USACE / NAVFAC / AFCESA / NASA UFGS-33 26 00.00 10 (April 2008)
--------------------------------
Preparing Activity: USACE (CW) Superseding
UFGS-33 26 00.00 10 (April 2006)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 33 26 00.00 10
RELIEF WELLS
04/08
NOTE: This guide specification covers the requirements for relief wells, (except
materials and equipment specified to be furnished by the Government) to be constructed
near dams or levees to relieve the excess hydrostatic pressures created by the
presence of pervious strata close to the surface.
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
PART 1 GENERAL
NOTE: Relief wells should be constructed of materials which will resist corrosion
when installed and should, where practicable, be designed to have a service
life equal to that of the structure they are designed to protect. Factors to
be considered in determining selection of material for wells are:
1. Operating conditions of wells,
2. Corrosive characteristics of soil and water,
3. Method of installations,
4. Size and depth of wells,
5. Type of joints, and
6. External pressures on well casings.
The riser pipe and screen should be designed in all cases to withstand, with
a suitable factor of safety, the crushing pressures at depths to which wells
extend. Design of relief wells to be constructed under structures must consider
loads that will be induced into the well pipe due to structural settlement.
The wells, including screen and riser pipe, should have a diameter which will
permit the maximum design flow without excessive head losses but in no instance
should the inside diameter be less than 150 mm (6 inches). Based on design
parameters it may require the designer to include a minimum collapse strength
for the pipe and well screen and a minimum clear inside diameter through the
fittings and screen to allow the installation of pumps at a later date.
Because of the large variation in design and wall thickness of the different
types of well screen, no generic specifications have been included. For large
contracts, specific necessary characteristics should be presented in detail.
References to manufacturers should be eliminated.
Information on the design of filter packs and relief wells can be found in the
Engineering Manual EM 1110-2-1901, "Seepage Analysis and Control for Dams".
The filter criteria specified in EM 1110-2-1901 should be used to determine
the gradation band of the filter material. To minimize segregation during installation
of the filter pack, the filter should have a relatively uniform grain-size distribution
band. The gradation band of the filter material should be more or less parallel
to the gradation curve of the material being drained. No point on the coarser
filter gradation curve should be greater than 25 times the corresponding size
of the material being drained.
The filter material should have a minimum thickness of 150 mm (6 inches) measured
radially from the outer circumference of the screen section, and its gradation
should depend upon the gradation of the strata being drained. Where unusual
conditions are encountered, filter tests should be performed in the laboratory
using the foundation sand and the selected filter. For examples of laboratory
investigations refer to Technical Report GL-87-22, dated August 1987, "Laboratory
Tests on Granular Filters for Embankment Dams (Includes Appendixes A-E)"; and
Technical Memoranda (TM) 183-1, dated Nov 1941, Rev Dec 1941, "Investigation
of Filter Requirements for Underdrains"; and Technical Memoranda (TM) 195-1,
dated Oct 1942, "Field and Laboratory Investigation of Design Criteria for Drainage
Wells", U. S. Waterways Experiment Station. Because of the high potential for
clogging by migrating fines or chemical precipitate, filter cloth should not
be used to protect relief well screens.
In adapting this specification to any project the form and phraseology should
be changed as necessary to properly specify the work contemplated. Changes
should be made in the original form to the extent required to adapt the guide
specification to local conditions. Work such as concrete for backfill, painting
of exposed metal surfaces and seeding of construction areas will have to be
specified in this section when such sections cannot be referenced as a part
of the contract.
For projects on which subsurface information is not sufficiently developed to
permit detailed design of each well, a section should be added to the specifications
requiring the drilling of a small diameter pilot hole at the location of each
well. Pilot holes should be sampled and logged in sufficient detail to define
the gradation of pervious zones and the depths between which screens should
be set. The specifications should require that samples of pervious materials
be taken at 750 mm (2.5 foot) intervals of depth. Grain-size distribution tests
should be performed to provide a basis for the design of the filter pack and
the screen openings. Samples taken by fishtail drilling and other wash boring
methods will not be permitted. Where the subsurface information previously
obtained is sufficient, pilot holes are not required.
1.1 UNIT PRICES
NOTE: If Section 01 22 00.00 10 MEASUREMENT AND PAYMENT is included in the
project specifications, this paragraph title (UNIT PRICES) should be deleted
from this section and the remaining appropriately edited subparagraphs below
should be inserted into Section 01 22 00.00 10.
1.1.1 [Relief Wells]
1.1.1.1 Payment
Payment will be made for costs associated with relief wells, which price shall constitute full compensation for
construction of relief wells. Wells ordered abandoned by the Contracting Officer before installation of well
screen and riser due to no fault of the Contractor will be paid for at [_____] percent of the contract unit price
per linear meter foot, for Bid Item No. [_____] "Relief Wells". Wells ordered abandoned by the Contracting Officer
due to no fault of the Contractor will be paid for at the full contract unit price for Bid Item No. [_____] "Relief
Wells". No payment will be made for placement or replacement of temporary casings or repair of damage resulting
from Contractor operations. No separate payment will be made for relief well screen, riser, check valves, gravel
pack, development, backfill, discharge or outfall pipes. No payment will be made for any wells that, in the
opinion of the Contracting Officer, are abandoned due to Contractor fault or neglect.
1.1.1.2 Measurement
Relief wells will be measured for payment by the linear meter foot of completed well between ground surface and
300 mm 1 foot below the bottom of the [well screen][tail pipe]. Wells ordered abandoned by the Contracting
Officer, due to no fault of the Contractor, will be measured for payment.
1.1.1.3 Unit of measure
Unit of measure: linear meter foot.
1.1.2 [Pump Tests]
1.1.2.1 Payment
Payment will be made for costs associated with pump test, which price shall constitute full compensation to perform
a satisfactory pump test as specified. No payment will be made for pump test not successfully completed.
1.1.2.2 Measurement
Pump tests will be measured for payment for each hour, measured to the nearest 15 minutes, of pump test successfully
performed as specified in paragraph PUMP TEST, and as otherwise directed. Testing time will not include time
required to place and remove testing and pump equipment.
