CA2142812C - Method and apparatus for continuous mixing and injection of foamed cement grout - Google Patents

Method and apparatus for continuous mixing and injection of foamed cement grout Download PDF

Info

Publication number
CA2142812C
CA2142812C CA002142812A CA2142812A CA2142812C CA 2142812 C CA2142812 C CA 2142812C CA 002142812 A CA002142812 A CA 002142812A CA 2142812 A CA2142812 A CA 2142812A CA 2142812 C CA2142812 C CA 2142812C
Authority
CA
Canada
Prior art keywords
pump
grout
foam
slurry
intake side
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002142812A
Other languages
French (fr)
Other versions
CA2142812A1 (en
Inventor
Patrick J. Stephens
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority claimed from PCT/US1993/007593 external-priority patent/WO1994004331A1/en
Publication of CA2142812A1 publication Critical patent/CA2142812A1/en
Application granted granted Critical
Publication of CA2142812C publication Critical patent/CA2142812C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Landscapes

  • Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)

Abstract

An apparatus and method for the continuous generation and placement of a foamed cement grout. The assembly is mounted on a fixed or mobile frame. There is a continuous foam generator (90), and this supplies finished foam to an intake port (148) of a screw-type, positive-displacement pump (90). Cement slurry is also supplied to the intake portion (118) of the pump, and this is mixed with the foam in the body of the pump and discharged from this through a conduit to the injection site on a continuous basis. The ratios of foam and slurry can be adjusted on a continuous basis to compensate for variations in grout quality which are observed at the injection site. The assembly is also provided with an onboard power generator and water pump for flushing the grout out of the injection lines.

Description

METHOD AND APPARATUS FOR CONTINUOUS
MIXING AND INJECTION OF FOAMED CEMENT GROUT
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates generally to apparatus and methods for filing voids with foamed cement grouts.
More particularly, the present invention relates to an apparatus and method for the continuous mixing of foamed cement grout, and pumping this to a desired injection site.
2. Background Art Foamed cement grouts have many applications in industry, such as for filling abandoned pipelines and other large voids in the earth, for grouting of tunnel liners and similar structures. These grouts axe formed by mixing a finished foam, which comprises a mass or aggregate of bubbles, with a cement slurry so that air spaces are entrained within the grout. Because of the relatively large volume of the entrained air, the amount of cement slurry which is needed to fill a particular cavity is greatly reduced from 1. .
;.. .;
f. ,. ".. .

t .

!~(? 94/14331 ~(.'T/US93/07593 ;. : , ~., ~~_4~ ~~~

s s I
that which would be needed if an unfoamed slurry ..

was used. This results in great cost savings, ~._.

especially when filling very large voids. Other , advantages of foamed cement grouts include the fact that, because they are fluid and non-shrinking, the need for contact grouting is eliminated.

Although foamed cement grout is thus a highly advantageous material for grouting, backfilling, I0 void filling, and so forth' its success in many of these applications has been limited to a significant degree by the manner in which it is conventionally prepared. ~n short, to the best of Applicant's knowledge, foamed cement grouts have I5 always been prepared for fill work by batch-type processes: the foam is typically mixed into the cement slurry in a tab ar other vessel to form a batch of the grout, which is then pumped from this to the injection site.

20 This batch-process :proach exhibits certain inherent inefficiencies and disadvantages, especially when it comes.to~large fill jobs.

While it maybe possible to prepare batches of foamed cement grout which are big enough~to 25 complete relatively small grouting jobs, this is simply not feasible in the case of larger jobs.

such as the filling of abandoned pipelines, which .

may call for hundreds or thousands of cubic yards of grant. Obviously, the repeated starting and 30 stopping which is involved in a batch process introduces a strong element of inefficiency on such projects, especially being that large crews .: ~, - ' ~~~'~~1?
~~

W~ 94/04331 .

_3_ of workers may be left standing idle between the a injection.of each batch.

r Furthermore, the need to mix up separate batches of grout and inject these individually invariably leads to quality control difficulties.

Apart from mix variations which occur inevitably from batch-to-batch, the batch-type processes are inherently incapable of permitting adjustment of the quality of the grout as it is being injected.

For example, although the bubble structure of the fluid grout is very stable, and will withstand high pressures without loss of integrity, significant bubble loss may occur due to friction between the grout and the piping through which it is pumped. These Friction losses are somewhat unpredictable, and naturally become more serious as pumping distances increase. The inability of the batch-type processes to adjust the quality of the grout (i.e., the foam content) to compensate for observed friction losses means that an entire batch of grout nay be placed at the injection site with the foam structure being significantly deterioraf.ed due to friction loss, resulting in a severe decrease in the volumetric yield of the batch. , Anather serious problem which has been , encoun~ered with such conventional grouting ' systems, particularly when filling abandoned . pipelines and other elongate voids, stems from their inability to deliver the grout continuously ~
' ' at a high volume rate over sustained pericds. as was noted abo-ve, the bubble structure of the grout ' !'n ~'~ 94/04331 PCT/US93/07593 .

~~ ~.i~~~;

1 _4_ i t is very stable so long as there is free liquid in,.
i the mixture, and so this can be pumped at ' relatively high pressures. However, once hydration of the grout proceeds to the paint where S it takes an initial set, the bubble structure ceases to exist and is replaced by a simple void which is maintained only by the cement paste which surrounds t; if this is subjected to external pressure, as by the injection of additional grout adjacent to or on top of the first, the void structure is vary easily collapsed, resulting in a severe loss of volumetric yield. Simply put, it is very difficult to avoid this. when using a .

batch-type process, since the process is slow by its very nature and injection must periodically i halt while another batch is being prepared, and the grout will continue to set up during these pauses; also the pumps and related equipment which are conventionally employed in these processes are not suited to high injection rates.

Accordingly, there exists a need for an apparatus and method for preparing foamed cement grout and pumping this to an injection site on a continuous basis, and not batch-wise. Also, there is a need for such an apparatus and method which will permit continuous monitoring and adjustment j of the quality of the grout which is produced. _ .

