I - MEASUREMENT AND
PAYMENT
Mobilization and
Demobilization:
Payment will be made for costs for assembling all plant
and equipment at the site preparatory to initiating the work and for
removing it there from when the drilling and grouting program has been
completed. Sixty (60) percent of the contract lump-sum price for
mobilization and demobilization will be paid following completion of
moving onto the site, including complete assembly, in working order, of
all equipment necessary to perform the required drilling and grouting
operations. The remaining forty (40) percent of the contract lump sum
will be paid when all equipment has been removed from the site.
Unit of measure: lump sum.
Drilling Grout Holes:
Drilling of grout holes will be measured for payment on
the basis of the linear feet.of holes actually drilled.
Unit of measure: linear foot.
Pipe and Fittings:
No payment will be made for costs associated with grout
and drain hole pipe and fittings remaining in the permanent work.
Portland Cement in Grout:
Payment will be made for costs associated with Portland
cement in grout.
Portland cement in grout will be measured.for payment on
the basis of the number of bags (94 pounds) of cement used in the grout
satisfactorily placed in grout holes and in, or wasted when such wasting
is not due to the Contractor's negligence.
Unit of measure: 1 cubic foot bag (94 pounds).
Fly Ash in Grout:
Payment will be made for costs associated with fly ash
in grout.
Fly ash in grout will be measured for payment on the
basis of the number of cubic feet (74 pounds) of fly ash used in the
grout satisfactorily placed in grout holes.
Unit of measure: 1 cubic foot bag (74 pounds).
Microfine Cement in Grout:
Payment will be made for costs associated with microfine
cement in grout.
Microfine cement in grout will be measured for payment
on the basis of 20 kg (44 lb.) of microfine cement used in the grout
successfully placed in grout holes.
Unit of measure: bags 20 kg (44 lb).
Sand in Grout:
Payment will be made for costs associated with sand in
grout.
Sand in grout will be measured for payment on the basis
of the number of cubic feet of sand, dry rodded measurement, used in the
grout satisfactorily placed in grout holes or in exploratory holes.
Unit of measure: cubic foot.
Admixes in Grout:
No payment will be made for costs associated with
admixes in grout.
Placing Grout:
The operation of placing grout will be measured for
payment on the basis of the number of cubic feet of materials,
satisfactorily placed, exclusive of water and admixes and regardless of
the proportions of the mixes, measure individually as specified in unit
price pay items "Portland Cement in Grout", "Fly Ash in
Grout", "Microfine Cement", and "Sand in
Grout".
II - SYSTEM DESCRIPTION
This section of the specifications covers; drilling,
washing and pressure testing grout holes; making grout connections;
furnishing, handling, transporting, storing mixing and injecting the
grouting materials; backfilling holes;; care and disposal of drill
cuttings, waste water and waste grout; clean up of the areas upon
completion of the work and all other such operations as are incidental
to the drilling and grouting. The work contemplated consists of
constructing a grout curtain [area grouting, the approximate locations,
limits, and details of which are indicated.
Materials Delivery,
Storage, and Handling
Cement:
A
sufficient quantity of cement shall be stored at or near the site of the
work to insure that grouting-operations will not be delayed by shortage
of cement. In the event the cement is found to contain lumps or foreign
matter of a nature and in amounts which, in the opinion of the Engineer,
may be deleterious to the grouting operations, screening through a
standard 100 mesh screen may be required. No payment will be made for
such screening.
Project / Site Conditions
The program shown and described is based on currently
available information. Conditions encountered during construction may
require additions or deletions. The grouting program shall not be
modified or curtailed as construction expediency. It is a required part
of design and shall not become secondary to any time or.scheduling
restrictions. Grouting mixes, pressures, injection rate and the sequence
in which the holes are drilled and grouted will be determined in the
field and shall be as directed.
III - PRODUCTS
Grouting Material:
Grout shall be composed of water and cement, admixtures,
and fillers. The grout mixes will be designed by the Engineer and will
be varied to meet the characteristics of each hole as determined by
conditions encountered. The various materials to be furnished by the
Contractor shall conform to the specifications listed in paragraphs
below.
