Hazardous waste containment system

A hazardous waste containment system for preventing the lateral migration of hazardous fluid substances (including both liquid and gas wastes) into the water table, particularly for sites which are located over a fluid impermeable strata of clay (20) or the like. The system uses an encircling (FIG. 7) barrier containment wall comprising a plurality of slidingly engaged, interlocked, vertical barrier members (3) which extend down to and sealingly interface with the underlyng fluid impermeable strata. The barrier members are slidingly engaged via interlocking male and female appendages (1 and 4), which mate and form a vertically extended chamber (33), which a fluid impermeable seal (7) is formed. A method for implementing the invention where caving is a problem includes the augured excavation of a series of adjacent, overlapping, vertical holes (18, 18a) of prescribed depth and width and/or diameter in the soil surrounding the area to be contained and extending down to the underlying strata, installing the vertical barrier wall in the holes, and sealing the joints formed by each connection and back-filling the holes. Two and three slotted guide boxes ( 15; FIG. 1; FIGS. 8c and 8d) are used to position and join adjacent sets of barrier members and prevent caving in of the surrounding soil. The method further includes the utilization of a sealant (25) at the base of the containment wall to prevent leaching under it (FIG. 2). The systems may be used to contain a variety of materials and may be implemented in various soil conditions with similarly successful results.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
The present invention relates principally to hazardous waste containment 
systems and more particularly to a method for preventing the migration and 
leaching of hazardous fluid substances into the water table, and apparatus 
used in conjunction therewith. 
The present invention teaches an apparatus for providing a containment wall 
comprising a plurality of slidingly engaged, interlocked vertical barrier 
members. The barrier members are engaged via interlocking connectors, 
which include therein a means for forming a fluid impermeable seal. 
The preferred method for implementing the invention includes the 
preparation of vertical openings of prescribed depth, width, and/or 
diameter in the soil surrounding the area to be contained, installation of 
the vertical barrier or containment wall, and engaging sealant means, 
filling cores of the barrier members, and backfilling. 
The present invention may be used to restrain the lateral migration of a 
variety of materials, both liquid and gas, and may be implemented in 
various soil conditions with similarly successful results. 
The system of the present invention provides an efficient and cost 
effective containment system, as will be shown infra. 
An alternative embodiment of the method of the present invention includes 
the engagement of the barrier members and welding of the interlocked 
connection at the joint formed by the mating interlocking parts to 
facilitate greater structural integrity and a greater sealing capability. 
Another alternative method of installing the present system includes the 
utilization of a guide box template/anti-caving system for properly 
aligning the barrier members and provides a means of installation where 
soil conditions are such that there is a likelihood for cave in. 
2. Prior Art & General Background 
As may be determined by a review of the below cited patents, the prior art 
has failed to contemplate a system as taught in the present invention. 
Further, the patents cited below are fully distinguishable in construction 
and use, and are cited only as being at best remotely pertinent to the 
claimed invention. 
A list of prior patents which may be of interest is presented below: 
______________________________________ 
U.S. Pat. No. Patentee(s) 
Issue Date 
______________________________________ 
2,101,285 Stevens 12/07/1937 
2,937,065 L. Harza 05/17/1960 
2,961,731 Buzzell et al. 
11/29/1960 
3,202,412 Hunsucker 02/07/1967 
3,411,305 A. Cella 11/19/1968 
3,848,855 Wiland 11/19/1974 
3,886,705 Cornland 06/03/1975 
4,808,039 Fischer 02/28/1989 
______________________________________ 
A cursory review of the above cited patents shows that the prior art is 
indeed distinguishable from the present invention. Indeed most, if not 
all, of the cited patents are not part of the prior art of the invention 
but rather are from disparate, non-analogous arts. 