1.1.2.3 Unit of measure
Unit of measure: per hour.
1.1.3 [Pump Installation/Removal]
1.1.3.1 Payment
Payment will be made for costs associated with installation and removal of the pumps used in pay item "Pump Tests".
No payment will be made for pump installation removal where pump test was not successfully completed.
1.1.3.2 Measurement
Pump installation/removal for pump test will be measured for payment on the base of the applicable contract unit
price per relief well pump tested.
1.1.3.3 Unit of measure
Unit of measure: each.
1.2 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
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.
[ASME INTERNATIONAL (ASME)ASME B1.20.1(1983; R 2006) Pipe Threads, General Purpose (Inch)ASME B31.9(2008) Building Services Piping][ASTM INTERNATIONAL (ASTM)ASTM A 312/A 312M(2008a) Standard Specification for Seamless, Welded, and Heavily Worked Austenitic Stainless Steel PipesASTM A 53/A 53M(2007) Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and SeamlessASTM C 136(2006) Standard Test Method for Sieve Analysis of Fine and Coarse AggregatesASTM C 33(2007) Standard Specification for Concrete AggregatesASTM C 387/C 387M(2008) Standard Specification for Packaged, Dry, Combined Materials for Mortar and ConcreteASTM C 94/C 94M(2007) Standard Specification for Ready-Mixed ConcreteASTM D 1056(2007) Standard Specification for Flexible Cellular Materials - Sponge or Expanded RubberASTM D 1784(2008) Standard Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride) (CPVC) CompoundsASTM D 1785(2006) Standard Specification for Poly(Vinyl Chloride) (PVC), Plastic Pipe, Schedules 40, 80, and 120ASTM D 2466(2006) Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 40ASTM D 2467(2006) Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 80ASTM D 2564(2004e1) Standard Specification for Solvent Cements for Poly(Vinyl Chloride) (PVC) Plastic Piping SystemsASTM D 297(1993; R 2006) Rubber Products - Chemical AnalysisASTM D 412(2006ae1e2) Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers - TensionASTM D 75(2003) Standard Practice for Sampling AggregatesASTM E 11(2004) Wire Cloth and Sieves for Testing Purposes]1.3 SUBMITTALS
NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are for [Contractor Quality Control approval.][information only. When used, a designation following the "G"
designation identifies the office that will review the submittal for the Government.] Submit the following in
accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-02 Shop Drawings
Shop Drawings[; G][; G, [_____]]
Shop drawings, as specified.
SD-03 Product Data
Well Screen[; G][; G, [_____]]
Well screens approved before installation.
Filter Pack[; G][; G, [_____]]
Approved filter pack material and its gradation, before it is placed.
Cement Grout Mixture Proportion[; G][; G, [_____]]
Cement grout mixture proportion to be used in plugging abandoned wells.
SD-06 Test Reports
Tests
Sampling and testing reports for each relief well, logs of the borings, well screen and riser
pipe, backfill material, and pump tests. Register each well with the state as required by the
state in which the well is installed.
1.4 QUALITY ASSURANCE
NOTE: The Designer should select and/or insert the applicable obligations for
compliance with specific code requirements of public authorities at the state
and/or local level. Guidance is given in memorandum from CECW-EG, "State Regulation
of Subsurface Drilling Activities", dated 21 February 91.
The [state statutory and regulatory] [_____] requirements listed herein form a part of this specification to
the extent referenced: [_____].
1.4.1 Shop Drawings
Show details of the proposed methods for drilling, coupling well screen and riser sections together, placement
of centralizers, installing the well screen and riser, and limit(s) of backfilling. Show on the shop drawings
the type of screen and size; [perforation size] [or] [slot size], shape and pattern; [bottom plug] [tailpipe]
material; and installation detail. The riser pipe, check valve(s) and well discharge details shall also be shown
on the shop drawings. Any Contractor-proposed substitutes or alternates in material construction details or
methods must be presented in the shop drawings. No phase of the work shall be initiated until all shop drawings
concerning that activity have been approved.
1.4.2 Depth of Well
NOTES: The first bracketed paragraph, Alternate, 1 is recommended for use whenever
the design of the system permits.
The second bracketed paragraph, Alternate, 2 should be used only when fully
penetrating wells are necessary, and when it is impracticable to predetermine
the depth of individual wells. The need for field cutting of screen or riser
pipe should be avoided. The depth of the well can ordinarily be varied in the
field to permit the use of predetermined length of screen and riser pipe without
field cutting.
[The length of well screen, length of riser pipe and the well discharge elevation shall conform to the [schedule
shown] [elevations established in the field by the Contracting Officer].] [The depth of wells as indicated on
the drawings is approximate. Penetration of [bedrock] [impervious layer] might be required. The maximum well
depth will not exceed [_____] meters feet. Whenever the depth to [bedrock] [impervious layer] is less than the
maximum well depth, the bottom elevation of each well shall be as determined by the Contracting Officer after
drilling of a pilot boring or the well boring.]
1.4.3 Well Design
NOTE: This paragraph should be deleted when well design data have been determined
in advance of the contract. Economical well construction cannot be secured
unless the design of the wells is established in advance of the bidding period.
From data obtained from exploratory drilling, the Contracting Officer will determine the diameter of the well
screen, size of openings, the lengths and positions of the screens, and the gradation of the material for the
filter pack which is to be installed around the well screen.
1.5 PROJECT/SITE CONDITIONS
1.5.1 Location
The exact location of each well, [with respect to the toe of the embankment] [or] [with respect to distance from
structure centerline], will be determined in the field by the Contracting Officer. The total number of wells
and spacings may be modified by the Contracting Officer as the work proceeds.
1.5.2 Obstructions Encountered
If obstructions are encountered in the foundation which, in the opinion of the Contracting Officer, render it
impracticable to complete the well to the directed depth, the Contracting Officer may adjust the depth. Alternatively,
the Contracting Officer may direct the Contractor to abandon the well, plug the hole by backfilling with approved
material by an approved procedure, and construct another well at an adjacent site.
