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Патент USA US2277286

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March 24, 1942.
Filed Nov‘. §, 19156
. .hi.§
Patented Mar. 24, 1942
‘ 2,277,286 ,
iPaul-Bechtner, Chicago, Ill.', assignor to Ameri
can Colloid 00., Chicago, 111., a corporation of
South Dakota
Application November 5, 1936, Serial No. 109,245
’ 13 Claims.
(Cl. 61--30)
I have discovered that water seepage may be
This invention relates to improved methods
prevented and that structures of various types
and means for impeding the flow of water and
may be safeguarded against-leakage by blocking
for reinforcing structures to prevent the seep
the path of. ?ow of .the water with bentonitic or
age of watervtherethrough. The seepage and
?ow of water through earthworks, dams, ma 5 highly colloidal clay which possesses the‘ ca
sonry constructions, water barriers and the like "
causes untold economical loss, much of which
can be prevented by the. invention-herein de
Seepage through water barriers, such as dams, 10
co?erdams, and water-retaining walls may bev
caused by any} of several conditions. The bed
pacity to swell and gelatinize upon ‘contact with
water. The type of clay best suited for the pres
ent' purposes is the true bentonite obtained in
regions of Wyoming and South Dakota, although
other highly colloidal, or bentonitic clays which
possess the property of swelling and gelatinizing
in water to a substantial degree are also use-M
ful. The degree of their e?ectlVeness depends
upon the closeness with which this swelling propplaced on porous bodies of materials such as sand _ 15. erty corresponds to that of true bentonite.
True bentonite is a material consisting prin
or gravel. Barriers formed of concrete or of
rock may not be impervious to flow. The cir
cumstances may require that‘ the barrier be '
cipally of the mineral “Montmorillonite” and oc
any of the usual materials are likely to crack
curring naturally in combination with about 25
or develop minute openings which allow seep
to 45% water. For commercial use this mate
age, or they may be formed of aggregate, sheet,
planks or the like, which are inherently sus 20 rial isgdug, dried to contain about 9% moisture,
and then granulated or powdered. Some physi- '
ceptible to leakage through scams or crevices in
cal characteristics which distinguish bentonite
the structure.
from other clays are its permeable texture and
In the sealing of mines against the ?ow of
its extremely small grain size. From 65 to 70%
underground water‘ it is common practice to
provide a wall of concrete across the mine shaft, 25 of the grains of a Wyoming bentonite are finer
than .2 micron; over 85% are ?ner than 2 mi
yet such an expedient often fails to accomplish
crons. ~These grains or particles, when wetted,
its purpose because of theleakage allowed by
adsorb ?lms of water that are thicker than the
shrinkage of the setting concrete away from the,
films which form on other clay-like materials,
walls against which it is cast. Such leakage, once
started, sometimes results in destruction of the 30 and after 'the bentonite has been wetted the
wall and complete release of the backed-up water. " water cannot be expelled, even at high pressures.
The strong adsorptive power of commercial ben- Similar problems are encountered in efforts
tonite, which will adsorb almost ?ve times its to exclude water from core trenches, excavations
weight of water, is therefore partially attributa
and "foundation walls of buildings and to con?ne
water to prescribed ditches or channels, In fact, 35 ble to the preponderance of extremely small
grains or particles, providing tremendous sur
these are but a few of the many circumstances
‘face area for the exertion, of adsorptive powers,
‘ under which it is highly desirable yet di?icult
effectively to prevent the ?ow or seepage of wa
and the ?lm retaining capacity of these parti
\An object of ‘my invention is to Provide im- , w
proved methods and means for inhibiting the‘
seepage of water through pervious structures and
for safeguarding against seepage or ?ow through
structures that are normally impervious but ,ca
pable of developing leaks.
Commercial bentonite swells, when contacted
with water, as much as 10 to 20 times its dry
One factor which causes this swelling
is the separation of the small particles by the
water ?lms adsorbed thereon. Another is the
distinctive nature of the particles themselves,
which are composed of minute plate-like struc—
tures that possess the peculiar property of al
lowing water molecules to penetrate their crys
‘ water seepage or ?ow.
tal lattice. The crystal structure itself is thus
Another object of my invention is to provide
,- such methods and means which are-permanent 50 expanded. A third factor is the mutual repul
sion of the particles, due to like negative po
' ly effective regardless of shrinkage, cracks, or
Another object is to provide improved barriers
which are constructed better to insure against
shocks ‘and distortions caused by subsidence,
_ earth movements and the like.