U.S. Pat. No. 2,101,285 teaches a "tubular interlocking piling" of steel 
having interlocking structures incorporated therewith. The specification 
teaches the system as being used in the construction or reinforcement of 
coffer dams, bridge piers and the like. It is noted that the apparatus 
does not contemplate the utilization of a containment structure although 
it does teach implementation as a support wall for above ground 
construction. Further, unlike the present invention, sealing means for 
preventing fluid migration is not taught. 
U.S. Pat. No. 3,302,412 to Hunsucker teaches "interlocking sheet piles and 
method of installation", including means to slidingly engage and seal the 
sheet piles. This system is likewise obviously distinguishable from the 
present invention, for a variety of reasons. The '412 patent is directed 
to sheet pilings for forming earthen walls or cofferdams, and is not 
directed to containment systems, as discussed in the present invention. 
Further, implementation of the system is impractical, very costly and 
would be highly unsuitable for use in the types of soil conditions 
anticipated by the system of the present invention. 
For example, the scraper 24 (FIG. 3) is inadequate to remove debris from 
the cavity 16 while the sheet pile is being driven into the soil. The 
"scraped" debris would not have anywhere to go, as the tolerance of the 
shoe and cavity connection is too little to be expected therethrough and 
the debris could not be pushed through the bottom of the cavity as it is 
already firmly embedded in packed soil. 
While the tolerance of the engagement system is too small to allow scraping 
of debris therethrough, it is of sufficient tolerance that it allows 
liberal leakage of a fluid sealant, to the point that it would be 
impossible to accurately project a fluid impermeable seal on a 
consistently monitorable basis. 
The lugs 30 (FIG. 2) as taught in '412 render the system unworkable in 
terms of taking away the tolerance necessary for slidingly engaging the 
panels. The tolerance or gap between the shoe and cavity is needed to 
allow a smooth installation. Lastly, the construction is overly costly and 
highly impractical, with the necessity of multiple apertures to be 
fabricated therein, the alignment of apertures to both cavities, the 
removal and replacement of the feed tube at each driven pile, and the 
implementation of scrapers as taught in the specification in the field 
would be very difficult and time consuming. Thus, even if the system works 
as taught, it would be usable only with extreme cost and complexity of 
fabrication. 
U.S. Pat. No. 3,886,705 to Cornland teaches a "Hollow Structural Panel of 
Extruded Plastics Material and a Composite Panel Structure Formed 
Thereof". The patent teaches a hollow structural panel configured to form 
partition walls or the like and is designed for resisting deformation due 
to load bearing. While '705 does teach the utilization of a rubber gasket 
for preventing leakage of snow, rain, or the like, this apparatus is 
unsuitable for utilization in conjunction with the system of the present 
invention. Apparently, the system of '705 would require complete 
fabrication above ground prior to installation, which would make the 
system unsuitable for use with the preferred method of the present 
invention. 
U.S. Pat. No. 3,411,305 issued 1968 to Cella teaches a "Tubular 
Interlocking Piling for Wall Assemblies". A variation of sheet piling 
technology, this patent contemplates a system of interlocking piling 
components in the construction of "cofferdams, walls, dams, piers, 
abutments, and other types of walls where strong construction is 
necessary." 
The '305 disclosure teaches the "tubular pile unit" of a sufficiently 
strong material for forming a substantial load bearing wall; it is noted 
that the disclosure does not teach in any manner a fluid impermeable unit. 
Consequently, this apparatus is likewise unsuitable for the preferred 
system contemplated in the present invention. Further, it is noted that 
load bearing is not a factor in the present invention, for which factor 
the '305 patent is primarily designed. 
U.S. Pat. Nos. 2,937,065 and 2,961,731 teach fluid impermeable gasket 
systems fully distinguishable in use, method and apparatus from the 
present invention. 
Not found during the patent search, but known to applicant, is an 
apparently unpatented method for containing hazardous waste. This present 
method of preventing the leaching of contaminated fluids from hazardous 
waste sites comprises the implementation of a "slurry" wall around the 
site. A trench is dug to a sufficient depth to contact a fluid impermeable 
natural earth strata, such as clay. 