PART 2 PRODUCTS
2.1 WELL SCREEN
[The Contractor may, as an option, furnish and install well screen of any of the alternate types specified.]
[Well screen shall be of the type and dimensions indicated.] Screen openings shall be uniform in size and pattern,
and shall be spaced approximately equally around the circumference of the pipe.
2.1.1 PVC Pipe Screen
Pipe, fittings, and screen shall be of the size and types [specified][shown.] Pipe, fittings, and screen shall
conform to ASTM D 1784, ASTM D 1785, ASTM D 2466, or ASTM D 2467. All joints in the PVC pipe shall include couplings
and shall be glued with a solvent cement conforming to ASTM D 2564. The PVC pipe strength properties shall be
equivalent to PVC 1120 Schedule [40] [80] unthreaded plastic pipe. [The well screen, pipe, and fittings shall
have a minimum collapse strength of [_____].] [The screen, pipe, and fittings shall have a clear inside diameter
of [_____].]
2.1.1.1 Couplings
Couplings shall be [bonded socket][threaded][certilock] type. Fittings shall be produced of the same material
and equal quality as specified for plastic pipe screen. Socket type fitting connections of pipe sections shall
be bonded with solvent cement. The determination of the proportions and preparation of adhesives, the method
of application, and the procedure used for making and curing the connections shall be the responsibility of the
Contractor. The system for making joints at the relief well site shall provide a curing period adequate to develop
the ultimate strength of the solvent cement. Self-tapping screws or other devices for holding pipe in the couplings
during the setting period may be utilized as long as the screws do not penetrate the inside of the pipe. In
no case shall a newly-made joint in the casing be stressed, lowered into the relief well, or be submerged in
water prior to complete curing of the solvent cement adhesive.
2.1.1.2 Perforations
The PVC well screen shall be [mill slot][continuous wire wrapped rod base] [continuous wire wrapped rod base
on perforated pipe] [continuous wire wrapped on perforated pipe screen] [similar to that manufactured by [_____]
Johnson Well Equipment, Inc., Pensacola, FL, telephone (904) 453-3131]. All well screen shall have smooth, sharp-edged
openings free of burns, chipped edges, or broken areas on the interior and exterior surfaces of the pipe. [The
[_____] mm inch diameter well screen shall have a number [_____] slot, [0.0_____] mm inch open slot.] [The length
of the slots measured on the inside of the pipe shall be [_____] mm inches.] There shall be a total open area
of not less than [_____] square millimeters inches per linear meter foot of [_____] mm inch diameter well screen.
The slots or groups of slots shall be distributed in a uniform pattern around the periphery of the pipe and shall
be oriented with the length of the slot, [parallel to,] [normal to,] [or] [diagonal with] the axis of the pipe.
2.1.2 Fiberglass Pipe Screen
Fiberglass pipe screen and fittings shall be manufactured from thermosetting epoxy resins and glass fiber by
either a centrifugal casting process or by a filament winding process. Glass fiber used shall be continuous
filament, electrical glass with a finish compatible with epoxy resins. Each glass fiber or filament shall be
thoroughly impregnated with epoxy resin. The resins used shall be diglycidyl ether of bisphenoa A or cycloaliphatic
diepoxides, or blends of the two. Curing agents for these resins shall be aromatic diamines, polycarboxylic
acid anhydrides and eutectics therefrom. Curing of the resin system shall be at a temperature over 150 degrees
C 300 degrees F for a minimum of one hour. Fiberglass pipe wall thickness, strength and durability requirements
shall be equivalent to [_____][the Fiberglass/Epoxy pipe produced by Fiberglass Resources Corporation of Farmingdale,
New York or Burgess Well Company, Inc., Minden, Nebraska, telephone (308) 832-1642]. All fiberglass pipe and
fittings shall be round and straight, of uniform quality and workmanship, and free from all defects including
indentation, delamination, bends, cracks, blisters, porosity, dry spots, resin segregation and resin-starved
areas. The inside of the pipe and fittings shall be smooth and uniform. The impregnation of the glass fiber
with resin shall be such that when the pipe is cut or slotted, no fraying or looseness of glass fiber occurs.
[The well screen, pipe, and fittings shall have a minimum collapse strength of [_____].] [The screen, pipe,
and fittings shall have a clear inside diameter of [_____].]
2.1.2.1 Couplings
Couplings for fiberglass pipe sections shall be socket threaded or mechanical key-type couplings. The couplings
shall be manufactured of the same materials used for the fiberglass pipe specified herein and may be either cast
integrally with the pipe sections or as separate components for attachment to the pipe in the manufacturers plant.
Every coupling attached to the pipe section as a separate component shall be proof tested in the manufacturer's
plant with a tensile load of 9 kN 2000 lbs. Key-type couplings shall consist of male and female halves designed
for joining and locking together by means of a key strip inserted in grooves in the coupling halves. The minimum
wall thickness remaining at any grooved section shall not be less than the minimum thickness specified for pipe.
Key strips and locking strips shall be of fiberglass, plastic or other non-corrosive material capable of withstanding
shearing and bearing stresses equivalent to the design load for the coupling. Socket type fitting connections
of the pipe sections shall be bonded with epoxy adhesive. The epoxy materials and bonding agents shall be as
recommended by the pipe manufacturer. The determination of the proportions and preparation of adhesives, the
method of application, and the procedures used for the making and curing of the joints shall be the responsibility
of the Contractor. The pot life, initial setting time and external heating requirements for curing of the adhesive
shall be suitable for the procedure and climatic and other conditions and shall be varied as required to suit
changes in climatic and other conditions. The system for making joints at the relief well site shall provide
a curing period adequate to develop the ultimate strength of the adhesive. Self-tapping screws or other devices
for holding adhesive-joined pipe in the couplings during the curing period may be utilized. In no case shall
a newly-made joint in the casing pipe be lowered into the relief well, or be submerged in water prior to complete
curing of the adhesive.