' Still further, there is a need for such an . apparatus and method which will permit the grout I
to be injected at a sustained rate sufficiently high to avoid injection on top of previously-injected grout which has taken an initial set. r t W(3 94/04331 PCT/US93/07593 i _,_ ;
One spec_ Lc application for foamed cement grout which wa noted above is for the grouting or backfilling of nel liners. In most cases, a tunnel is not c~ late until a liner has been placed along the perimeter of the bored hole. In a typical technique, a tubular tunnel liner is placed within the cylindrical wall of the tunnel, ;
which results in an annular cavity being formed between these.
It has been found advantageous to fill this cavity with foamed cement grout, but difficulties have been encountered when using this material in relatively long tunnels. The grout, once mixed, is usually relatively viscous, and tends to compxess and cause friction and back-pressure when pumped through conduits. This difficulty becomes serious if it is necessary to pump the grout over great distances, as from the surface to an injection point far inside a tunnel. Attempts have been made to overcome these problems by ..
mixing batches of foamed cement gout within the y:
tunnel, as by transporting dry cement in bags to a small batch mixer inside the tunnel and then mixing this with water and foam to form,the grout;
however, this batch-type appa~oach shares the disadvantages discussed above, being that it has proven exceedingly slow and expensive to practice, and it is very difficult to carry out with adequate quality control.
30~ Accordingly, there exists a need for an 3-.:: v.
apparatus and method for employing foamed cement a..
grout to backfill tunnel liners which avoids the ;.. , i .
i.,:.
i.. , ;.
:,.:
i~Y~ 94104331 PCT/U593/07593 -."; . i ~~~w~~~

I
need to pump the grout over long distances into ~ ;
the tunnel bore. Furthermore, there is a need for such an apparatus and method for continuously .
forming and injecting such foamed cement grout within the tunnel, so that high volumes of .grout can be placed over long distances quickly, and with a high degree of quality control.
SUMP-f~RY OF THE INVENTION
The present invention has solved the problems cited above, arid is an apparatus for the continuous generation and placement of a foamed .
'cement grout, this comprising broadly: means for 15generating a finished foam on a continuous basis, means for mixing the. finished foam with cement slurry on a continuous basis to form a foamed cement grout, and means for pumping the foamed cement grout to a selected injection site on a continuous basis.
The apparatus may further comprise means for selectively adjusting the ratio at which the finished foam is mixed with the cement slurry on a continuous basis so as to compensate for observed variations in the quality of the grout. This may comprise control means for selectively adjusting the rate at which the finished foam is outputted from the generating means to the mixing means. '-The means for pumping the foamed cement grout .
may comprise a screw--type, progressive-cavity pump, and the means for mixing the finished foam .
with the cement slurry may be this pump, the pump . ,. ;~. _.
i .. .;
W~ 94/04331 PCT/LJ~93/0?593 ;.

i, I
having an intake portion which is configured to receive the foam and slurry, and a main body portion which is configured to mix the foam and S

slurry to farm the grout as the foam and slurry <,, s~ 5 move through the pump from the intake portion to a discharge portion. The intake portion of the pump may comprise an intake port for supplying the cement slurry to the intake portion of the pump at a first point along a direction of flow in the I0 pump, and an intake port for supplying the finished foam to the intake portion of the pump at a second point,which is spaced downstream along the direction of flow from the first point. There 'i may also be conduct means for conveying the foamed ,;

I5 cement grout from the discharge portion of the pump to the selected injection site.

The apparatus may further comprise frame means to which the foam generating means and pump v are mounted. This frame means may be configured 20 for placement in a stationary location from which the grout is pumped to the injection site, or the frame means may be configured for rolling movement from a first location to a second location so as to permit the foam generating means and pump to be 25 positioned relatively closely adjacent the injection site.

There may also be means for selectively flushing the grout out of the conduit so as to prevent the grout from setting up therein. This 3P~ may comprise pump means ~aounted to the frame for selectively generating a stream of high pressure water, and a conduit for directing this stream ;.. . -:-, . . . " . . .: , , . , .
,.:
.::;
1.
rp~~194/04331 ~Cf/US93/07593 _$_ from the discharge end of the pump into the main M
conduit so that the stream of water flushes the ~...,:, grout out through a discharge end thereof.
A method is also provided for the continuous generation and placement of foamed cement grout, this comprising broadly the steps of: generating a finished foam on a continuous basis, mixing the finished foam with a cement slurry on a continuous basis to form a foamed cement grout, and pumping the foamed cement grout to a selected injection site on a continuous basis.
The method may further comprise the step of selectively adjusting the ratio at which the finished foam is mixed with the cement slurry on a continuous basis, so as to compensate for observed variations in the quality of the grout. This step may comprise adjusting the rate at which the finished foam is outputted and then mixed with the cement slurry.
The method may also further comprise the step of injecting the grout at the injection site at a sufficiently high rate that the injection site is.
filled continuously without injecting fresh grout under pressure adjacent previously-injected grout which has taken an initial set, so as to avoid collapsing void spaces in the previously-injected grout due to the injection pressure of the fresh .
grout.
. The step of mixing the finished foam with the .
.: .
3~ cement slurry may comprise supplying the foam and ~' the slurry to an intake portion of a screw-type.
progressive-cavity pump, and mixing the foam and ,..
a 1 ~ ~ !~ ~ ~ ~. ~ '~;
:'iYV~ 9a/0 33 1'CT/U593107593 r..
;.
_9_ i i i t the slurry in a main body portion of the pump as~
the foam and slurry move through the pump to a discharge portion. The step of supplying the foam :, and slurry to the intake portion of the pump may ;;
comprise supplying the cement slurry to the intake portion of the pump through an intake port at a 'i first point along a direction of flow in the Bump, and supplying the finished foam to the intake portion of the pump through an intake port at a .i 10 second point which is spaced downstream along the direction of flow from the first point.
'' These and other novel features and advantages of the present invention will become apgarent from ' -the following detailed description, wherein :;
reference is made to the Figures in the accompanying drawing.
BRIEF DESCRIPTION OF THE DRRWINGS
FIG. 1 is a cross-sectional view of a tunnel :j having a mobile grouting machine in accordance with the present invention positioned therein, e; this being supplied with cement slurry from a surface ~aixing plant;
2.5 FrG. 2 is an elevational view of the wheeled cars making up the grouting machine of FIG. I, showing the individual components mounted thereon;
FTG. 3 is a schematic view showing the systems of the machine of FIG. 1 which generate 30~ finished foam and mix this with cement slurry on a <:
:._ 3 continuous basis to form the foamed cement grout:
i .: . _ i FIG. ~ is a plan view of a second embodiment of continuous grout mixing and pumging machine in accordance with the present invention, this being mounted on a stationary frame at an above-ground location;
FIG. 5 is an elevational view, partly in -a cross-section, showing the machine of FIG. 4 employed in the grouting of a tunnel liner;
FIG. 6 is schematic view of the hydraulic ':i system,of the machine of FIGS. 4-5;
w FIG. 7A is an elevational view similar to ':j ;that of FIG. 5, but to a reduced scale, showing the machine of FIGS. 4-5 employed in the filling of an abandoned pipeline; and I5 FTG. 7B is a view similar to FIG. 7A, showing the machine being used to fill a void an the f earth.

