Technical Field

The present invention relates principally to hazardous waste containment systems and more particularly to a method for preventing, for example, the migration and leaching of hazardous fluid substances into the water table, including gases such as methane gas, using a containment wall, including a guide box assembly system for installing the wall components.

The present invention teaches the use of an in-ground containment wall comprising a plurality of slidingly engaged, interlocked, vertical barrier members installed in the ground. The barrier members are engaged by means of, preferably, interlocking connectors, which include therein a means for forming a fluid impermeable seal. In some applications it may be desired to allow the controlled flow of fluids through the containment wall, and a "pass-through" structure and methodology is provided for this purpose. The preferred method for implementing the invention includes the preparation by trenching, auguring or digging, etc. , of vertical openings or excavations of prescribed depth, width, and/or diameter in the soil surrounding the area to be contained down preferably to an underlying, impermeable strata; installation of the interconnected, sealed, vertical barrier members to produce the in-ground, sealed, containment wall therein using a series of guide box assemblies preferably spaced from the side walls of the excavation and having two, spaced wall panels forming an

isolated work space for the barrier members between them; at least partially filling any open cores of the barrier members and at least partially back-filling the opening between the interior sides of the wall panels themselves and between the outer sides of the wall panels and the sides of the openings or excavations; and ultimately removing the wall panels of the guide box assemblies, leaving, for example, a series of bottom, anchoring, spreader base plates in the bottom of the openings or excavations into the impermeable strata and underneath the bottoms of the barrier members.

The present invention may be used to restrain the uncontrolled 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 effi¬ cient and cost effective containment system, as will be shown infra.

As noted above, the method of installing the present system includes the utilization of a guide box template/anti-caving assembly system for properly aligning the barrier members and providing an open, isolated, work space, particularly where soil conditions are such that there is a likelihood for cave-in.

Background Art

The prior art has failed to contemplate a system as taught in the present invention. Further, the prior art is fully distinguishable in construction and use. The present invention is anticipated to cost substan¬ tially less than the most cost efficient prior art system, as it does not require sheet pilings or any other means of preventing "caving" because the present invention provides a series of guide box assemblies that create a temporary, isolated work space for the insertion and joining of the barrier members. Other material costs of the present system are likewise expected to be less.

The present invention does not require the utilization of piling equipment, heavy lift equipment, or extensive labor, as is necessary for implementation of some of the approaches of the prior art. Instead, no piling equipment, and only relatively available lifters and less extensive labor is needed. General Discussion of Invention The present invention overcomes the problems of the prior art by providing a barrier wall installation system which is reliable, relatively economical and less hazardous.

As may be noted from the above, the prior art has not provided a relatively inexpensive yet consistently imper e- able, readily implemented containment system for preventing the leaching of toxic materials from dump sites and the like. However, such is achieved in the present invention, and the exemplary embodiments of the present system comprise

the utilization of a plurality of barrier members, each barrier member having a tubular or double-wall body or, alternatively, a single wall structure, with edge appendages on the opposite or complementary ends of the barrier member, with the barrier members being installed and interconnected in a protected, open work space provided by a series of interconnected guide box assemblies. The barrier member appendages are of a "male" and "female" type, respectively, and are configured to slidingly engage and lockingly interconnect juxtaposed barrier members in a vertical fashion.

Further, the appendages are configured with each to include a fluid impermeable seal between the associated appendages of the interconnected barrier members. 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 one another. For example, a ninety (90°) degree separation would be used for a ninety degree "corner" barrier member, while a variety of other degree separations could be utilized to form, for example, 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, which need not be completely closed in certain conditions. It is noted that the engagement appendages for all configuration barrier

members are designed to mate with the opposite appendages of other members of this invention.

The present invention of providing a vertical wall as a containment barrier is possible as the wall is installed down to a depth to intersect with, for example, an underlying 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 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, such as, for further example, bedrock, with satisfactory results.

Another step, when desirable, in the installation 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 bottom intersection of the wall and the strata. This may be, for example, four (4") or more inches, and more typically twelve or eighteen (12" or 18") inches. It is also noted that, in some situations, this step may not be necessary.