A problem with preparing such a trench, however, relates to the soils' 
cohesive strength and its propensity for "caving." This system therefore 
often has had to resort to expensive sheet pilings to retain and 
strengthen the trench walls. As the sheet pilings typically were 
insufficient to prevent seepage of the containment therethrough, a still 
more expensive medium, typically bentonite, a naturally occurring clay, 
was used to fill the trench. This slurry would solidify, forming a fluid 
impermeable subterranean "dam" for containment. 
The present invention is anticipated to cost substantially less than the 
most cost efficient slurry wall system as it will not require sheet 
pilings or any other means of preventing "caving" as such means is 
inherent in the present system. 
Other material costs of the present system are likewise significantly less, 
requiring as little as one-one-hundredth (1/100) of the amount of 
bentonite. It is noted that the bentonite costs fluctuate, but may run as 
high as $200.00 per ton including freight (freight on board) job site. 
Likewise, the present invention does not require the utilization of piling 
equipment, heavy lift equipment, or extensive labor, as is necessary for 
implementation of the above system. 
GENERAL, SUMMARY DISCUSSION OF THE INVENTION 
The present invention overcomes the problems of the prior art by providing 
a system which is reliable, relatively economical and less hazardous. 
As may be noted above, the prior art does not contemplate a relatively 
inexpensive yet consistently impermeable, readily implemented containment 
system for preventing the leaching of toxic materials from dump sites and 
the like. 
The only method vaguely pertinent to the present invention relates to an 
expensive process requiring heavy machinery and costly materials; namely, 
the method of providing slurry wall systems having sheet pile walls. 
The exemplary embodiment of the present system comprises the utilization of 
a plurality of barrier members, each barrier member having an extruded 
tubular body structure with appendages on the exterior wall at a hundred 
and eighty (180) degree separation from each other. The appendages are of 
a "male" and "female" type, respectively, and are configured to slidingly 
engage the barrier members longitudinally in vertical fashion. 
Further, the appendages are configured with each having a slot to form a 
vertical, self-aligning void or chamber when they are slidingly mated with 
the associated appendage of another member. This vertical chamber may then 
be filled with a sealant to prevent leaching of migrating substances out 
of the containment area into the surrounding areas and thence into the 
ground water. 
It is noted that the appendages are not limited to a hundred and eighty 
(180) degree separation and may be implemented in a variety of 
circumferentially located positions relative to the other. For example, a 
ninety (90) degree separation would be used for a "corner" barrier member, 
while a variety of other degree separations could be utilized to form a 
"kidney" configured containment area. Other degree separations may be 
utilized for forming still other geometric containment configurations. 
Thus, the containment system need not necessarily form a circle or 
rectangle, and may be configured to contain any desired layout. It is 
noted that the engagement appendages for all configuration barrier members 
are designed to mate with the appendage of other members of this 
invention. 
The present invention of providing a vertical wall as a containment barrier 
is possible as the wall is implemented to a depth to intersect the clay 
strata in the soil, a fluid impermeable strata found at varying depths. 
Thus, various sites require different depths of implementation utilizing 
differing member lengths. Normally it is not necessary to go deeper than 
forty (40') feet, and, thus, conventional excavation equipment tools may 
be used in the present system. It is noted that clay is not the only fluid 
impermeable strata, and the present system may be used in conjunction with 
other fluid impermeable strata as well with satisfactory results. 
Another step, when desirable, in the method of the present invention is the 
implementation of a sealing media to embed the base of the containment 
wall to prevent leaching thereunder. 
The exemplary embodiment of this step utilizes, when desirable, the 
naturally occurring clay bentonite as taught in the slurry wall concept 
for the base sealant, but in far less amounts. The base sealant need be 
implemented only in an amount sufficient to embed the intersection of the 
wall and the strata. This may be, for example, four (4") inches. It is 
noted that, in some situations, this step may not be necessary. 