Another'object is to provide special methods
and means by which it is possible to correct ex
isting conditions of seepage or flow without re
' quiring freedom from contact with ‘the water.
Stillcfurther objects and advantages of the
invention will be apparent from the following
In its swollen condition bentonite ‘has several
advantageous properties; it will carry materials
55‘ in suspension; it exerts a cohesive effect; when
left quiescent it forms a permanent gel the vis
cosity of which increases upon aging. An im
‘portant aspect of the swelling of bentonite which
I have discovered is that it will swellv only to the
60 extent necessary to ?ll available space, without
exerting substantial pressure when con?ned
against further swelling.
Another important
quality is that repeated drying and contraction
of swollen bentonite in no way impairs its ca
pacity to swell again upon renewed contact with
water. These properties make it an ideal ma
the ditch through pervious earth adjacent there
Fig. 9 is a cross section of a structural unit of
bentonitic clay, constituting a special feature of
the invention.
Fig. 10 shows another embodiment of a struc- .
terial for incorporation in a dry or slightly moist
tural unit.
state into dams and other water barriers, at
In Figures 1 to 4, inclusive, I illustrate im
points where leakage possibilities occur, so that
proved dam constructions utilizing the principles
in case cracks or other leakage develop the 10 of my invention. Within the dam structure at
bentonite will come into contact with the leak
points likely to be affected by seepage, cracks or
ing water and swell to stop the leak but will
the like, I provide inserts of bentonite so that
not create‘ pressure which might cause further
water seeping through the structure will contact
the bentonite.
I have discovered that a blanket or wall of
For example, in the construction of Figure 1,
bentonite which possesses the capacity to swell
the dam I0 faces against abutment walls I2 and
upon contact with water will permanently resist
I3, and at the meeting surfaces of these mem
seepage or ?ow of water therethrough. When
bers wells l4 and I5, extending for the height
the bentonite is contacted with water it swells
of the dam into the concrete or other material
to ?ll available voids or spaces. Thereafter it is 20 of which the dam is formed, are provided. The
impervious, and it remains impervious to water
wells are filled with a dry bentonitic clay hav
as long as water is present. If water is not con-'
ing the capacity to swell and gelatinize upon
tinuously present the bentonite may contract
contact with water. Figure 2 may be considered
as it dries, but its resistance to seepage is im
as a section taken vertically along the axis of
mediately restored upon renewed contact with 25 the dam and through the well IS. The abutment
I have found also that bentonite confined with
in masonry structures or the like, when wet, ‘
I3 is illustrated as comprising a concrete portion
positioned on rock at I8. Well I5 extends, for the
height of the dam, across the joint I 6 between
the main wall I 0 and the abutment, and it is
does not exert swelling pressures su?icient to
harm the structures in any way, yet it forms an 30 filled with bentonite as indicated at ll.
impervious seal with the con?ning surfaces.
Figure 3 represents an arch-like dam having a
Furthermore, the bentonite, either in dry or wet
central wall 20, wings 2| and 22,. and, at the
swollen condition, may be subjected to shocks,
joints between the wall 20 and the wings, wells
earth movements or subsidence without destroy
which con?ne masses 23 and 24 of bentonitic
ing its sealing power. The swelling capacity of 35 clay. In Figure 4, a dam 25 positioned on bed
the material is completely exhausted only when
rock 26 is provided with an insert of bentonitic
it is suspended freely in many times its volume
clay at 21, bridging the seam between the dam
of water. Accordingly, by utilizing a blanket or
and the rock.
vwall of bentonite to block the ?ow or seepage
Dams constructed with inserts of bentonite at
of water I am able to effect permanent imped-_ 40 points susceptible to leakage are surprisingly re
ence of such ?ow or seepage under many diffi
sistant to the passage of water. The shrinkage
cult conditions. Appropriate combinations pf
of setting concrete, earth movements, contrac
bentonite and strength giving structure produce
tion and expansion due to changing tempera
barriers that are resistant to water under great
tures, etc., are likely to result in water per
45 meable seams and crevices. The presence of a
Several preferred modes of practicing my in
mass of bentonite at such points, however, pro
vention are illustrated diagrammatically in the
vides permanent protection against seepage.
drawing, wherein
When the confined bentonite is contacted with
Fig. 1 is a diagrammatical plan view of an
water which has traversed the structure to the
embodiment of‘ my invention in which inserts of 50 location of the bentonite it immediately adsorbs.
bentonite are employed to reinforce a dam
water, swells enormously, and forms a gelatinous
against water seepage.
mass which itself is impervious to water and pro
Fig. 2 is a diagrammatical vertical section
vides an impervious seal with the con?ning walls
through a portion of a dam at a joint between
of the structure.
the main wall of the dam and the-abutment.