For installation of the present invention particularly in soil conditions having a likelihood of "caving", the present invention teaches the implementation of a "guide box" template or guide box assembly system, into which the barrier members are placed and interconnected, extending the full depth and ultimately the full length of the excavation. The "guide box" serves at least five purposes, namely: 1) it provides an outer support structure which prevents 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 can act as a guide for the auger, if auguring is used; and 5) it can allow for gradual and controlled back-filling by being slowly extracted from the excavation, if so desired. However, the first two purposes are the primary purposes of the guide box assemblies of the invention.

Each guide box assembly typically includes two, spaced wall panels providing the protected, open work space for the barrier member installation between them, which wall panels can be easily assembled into a rigid unit by means of a series of laterally extending, top and bottom spreader bars. The lower or bottom spreader bars, which preferably can also serve as anchors for the guide box assemblies and bases for the barrier members, are easily detached and left down in the ground when the wall panels are removed from the

excavation. This is achieved by the use of a series of, for example, vertical, parallel, guide shafts extending through the full height of the wall panels, connected at their tops to the top of their respective wall panels and temporarily connected at their bottoms to the anchoring spreader bars by means of, for example, rotatable interconnections, which can be easily reversed to detach the bottom spreader bars from the wall panels.

In those containment applications in which it is desired to allow the controlled removal of fluids from the contained area, a "pass-through" structure is included in one or more of the interconnected barrier members. This allows, for example, the controlled drainage of toxic fluids from the contained area to, for example, an adjacent toxic fluids processing area for on-site treatment of the contaminants before final removal from the site.

Thus, at least one of the guide box assemblies also preferably includes pass-through areas, through which access to the pass-through in the guide box's associated barrier member is possible. A typical, completed pass-through will include one or more pipe sections feeding through or otherwise communicating with, for example, an integral, flanged pass-through in the barrier member. The guide box assembly with its pass-through areas is preferably left "permanently" in the ground, rather than removed like the other guide box assemblies. The leaving in the ground of the pass-through guide box assembly helps to strengthen and secure the pass-through of the associated barrier member. However, after the site has been processed and cleaned up

and the pass-throughs and barrier walls are no longer needed, they likewise can then be removed, if so desired, returning the site to its natural state.

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 to provide a system for containing hazardous wastes, which utilizes a plurality of slidingly engaged, interlocking containment members which are installed in a protected, open work space provided by a series of interconnected guide box assemblies.

It is yet another object to provide double seals between the engaged barrier members, particularly ones using at each engagement a single sealing member having opposed "Y" shaped seals at its opposite ends.

It is yet still another object to provide a "pass- through" structure in at least one barrier member to allow the controlled removal of fluids from the contained area, when such is desired.

It is a still further object to provide a system for containing hazardous wastes that is adaptable to a variety of dump site configurations.

It is another object to provide a system for containing hazardous wastes which provides reliable containment for a period of time equal to or exceeding conventional methods.

It is another object to provide a system for containing hazardous wastes until such time as it can be removed or neutralized as desired.

It is a further object 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 or assembly which aids in the installation process.

Brief Description of Drawings

For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

Figure 1 is a perspective view, partially cut away, of a first, exemplary guide box assembly of the invention, with all of its parts fully assembled together but without any barrier member contained within it.

Figure 2 is a perspective view of an initial set of two guide box assemblies (of the type shown in Figure 1) being installed in the ground to start the in-place formation of the containment wall, with the second guide box assembly being interconnected to the initial guide box assembly having a barrier member positioned within it, as the former is being lowered into a trench formed in the ground adjacent to the initial guide box assembly; while

Figure 3 is a side view of the step illustrated in Figure 2.

Figure 4 is a perspective view of an exemplary series of three guide box assemblies (of the type shown in Figure 1) fully interconnected together as they would exist in the ground, with the ground not being shown to better view the guide box assemblies and without any barrier members being placed in any of the guide box assemblies for purposes of simplicity.