t>.;
c, ..
1;, : .
f ; ;-.
.; VN~ 94/04331 ~ ~. ~ ? ~ .~ -~ P~CT/US93/07593 r' '..
i -11- i i nETAI~,En psscRZpTION
,, Mobile Plant f i. Overview , , SIG. 1 shows a mobile grouting machine 10 in accordance with the present invention, this being positioned for longitudinal movement in a subterranean tunnel 20. Tunnel 20 comprises generally a cylindrical bore 22 Formed in earth formation 24, and a cylindrical liner 26 which has been installed in the bore. The liner 26 is necessarily smaller than bore 22 so ws to permit -this to be installed, and an annular gap 28 is consequently formed between the liner and bore.
Access is gained to the tunnel from surface 2~ via a shaft 30.
Grouting machine 10 is positioned inside liner 26, and comprises generally a train of wheeled cars 3~, 36, '38. By using three cars arranged in a train, it has been found possible to configure the equipment so that it will fit within a relatively small-diameter (e. g., 6-foot diameter) liner, and this also provides sufficient flexibility that the train will accommodate bends in the tunnel; however, for relatively large-diameter (e. g., 12.5-foot diameter) tunnel liners, it may be preferable ~o mount the equipment on a - single car. =:
A tractor 40 is avtached to one end of the '~r i train to pull the cars through the tunnel. A

i '/,:
..
1~'O 94/d~4331 ~ ,~, l~. ~ ~ ~ ~ P~'T/US93/0'~593 -lz-second tractor 42 may be attached to the other end of the train to pull it in the other direction, and this can also be used to bring loads of liquid foam concentrate or other materials to the train while it is in operation. Tractors 40 and 42 may ~! preferably be conventional diesel-powered front loaders. Of course, other locomotive devices may be substituted for tractors 40, 42, including, for example, winches having cables attached to the train.

The wheeled cars carry the equipment for generating finished foam and mixing this with r cement slurry which has been pumped to the train .

from a remate source. As is shown in FIG. 1, the cement mixing plant 5~ is typically positioned on tha surface, outside of the tunnel. The plant includes a dry cement hopper 52 and a water hopper 54, the contents of which are mixed to form the slurry. An output pump 56 discharges the fluid cement slurry from the mixing plant under pressure. Inasmuch as such conventional cement mixing plants are well known to those skilled in the art azad do not themselves form Bart of the present invention, mixing plant 50 will not be described in greater detail.

A conduit 6~ conveys the slurry from pump 56 to grouting machine 10. because the unfoamed ~i ~ ~ cement slurry is relatively fluid, it is easily Bumped over the relatively great distances from access shaft 30 to grouting machine 10, without developing the excessive gressures which would be encountered in pumping foamed cement grout over H ..
_ f .:.
i~ ') 'a~ ~~ t'.--r:
W~f 94/04331 ~° ~. :~' ;."' :.7 ~ ~ i '.= ~, P~ I'/ US93/07593 ~; ;.::

such distances; for example, the,slurry can ..
;. .
readily be pumped in excess of 10,000 lineal feet, '., .
and pumping distances on the order of 30,000 feet can be attained if suitable high pressure conduit is available. In order to further facilitate this pumping, it has been found advantageous to form conduit 60 of low-friction, segmented, steel pipe known to bhose skilled in the art as "slickline".
The cement slurry which is pumped through conduit 60 feeds machine 10 on a continuous basis, and this is mixed with finished foam to produce the foamed cement grout. This is then pumped -through a second conduit 62 (which may be another "slickline") to a grout distribution manifold 64, this distance being up to about 3,000°4,000 lineal feet. From the manifold, the grout is distributed .
to a plurality of relatively short injection hoses 66. The end of each of the injection hoses is inserted through a port 68 in liner 26 so as to be in fluid cammunicati.on with annular cavity 28.
The injection hoses are preferably flexible, so that they can be bent back on themselves from manifold 64 to a first injection port, in the position shown by broken line image 66°, and can 2~ also extend down the tunnel from the manifold to a second injection port, in the position shown by j solid 1-ine image 66, without having to move i manifold 64 Or Cars 34, 36, 38.
. 8eeause ~.he foamed grout need only be pumped .
relatively short distances through conduit 62 and 'v=
hoses 66 before it is injeoved into the cavity.
r~ _ the viscosity and resistance to pumping which are .y a:,. .

!r~'O 94/04331 PCT/US93/07593 . ... .

exhibited by this material do not present the '"
i;
problems which they would if greater distances i"
were involved. v In a typical application, machine 10 may start at an initial position near a set of injection ports 68 close to the opening into the tunnel, first injecting foamed cement grout into these and then moving sequentially to positions further along the length of the tunnel. Hy this approach, a uniform and effective grouting of the annular cavity over the whole length of tunnel 20 can be achieved expeditiously and efficiently.
The continuous injection of grout over each segment which is made possible by machine 10 enables a heretofore unknown rate of backfilling and control over the quality of the backfill material to be achieved.
iiw Systems Description z~
Having provided an overview of the grouting machine of the present inveaition, a number of the components thereof will now be described in greater detail.
FIG. 2 shows cars 34, 36, and 38 of grouting machine 10. Each of these comprises a I platform 70, 72, 74, on which the mixing, pumping, . , and other related components are mounted, and ..
which rides an wheels 44 which perpendicularly .
engage the caall of the tunnel liner. 'The cars are I
i connectEd to one another by means of tow bars 76.
i i i i ;..; , ~'O 94/04331 ~ ~ ~~ ~ ~j ~ ~ PC,'T/US93/07593 x i r -15- ' i r a i The cement slurry which is supplied to ,.

machine 10 through conduit 50 is discharged into a hopper 80, which provides a constant supply of i cement slurry to the mixing and pumping apparatus of the machine; the hopper is sized sufficiently large that the supply of slurry therein "smooths out" variations in the flow of cement from the a surface mixing plant. A series of paddles 82 are attached to a shaft 84 which is rotated by a w hydraulic motor 86, so that these agitate and remix the slurry in hopper 80.