The present system teaches an alternate or supplemental step for use where 
greater structural integrity of the barrier wall and/or higher sealing 
properties are desirable. This additional step comprises the welding of 
the engagement joint in the areas within the sealant chamber prior to 
injection of the sealant. The welding of the engagement area is performed 
utilizing a specially designed welding probe, which is lowered into the 
chamber after the barrier members have been slidingly engaged. Once the 
weld is complete, a sealant will be deposited or injected into the 
remaining void. 
For installation of the present invention in soil conditions having a 
likelihood of "caving", the present invention teaches the implementation 
of a "guide box" template system extending the full depth of the 
excavation. The "guide box" serves five apparent purposes, to wit: 1) it 
provides a support structure which will restrain any caving walls of the 
excavation from entering the area where the members are to be installed, 
lessening the likelihood of complications during engagement of the barrier 
members; 2) it provides a template for easy engagement and proper 
alignment of the barrier members during installation; 3) it provides 
protection for previously installed members against damage from the auger 
(when an augured hole is desirable); 4) it acts as a guide for the auger; 
and 5) it can allow for gradual and controlled backfilling by being slowly 
extracted. 
The present system contemplates excavation of the ground soil via trenching 
or auguring, but expressly teaches that other methods of excavation may be 
utilized with satisfactory results. 
It is therefore an object of the present invention to provide a system for 
containing hazardous wastes, which is efficient, utilitarian, and cost 
effective, and which provides reliable protection against the threat of 
migrating contamination of adjacent aquifers and soil. 
It is a further object of the present invention to provide a system for 
containing hazardous wastes, which utilizes a plurality of slidingly 
engaged interlocking containment members. 
It is a still further object of the present invention to provide a system 
for containing hazardous wastes that is adaptable to a variety of dump 
site configurations. 
It is another object of the present invention to provide a system for 
containing hazardous wastes which provides reliable containment for a 
period of time equal to or exceeding convenient methods. 
It is another object of the present invention to provide a system for 
containing hazardous wastes until such time as it can be removed or 
neutralized as desired. 
It is still another object of the present invention to provide a method of 
sealing slidingly engaged vertical barrier members, including the step of 
welding the engaged area via a specially designed welding probe lowered 
into the sealant chamber. 
It is a further object of the present invention to provide a method of 
installing a hazardous waste containment system utilizing a plurality of 
vertical barrier members wherein the method includes the utilization of a 
"guide box" template which aids in the installation process.

DETAILED DESCRIPTION of the PREFERRED, EXEMPLARY EMBODIMENTS 
As can be seen in FIG. 1, the containment system of the present invention 
comprises the implementation of a plurality of adjacent, associated 
barrier members 3 slidingly engaged to form a subterranean, vertical 
barrier wall and the subsequent sealing thereof, with the wall placed in a 
trench 9 configured to contain the waste area. The apparatus and system of 
the present invention will be described in greater detail infra. 
As illustrated in FIG. 3 of the drawings, the exemplary barrier member 3 of 
the present invention comprises a cylindrical body made of, for example, 
polyethylene, polyvinyl chloride (PVC), polypropylene, polyurethane or the 
like. Illustrated in the present figure are two exterior appendages 1,4 at 
one hundred and eighty (180) degree separation from one another about the 
periphery of the cylindrical body. Appendage 1 comprises the male portion 
of an interlock system which slidingly engages and lockingly mates with a 
second, female appendage of an adjacent mating member to form a barrier 
wall. 
Included with the male portion 1 is a void or slot 2 comprising a seal 
receptor pocket. This chamber 2 will be discussed in further detail infra. 
The second appendage 4 comprises the female portion of the interlock system 
having an open, slotted area 4a for receiving a male portion and also 
includes a seal receptor pocket 5. As can be seen in the figure, the body 
3 also includes an open core section 6. 