Although the insert 21 of bentonite in Figure 4
Fig. 3 shows an application of my invention
is illustrated as surrounded by dam structure
similar to Fig. 1 in which the bentonite is placed
and bedrock, other arrangements may be fol
in wells adjacent the connection of the main
lowed without sacri?cing results. Substantial
portion of a dam with the wings thereof.
ly dry bentonite is notable for its extreme density
Fig. 4 represents a vertical cross section of 60 and compressive strength when packed into a
another type of dam construction,.in which a
compact mass. Wherever the bentonite is sub
blanket of bentonite is interposed between the
ject to flowing water currents which would car
bedrock and the bottom of the dam.
ry away the gels as they formed this erosion
Fig. 5 illustrates the application of the inven
may be prevented bymaintaining a layer of sand
tion to the closing of a mine or conduit against 65 or other erosion resistant material between the
the ?ow of water therethrough.
bentonite and the ?owing water. The bentonite
Fig. 6 illustrates the use of a blanket of ben
then forms a tight-?lter-cake on the surface of
tonite to protect the foundation wall of a build
the sand.
ing against water seepage.
Figure 5 is a diagrammatical showing of a con
Fig. '7 is a partial view, in vertical section, of 70 struction which is effective to block the flow of
a floor provided with an underlying layer of
water through mines, or water conduits in gen
eral. A pair of spaced forms or bulkheads 32
Fig. 8 represents, in cross section, a trench or
and 34 extends across a mine shaft 30, and a
ditch bordered by a blanket of bentonite in such
mass of bentonite or similar colloidal clay is
manner as to prevent the seepage of water from 75 located ‘at 35 between these forms. The forms
may be of wood, masonry or any other suitable
material. 'The bentonite may be in ?nely digided
that remains impervious as long as ‘water is pres
ent and is not destroyed by subsidence, earth
form, or in the form of blocks or bricks, or it
‘may be combined with other material, for ex
ample, sand or gravel.
In the use of this embodiment of the inven
movements or the like.
The drawing and the foregoing description re
lating thereto are illustrative of only a few of
the many improved constructions resulting from
tion distinct, advantages are obtained as com
the use of the invention and of only a few modes
pared with concrete walls and other types of
barriers heretofore employed for the same pur
of applying the same. To the skilled engineer
it will be obvious that the invention may be
poses. The leakage permitted by the shrinkage 10 utilized in many di?erent ?elds and in many
of concrete walls away from the walls of a mine
different ways.‘
While‘ strong gels‘ and high resistance to water
penetration are obtained by the use of pure,
or conduit \during the setting of the concrete is
completely avoided. Whenever the form 32 al
lows backed-up water at 38 to contact the ben
tonite at 36, the bentonite ?rst contacted ad‘
bentonite or pure bentonitic clay, I have discov- ,
ered also that the resistance of the mass to high
water pressures may be increased by employing
. sorbs water, swells and forms a gel which is ,
permanently resistant to seepage. The same ef
feet is produced whether the water contacts the
‘ bentonite along, the walls of the mine or conduit .
or remote from the walls.
A characteristic feature of this and the other
embodiments of the invention is that the swelling/
of only a‘ small portion of the mass of bentonite, '
the portion ?rst contacted with water, is usually
effective to block seepage through'to other‘ por
mixtures of bentonite or bentonitic clay and
other granularv materials, for example, sand. For
example, when a mixture of equal parts of ben
tonite and beach sand is poured into a T-shaped
section of 3 inch pipe to a height of 20 inches in
the longer arm of the T and lightly tamped
therein, the mass is not moved by continuing
water pressures of 1000 lb. per square inch, and
the water penetrates the mass a‘ distance of only
tions of the mass. Thus these other portionsu'e
about 5 inches.
tain their full capacity to absorb and swell. and ’
An important advantage of the invention re
block further ?ow or seepage in the event that
sults from the variety of methods which may be_
the ?rst gel formation should be disturbed.
employed to form the seepage-resistant mass of
Another important advantage .is that the ex" 30 bentonite. In one embodiment ordinary com
pense and care incident to the. provision of bar
mercial powdered or granulated bentonite may be
riers such as concrete walls are avoided. The
used. Even when loosely put in place as by pour
forms 32 and 34 need not be impervious to water;
ing, such ?nely-divided material provides a per- »
it is su?icient that they give strength to the bar
manent barrier against seepage, since vthe swelling
rier and that form 34 include no openings permit- " ' power of dry bentonite is so great that voids in
' ting escape of the bentonite therethrough. The '
the mass are blocked upon contact with water.