Water:
The
water used in the grout shall be furnished by the Contractor. It shall
be fresh, clean and free from injurious amounts of sewage, oil, acid,
alkali, salts, or organic matter.
Cement:
Portland
cement used in grout shall conform to the requirements of ASTM C 150,
Type I or II. The Contractor shall submit to the contracting Officer of
the source of cement, brand name and type.
Fly Ash shall conform to ASTM C-618 grade c or grade f.
Alternate sources of fly ash may be submitted and will be considered.
The microfine cement material furnished shall be
selected from one or more of the following:
-
A blend of approximately 50 percent microfine
Portland cement and 50 percent microfine slag, with 98 percent of
the particles less than 10 microns and 50 percent of the particles
less than 4 microns.
-
100 percent microfine Portland cement, with 90
percent of the particles less than 10 microns and 50 percent of the
particles less than 3 microns.
-
A mixture of microfine slag, with 98 percent of the
particles less than 7 microns and 50 percent of the particles less
than 3 microns and microfine Portland cement, with 90 percent of the
particles less than 10 microns and 50 percent of the particles less
than 3 microns. The mixture shall be at least 25 percent microfine
Portland cement, as determined by the Contracting Officer.
Admixture:
Admixtures
may be added to the grout immediately before or during its mixing and
will consist of accelerators, retarders, water reducers, and fluidifiers.
Sand:
Sand
for grout shall be clean and consist of hard, tough, durable, un-coated
particles meeting the requirements and graduation of masonry sand ASTM
C-33.
Pipe and Pipe Fittings:
Pipe and fittings required for constructing grout,
drainage and exploratory holes shall be furnished, cut, threaded, and
fabricated by the Contractor.
Pipe:
Pipe
will be PVC of the diameter and in the location indicated. The pipe
shall conform to ASTM.
IV - EXECUTION
Equipment:
General:
All drilling and grouting equipment used shall be of a type, capacity
and mechanical condition suitable for performing the work, as determined
by the Engineer. The power and equipment and the layout thereof shall
meet all applicable requirements of local, State, and Federal
regulations and codes, both safety and otherwise.
Drilling Equipment:
Standard
drilling equipment of the rotary type shall be used to perform the
drilling as specified in paragraphs GROUT HOLE DRILLING. Water or Air
shall be used for removing cuttings from the hole during drilling
operations. Supplies shall include all bits, drill rods, tools, casing,
piping, pumps water, and power to accomplish the required drilling. All
drilling rigs and pumps will be equipped with pressure gages.
Grouting Equipment:
The
grout plant shall be capable of supplying, mixing, stirring and pumping
the grout and additives, to the satisfaction of the Engineer. The plant
shall have a minimum capacity of ( 30 ) gpm ( ___) cfm of
grout injected at a pressure not greater than ( 100 ) psi. It
shall be maintained at all times and any grout hole that lost or damaged
due to mechanical failure of equipment or inadequacy of grout supply
shall be replaced by another hole, drilled by the Contractor at his
expense. The amount of grouting equipment shall be as necessary to
perform the work specified herein. The type to be furnished shall
include the following.
-
A progressive cavity pump capable of generating
pressures up to ( 100 ) psi and pumping a maximum of ( 30 )
gpm ( ) cfm. In no case will the pump be separated by more
than (200) feet of grout line from the header of a hole being
grouted.
-
A colloidal or paddle type grout mixer having a
minimum drum capacity of approximately (10) cubic feet with a
mix batch of ( 6 ) cubic feet. Mixing time shall be
approximately ( 60 ) seconds per batch.
-
A mechanically agitated sump having a minimum
capacity ( 10 ) of cubic feet.
-
A circulating grout header with control valves and a
pressure gage with protector as shown on the plans. Control valves
shall be connected to the return line and header. The header shall
be joined directly to the riser pipe at the hole by means of a quick
connector union.
-
A water meter graduated in cubic feet and tenths
having a direct reading totalizer.