FIGS. 4 and 5 illustrate in greater detail the various design features of 
the barrier member 3 of the present invention. In addition to a seal 
receptor pocket 2, the male portion 1 of the interlock system also 
includes an aligning shoulder 11 which slidingly communicates with the 
aligning shoulder 10 of the female member 4 to provide for more efficient 
installation with desirable tolerances, as well as providing for a medium 
with which a consistently fluid impermeable seal can be projected. 
Male member 1 also includes an interlock neck 12, which slidingly mates 
with and extends through the interlock collar 13 of the female member 4. 
As shown in FIG. 5, the appendages 1, 4 of the alternative, exemplary 
barrier member 3a may be implemented at configurations other than one 
hundred and eighty (180) degrees. For example, the appendages may be 
configured at forty five (45) degrees for the corner members to form 
triangular containment, or at ninety (90) degrees to form square 
containment or at any other desired angle. 
The one hundred and eighty (180) degree configuration members 3 may be used 
in conjunction with members having appendage configurations 3a other than 
one hundred and eighty (180) degrees, thereby allowing implementation of 
walls other than strictly linear or ones. For example, as shown in FIG. 7, 
a "kidney" shaped configuration is illustrated for encapsulating a 
similarly configured dump site 31 with its waste 30. 
As further illustrated in FIG. 7, the present "slurry wall" method and/or 
the utilization of sheet pilings would not allow for this flexibility as 
to the configuration, requiring a more or less linear perimeter 32 
substantially in excess of what is needed, at a greatly increased cost. 
FIG. 1 illustrates an above ground view of the installation system of the 
present invention. The first step in the installation process is the 
excavation of a trench area around the periphery of the site to be 
contained. The trench 9 is of a sufficient width to allow placement of the 
vertical barrier members 3 without caving. Trench 9 must also be of 
sufficient depth to communicate with a fluid impermeable strata in the 
soil such as clay or the like. 
The vertical barrier members 3 may be slidingly engaged to form a barrier 
wall via the male and female sliding interlock appendages 1 and 4, 
respectively. Once the barrier members are joined, a sealant that expands 
and hardens to a fluid impermeable state, such as (but not limited to) 
silicone, may be injected into the seal receptor chamber 33. Chamber 33 is 
formed by the mating of slot 2 in appendage 1 and slot 5 in appendage 
leaving an open area formed between them. The sealant fills chamber 33 and 
migrates into the curved tolerance void remaining between the male 1 and 
interior wall of the female 4a interlocks, forming a fluid impermeable 
seal 7a, as illustrated in FIG. 6. 
To form a corner, a member 3a having engagement appendages 1 and 4 
configured at ninety (90) degrees relative to the other is used. 
As further illustrated in FIG. 1, the core section 6 of the vertical 
barrier member body 3 may be filled with backfill, sand or the like 8 
either prior to or after installation. If implemented prior to 
installation, the added weight can aid in the placement and engagement of 
the barrier members 3. 
Also illustrated in FIG. 1 is the "guide box" 16 discussed in the "general 
discussion of the invention" section supra. The "guide box" is used where 
a precise alignment and/or prevention of caving is necessary, and 
comprises an elongated structural member configured with a plurality of 
slots 16a for use as a guide for the installation of the vertical barrier 
members. The method of installation utilizing the "guide box" will be more 
fully disclosed infra in connection with the discussion of FIGS. 8a-8d. 
FIG. 2 is a side view of the vertical barrier member wall in its 
implemented state, illustrating a cross-sectional view of the present 
invention and containment area, showing via arrows 24 an exemplary 
migration of contaminants. 
As shown in the figure, the containment wall is implemented vertically in a 
mostly subterranean manner to a sufficient depth to communicate with a 
fluid impermeable strata 20 such as clay or the like. The fluid 
impermeable vertical barrier wall system, communicating with the clay 
strata, forms an impregnable "container." 