2.1.2.2 Perforations
All fiberglass well screen shall be [mill slot][continuous wire wrapped rod base]. All relief well screen shall
have smooth, sharp-edged openings free of burrs, chipped edges, or broken areas on the interior and exterior
surfaces of the pipe. [The [_____] mm inch diameter well screen shall have a number [_____] slot, [0.0__] mm
inch open slot.] [The length of the slots measured on the inside of the pipe shall be [_____] mm inches.]
There shall be a total open area not less than [_____] square millimeters inches per linear meter foot of [_____]
mm inch diameter well screen. The slots or groups of slots shall be distributed in a uniform pattern around
the periphery of the pipe and shall be oriented with the length of the slot [parallel to,] [normal to,] [or]
[diagonal with] the axis of the pipe.
2.1.3 Steel Pipe Screen
NOTE: Metal pipes, plugs, screen and joints for most installations may require
a coating to protect the metal from corrosive ground water and soil. The type
of coating selected to accomplish this purpose will depend upon the corrosive
characteristics of the ground water and soil. The Contracting Officer should
therefore make complete analysis of the corrosive characteristics of the ground
water and add to these specifications such requirements as are necessary to
protect the pipe. The coating should be applied after perforating or slotting
and should completely cover all exposed metal. Care should be taken to ensure
that the openings are not closed or reduced in required size by the coating.
Steel well screen shall consist of perforated or slotted sections of steel pipe conforming to the requirements
of ASTM A 53/A 53M, Type [_____], Class [_____]. [The well screen, pipe, and fittings shall have a minimum collapse
strength of [_____].] [The screen, pipe, and fittings shall have a clear inside diameter of [_____].]
2.1.3.1 Couplings
Couplings for steel pipe screen shall be welded joints or threaded couplings. Welding shall be performed in
accordance with requirements in ASME B31.9. Couplings shall meet the material requirements specified for steel
pipe screen, except perforations shall be omitted. All threaded pipe and fittings shall be threaded in accordance
with ASME B1.20.1. All threaded pipe sections may be field connected. Couplings shall be given the same protection
against corrosion as specified for the well screen pipe. Protective coatings damaged while making couplings
shall have the areas recoated.
2.1.3.2 Perforations
All steel pipe to be used as relief well screen shall be provided with perforations which shall consist of either
machine-cut slots; drilled or punched openings. The slots shall have a width of [_____] mm inch with a tolerance
of plus or minus [_____] mm inch. The length of the slots measured on the inside of the pipe shall be [_____]
mm inches with a tolerance of plus or minus [_____] mm inch. For slotted openings there shall be a total open
area not less than [_____] square millimeters inches per linear meter foot of [_____] mm inch diameter relief
well. The slots or groups of slots shall be distributed in a uniform pattern around the periphery of the pipe
and shall be oriented with the length of the slot [parallel to,] [normal to,] [or] [diagonal with] the axis of
the pipe. Drilled or punched openings shall be [_____] mm inch in diameter and shall provide a total open area
not less than [_____] square millimeters inches per linear meter foot of [_____] mm inch diameter well screen.
The pattern of the openings shall be uniformly spaced around the periphery of the pipe.
2.1.4 Stainless Steel Well Screen
The well screen and fittings shall be fabricated entirely from stainless steel conforming to ASTM A 312/A 312M
, Type 304, 304-L, 316 or 316-L. The well screen shall be of stainless steel with a keystone wire-wrapped continuous
slot strainer equivalent to [_____] [that manufactured by [Howard Smith Screen Company, Houston, TX, telephone
(713) 869-5771] [Johnson Screens, St. Paul, MN 55164, telephone (612) 636-3900]]. [The well screen, pipe, and
fittings shall have a minimum collapse strength of [_____].] [The screen, pipe, and fittings shall have a clear
inside diameter of [_____].]
2.1.4.1 Couplings
Couplings for the stainless steel well screen shall consist of the same material as the well screen and shall
be threaded, flanged, and/or fitted with a welding ring. The couplings shall conform in design to the couplings
recommended by the manufacturer of the well screen.
2.1.4.2 Perforations
The [_____] mm inch diameter well screen shall have a number [_____] slot, [0.0_____] mm inch open slot. There
shall be a total opening of not less than [_____] square millimeters inches per meter foot of [_____] mm inch
diameter well screen.
2.1.5 Tailpipe for Well Screen
The tailpipe for each well screen shall be made of the same material and at least the same minimum thickness
as the riser pipe and shall include a bottom plug. Tailpipes shall be a minimum of [1] [_____] m [3] [_____]
feet in length and fastened to the bottom of the screen in an approved manner.
2.2 RISER PIPE
The relief well riser pipe material and method of manufacture shall conform to the requirements specified in
paragraph WELL SCREEN, except that the screen perforations or opening shall be omitted. The relief well riser
pipe diameter and discharge details shall be as shown. Couplings to the well screen and between riser pipe sections
shall be as specified in paragraph COUPLING.
2.3 FILTER PACK
Material for the filter pack around the riser pipes and screens shall be a [washed gravel] [washed sand] [dry
processed sand] composed of hard, tough, and durable particles free from adherent coating. The filter pack shall
not be crushed stone. The filter pack material shall contain no detrimental quantities of organic matter nor
soft, friable, thin, or elongated particles in accordance with the quality requirements in ASTM C 33, Table 1
and Table 3, Class 5S, and in ASTM E 11, Table 1. The filter pack shall meet the following gradation requirements:
ASTM E 11 PERCENT BY WEIGHT
SIEVE SIZE (SI) PASSING
[_____] [_____]
[_____] [_____]
U.S. STANDARD PERCENT BY WEIGHT
SIEVE NO. PASSING
[_____] [_____]
[_____] [_____]
2.4 CHECK VALVES
NOTE: Insert provisions describing the materials and construction of a well
pit, collector pipe, or ditch or any other proposed outlet for the relief well.
Discharge details should be clearly shown on the drawings.