-
Such valves, packers, pressure gages, pressure hose,
supply lines, and small tools as may be necessary to provide a
continuous supply of grout at accurately controlled pressures as
specified. The inside diameter of the pressure hose and grout supply
line shall be not less than ( 1 ) inches. An accurately
calibrated, high precision pressure gage shall be used to check the
accuracy of all gages used in the grouting. Gages shall be checked
at least every 24 hours, or more frequently if the Engineer so
determines. When defects are found, grouting operations will be
stopped until calibration of gages has been obtained.
Grout:
All holes for grouting, shall be drilled at the
locations, in the direction, angle, and to the depths indicated or as
directed by the Engineer. A maximum tolerance for deviation in angle and
direction shall be ( 30 ) The first series of holes to be drilled
and grouted shall be at ( 10 ) - foot intervals and hereinafter
are referred to as primary holes . The location of secondary and
succeeding series (intermediate) holes shall be determined by the split
spacing method as defined in paragraph SPLIT SPACING. The number of
grout holes shall be increased, progressively, by the split spacing
method as defined in paragraph SPLIT SPACING. The number grout holes
shall be increased progressively, by the split spacing method as deemed
necessary by the Engineer until the amount of grout used -indicates that
the foundation is tight. Each hole drilled shall be protected from
becoming clogged or-obstructed by means of a cap or other suitable
device on the collar and any hole that becomes clogged or obstructed due
to fault of the contractor before completion of operations shall be
cleaned out in a manner satisfactory to the Engineer or another hole
provided by and at the expense of the Contractor.
Grout Hole Drilling:
Grout
holes shall be drilled with standard.rotary drilling equipment. No core
recovery will be required and the type bit used shall be optional with
the Contractor. The hole shall be of sufficient diameter to allow use of
an expansion plug or packer with an effective inside diameter of not
less than 1 inch. The minimum diameter of hole shall be 2 inches at the
point of maximum penetration. No grout hole will be drilled at an angle
greater than ( 30 )degrees measured from the vertical nor to a
depth greater than ( 40 )feet measured from the collar of the
hole. It is determined that holes to depths greater than indicated are
necessary, drilling to such greater depth will be ordered in writing,
and the drilling to depths in excess of ( 40 ) feet will be paid
for at a negotiated unit price.
Drilling will be done in accordance with the applicable
grouting method hereinafter described. Whenever as much as ( 50 )
percent of the drill water is lost or the cumulative total of successive
water losses is estimated to amount to ( 50 ) percent loss, or
artesian flow is encountered, the drilling operations shall be stopped,
the hole washed, pressure tested and grouted before drilling operations
are resumed in such hole. The grout so injected remaining in a partially
completed hole shall be removed therefrom by washing or other methods
before it has set sufficiently to require redrilling. Redrilling
required because of the Contractor's failure to clean out a hole before
the grout has set shall be performed at the Contractor's expense. Except
that where the grout has been allowed to set by direction of the
Engineer, the redrilling will be paid for at the contract price for
drilling the grout hole. Upon completion of drilling of any hole and
prior to pressure testing, all drill cuttings and slurry shall be
removed by applying water to the bottom of the hole through open end
rods and returning the wash water through the hole to the surfaces until
the return water is clear. No separate payment will be made for this
washing.
Definitions and Procedures
for Drilling and Grouting:
General:
The
drilling and grouting shall be accomplished in single or multiple lines
as shown. Zones, using the split spacing shall do the drilling and the
grouting.
Split Spacing:
Split
spacing is the procedure of locating an additional grout hole midway
between two previously drilled and grouted holes.
Primary Holes:
Primary
holes for foundation grouting shall be drilled to their full depth. The
depths will be governed by the foundation conditions.
The holes thus drilled shall be washed and pressure
tested, and then grouted.
Successive Holes:
After the primary holes have been completed in any section as specified
above, the second and succeeding series of holes, as determined by the
"split spacing method," shall be drilled and grouted as
directed.
As the drilling and grouting work progresses, it may
develop that conditions are such that all or parts of the foundation
already grouted require additional grouting. In such event, the
equipment shall be returned and additional holes for grouting shall be
drilled and grouted as directed and no allowance above contract unit
prices will be made for drilling and grouting such holes or for the
expense of any movement of equipment necessary to the performance of
such work.