Figure 5 is a plan, cross-sectional, detail view of the sealed, male/female interconnection joint used in a first exemplary embodiment of two adjacent, interconnected barrier members, which with a series of like barrier members is used to make up the containment wall of the invention.

Figure 6 is a perspective view, with the surrounding dirt and the adjacent barrier member cut away for purposes of illustration, showing the removal of the two, end guide shafts from the keyed holes of the spacer plate at one end of a guide box assembly, with the side walls of the assembly having already been removed, leaving the spacer plate under the barrier member in place in the ground.

Figure 7 is a perspective, cut-away view showing the interconnection between two, installed barrier members of the type of Figure 5, with the closer one filled with material and with the side areas on the outside of the barrier members also filled with preferably the excavated material from the trench.

Figure 8 is a plan, generalized or simplified view of an exemplary, completed, in-ground barrier containment wall system, comprised of a series of vertically disposed or arrayed, edge-to-edge interconnected barrier members of a suitable type with which the present invention can be used.

Figure 9 is a partial, side, cross-sectional view of the initial, exemplary embodiment of the barrier member of the present invention, completely installed, illustrating the sealing characteristics of the fluid impermeable barrier relative to an exemplary migration of toxic fluid waste and

further illustrating the use of a clay-like substance embedding and sealing the base of the barrier wall.

Figure 10 is a bottom view of an alternate embodiment of the guide box assembly with an alternate embodiment of the barrier member of the present invention, both of which are the currently preferred embodiments in 1992.

Figure 11 is a plan, cross-sectional, detail view of the sealed, male/female interconnection joint used in the preferred, alternative, barrier member embodiment of Figure 10, showing in detail the sealed, male/female interconnection joint between two adjacent, interconnected barrier members, which with a series of like barrier members is used to make up the preferred containment wall of the invention. Figure 12 is a perspective, exploded, detail view of the spacer plate and guide shafts of the guide box assembly embodiment of Figure 10, upon which spacer plate the bottom of its respective barrier member is supported in the ground, with the barrier member not shown for purposes of simplicity; while

Figure 13 is an end, detail view of the spacer plate of Figure 12 buried in the ground.

Figure 14 is a perspective, generalized or simplified view of an exemplary, completed, in-ground barrier containment wall system, comprised of a series of vertically disposed or arrayed, edge-to-edge interconnected barrier members of a suitable type with which the "pass-through" aspect of the present invention can be used, with an adjacent satellite work and equipment area or cell defined

by a series of edge-to-edge interconnected barrier members with associated guide box assemblies left in place in the ground, with a first pass-through being provided between the confined waste area and the adjacent work/equipment area and a second pass-through being provided between the work/equipment area and the outside, non-confined area.

Figure 15 is a side, cross-sectional, detail view of an exemplary pass-through structure, of the type which can be used in the application illustrated in Figure 14, integrated into a single wall type barrier member with open areas being provided in the adjacent guide box assembly walls, which allow access to the pass-through in the barrier member.

Figure 16 is a plan, close-up view of an adjacent satellite work/equipment area similar to that illustrated in Figure 14 but further illustrating the inclusion of a series of spreader beams to solidify the surrounding walls.

Modes for Carrying Out the Invention

- Structure of Ini tial Guide Box Assembly (Figs . 1 +) - As can best be seen in Figure 1, the first, exemplary embodiment of the guide box assembly includes two, like, opposed, parallel, vertical wall panels 200A & 200B having a mortise and tenon connector 201 for the right-hand wall panel & another, like mortise and tenon connector 202 for the left-hand panel, and a double mortise connector 203 for the right-hand panel & a like double mortise connector 204 for the left-hand panel. To provide male/female, interconnecting joint elements, the wall panels have two, flanking connector tenons 205 at one end and two, flanking connector mortises 206 for mating with connector tenons (like 205) of another, adjacent panel at the other end, respectively.