The following requirements are for two different check valves that have been
specified by the Vicksburg District. Details of the fabricated check valves
are available upon request from CELMK-ED-G, telephone (601) 631-5208 or (601)
631-5633 . The soft sponge rubber should be used on valves which can be replaced
on a regular basis and used under low head conditions. The medium sponge rubber
should be used where access to the check valve is limited.
a. [The check valve shall be a one piece reinforced all rubber (neoprene) check valve with an integral
elastomer flange similar and equal to the Red Valve Series [35][_____], Size [150][_____] mm [6][_____]
inch, manufactured by Red Valve Company, Inc., 700 North Bell Ave., Pittsburgh, PA 15106, telephone (412)
279-0044. The check valve shall be designed to withstand a maximum back pressure of [100][_____] kPa
[15][_____] psi. The backup ring for the check valve shall be stainless steel. Stainless steel bolts,
washers, and nuts shall be used to fasten the valves onto the flanged end of the pipes. The check valve
shall be installed with the flared end duck bill in a vertical position.]
b. [Fabricate check valves of [brass][stainless steel][aluminum] plate, threaded fasteners and rods
as detailed on the drawings. Fabricate sealing disc of [10][_____] mm [3/8][_____] inch silicone sponge
rubber free of porous areas, foreign materials, and visible defects.]
c. Silicone sponge rubber shall meet the following specifications:
TEST VALUE ASTM
PHYSICAL TEST SOFT MEDIUM TEST METHOD
Compression Deflection 15 to 50 kPa 40 to 100 kPa ASTM D 1056
(compressed 25 percent at
room temperature)
Tensile Strength 345 kPa(min) 515 kPa(min) ASTM D 412
Elongation at break 75 percent 100 percent ASTM D 412
(min) (min)
Compression Set 15 percent 5 percent ASTM D 297
(Compressed 50 percent (max) (min)
for 22 hours at 100 C
Density 0.012 0.017 ASTM D 297
pci(min) pci(min) Hydrostatic
Method
TEST VALUE ASTM
PHYSICAL TEST SOFT MEDIUM TEST METHOD
Compression Deflection 2 to 7 psi 6 to 14 psi ASTM D 1056
(compressed 25 percent at
room temperature)
Tensile Strength 50 psi(min) 75 psi(min) ASTM D 412
Elongation at break 75 percent 100 percent ASTM D 412
(min) (min)
Compression Set 15 percent 5 percent ASTM D 297
(Compressed 50 percent (max) (min)
for 22 hours at 212 F
Density 0.012 0.017 ASTM D 297
pci(min) pci(min) Hydrostatic
Method
d. Workmanship and metalwork fabrication of check valves shall be in accordance with the details shown.
Install check valves accurately vertically and adjust to the required elevation.
2.5 CONCRETE
Concrete shall conform to [the requirements specified in Section [03 30 53 MISCELLANEOUS CAST-IN-PLACE CONCRETE]
[_____]] [ASTM C 94/C 94M, Option A, with a [19][_____] mm [3/4][_____] inch Nominal Maximum Size of Aggregate,
a maximum slump of 125 mm 5 inches, air content of [5] [_____] percent, and a compressive strength of [17.2][_____]
MPa [2500][_____] psi] [packaged normal weight concrete conforming to ASTM C 387/C 387M].
PART 3 EXECUTION
3.1 DRILLING
Wells may be drilled by the reverse rotary circulation method or other method approved, which will insure proper
placement of the well screen, riser pipe, and filter pack. Methods which involve radical displacement of the
formation, or which may reduce the yield of the well, will not be permitted. Excavated material shall be disposed
of as directed.
3.1.1 Reverse Circulation Method
NOTE: Where the Contracting Officer approved use of drilling fluid, it will
be a suspension of fine grained soil or commercial product of a recognized manufacturer,
having the characteristic of being readily removable from the filter pack and
the walls of the foundation by development as specified in paragraph DEVELOPMENT.
If the reverse circulation method is used for drilling wells, remove all of the drilling fluid from the filter
pack and the natural pervious formation. If in the opinion of the Contracting Officer the walls of the hole
above the top of the filter pack require support during development operations, place a temporary casing similar
to that specified in paragraph TEMPORARY CASING. The diameter of the hole shall be such as will permit the placement
of the minimum thickness of filter pack as specified in paragraph FILTER PACK PLACEMENT. The drilling fluid
shall be a suspension of fine grained soil or shall be a commercial product of a recognized manufacturer, shall
be approved by the Contracting Officer, and shall have the characteristic of being readily removable from the
filter pack and the walls of the formation by development as specified in paragraph DEVELOPMENT. The use of
bentonite will not be permitted.
3.1.2 [Temporary Casing
Temporary well casing of either iron or steel of sufficient length to case to the bottom of all borings shall
be available at the construction site. The Contracting Officer will direct the use of a temporary casing to
the bottom of the boring during drilling and placement of screen, riser, and filter pack when he believes it
is necessary to provide adequate support to the sides of the hole. When the walls of the boring will require
support only during development operations a temporary casing will be required to extend only to a depth 1 m
3 feet below the top of the filter pack. The temporary casing, shall have an inside diameter of not less than
[_____] mminches, shall have sufficient thickness to retain its shape and maintain a true section throughout
its depth, and may be in sections of any convenient length. The temporary casing shall be such as to permit
its removal without disturbing the filter pack, riser, or well screen. The setting of temporary casing shall
be such that no cavity will be created outside of it at any point along its length. In the event the temporary
casing should become unduly distorted or bent it should be discarded and a new casing should be used during installation
of any additional relief wells.]
3.2 INSTALLATION OF RISER PIPE AND SCREEN
3.2.1 Assembly
All riser pipe and screen shall be in good condition before installation and all couplings and other accessory
parts shall be securely fastened in place. The successive lengths of pipe shall be arranged to provide accurate
placement of the screen sections in the bore hole. [The riser-pipe shall be provided with an approved cap and
a flanged top section, the top of which shall be set at the elevation directed or shown.] Centralizers shall
be attached to the assembled riser pipe and screen in such numbers and of a type that they will satisfactorily
center the riser pipe and screen in the well and will hold it securely in position while the filter pack material
is being placed.