blanket or wall‘ 35 of bentonite is formed with-7
The physical strength of such a mass may be
out difficulty, and it is effective as soon as formed,
increased by tamping or packing the bentonite in
in contrast to concrete which requires consider
able time to set. In addition, the bentonite may 40
Under somé circumstances of use it is imprac
‘be removed easily; whereas the destruction of a
tical to provide temporary or permanent support
barrier composed of masonry is a difficult task.
ing means for the bentonite before forming the
My invention is also applicable to impede the ' mass; 1. e., the bentonite must be placed ?rst.
seepage of water through foundation walls and
For example, in sealing a wall against leakage I
?oors of buildings, as illustrated in Figures 6 45 from the outside earth the most practicable pro
and 7. Between the foundation wall 40 of a ‘' cedure may be to form the mass of bentonite
building (Fig. 6) and the adjacent soil 42, a
adjacent the wall and then ?ll in the earth. Ac-v
blanket‘of bentonite is interposed as indicated‘
cording to another embodiment of my invention
at 44. As in the other embodiments described
this may be accomplished by incorporating the H
above, the bentonite swells when contacted with 5 bentonite with from one to one and a half times
water and forms an impervious barrier which
as much water to form a stiff putty-like mass
prevents the water from seeping to and through
which is su?iciently cohesive to adhere to rough I
or around the wall 40. An arrangement such as
or smooth surfaces. In this form it will continue
that shown in Fig. 7 is particularly suitable for
to adhere as long as it is moist; yet it retains
the ground ?oors of buildings placed in low, damp
about 70 to 80% of its potential absorbent and
ground. A blanket 41 of bentonite is placed on
swelling property, to ‘be exerted when water is
the base 46 for. the ?oor, and the ?oor 48, which
brought into contact.
may be of concrete or any other suitable‘mate
Still other embodiments of the invention pos
rial, is applied over the bentonite.
sessspecial advantages for use under certain
Figure 8 illustrates a mode of applying the 60. conditions. The stiff putty-like bentonite pre
invention to the prevention of seepage from a
pared, as above described is improved for use
ditch or the like formed in pervious soil. In the
construction of the ditch a blanket 52 of bentonite '
,where water‘ is present by fashioning ‘it roughly
into bricks or blocks each having a quantity of
dry ?nely-divided bentonite in its interior. Sim
ilar results may be obtained, as illustrated in
is placed adjacent the wall of, the earth 50, and
this blanket 52 is covered by“ erosion resistant
material as indicated at 54, forming the bottom
of the ditch. A preferred type of covering mate
rial for this and similar embodiments of the in
vention includes a layer of ?ne sand next to the
blanket of bentonite and a layer of gravel or the
like adjacent the sand. The blanket of bentonite
effectively prevents the seepage of the water at
56 from the ditch through the underlying soil.
Figure 9, by forminga bricklike body ‘Ill of hen
tonite which has been moistened only sufficiently
to produce slight coherence and then contacting
the outsides of thesbody with water, as by dipping
or spraying. The water does not,- penetrate far
into the body but causes the bentonite at the
surfaces thereof to swell and form a cohesive
sheath or enclosure as indicated at _'|2, which
As the bentonite is contacted woth water it swells
strengthens the unit so that it can be handled
to form an impervious gelatinous barrier, one 75 and placed in position. Another suitable pro
cedure (see Figure 10) is to use a fabric enclosure,
of such seepage or ?ow and ?lling into and con~
for example, a paper cartridge as indicated at 80,
?ning within said space a mass of substantially
?lled with dry bentonite 82. Still another, which
is useful under circumstances prohibiting the
dry, ?nely-divided swellable bentonite mixed
construction of a solid blanket of bentonite, as in
the prevention of seepage through water covered
porous rock or gravel structures, is to force a
’ with sand, said mass being of su?icient thickness
and bentonite concentration to form across said
path, upon contact by the water, a water-imper
vious barrier of swollen bentonite adjacent its
heavy pumpable suspension of bentonite into the
face merging into substantially unswollen ben
structure and thus build up a blanket of bentonite
in the path of seepage.
The' invention is not ‘limited to the speci?c
tonite ‘within the mass.