Opposed, laterally directed, connector mortises 207 are provided on the interior ends of the wall panels 200 for mating with gate tenons 602 on laterally extending, end gates 601. The gates 601 in combination with the wall panels 200 define an enclosed, protected space into which appropriate barrier members can be placed, isolated and protected from any incursion of dirt or other debris from the surrounding ground.

Each gate 601 also includes a gate lifting-eye 603 to allow for its easy removal from the wall panels 200 when so desired. Thus, the two, laterally disposed, end gates 601 are slidingly engaged between the wall panels 200 at their longitudinally spaced ends, closing off their longitudinal

spaced ends, with each gate having a width great enough to accommodate the lateral thickness of a barrier member.

If so desired, a series of oppositely opposed holes (not illustrated) can be provided in the sides of each gate 601 spaced along its vertical height at least in its upper portion. With the use of locking or stop pins, which are placed in selected ones of the opposed holes in the sides of the gate, the gate would be allowed to be only partially inserted into the wall panels 200 down a desired distance. Each wall panel 200 includes an outer skin 208 forming an interior wall surface and a parallel, inner skin 209 forming an interior wall surface, which includes through it a series of hand access openings 210, allowing easy access to the inside of the panel for ease in, for example, bolting and unbolting various items which might be connected to the underside of the panel. A bottom gate stop 211 is provided on the bottoms of the wall panels 200 at least in the areas underlying the female mortises 206. When a series of vertically stacked and connected panels 200 are incorporated in a stacked configuration (not illustrated) , the gate stop 211 is installed only on the lower most panels.

A series of vertically extended, structural, angle irons 212 are included in each wall panel 200, each one serving as a vertically extended, structural member and as a guide slot for a vertically disposed guide shaft 301 having a guide shaft dog 302 at its bottom area (see also Figure 6) . Each angle iron element 212 provides a guide slot 213 for its respective guide shaft 301 and its guide- shaft-dog 302.

To complete the basic wall panel structure, an upper, longitudinally extended, stiffener/mounting plate 214 and a lower, longitudinally extended, stiffener/mounting plate 218, are provided affixed to the outer and inner skins 208, 209, respectively, with the stiffener plates being welded to the structural angle iron members 212 and with each plate having a series of mounting holes 215, 219, respectively, spaced along its respective, longitudinal length for use in, for example, bolting together a series of vertically stacked panels for a containment wall of a height greater than the height of a single wall panel 200. Thus, the guide box assemblies can be provided in a variety of standard heights, with greater heights being achieved by bolting together appropriate ones of two or more individual wall panels using the upper and lower bolt holes 215/219 to bolt an upper one to a lower one. Hence, for example, two sets of ten (10') foot height panels 200 could be bolted together to install a twenty (20') foot height containment wall.

The upper holes 215 (on the top two panels) are also used to affix by bolting sets of rigid, spacing and lifting bars 801, which are made of, for example, steel, and laterally extend across from one wall panel 200A to the other 200B. Each bolting unit 1001 typically would include a bolt, nut, and two washers. At the top of each panel 200 are affixed aligning and plumbing clips 216 provided along the panel's length, each of which includes a hole 217 for easy attachment of a standard cable and ratchet assembly (not illustrated) .

As can be seen in Figure 1, a guide shaft 301 is positioned in each one of the guide slots 213 with its bottom end extending through and locked into a respective one of a series of laterally extending, rigid, anchoring, spacer plates 701 (note also Fig. 6) made of, for example, steel. As can be seen in Figure 6, each spacer plate 701 includes two circular holes 703, each with a key-way, radial slot 704 in it, designed to allow the passage of the radial lug or dog 302 on a guide shaft 301 through it. Once the dog 302 has passed through the key-way slot 704 and the shaft 301 appropriately rotated, the bottom end of the shaft is locked into its respective anchoring spacer plate 701. By reversing this action, i.e., oppositely rotating it, the shaft can be unlocked from the spacer plate. An upper slot 303 is provided in the top end of each guide shaft 301, into which a tapered, "draw-up" plate 401 is driven. This causes its respective guide shaft 301 to be drawn up in its respective slot 213 until the respective spreader plate 701 to which the shaft is locked bears up against the bottom stiffener plate 218. When this is done for all six shafts 301 and the upper spacers 801 are bolted in place, the two panels 200 are relatively tightly assembled together in a rigid assembly unit and moveable around as an integral unit under the lifting action and control of, for example, a crane. The guide box assemblies, when fully assembled, are free standing, rigid and self- supporting.