Grouting Pressures:
Grouting pressures to be used in the work will vary with conditions
encountered in the respective holes and pressures used shall be as
directed. It is anticipated that pressures will range from ( 0 )
psi to ( 5 ) psi but in no event will pressures in excess of (
5 ) psi be required or allowed.
Grouting:
All
pressure grouting operations shall be performed in the presence of the
Engineer, and shall be in accordance with the following general
procedures.
Grout Mixes:
Mixes
shall be in the proportions directed by the Engineer who will, from time
to time, direct changes to suit the conditions found to exist in the
particular grout hole.
-
Cement Grout shall consist of cement, and water.
-
Mortar Grout shall consist of cement, sand, and
water.
Grout Injection:
In general, if pressure tests indicate a tight hole,
grouting shall be started with a thin mix. If an open hole condition
exists, as determined by loss of drill water or inability to build up
pressure during washing operations, then grouting shall be started with
a thicker mix and with a grout pump operating as nearly as practicable
at constant speed at all times; the ratio will be decreased, if
necessary, until the required pressure has been reached. If this
procedure does not produce the desired pressure, mortar grout shall be
used and the mix varied as necessary to produce the desired results.
When the pressure tends to rise too high, the
water/cement ratio shall be increased and/or the mix of mortar, grout
changed or discontinued as may be required to produce the desired
results. If necessary to relieve premature stoppage, periodic
applications of water under pressure shall be made. Under no conditions
shall the pressure or rate of pumping be increased suddenly as either
may produce a water-hammer effect, which may promote stoppage.
The grouting of any hole shall not be considered
complete until that hole takes grout at the rate of one cubic foot of
grout or less in ten minutes measured over at least a five minute period
at the pressure required for that portion of the hole being grouted.
Should grout leaks develop, the Contractor shall caulk
such leaks when and as directed, the cost thereof being included in the
contract price for unit price pay item "Placing Grout", in
accordance with MEASUREMENT AND PAYMENT.
If, due to size and continuity of fracture, it is found
impossible to reach the required pressure after pumping a reasonable
volume of grout at the minimum workable water/cement ratio or mortar
grout materials ratio the speed of the pumping shall be reduced or
pumping shall be stopped temporarily and intermittent grouting shall be
performed, allowing sufficient time between grout injections for the
grout to stiffen. Following such reduction in pumping speed, if the
desired result is not obtained, grouting in the hole shall be
discontinued when directed. In such event, the hole shall be cleaned,
the grout allowed to set, and additional drilling and grouting shall
then be done in this hole or in the adjacent areas as directed, until
the desired resistance is built up.
Grout that cannot be placed, for any reason, within two
hours after mixing shall be wasted. If such grout is mixed at the
direction of the Engineer or with his knowledge and consent, such wasted
grout, except as specified in MEASUREMENT AND PAYMENT, shall be paid for
at the contract unit prices for the materials contained therein.
Backfilling of Holes:
Holes shall be backfilled with grout proportioned as
directed by the Engineer and generally having a water/cement ratio less
than 1.0. The backfilling shall be accomplished by injection of grout
through a tremie pipe or hose inserted to full depth of hole. When grout
vents at the surface, the tremie shall be gradually withdrawn,
maintaining grout in pipe or hose until completely removed. Holes
containing freshly injected grout shall not be backfilled until the
injected grout has set, grout will be paid for at the contract unit
price for the Portland cement therein.
Equipment Arrangement and
Operation:
The arrangement of the grouting equipment shall be such
as to provide a continuous circulation of grout throughout the system
and to permit accurate pressure control by operation of a valve on the
grout return line, regardless of how small the grout take may be. The
equipment and lines shall be prevented from becoming fouled by the
constant circulation of grout and by the periodic flushing out of the
system with water. Flushing shall be done with the grout intake valve
closed, the water supply valve open, and the pump running at full speed.
Records:
The Engineer will keep records of all grouting
operations, such as a log of the grout holes, results of washing and
pressure testing operations, time of each change of grouting operation,
pressure, rate of pumping, amount of cement for each change in
water/cement ratio, and other data deemed by him to be necessary. The
Contractor shall furnish all necessary assistance and cooperation to
this end.