3.2.2 Joints
Sections of relief well pipe shall be joined together as specified in paragraph COUPLINGS. Joints shall be designed
and constructed to have the strength of the pipe and where possible a strength capable to support the weight
of the relief well stem as it is lowered into the hole. When not practicable to construct joints that will support
the weight of the relief well stem, the stem shall be supported at the lower end by any approved means that will
assure that the joints do not open while being lowered into place in the well.
3.2.3 Installation
The assembled riser pipe and screen shall be placed in the bore hole in such manner as to avoid jarring impacts
and to insure that the assembly is centered and not damaged or disconnected. The screen should be suspended
in the hole and not resting on the bottom of the hole. After the screen and riser pipe have been placed, a filter
pack shall be constructed around the screen section as specified in paragraph FILTER PACK PLACEMENT and the well
developed as specified in paragraph DEVELOPMENT. The top of the riser pipe shall be held at the designated elevation
during placement of the filter pack.
3.2.4 Check for Plumbness and Alignment
NOTES: Alignment and plumbness tests are performed to determine if a pump will
be able to be installed into the well at the end of development so that a pump
test can be performed. The variation of the plumbness should not vary more
than two-thirds of the inside diameter of the well in 30 m (100 feet).
Select appropriate alternate paragraph.
a. [Each well shall be sufficiently straight and plumb, such that a cylinder [3][6][10][15] m [10][20][40]
feet in length and with an outside diameter 13 mm 1/2 inch smaller than the inside diameter of the well
may be lowered for the full depth of the well and withdrawn without binding against the sides of the
well. Furnish the dummy cylinder and perform the alignment check and plumbness check in the presence
of the Contracting Officer. A variation of [150][_____] mm [6][_____] inches per 30 m 100 feet of depth
will be permitted in the plumbness of well from a plumb line at the top of the well; however, this will
not relieve the Contractor of the responsibility of maintaining adequate clearance for installation of
the surging and pumping equipment required for testing and pumping the wells. At least one plumbness
check and alignment check shall be performed on each well after placement of the filter pack. Additional
tests may be made during the performance of the work at the option of the Contractor.]
b. [The well shall be constructed and all casing set round, plumb, and true. Perform the following
tests after the installation of the well but prior to backfilling, and before its acceptance. Additional
tests may be made during the performance of the work at the option of the Contractor. Should the Contractor
fail to correct, at no additional cost to the Government, any faulty alignment or plumbness disclosed
as a result of these tests, the Contracting Officer may refuse to accept the well. If in the judgement
of the Contracting Officer the Contractor has exercised all possible care in constructing the well and
the defect is due to circumstances beyond the Contractor's control or if the utility of the completed
well is not materially affected or if the cost of necessary remedial measures will be excessive, the
requirements for plumbness may be waived. In no event will the provisions with respect to alignment
be waived.]
3.2.4.1 Plumbness
Test plumbness by use of a plumb line. The plummet shall be a short cylinder with an outside diameter approximately
6 mm 1/4 inch smaller than the inside of the well and/or temporary casing. It shall be suspended from a small
diameter wire rope and its point of suspension shall be in the exact center of the plummet. The plummet shall
be sufficiently heavy to stretch the wire rope taut. The wire rope shall pass over a guide sheave which shall
be positioned at least 3 m 10 feet above the top of the well and adjusted horizontally so that the plummet hangs
in the center of the well. Displacement of the wire rope during the plumbness check shall be measured by means
of a transparent plastic sheet on which a number of concentric circles shall be scribed or drawn, and which is
centered on the top of the well. The exact center of these circles shall be marked, and then a slot, slightly
larger than the plumb line and extending from this center to the edge, shall be cut in the plastic sheet. As
the plummet is lowered, any out-of-plumb condition of the well will be indicated by the wire rope tending to
drift away from the center, and the plastic sheet shall be rotated until the slot is oriented in the direction
of this drift, while at all times maintaining the center of the concentric circles coincident with the center
of the well. Measurement of the amount of drift shall be made along the edge of the slot for each increment
by which the plummet is lowered into the well. Drift at any depth shall be determined by multiplying the measured
plumb line displacement by the total length of the plumb line and dividing the result by the fixed distance between
the guide sheave and the top of the well. If desired, alignment may be calculated from the plumbness data in
lieu of the alignment check described in paragraph ALIGNMENT. Should the well vary from the vertical in excess
of [150][_____] mm [6][_____] inches per 30 m 100 feet of depth, the plumbness of the well shall be corrected
by the Contractor at no additional cost to the Government.
3.2.4.2 Alignment
Test the alignment by lowering into the well a section of cylinder [3][6][10][15] m [10][20][40] feet long or
a dummy of the same length. The outside diameter of cylinder shall be not more than 13 mm 1/2 inch smaller than
the inside diameter of the well. Should the cylinder fail to move freely throughout the length of the well,
the alignment of the well shall be corrected at no additional expense to the Government.
3.3 FILTER PACK PLACEMENT
After the well screen and riser pipe have been installed, the filter pack material shall be placed by tremie,
when using a well graded material, in an approved manner such that segregation will not occur. When using a
uniform graded filter material, the material may be poured around the well screen at a rate that will prevent
bridging of the material. The material should be placed around all sides of the screen to assure that the screen
is not pushed against the side of the bore hole causing the screen to come in contact with foundation material
or prevent the proper thickness of filter from being placed uniformly around the screen. The filter pack shall
have a minimum thickness of [_____] mm inches between the outside of the well screen and the natural formation.
