout mix specified in

SECTION 33 24 13 Page 15 paragraph CEMENT AND BENTONITE GROUT. If required, backfill the top with soil. Maintain a piezometer decommissioning/abandonment record as specified in paragraph Piezometer Decommissioning/Abandonment Records.

Measure groundwater levels, if encountered before the decision is made for decommissioning/abandonment, in all borings prior to backfilling. Include these water levels in the piezometer decommissioning/abandonment records.

No piezometer may be decommissioned/abandoned without the approval of the Contracting Officer.

3.8 PIEZOMETER ACCEPTANCE

It is the responsibility of the Contractor to properly design, construct, install, develop, and test all piezometers according to the requirements of this specification so that they are suitable for the intended purpose.

If the Contractor installs piezometers that are not functional or not in accordance with these specifications, the Contracting Officer will disapprove the piezometer and direct the Contractor to repair or replace it, and to abandon the disapproved piezometer in accordance with this specification.

3.9 SITE CLEANUP

After completion of the work, remove tools, appliances, surplus materials, temporary drainage, rubbish, and debris incidental to work. Backfill excavation and vehicular ruts and dress to conform with the existing landscape or terrain. Utilities, structures, roads, fences, or any other pre-existing item which must be repaired or replaced due to the Contractor's negligence are the Contractor's responsibility; accomplish repair or replacement prior to completion of this contract.

3.10 DOCUMENTATION AND QUALITY CONTROL REPORTS

Submit reports for piezometer construction and development. Establish and maintain documentation and quality control reports for piezometer construction and development to record the desired information and to assure compliance with contract requirements, including, but not limited to, the following:

3.10.1 Project Photographs

Submit photographs taken before, during, and after completion of the work, of each piezometer installation site. Provide color prints with an information box, showing (typewritten) the following information:

Project No. Contract No.

Contractor/Photographer:

Photograph No. Date/Time:

Description:

Direction of View:

3.10.2 Survey Maps and Notes

Prepare and submit a tabulated list of all piezometers and monuments, maps showing the locations, and elevations of all piezometers, and all computation sheets, consisting of the designated number of the piezometer

SECTION 33 24 13 Page 16 or monument, the X and Y coordinates, and all the required elevations.

Provide photographs as described in Submittals, Project Photographs.

3.10.3 Piezometer Construction Details

Prepare and submit a construction diagram for each piezometer, showing depths of pipe, screen, all seals, and depth of transducer. Detail shall show depths and elevations of piezometer top (highest point on riser) and bottom and ground surface. Elevations and dimensions of pipe and screen shall be measured and shown on the diagram to the nearest 0.01 foot.

Other measurements and the ground surface elevation adjacent to piezometer shall be measured and shown to the nearest 0.1 foot.

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