_ 8. A water barrier comprising rigid supporting
illustrative uses and methods of use described
water seepage or ?ow and a compact mass of
structures having space therein in the path of
hereinabove, although these possess their own
?nely-divided swellable bentonite con?ned across
individual advantages. When dry or swellable
said path in said space, said mass being of su?i
bentonite is applied to expansion joints, shrink 15 cient thickness and bentonite concentration to
age joints, or adjacent corners where cracks are
swell at its face and form across said path, when
likely to develop in concrete dams, or when used
contacted by water, a water-impervious barrier
of swollen bentonite merging into substantially
unswollen bentonite‘.
9. The method of blocking the flow of water
this is within the scope of my invention, and inas 20
in any water barrier where, upon coming in con
tact with water, it will swell and stop the leakage,
under pressure through a determinate path
much as I have discovered that bentonite can be
which comprises restraining the water from a
used in this manner without developing appreci
part of said path, forming across said path at
able pressures on swelling, innumerable further
said part a compact mass including substantially
uses for bentonite in sealing water barriers, based
on the principles I have disclosed, will occur to 25 dry swellable bentonite of sumcient thickness and
bentonite concentration to swell adjacent the
those skilled in this art.
I claim:
water face and form across said path a water-M
impervious barrier of swollen bentonite merging
l. A dam comprising a masonry wall positioned
on a supporting bed and abutting against end
into substantially unswollen bentonite, providing
abutments, said masonry having a compartment 30 supporting structure of su?icient strength to hold
said mass in place against the water pressure and
therein at a point susceptible to leakage, and a
con?ning said mass by said structure, and ?nally
compact mass of swellable bentonite con?ned
admitting the water into contact with said mass.
within said compartment.
10. A water barrier for preventing seepage or
2. A dam comprising a masonry wall positioned
on a supporting bed and abutting against end 85 ?ow from a body of water through a determinate V
path comprising rigid supporting structure hav
abutments, a compartment extending along the
joint between said wall and an abutment, and a
ing space therein across the water path and a
compact mass of swellable bentonite ?lling said
compact mixture of ?nely-divided swellable ben
tonite and granular material con?ned across said
3. A water dam comprising a concrete dam (0 path in said space, said mixture being of suffi
cient thicknessand bentonite concentration to
structure having pockets of swellable bentonite
swell at its face and form across said path, where
contacted by water, a water impervious barrier
4. A self-sustaining structural unit for the for?
of swollen bentonite marging into a reserve mass
mation of barriers impervious to water compris
ing ?nely divided, slightly moist swellable ben 45 of substantially unswollen bentonite.
11. The method of preventing ?ow or seepage
tonitic clay in the interior thereof and wet ben
of water through rigid structures susceptible to
tonitic clay constituting a cohesive enclosure
water penetration which comprises placing and
supporting adjacent a side of such structure and
5. The method of making structures resistant
to seepage or ?ow of water therethrough which 60 across the path of water penetration a compact
blanket including ?nely-divided, swellable ben
comprises positioning a mass including swellable
tonite and of sut?cient thickness and bentonite
bentonite across the path of such seepage or ?ow
concentration to swell at its face upon contact
and con?ning said mass between spaced rigid
by the water and form across said path a water
supporting structures, said mass being of suffi
cient thickness and bentonite concentration to 55 impervious barrier of swollen bentonite merging
into swellable bentonite, and providing means
swell and form adjacent the water face, when
adjacent the face of said blanket for holding the
contacted by the water, a supported, water-im
same in place.
pervious barrier of swollen gelatinous bentonite
12. A bulkhead or the like for preventing water
merging into swellable bentonite. ,
6. The method of preventing ?ow or seepage 60 ?ow through a determinate path ‘comprising sub
stantially rigid structures spaced apart and ex
from bodies of water which comprises forming
tending across the water path, said structures
and supporting and con?ning across the water
being susceptible to water penetration, and a
path a compact blanket of ?nely-divided, sub
compact mass of ?nely-divided bentonite, con
stantially dry swellable bentonite-of su?icient
thickness and bentonite concentration to swell 65 ?ned within the space between said structures.
13. A bulk head or the like for preventing
adjacent its face upon contact by the water and
water flow through a determinate path compris
form across said path a water-impervious barrier
‘ of swollen bentonite merging into a reserve mass
ing substantially rigid structures spaced apart
and extending across the water path, said struc
of substantially unswollen bentonite.
7. The method of making structures such as 70 tures being susceptible to water penetration, and
a water-impervious mixture of ?nely-divided
' dams, bulkheads, masonry walls and like water
barriers impervious to seepage or flow there
bentonite and sand con?ned within the space
through from bodies of water, which comprises
between said structures.
providing space in the structure across the path
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