The slurry from hopper 80 is mixed with finished foam to produee foamed cement grout. , Conventional finished foams are made by mixing liquid foam concentrate with air and water;

;y turning then to FIG..2, we see that a supply of foam concentrate is carried on car 38 in drums 88.

The concentrate is fed from these to the foam generator 90,,and the water is supplied to generator 9~l by means of a hose which is run .a through the tunnel. Air, in turn, is supplied by :', an air compressor 92, and the foam generator mixes these to produce the finished foam. This is pumped from generator 90 to grout diseha~rge pump 95. The cement slurry is also fed into pump 95 from hopper 80, and the finished foam and cement slurry are mixed together in this to form the foamed cement grout. This is then discharged through line 62 to the manifold and injection lines.
z .:

.

Power is provided for the grout pump motor s and other hydraulic motors of machine 10 by a S

a. . .;
t..~:
,.
1WG 94/Q4331 ~ ~ ~ '~ ~ ~ ~ PCT/~JS93/07593 ;-... .
_16_ .
hydraulic pump 97 mounted on car 36. Pump 97 draws fluid from reservoir 102, and a cooler 104 is installed to keep the temperature of the fluid within proper parameters. The pump is driven by an electric motor 98; this receives its power from an electrical panel 100, to which power is supplied by cables which extend through the tunnel. In other embodi~ents, a generator may be mounted on the cars to provide the electrical power, or an engine may drive the hydraulic pump directly. Alternatively, the various systems may be operated by electric or air motors.
F'IG. 3 provides a more detailed view of the systems for generating the foam and mixing this with the cement slurry. As was noted above, the cement slurry is discharged into hopper 80, in the direction indicated by arrow 110: from here the slurry flows through throat 112 into an intake port 118 at the suction end of pump 95; the ;
vertical drop between the hopper and the intake w serves to provide the pump with a constant head of supply pressure. Tt has been found advantageous in some embodiments to route throat lit along a somewhat circuitous path so as to help prevent the 2S foam from bubbling back up through this.
Pump 95 itself is preferably a progressive-cavity, screw-type pump, this preferably being -operated by a hydraulic.motor 116 so as to provide t a wide range of available speeds (i.e., rpm°s); a i_ .
pump of this configuration facilitates mixing of the foam and slurry within tire b=dy of the pump, and also contributes to the rapid grout output '.
t'~O 94/04331 ~ ~. !~y l ~ ~ ~ PCT/US93/a7593 i i i rate of the system, as will be discussed in ..
greater detail below> A pump of this type which has been found eminently suitable for this application is a Model L-12 rotor-stator type S "Moyno" pump available from Robbins & Meyers, Inc., Dayton, Ohio, and so pump 95 may be referred to from time-to-time hereinafter as a "Moyno"
pump.
From intake 118, the slurry moves longitudinally through Moyno pump 95 in the direction indicated by arrow 120, and downstream of intake 118, but still on the suction side of the pump, the finished foam is also fed into the pump cavity. It has been found preferable to position foam intake port 148 some distance downstream of the slurry intake port 118, because this also helps prevent the finished foam from "bubbling" back up through throat 1i2. Downstream of the foam injection point, the slurry and foam are mixed proportionally within the body of the Moyno pump by the action of its screw pump mechanism, so as to farm well-mixed foamed cement grout. This is discharged through the discharge end 150 of the pump, and into grout discharge line 62 in the direction indicated by arr~w 120; -additional mixing and homogenization of the foamed grout continues to take place within the: first 100 feet or so of the discharge line.
Tt should be noted at this point that, while the Moyno-type pump described above has been found a s.._ preferabbe for mining and pumping the grout in the gresent invenf.ion, suitable pumps of other types, such as piston pumps or squeeze pumps, may be substituted for this, with or without a r supglemental mixer for the foam and slurry.
FTG. 3 also illustrates the foam-generation side of the system. As was noted above, the finished foam is generated from a mixture of foam concentrate, water, and air. An exemplary foam concentrate whidh is suitable for use in the present invention is available from the Mearle Corporation, Roselle Park, New 3ersey, under the trade nape "Mearle Geocel Foam Liquid". 'The liquid concentrate is drawn from container 124 by a suction line 126 which is connected to the foam -generator unit 90. The compressed air is supplied to the generator unit from a reservoir 94, through line I34, and finally, the water is supplied through line 13~. The foam generator unit meters the concentrate, compressed air, and water, and mixes these to form the finished foam. A
generator unit which has been found eminently suitable for this is a Model AE'S-2H-20V Autofoam unit, also available from ttie Mearle: Corporation.
The Autofoam~ unit is equipped with pumps far drawing bhe foam concentrate to the unit and i 25 mixing the foam, and for discharging the finished foam through line 142, in the direction indicated a _ ! by arrow 144.
The finished foam line 142 discharges through a conduit 146 into the suction side of the Moyno --pump at foam intake port 148. The proportions of the cement slurry and foam supplied to the pump are regulated according to the specifications for i.;'.:
W() 94/04331 pCT/US93/07593 _19_ a particular project: for example, the following mix design has been found suitable for grouting w tunnel liners using the machine described above:
Cement jlurrv Cement 341 Ibs. 1.740 CF
Fly Ash 341 lbs. 2.368 CF
Water 362 lbs. 5.801 CF
Foam Faam 35.7 lbs. 17.090 CF
Total 27 CF or 1 cu. yard This provides a grout having a water~solids ratio of about 0.53 and a wet density of about 40 PCF.
The systems of the present invention may thus loe provided with an initial setting such that the quality of the grout which is produced approximates what has been specified for a particular job. However, as was noted above, various factors, such as loss of bubble structure due to friction with the pumping line, may cause the quality of the grout at the injection site to vary significantly from what is produced at the discharge end of the main pump. Accordingly, it is an important aspect of the present invention that the quality of the grout which is produced at the pump outlet can be adjusted on a continuous basis to compensate for such losses or other factors, s9 that the quality of the grout at the injection site can be maintained continuously within proper parameters. The systems of the present invention make this possmble, primarily by '"
permitting continuous adjustment of the quality a laV~ 94/04331 P~T/US93/U7593 .
i ~~4?~12 and quantity of finished foam which is produced by~- i the foam generator, and which is injected into the i...
'. continuous flow of slurry through the pump. The variable speed of the pump provides another '- S control factor. Therefore, for example, if the operators at the injection site weight the grout and determine that it is being delivered at that point with insufficient foam content, so that its unit weight is too high, the rate at which the '' 10 foam is produced can be increased almost instantaneously (by telephone directions) so as to increase the proportion of foam in the grout to compensate far the loss. Conversely, if the grout at the injection site is observed to be too light 15 due to excess foam content, the proportion of foam can be reduced at once to compensate for this.
P.ccordingly, variations in the quality of the grout can be corrected on a continuous basis, as opposed to~th;e situation which occurs in a batch-'.,; 20 type process, where perhaps an entire batch of ~i grout would have to be injected before the problem could be corrected, or (if it is too far out of specification) dumped into the tunnel bore for subsequent disposal.
'S