Each spacer and lifting bar 801 includes a lifting-pad 802 with a lifting-pad eye 803, to which a crane cable and

cradle assembly 1002 (see Fig. 2) can be easily attached. Each spacer bar 801 also includes, on its bottom, opposed sets of inner spacing shoulders 804 and outer spacing shoulders 805 for fitting about and holding between them the wall panels 200.

If so desired, a series of (or one continuous) longitudinally and downwardly extended, lateral-shift- preventing plate(s) (not illustrated) could be bolted or otherwise attached to the bottom of the stiffener plate 218. Such a lateral-shift-preventing plate would then be tapped down into the ground when the guide box assembly is placed into a trench into the ground for stability and anchoring purposes.

The foregoing described, initial embodiment of the guide box assembly of the present invention can be used to install, for example, a containment wall made up of the type of double wall barrier members 501, which can be seen in the initial guide box assembly unit (unit to the left in figure) shown in Figure 2 and illustrated in some detail in Figure 5.

As can best be seen in Figure 5 hereof, the barrier members 501, each of which includes a rectangular, double- wall, hollow, main body section 500, are interlocked together by means of a pair of longitudinally and laterally directed, interlocking members 502, 503 and 504, which form mating "T" members & cavities 502 & 502' and flank the sealed male/female coupling 509/510. These basic barrier wall elements 501 can be made of, for example, extruded thermoplastic made in the desired heights for the barrier

members, e . g. , ten (10'), fifteen (15') and twenty (20') foot heights.

As can be seen in Figure 5, barrier members 501 employing the same design are included on the opposite sides interconnected together to form a complete barrier of the size and configuration desired. This design provides a joint having essentially the same strength as the body member 500.

In order to prevent passage of fluid through the joint, an elastomeric gasket 508, preferably of the type known as U-packing, which includes diverging "Y" shaped seals at its opposite ends when the seal member or gasket 508 is in its "natural," uncompressed state, is placed in the side cavity formed between the longitudinally extended male member 509 and an opposed one of the longitudinally extended, flanking members 507, which extend parallel and along side the male member forming the female cavity 510. As noted above, the elastomeric material chosen for the gasket depends on the fluid being retained, with, for example, buna-n rubber being very suitable for water, but vinylidene fluoride hexaflouro- propylene copolymer ( e . g. "Viton"™) , for example, being preferred where corrosive chemicals are involved.

As can be seen in Figure 5, the gasket 508 includes two seals formed back to back, sealing a gap between the male member 509 and an opposed one of said female cavity members or legs 507, so that pressure can be restrained in either direction. A groove, typically about thirty-seven hundredths (0.37") of an inch wide by twenty-five hundredths (0.25") of an inch deep, is provided in order to locate and

hold the gasket 508 in place over the laterally directed member or boss 506, which interfaces with the gasket slot 580. The gasket 508 thus rides on the boss 506 and, through the boss, on the side of the male member 509. Although the presence of the boss slot 580 makes the gasket have somewhat of a "U" shaped configuration with the lips then being described as extending out from the sides of the "U" shape, the gasket more accurately may be considered to have an extended, straight shape, with the lips extending directly out from the distal ends of the extended, straight shape.

In order to further prevent or at least retard any movement of the gasket 508 during installation, the gasket is secured in place by means of, for example, an adhesive. Installation of two adjacent, engaged barrier members 501 is accomplished by sliding the members together with their respective male/female members 509/510 and their respective side, flanking "T" members 502/502' mated and engaged.

Beveling the edges of the members 507 and applying, for example, a coating of vegetable soap or other suitable lubricant to the gasket 508 facilitates assembly.