The filter pack shall be placed at a constant rate from the start of placement until it has reached the elevation
[shown], [directed] [a minimum of 600 mm 2 feet above the top of the well screen]. If a tremie is required,
a double string of tremie pipe shall be used. The pipes shall be placed on opposite sides of the screen and/or
casing, that is, 180 degrees apart, and shall be guided in such a manner that they will remain in this position
throughout the placing process. The tremie pipes shall be set in place, filled completely with filter pack prior
to being lifted off the bottom of the hole. The filter pack in the tremie pipe shall be kept a minimum of 300
mm 1 foot above the water surface in the well throughout the placing process. In no case shall the gradation
of the filter pack fall outside of the range specified in paragraph FILTER PACK.
3.4 DEVELOPMENT
NOTE: The method of surging specified may be modified to specify a procedure
considered most suitable for the particular project. Violent surging, as with
compressed air, should not be permitted.
Following placement of filter pack materials, develop the relief well by jetting, surging, intermittent pumping,
or other approved methods as may be necessary to give the maximum yield of water per 300 mm foot of drawdown.
At the time of development of any relief well, the well shall be free of drawdown or surcharge effects due to
pump testing, developing or drilling at another location. The Contractor is responsible for maintaining at the
relief well the needed access and work area and clearance in the relief well necessary to accomplish development.
Furnish, install, or construct the necessary discharge line and troughs to conduct and dispose of the discharge
a sufficient distance from the work areas to prevent damage. Development shall be conducted to achieve a stable
well of maximum efficiency and shall be continued until a satisfactory sand test, as specified in paragraph SAND
TEST, is obtained. As development proceeds, filter pack material shall be added to the annular space around
the screen to maintain the top elevation of the filter pack to the specified elevation. Provide an open tube
or other approved means for accurately determining the water level in the well under all conditions. If, at
any time during the development process it becomes apparent in the opinion of the Contracting Officer that the
well may be damaged, development operations shall be immediately terminated. The Contracting Officer may require
a change in method if the method selected does not accomplish the desired results. The Contracting Officer may
order that wells which continue to produce excessive amounts of fines after development for 6 hours be abandoned,
plugged, and backfilled, and may require the Contractor to construct new wells nearby. All materials pulled
into the well by the development process shall be removed prior to performing the pumping test.
a. Jetting should be performed using either a single or double ring jet. If a double ring jet is used
the rings should be 600 mm 2 feet apart. The jetting tool shall be constructed of high-strength material
and conservatively designed and proportioned so that it will withstand high pressures. The jetting tool
shall have [two [7][8][10] mm [3/16] [1/4][3/8] inch diameter hydraulically balanced nozzles spaced 180
degrees] [four [7][8][10] mm [3/16][1/4][3/8] inch diameter holes spaced 90 degrees] apart and which
shall exert the jetting force horizontally through the screen slots. The rings shall be constructed
such that the tips of the jets shall be within 13 mm 1/2 inch from the inner surface of the well screen.
The pump used in conjunction with the jetting tool shall be capable of providing [pressures up to [1700]
[_____] kPa [250][_____] psi.] [a minimum jetting fluid exit velocity of 45 meters per second 150 feet
per second.] Prior to commencing jetting, and following each jetting cycle, all sand and/or other materials
shall be removed from inside the screen. The jetting process shall start at the bottom of the screen
and consist of rotating the jetting tool [slowly] [1 cycle per 30 seconds] [[_____] cycles per [_____]
seconds] while rotating the pipe [180][90] degrees for two minutes at each location then raising the
pipe [150][_____] mm [6][_____] inches. All wells, more than 100 mm 4 inches in diameter, shall be pumped
during the jetting cycle to remove incoming sand and other material. Such pumping shall be at a rate
not less than 115 percent of the rate at which fluid is introduced through the jetting tool. This will
allow a flow of material into the well as it is being developed. Water used for development shall be
free of sand. The contracting officer may require other means of developing the well such as intermittent
pumping method, variation of the intermittent pumping method, or surge block if it appears that the development
of the well is not producing the desired results.
b. Intermittent pumping shall be performed by pumping the well at a capacity sufficient to produce a
rapid drawdown of approximately [_____] m feet stopping the pump (backflow through pump will not be permitted)
to permit the water surface to rise to its former elevation, and repeating this procedure. Cycle time
for this procedure will vary as directed but will not be more than 3 cycles per minute. A pump discharge
in excess of [_____] L/s gpm will be required. A deep well turbine pump, or electric submersible pump
with check valve, shall be used with any attachment necessary to accomplish rapid starting and stopping
for intermittent pumping. The intake shall be set at least 3 m 10 feet below the maximum expected drawdown
in the well. Prior to commencing intermittent pumping, and periodically during development by this method,
all sand and/or other materials shall be removed from inside the screen. The amount of drawdown may
be decreased if, in the opinion of the Contracting Officer, the efficiency of the well might otherwise
be impaired.
c. Surging of the well shall require use of a circular block which is approximately 25 mm 1 inch smaller
in diameter than the inside diameter of the relief well and is constructed of a material which will not
damage the screen if the block comes in contact with the screen, and a bailer or pump to remove materials
drawn into the well. The surging shall be continued for a period of approximately one hour or until
little or no additional material from the foundation or filter pack can be pulled through the screen.
The surge block shall be moved by a steady motion up and down the full length of the well screen. Prior
to commencing surging, and periodically during development by this method, all sand and/or other materials
shall be removed from inside the screen. All materials pulled into the well by the surging process shall
be removed.
3.5 BACKFILLING
[After the well has been developed, additional filter pack should be added if necessary to meet the requirements
of paragraph FILTER PACK PLACEMENT. Then the annular space above the filter pack, shall be backfilled by first
placing a 300 mm 12 inch minimum layer of concrete sand on the filter pack and then filling the remainder of
the space up to the [finished ground surface] [well pit] with grout or concrete. The concrete backfill shall
be placed to a depth at least equal to the existing impervious blanket, but in no case less than [_____] m feet
.] [For PVC riser pipe, after the well has been developed, additional filter pack should be added if necessary
for it to meet the requirements of paragraph FILTER PACK PLACEMENT. Then the remaining annular space above the
filter pack shall be backfilled by first placing a 300 mm 12 inch minimum layer of concrete sand on the filter
pack and then filling the remainder of the space up to the [finished ground surface] [well pit] with bentonite.]