b. Stationary Plant i. Overview ... ..
30 The foregoing description has focussed an 3..:..
embodiment or the present invention in which the apparatus for continuously generating and ( \..i:'.,: '., .:,. .~.. , ... .; ' : ' '. '..~ . : .~:~..~, . ,.. .., . ' ..
. . ., . . . . . . , I :.s.t W~ 94/04331 ~ ~_ .1,~ ~~ ~ ~ ~ Pt.'T/US93107593 I

I
-i injecting the foamed cement grout is mounted on a mobile train . FIGS. 4-7, in turn, illustrate I
another embodiment in which the continuous foam generating and pumping assemblies are constructed for stationary operation, and which is especially suited for large-volume filling projects. In this embodiment, the,foamed cement grout is pumped from the stationary mixing app aratus to the injection site, and so this is particularly suited to applications where the pumping distances are not too great; for example, being that the foamed grout can be pumped some 3,000-4,000 lineal feet without difficulty, this embodiment is especially suited to tunnel grouting jobs where the distances between adjacent-access shafts is 8,000 feet or less. Also, the stationary plant may be more economical for many projects, being that there is less equipment to transport than in the case of the mobile machine, and it requires fewer gersonnel to operate.

Accordingly, FIG. 4 shows an overhead view of continuous grout generating. and pumping assembly 300 mounted on a stationary frame 302. The primary power source for this assembly is a diesel engine 304 which operates a hydraulic pump 306.

Hydraulic fluid storage tank 312 provides a supply of fluid for pump 306, and diesel fuel is supplied from fuel tank 314. The hydraulic pressure from . pump 306 drives several motors of the asseaably.

Chief amongst these is drive motor 30S for Moyno :y pump 310. This is substantially similar to the (.

Moy~io pump described above, although possibly having a somewhat larger capacity; for example, a~
Bobbins & Meyers 2000 Series Moyno pump has been found eminently suitable for this application, this having a rated capacity of 100 gal. @100 rpm.
As previously described, the cement slurry is fed into the intake end 316 of the Moyno pump through a slurry supply conduit 318. In the embodiment which is illustrated, the supply conduit is connected to a slurry tank 320 which is filled by periodic deliveries from slurry trucks, the discharge chute 322 of one of these being seen in FIG. 4. As is also shown, slurry tank 320 may be provided with rotating paddle assemblies 324 whack insure homogenization of the slurry and prevent it from setting up, much in the same manner as the corresponding paddle assemblies in the slurry hopper described above. However, it i will be understood that any suitable means for providing a steady supply of slurry to assembly 300 may be substituted for the slurry tank 320 which is shown in FIG. 4, including, or example, a conventional mixing plant of the type described above.
'the finished foam, in turn. is provided by ~5 foam generator assembly 326, the output of which is injected through foam eonduit 328 into an intake portion 330 of Moyno pump 310 which is .
' downstream of the slurry intake, but still on the intake side of the pump. In the same manner as .
was described above, the foam and slurry are mixed it within the body of the Moyno pump to produce the foamed cement grout, and then this passes through a the discharge end 332 of the pump into injection s >i .~

a'! line 334.

Assembly 300 is also provided with an ):

auxiliary flushing or "blowdown" system for flushing the grout out of the injection lines in :a , .1 the event of failure of the main puanping system, or for simply cleaning out the lines upon completion of the work. This comprises a reciprocat~.ng pump 336 (which may be, for example, a "frac" pump commonly available from oil field service companies) which is driven by a hydraulic motor 338 through coupling 340. Power is supplied to this by an electric motor 342.driving a .

dedicated hydraulic pump 344; motor 342 receives its power from power cables (not shown), and this conseguentiy provides a power source independent 'j of the main hydraulic system of assembly 300, so that pump 336 will continue to be operable in event of failure of the main system.