Assembly is further facilitated by providing a sufficient gap or loose fit between members 502, 503 and 504 to minimize frictional forces. The gap should preferably be in the range of fifteen thousandths (.015") to thirty thousandths (0.030") of an inch.

This gap allows one barrier member 501 to move in relation to the one to which it is coupled. This movement has no effect on the seal, as the gasket 508 moves inward or

outward in the cavity formed between the male member 509 and its opposed member 507, and a tight seal is maintained regardless of its position in the cavity.

The initial seal of the gasket 508 is caused by compression of the gasket lips between the members 509 and 507. As pressure is applied to the internal U-shaped cavity, the seal becomes tighter.

In addition, when pressure is applied from side A, the pressure acting over the region C-D causes the nearest member 507 to deflect against the sealing gasket 508, causing a tighter seal. Similarly, when the pressure is applied from side B, pressure applied over the region E-F causes the centralized male member 509 to deflect against the gasket, also providing a tighter seal. - 2nd Embodiment of Guide Box Assembly & Barrier Member

(Figs . 10-13) - An additional, currently more preferred, exemplary embodiment will now be described with reference to Figures 10-13, including second, exemplary embodiments of the guide box assembly and barrier member. However, for the sake of brevity, because many of the elements are the same or analogously the same (in which case analogous reference numbers were used) , a description of all of them will not be provided to avoid redundancy. As can be seen in Figures 10 and particularly 11, a second, currently more preferred embodiment 101 for the containment barrier member of the present invention includes a rectangular, single-wall, flat, main body sheet or section 100, which is assembled and joined together into a

continuous, integrated in-ground, containment wall W with other like barrier members (see Fig. 8) by means of interlocking members 102 and 104.

The main body 100 includes two, connected coupling end pieces 100A & 100B affixedly connected at heat fused areas lOOC. All three of these basic barrier wall elements can be made of, for example, extruded plastic made in the desired heights for the barrier members 101, e . g. , ten (10'), fifteen (15') and twenty (20') foot heights. Exemplary plastic material for the barrier member 101 are medium ( e . g.

0.934 g/cc density, ASTM) polyethylene or high density polyethylene (density great than 0.939 g/cc) polypropylene or possibly polyvinyl chloride (PVC) or other material inert to the materials to be confined by the barrier wall W or other thermoplastic material.

As can be seen in the assembly of Figure 11, adjacent barrier members 101 employing essentially the same design (or an analogous design for a corner unit) are included on the opposite sides interconnected together to form a complete barrier of the size and configuration desired. This design preferably provides an interlocked joint (100A/100B, 102/104) having essentially the same as or greater strength than the main body member 100.

As can be seen in general in Figure 10 and in more detail in Figure 11, the coupling end element 100A has at its distal, coupling end a male coupling, including a centrally located, longitudinally extended male member 109 flanked by two, inwardly or laterally directed, "J" shaped members 102. The coupling end element 100B has at its

distal, coupling end a female coupling, including a centrally located, longitudinally extended female chamber 110 formed by the interior of the sealing gasket 108 and two, longitudinally extended legs 107, which form part of the "H" shaped joint member 104.

When these two, male/female end pieces are mated and coupled together to opposite type end pieces on adjacent barrier wall sections 101, the "H" shaped piece 104 fits and nests within the opposed, "J" shaped members 102, with the tips of the "Jε" curving around and holding in the lower legs of the "H". As can be seen in the assembled joint of Figure 11, the combination provides in its coupling thickness five (5), parallel, flat, plate-like, relatively thin elements sandwiched together with the two (2) , parallel legs of the "U" shaped gasket 108, described more fully below, namely the two (2) , outside, side walls of the joint element 102, the two (2), enclosed legs of the "H" shaped joint element 104, and the centrally located, extended male member 109. In order to prevent passage of fluid through the joint, an elastomeric gasket 108, also preferably of the type known as U-packing and also having diverging "Y" shaped sealing ends, is placed at the bottom of the female cavity 110 formed by the flanking, longitudinally extended, side members 107. The elastomeric material chosen for the gasket depends on the fluid being retained, with, for example, buna-n rubber being very suitable for water, but vinylidene fluoride hexaflouropropylene copolymer (e.g. "Viton"™) , for

example, being preferred where corrosive chemicals are involved. A further exemplary material is "Santoprene"™.