The temporary casing, if used, shall be withdrawn in increments as the backfill is placed. Fill with impervious
material, to original grade, all pits such as those incidental to the reverse rotary circulation method of drilling.
3.6 PLUGGING OF ABANDONED WELLS
NOTE: Regulatory requirements shall be stated along with applicable paragraphs
to direct Contractor on how a well is to be abandoned. If there are no code
requirements the following should be used.
[The Contractor has the option of attempting to remove the well screen. If the well screen can be removed, grout
the bore hole starting from the bottom of the hole to within 1 m 3 feet of ground surface. The grouting shall
start at the elevation of the bottom of the tailpipe of the well. If the well screen could not be removed or
broke off during the removal attempt, the Contractor shall still be responsible for grouting the well from the
bottom of the tailpipe to within 1 m 3 feet of ground surface. Either of the above abandonment procedures may
require the Contractor to redrill the hole so that the bore hole can be grouted.][The well shall be grouted from
the bottom of the tailpipe to within 1 m 3 feet of ground surface. After the grout has setup the riser pipe
shall be cutoff 1 m 3 feet below ground. Then the hole shall be backfilled.] The cement grout mixture proportion
to be used shall be submitted for approval.
3.7 TESTS
3.7.1 Pump Test
NOTE: A six-hour continuous test is ordinarily adequate to determine that a
well is performing properly. It is recommended that the specified draw-down
(or discharge) during a routine test be approximately 1.5 times the estimated
head (or discharge) for which the system is designed. In addition to the routine
tests, the wells may be pumped for longer periods and at various draw-downs
or discharges to secure, or to check, design data.
Upon completion but before acceptance, each well shall be subjected to a pump test of which a sand test will
form a part. Provide a [deep well turbine] pump, capable of producing the specified drawdowns over periods of
time sufficient to satisfactorily perform the pump test specified herein. The intake shall be set 3 m 10 feet
below the maximum expected drawdown in the well. The amount of sand should be measured after each test. The
pump shall be complete with either gasoline, diesel, or electric motor of adequate size. In case an electric
motor is used, provide, without additional cost to the Government, the electric power and the necessary wiring.
Provide an open tube or other approved means for accurately determining the water level in the well. Furnish
and install an orifice meter of approved design or other approved equipment for the purpose of measuring the
discharge from the well during the pumping test. Furnish, install, or construct the necessary pipe discharge
line, troughs, or ditches necessary to dispose of the pumping test discharge a sufficient distance from the work
area to prevent damage. The tests will be conducted under the direction of the Contracting Officer and may be
made as soon as each well is completed [and adjacent Government installed piezometer tubes are operational].
Test data will be recorded by Government personnel. Test each well by pumping continuously for a minimum of
[6] [_____] hours. Prior to starting the pump test all material shall be removed from the bottom of the well.
The pumping shall be at a rate [of [_____] L/s gpm][sufficient to produce approximately [_____] m feet of draw-down].
If the test is interrupted, other than by order of the Contracting Officer, prior to the completion of the specified
period of continuous operation, the test shall be re-run. In addition to the required pumping test, the Contracting
Officer may direct the Contractor to perform additional pump tests. Such additional testing shall conform in
general to the requirements specified herein except that the duration of the tests and the approximate draw-down
will be determined by the Contracting Officer. In the event that sand or other material collects in the well
as a result of the pump test, accurate measurements shall be taken as to the quantity of material in the well
and all such material shall be removed. Upon completion of the pump test, remove all equipment, discharge lines,
electrical lines, lumber, and debris, and shall backfill any excavated areas with impervious material.
3.7.2 Sand Test
As part of each Pump Test or at the end of each intermittent pumping a determination of the amount of sand (filter
pack and/or foundation material) a well is producing shall be performed. Prior to starting the sand test all
material shall be removed from the bottom of the tailpipe. Test each well by pumping at a rate [of [_____] L/s
gpm] [sufficient to produce approximately [_____] m feet of draw-down]. After the pump is at the desired pumping
rate the flow from the discharge shall be diverted [into a container that will collect all the sand being carried
by the water][through a Rossum Sand Tester]. Development of the well is satisfactory if the amount of sand collected
is less than 0.5 L per 100 000 L 1 pint per 25,000 gallons of water pumped at the specified rate. Upon completion
of the test the amount of sand in the tailpipe shall be determined to verify that no material is being deposited
in the bottom of the well.
3.7.3 Filter Pack Sampling and Testing
Verify that all materials conform to the specifications before delivery to the project. The particle size distribution
of the filter pack shall be sampled and tested in accordance with ASTM C 136 and ASTM D 75. [Prior to delivery
to the project site, at least two samples of material should be collected and tested for every 700 metric tons
750 tons (2000 lb) produced under this contract.] [Within 48 hours before being placed in the relief well to
be back-filled, the filter pack shall be sampled from the material stockpiled at the project site. There shall
be at least one particle size distribution test on the filter pack for [each well] [every [_____] wells].] A
pump test shall be performed in accordance with technical provisions herein specified.
3.7.4 Reports
Include in the reports for each relief well, logs of the boring, elevations of the well screen, top of riser
pipe, bottom of the tailpipe, filter pack gradation, quantity of filter pack added during development, pump test,
sand test, and report of backfilling. The elevation of changes between materials on these logs shall be to the
nearest 30 mm 0.1 foot. The log of backfill material shall include the filter pack particle size distribution
test data, and notes concerning installation and development of the relief well. The pump test log shall include
the duration of the test and rate of flow in L/s gpm, and the draw-down response data with time in the pumped
well, in adjacent wells, and in nearby piezometers. The relief well log and the pump test log shall be submitted
to the Contracting Officer as part of the weekly quality control report specified in Section 01 45 01 USACE QUALITY
CONTROL. Also submit a report of the well installation to the appropriate public agency and in the form required
by state statutory and/or regulatory requirements specified in paragraph REGULATORY REQUIREMENTS.