Pump 336 is used to selectively flush the grout out through the downstream end of injection y line 334; so as to prevent this from setting up in the line and ruining it. To do this, motor 342 is energized o provide hydraulic power to motor 338 , (alternatively, power may be supplied from engine 304 and pump 306), and water is supplied to the intake knot shown) of pump 336. The discharge '' ~ ports of the pump are connected via a manifold 346 and jumper hose 348 to a diverter valve 350 ~

tY

:, 30 mounted in line 334. During normal operation. of ,._.

r_'..S
the machine, va've 350 is aligned to direct the discharge from the Moyno pump through injection ~, .

f JA
t~r~A
line 334; then, when flushing pump 336 is being r operated, valve 350 is realigned to direct the !~
flow from jumper hose 348 into injection line 334 so that water flows through this and displaces the grout.
FIG. 5 shows assembly 300 employed in an exemplary application, namely the grouting of a tunnel liner similar to that described above.
Accordingly, FIG'. 5 shows the injection line 334 extending through an access shaft 352 and into tunnel bore 354. Within the bore, the injection line is laid out in a series of segments 334a,b,c, etc., of a given length te~g~, 250 feet), these -being joined by couplings 355a,b,c. To inject the Z5 grout sequentially along the tunnel, a first coupling 355 is broken, and a ball valve 356 and manifold 357 are mounted on the end of the injection line 334. Depending on the number of injection ports to be serviced, manifold 357 may be a single hose or a simple Y-fitting, as shown in FTG. 5, or this may be provided by one or more lateral connections connected in a series and having a Y-fitting at their end. The manifold supplies grout to a plurality of injection hoses 358, The ends of the injection hoses, in turn, extend through injection ports 36~ formed in tunnel Liner 362 so as to inject the grout into an .
' annular space 364 between this and the wall 366 of . the excavation. The grout 368 flows T
longitudinally through the annular cavity, and when grouting of a given segment of the tunnel has been completed, the ball valve 356 is closed to f~ ~.:
~'~ 94/~?4331 ~ ~ ~ ? ~ ~. ~ PCT/US93/07593 discontinue injection of the grout. Pumping is then temporarily halted while the broken '~ fitting 355 is reconnected, and then the ball valve, manifold, and injection hoses are moved down the tunnel to the next coupling; this is then broken in the same manner as the preceding coupling, and the valve and manifold are connected a~ to the injection line 334 at this point so that pumping of the grout can begin again. In this manner, the entire length of the liner can be .' grouted by moving the manifold and hoses sequentially througk~ the length of the tunnel, '1 from one connection 355 to the.next. However, it _ will be understood that it may be preferable in ,a some applications to pre-install the ball valves, mahifold; and hoses at the junctions along line 334, as on '~-fittings; this would permit the liner to be grouted by simply opening the valves sequentially along the length of the tunnel;

~0 although this would also necessitate the cleaning of additional equipment upon completion of the job.

Accordingly, it will be understood that the stationary assembly 300 may be employed for a continuous grouting of a tunnel liner in place of the mobile assembly described above, although it may be-desirable to lower the entire assembly 300 ' on frame 3~2 down the shaft and into the tunnel so i that this will located at a site which is relatively closer to the injection points than is shown in FIG. 5. ' i a : ..

I
r.;:.
f ;,,:~'.
WO 94/04331 PCT/US93/07593 : w- .

b. Systems Description Having provided an overview of the stationary grout generating and pumping assembly 300, the systems which make this up will now be described in greater detail. FzG. 6 shows a diagrammatical view, somewhat simplified, of the hydraulic and other systems of the assembly, and how these are related. As was noted above, the primary power source for the assembly is the diesel engine 304, and this receives fuel from tank 314 through fuel line 370, via cutoff valve 372 and fuel/water separator 374. The output of the hydraulic~pump 306 which is driven by the engine is d:lrected via pressure supply lines 372a-c to a control station indicated schematically at 380 (see also FIG. 4). -A first control valve 382 selectively directs the hydraulic pressure through supply lines 384a-c to drive motor 308; and these, in conjunction with a directional valve 386, control the speed and direction of rotation of the Moyno pump 310.
A third control valve 390 selectively supplies hydraulic pressure through Iine 392 to the foam generator assembly 326. The construction of foam generator assem~aly 326 will be outlined here to provide the reader with fuller understanding of how the systems of assembly 300 operate; however, it will be understood that a conventional foam generator unit may be employed _ s-in this system, such as the Mearl Autofoam~ unit described above. .

~~.~~f 1~
Vf~ 94i~331 P~.'TlUS93/07~93 i ., _27._ The pressure supplied through line 392 r operates a hydraulic motor 394 which drives a pump ~.
396, and this mixes the foam concentrate and water and discharges this under pressure. Foam concentrate is supplied to this from a concentrate tank 398; the foam concentrate is supplied to the tank through line 400, this flow being controlled ' by a float valve 402 so as to maintain the desired , level of liquid in the tank. Similarly, the assembly includes a water tank 404, to which water is supplied via line 406 and float valve 408.
Mixing pump 396 draws water and foam from tanks 404 and 398 through gravity feed lines 412 and 414, with the flow being controlled by metering valves 416 and 418, respectively. The water and foam concentrate are mixed in the proper ratio te~g~. 96:4? by Pump 396, and are discharged from this through line 420. This passes through a backflow-preventer check valve 424, and into the first side of a blending subcircuit 426.
pressurized air from a compressor or. supply hose enters the other side of the subcircuit through air supply line 428. The air pressure passes through a water trap 432 to an operating valve 434; when this opened, this distributes air pressure through line 436 to check valve 424 and air-actuated cutoff valves 438, 440 so as to open i ' these simultaneously. This initiates the simultaneous flow of air and waterlfoam concentrate into the blending subcircuit; the two fluid streams pass upwardly through flow control gate valves 442, 444 to junction 446, where they ~:-:, f ;-y;
,...
&~~ 94/04333 PCT/U~93/07593 .: :-.. j .v;
1.. .
V
W ~. ~~ FJ ~ nJ
.28.
merge and mix. The flow then passes hack ~ '.
i downwardly through the main control valve 448, and thence through foam nozzle assembly 450 to produce the finished foam. As was described above, the finished foam is then delivered into Moyno pump 310 through foam conduit 328.

A second branch from air supply line 428 passes through cutoff and speed control valves 452 and 454 to dgive air~op.erated concentrate pump 456; this draws fluid through line 457 and discharges it through line 400 into concentrate ' tank 398. A gauge panel 458 monitors the air i pressure and other operating pressures within the generator assembly.

The final subsystem of assembly 300 is the ' flushing or "blowdown' pump. A control valve 459 is provided in control station 380 far this, and ,t this selectively directs a supply of hydraulic pressure from the main hydraulic pump 306 through line 460 to operate reciprocating pump 336. This pressurizes water which is supplied thereto through wader line 452, and diseharges this to the injection line through jumper 348. As was also noted above, this subsystem is intended to be able 25~ to operate independently of the remainder of assembly 300, and so a separate electric motor 342 and hydraulic pump 344 are also provided for this.