In the present example, toxic waste material 23 in a dump or the like 
contains contaminated fluids 24 or suspended material which may migrate 
through the natural soil 22 to the ground water aquifer 21 which, without 
containment, would increase its rate of migration out of the area, 
contaminating lakes, rivers, and the water supply. It should be noted that 
neither the aquifer 21 nor the contaminant 24 permeates the clay strata 
20. 
The present invention prevents migration of the contaminant 24 in the site, 
and cuts off flow of the natural aquifer 21 in the containment area. 
The vertical barrier wall, with its impermeable seal 7 prevents migration 
of the contaminant and any tainted water in the containment site. In order 
to prevent leeching of the contaminant between the barrier and the clay 
strata 20, a layer of bentonite 25 or the like may be deposited at the 
base 3b of the trench prior to installation of the system. To further 
prevent leaching under the barrier wall, the wall may be "tapped" into the 
clay strata 20 a short distance to further seal the system into the 
underlying strata. 
The excavation of a trench 9 for installation of the wall as taught in FIG. 
1 infra may be satisfactorily implemented in areas with highly cohesive 
soils, but may not be satisfactory where the soil has a very high moisture 
content, is sandy or otherwise likely to "cave". 
Thus, an alternative method of installation may be used where soil caving 
is likely to be a problem. This alternative method is critical as the 
excavation may have to be as deep as forty (40') feet and require that the 
hole be "clean" prior to installation of the vertical barrier members. 
Loose sand, gravel, or the like can interfere with the engagement of the 
barrier members 3 Further, debris forming at the bottom of the hole during 
installation may tend to prevent communication of the barrier with the 
clay strata, thereby allowing migration of the contaminant between or 
below them. 
It is for these reasons that an alternative method of installation has been 
developed which is particularly suitable for such situations This 
alternative method of installation is illustrated in FIGS. 8a-8d and 
comprises the utilization of the "guide box" apparatus referred to supra 
with the discussion of FIG. 1. 
FIG. 8a illustrates the first step of the alternative method of installing 
the present invention, illustrating a top view of a cylindrical excavation 
18 created with an auger or like device. It has been found that such an 
excavation is less prone to caving as compared to a vertical, rectilinear 
trench. This property of reduced caving is believed due to the cylindrical 
configuration of the excavation, which has a higher propensity for 
cohesiveness, and also perhaps due to the auguring operation itself, which 
has been found to pack the excavation walls to a greater degree than 
linear trenching. 
A problem, however, with utilizing a plurality of augured holes is that the 
drilling operation, when communicating with an adjoining hole as shown in 
FIG. 8c, will tend to deposit soil into the new hole into the adjoining 
excavation. 
After preparing the initial excavation with an auger, the second step in 
the alternative method entails depositing an initial two hole "guide box" 
15. The "guide box" 15 illustrated is a "starter" design, designed to fit 
into the initial, augured excavation 18, and act as a template guide for 
two barrier members 3 to be slidingly engaged As discussed above, the 
"guide box" 15 also acts to guide the joining of the barrier members 3 as 
they engage to become a subterranean containment structure and prevent 
complications resulting from "caving" of the walls of the excavation. 
FIG. 8c is a top view of the third and fourth step(s) of the alternative 
method, illustrating the installation of the barrier members 3 in the two 
slot starter guide box 15 and the excavation 18a of an adjoining area to 
the original excavation 18. The two slot guide box 15 is used initially as 
it fits into the excavation 18, which is of an approximate twenty-four 
(24") inch diameter. Barrier members 3 may be installed into the 
excavation area by placing the guide box 15 into the excavation area first 
and sliding and joining the barrier members 3 therein, or by placing 
barrier members 3 into the guide box 15 out of the excavation 18 and then 
installing the guide box 15 with the barrier members 3 therein into the 
excavation 18. It is noted that installing the barrier members 3 into 
guide box 15 out of the hole has advantages in maneuvering and general 
ease of placement into excavation 18. 