These draw hydraulic fluid from hydraulic v . reservoir 3I2 through an intake line 464, in much -the same manner that the main hydraulic pump does 'Y

Y:

so through its own intake line 466. A control ~
' i 4 valve 470 controls the flow from pump 344 through r' ~.:
~~.4a~~
,.
~V~ 94/04331 PCF/US93/07593 line 472 to motor 338, and thence the low pressure fluid returns to reservoir 312 through return line 474. The return flow passes through a filter 476 to remove impurities, and the return 1 , lines 478 and 480 from drive motors 308 and 394 similarly return to the hydraulic tank through this filter.

From the foregoing description, it will be apparent that an apparatus for effectively generating and injecting foamed cement grout on a a continuous basis has been disclosed herein. As f was noted above, this system has a great many potential applications, in addition to grouting .

tunnel liners. FTGS. 7~. and 7B demonstrate two of 18 these possible uses, and also illustrate how the rapid output rate of. the machine of the present invention serves to avoid the problem of pumping on top of. grout which has taleen an initial set.

Far example, F'IG. 7A shows the apparatus 300 being employed to entirely fill an abandoned pipeline 484 with grout. First and second dams or bulkheads 46, 48 are installed at longitudinally spaced apart locations within the tunnel; the end of the injection line 334 is inserted through one of these, and a vent 490 is formed in the other. ;

The machine 300 is energized and grout is pumped through-the injection port. Rs this is done, the i ~ grout builds up behind the bulkhead and forms a . front 492 which advances through the tunnel bore toward the other bulkhead, in the direction .

7 r.
..

indicated by the arrow in FIG. 7P; the air which is displaced by this front escapes through f r i ...._.. . . . ~,~ .... ; .: :..,; . ~-:., .,. ...., ...~... ~.. :.. ..,.

~r ; "

;;.
,,.
':.~ 4,.!~I l r... . ; -.
i'4~~ 94/9?4331 PC TlUS93107593 ; ~ .

vent 490. Because the machine 300 is able to ~- j produce the foamed cement grout on a continuous . ~ ,,.

basis and also injects this at a high rate, the front 492 is able to advance a relatively great distance down the tunnel bore before the initially injected grout begins to take an initial set, thus avoiding pumping fresh grout on top of this and causing collapse of the void structure.

Accordingly, the bulkheads 486, 488 may be spaced a relatively great distance apart, and the abandoned tunnel can be filled in relatively long segments, resulting in significant economic advantages.

Similarly, FZG. 7B shows machine 300 being used to fill a cavern 494 with grout. The cavern is penetrated by an injection pipe 496 and a vent pipe 498; the injection line 334 is led down the first pipe so as to inject grout into the cavity, and the displaced air escapes therefrom through the second. The tremendous volumes of grout which are required to fill such a cavity render the machine of the present invention highly advantageous simply .from the standpoint of it being able to produce large amounts of grout on a continuous basis, but again, the high injection rates make it impossible to fill the cavity without-pumping material on top of grout which has taken an initial set and causing this to collapse:

. as the grout is pumped into the cavern, the upper surface 499 of this mores upwardly to fill a relatively great portion of the cavity before the initially injected grout in the lower portions ., !'r~ 94/04331 PCT/US93/07~93 1:

'' take an initial set. In the event that the cavern ;i 43 is so large that it cannot be completely filled .

, fi before the bottom-most grout begins to set, injection can be terminated for a period of time (e.g., overnight) until the first layer has j completely set up, and then injection can commence t again; even though this represents a step-wise approach to filling the cavity, the fact that the 'r system of the present invention can fill a much 1P~ greater portion of the cavity before having to shut down for the grout to harden then would be ~i possihle using a batch-type process means that the ~, cavern can be filled in far fewer stages. .

Many possible embodiments may be made of the present invention without departing from the scope thereof; for example, the grouting apparatus and s method of the present invention may be applied to the construction industry, such as for the ,:

fabridation of cement roof deck structures. It is therefore to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. It will be understood that certain features and subcomb,~.nations are of utility and may be employed without reference to 'I other features and subcombinations. This is contemplated by and is within the scope of the ;i appended claims.

i :

, '.

y .

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for the high capacity continuous generation and placement of a foamed cement grout, said apparatus comprising:
means for providing a supply of cement slurry on a continuous basis;
means for generating a supply of finished foam on a continuous basis;
a positive displacement screw-type, progressive-cavity pump having (a) an intake side, (b) a discharge side, and (c) a body portion which is configured to mix said slurry and said foam therein as said foam and said slurry flow from said intake side to said discharge side of said pump;
means for feeding said cement slurry and said finished foam substantially separately to said intake side of said pump on a continuous basis, so that said slurry and said foam are mixed within said body portion of said pump so as to form said foamed cement grout on a continuous basis; and conduit means for conveying said foamed cement grout from said discharge side of said pump to a selected injection site on a continuous basis.
2. The apparatus of claim 1, further comprising:
means for selectively adjusting a ratio at which said finished foam is mixed with said cement slurry on a continuous basis so as to compensate for observed variations in the quality of said grout.
3. The apparatus of claim 2, wherein said means for selectively adjusting said ratio at Which said finished foam is mixed with said slurry comprises:
control means for selectively adjusting a rate at which said finished foam is outputted from said generating means to said pump.
4. The apparatus of claim 3, wherein said means for feeding said cement slurry and said finished foam separately to said intake side of said pump comprises:
a first supply line for feeding said slurry to said intake side of said pump at a first point thereon; and a second supply line for feeding said foam to said intake side of said pump at a second point thereon;
said first and second points on said intake side of said pump being spaced apart along a generally linear direction of flow therethrough.
5. The apparatus of claim 4, wherein said second point at which said finished foam a.s fed to said intake side of said pump is positioned downstream from said first point a sufficient distance to present said foam from bubbling up through said supply line which feeds said cement slurry to said pump.
6. The apparatus of claim 4, further comprising frame means to which said foam generating means and pump are mounted.
7. The apparatus of claim 6, wherein said frame means is configured for placement in a stationary location from which said grout is pumped to said injection site.
8. The apparatus of claim 6, wherein said frame means is configured for rolling movement from a first location to a second location so as to permit said foam generating means and pump to be positioned adjacent said injection site.
9. The apparatus of claim 6, further comprising:
motor means for operating said pump; and power generating means mounted to said frame for selectively supplying power to operate said motor means.
10. The apparatus of claim 7, further comprising means for selectively flushing said grout out of said conduit means so as to prevent said grout from setting up therein.
11. The apparatus of claim 2, wherein said means for flushing said grout out of said conduit means comprises:
pump means mounted to said frame means for selectively generating a stream of water; and a conduit for directing said stream of water into said conduit means so that said stream of water flushes said grout out through a discharge end of said conduit means.
12. A method for the high capacity continuous generation and placement of a foamed cement grout, said method comprising the steps of:
providing a supply of cement slurry on a continuous basis;
generating a supply of finished foam on a continuous basis;
feeding said cement slurry and said finished foam substantially separately and on a continuous basis to an intake side of a positive displacement screw-type, progressive-cavity pump having (a) said intake side, (b) a discharge side, and (c) a body portion which is configured to mix said slurry and said foam therein as said foam and said slurry flow from said intake side to said discharge side thereof, so that said slurry and said foam are mixed within said body portion of said pump so as to form said foamed cement grout on a continuous basis; and conveying said foamed cement grout through conduit means from said discharge side of said pump to a selected injection site on a continuous basis.
13. The method of claim 12, further comprising the step of:
selectively adjusting a ratio at which said finished foam is mixed with said cement slurry on a continuous basis so as to compensate for observed variations in the quality of said grout.
14. The method of claim 13, wherein the step of selectively adjusting said ratio at which said finished foam is mixed with said slurry comprises:

selectively adjusting a rate at which said finished foam is outputted and mixed with said cement slurry.
15. The method of claim 12, further comprising the step of:
injecting said grout at said injection site at a sufficiently high rate that said injection site is filled continuously while avoiding injection of fresh grout under pressure adjacent previously-injected grout which has taken an initial set, so as to avoid collapse of void spaces in said previously-injected grout due to injection pressure of said fresh grout.
16. The method of claim 12, wherein the step of feeding said cement slurry and said finished foam separately to said intake side of said pump comprises:
feeding said slurry through a first supply line to a first point on said intake side of said pump; and feeding said foam through a second supply line to a second point on said intake side of said pump;
said first and second points on said intake side of said pump being spaced apart along a generally linear direction of flow therethrough, and said second point at which said finished foam is fed to said intake side of said pump being positioned downstream from said first point a sufficient distance to prevent said foam from bubbling up through said supply line which feeds said cement slurry to said pump.
CA002142812A 1992-08-24 1993-08-13 Method and apparatus for continuous mixing and injection of foamed cement grout Expired - Fee Related CA2142812C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US93442192A 1992-08-24 1992-08-24
US07/934,421 1992-08-24
PCT/US1993/007593 WO1994004331A1 (en) 1992-08-24 1993-08-13 Method and apparatus for continuous mixing and injection of foamed cement grout

Publications (2)

Publication Number Publication Date
CA2142812A1 CA2142812A1 (en) 1994-03-03
CA2142812C true CA2142812C (en) 2005-10-04

Family

ID=25479629

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002142812A Expired - Fee Related CA2142812C (en) 1992-08-24 1993-08-13 Method and apparatus for continuous mixing and injection of foamed cement grout

Country Status (1)

Country Link
CA (1) CA2142812C (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111236981A (en) * 2020-03-30 2020-06-05 河南力行科创矿山技术开发有限公司 Underground coal mine movable integrated automatic grouting system and using method

Also Published As

Publication number Publication date
CA2142812A1 (en) 1994-03-03

Similar Documents

Publication Publication Date Title
US5419632A (en) Method and apparatus for continuous mixing and injection of foamed cement grout
US5141363A (en) Mobile train for backfilling tunnel liners with cement grout
US5795060A (en) Method and apparatus for continuous production of colloidally-mixed cement slurries and foamed cement grouts
US7766537B2 (en) Lightweight foamed concrete mixer
US5803665A (en) Method and apparatus for continuous production of quick-setting foamed cement grout with selectively adjustable proportions
US6415824B2 (en) Method and composition for grouting water-flooded conduits
AU2022202759A1 (en) Mixing and pump apparatus, system and associated method
CN203321540U (en) Multifunctional mining long-distance wet spraying machine with automatic proportioning
CA2142812C (en) Method and apparatus for continuous mixing and injection of foamed cement grout
CN211306899U (en) Equipment for preparing foamed light soil for railway roadbed
KR101982814B1 (en) Shotcrete construction machinery equipped with digital indicator of fiber input and shotcrete construction quantities, and fiber Dispersion device
WO1994004331A1 (en) Method and apparatus for continuous mixing and injection of foamed cement grout
AU597629B2 (en) Apparatus for securing rock bolts
JPH10131699A (en) Cavity filling method
KR102391426B1 (en) Facilities for depositing lightweight aerated concrete and foam regeneration-mixing-transmission device
AU2016100927A4 (en) A system for providing a continuous stream of foamed cement product and a mixing and pump apparatus, system and an associated method for providing a stream of foamed cement material
KR101872454B1 (en) Automatic powder suppling plant unificated a body with weighing, mixing and conveying processes to supply powder type materials for soft ground improvement to a stirring axis of mixing treatment equipment in 1.5 shot mode
JPH07180355A (en) Pressure conveying device and method for hydraulic fluid and spraying method using the same
CN206706768U (en) City integrated piping lane 3D printer
AU2023214263A1 (en) A system for providing a continuous stream of foamed cement product and a Mixing and Pump Apparatus, System and an Associated Method for Providing a Stream of Foamed Cement Material
RU62157U1 (en) COMPLEX OF EQUIPMENT FOR CEMENTING WELLS
JPS59154297A (en) Impregnation method of air mortar in long-distance pressure forwarding
KR100746376B1 (en) powder material conveying apparatus for shotcrete
CN214883077U (en) Self-propelled box culvert repairing device
CN216194663U (en) Grouting device suitable for double-liquid grouting

Legal Events

Date Code Title Description
EEER Examination request
MKLA Lapsed