For example, with barrier members 3 slidingly engaged in the guide box 15 
while being up out of the hole, the contained barrier members 3 may be 
filled with sand or other fill material, giving the guide box 
significantly greater mass. This results in greater ease in lowering the 
system into the excavation and joining members in the guide box to the 
previously installed members, et cetera. 
As can be seen in FIG. 8c, the closed end of guide box 15 faces the second 
excavation 18a, acting to prevent soil and the like from entering the 
female engagement appendage of the associated barrier member 3 and 
allowing for a "clean" continuation of the excavation. 
FIG. 8d is a top view of the fourth, fifth, and sixth steps in the 
alternative method of installing the present invention, illustrating the 
removal of the first, two slot "guide box", placement of a second, three 
slot guide box 17 in such a manner as to engage at least one of the 
vertical barrier members and extend into the second excavation, and 
further including the installation of the barrier members in the vacant 
slots. 
As can be seen in FIG. 8d, the open end of the guide box 17 engages the 
joined appendages of barrier members 3A and 3B, and the closed end once 
again faces the next area to be excavated, near member 3D. 
In continuing the process, the steps of FIGS. 8c and 8d are repeated, until 
the desired area is contained. 
Returning to FIG. 1, a corner guide box 16 is illustrated in use in the 
utilization of the template or guide box method of installation in 
conjunction with a linear trench, as opposed to the auger excavation 
method detailed above. The corner guide box 16 as used in the illustration 
has a side opening to allow communication of the engaged barrier member 
appendages when at least one of said appendages is of a configuration 
other than one hundred and eighty (180) degrees, as in member 3a. 
After the barrier members are slidingly engaged in place, the sealant 
chambers 33 are filled, and the hollow core 6 of the barrier member 3 is 
filled with sand or backfill 8. The excavation 9 surrounding the structure 
is then filled. It is noted that the barrier members 3 are not 
particularly completely covered over when the system is implemented, and 
it may be desirable to have the barrier wall protrude up out of the ground 
so as to prevent water runoff from the surface to other areas, as the 
runoff may contain contaminants as well. The top of barrier members 3 may 
also be capped to prevent the filling of the core 6 with water, as such 
could result in cracking or breakage of the structure if the liquid were 
to expand to form ice. 
FIG. 9 illustrates a bottom plug 19 to be implemented at the base of the 
barrier member 3. The plug is welded 19a at the base of the hollow cavity 
or core 6. The plug 19 is particularly necessary when the barrier members 
are placed into the guide boxes and filled with sand or backfill prior to 
the guide box being placed into the excavation area. 
Plug 19 may be implemented at the very bottom of the core 6 or it may be 
welded a small distance up from the bottom, such as for example from a 
half (1/2") inch to about five (5") inches, so as to allow the bottom of 
the heavy barrier member to settle down into the clay strata, creating a 
better seal. The barrier members may also be tapped or vibrated to 
encourage further "settling" into the strata. 
FIG. 11 illustrates a further alternative in the system of the present 
invention, detailing the location and degree of a heat seal or weld 27 
implemented in the sealant pocket or cavity 5 prior to injection with 
sealant 28. The weld 27 acts to tighten the bond between the two 
appendages, essentially blocking off any tolerance between the male 1 and 
female 4 appendages, and increasing structural integrity by permanently 
bonding the barrier members 3 together. 
Although the preferred application for the present invention in the 
containment of fluid wastes overlying a fluid impermeable strata, the 
invention can also be applied to other fields such as, for example, soil 
containment for levees, containment of solid wastes, etc. 
The embodiments described herein in detail for exemplary purposes are of 
course subject to many different variations in structure, design, 
application and methodology. Because many varying and different 
embodiments may be made within the scope of the inventive concept(s) 
herein taught, and because many modifications may be made in the 
embodiments herein detailed in accordance with the descriptive 
requirements of the law, it is to be understood that the details herein 
are to be interpreted as illustrative and not in a limiting sense.