The sealing gasket 108 includes two seals, i.e. double seals, formed back to back by the two, "Y" shaped pairs of diverging, flexible lips 181/182 & 183/184, so that pressure can be restrained in either direction. These pairs of diverging lips are located at and divergingly extend out from the distal ends 186 of the "U" shape of the gasket 108, and, as can be generally seen in and generally understood from Figure 11, form oppositely directed seals at two spaced areas between opposite sides 191 & 192 of the distal end of said male member and opposed ones of the interior wails of the flanking female cavity legs 107.

In order to prevent or at least retard any movement of the gasket 108 during installation of the barrier panels 101, the gasket is secured in place by means of, for example, an adhesive or by heat fusion when the gasket member is made from a thermoplastic elastomer which is compatible with the joint material. Installation is accom- pushed by sliding the adjacent, mating barrier members 101 together.

Applying a coating of vegetable soap or other appropriate lubricant to the gasket 108 facilitates assembly. Assembly is further facilitated by providing a sufficient gap between the joint interlocking members 102 and 104 to minimize frictional forces as the adjacent members are slid down with respect to one another. The gap should preferably be in the range of (.015) to (0.030) inches.

This gap allows one barrier member 101 to move in relation to the one to which it is coupled. This movement has no effect on the seal, as the flexible gasket 108 moves inward or outward in the bottom area of the cavity formed by the longitudinally extended members 107, and a tight seal is maintained regardless of its position in the cavity.

The initial seal of the gasket is caused by compression of the gasket lips 181/182 & 183/184 between the distal sides 191 & 192 of the male member 109 and the bottom portions of the interior sides of the flanking members or legs 107. As pressure is applied to the internal U-shaped cavity, the seal becomes tighter.

With respect to the alternative, now currently preferred embodiment of the guide assembly box illustrated in Figures 10, 12 & 13, the two embodiments are very similar. The primary differences revolve around the use of: circular, cylindrically extended, pipe slots 1213 provided by structural, vertically extended, pipe sections welded to the upper and lower stiffener plates, each having an inner diameter a little bit greater than the outer diameter of the guide shafts 1301 ( vis-a-vis the triangular, angle iron slots 213 for the guide shafts 301) ;

"T" shaped male/female members 1205/1206 ( vis-a ¬ vis the mortise/tenon interconnections 205/206) for the male/female interconnecting joints between the guide assembly boxes;

"T" shaped male/female members 1207/1602 ( vis-a ¬ vis the mortise/tenon interconnections 207/602) for the

joints between the gates 1601 and the ends of the wall panels 1200A & B and threaded engagements (note Fig. 12) for the temporary connections between internally, female threaded, bottom ends 1302 of the guide shafts 1301 and threaded male bosses 1702 on the upper side of the base anchoring and bottom spreader plates 1701 ( vis-a-vis the dog 302 and slotted, key-way opening 702/703) ;

Additionally, as can be seen in Figures 12 & 13, the base anchoring, centering and bottom spreader plates 1701 include laterally extended wings 1704 having vertically extending side plates 1705 at their distal ends which are provided to bear up against the side of a trench 9 (note Fig. 13) , using said vertically extending distal end pieces to laterally stabilize the guide box assemblies against the side walls of the excavation. Also, a vertically and laterally extending anchoring plate 1706 is affixed to the bottom of each bottom spreader plate 1701 for anchoring the box assembly in the ground and preventing (or at least substantially retarding) any longitudinal movement of a guide box assembly once it has been interconnected to an adjacent barrier member and lowered into the ground (note Figs. 2 & 3) . As further shown in the bottom view of Figure 10, the two, bottom, spreader, base plates 1701 toward the ends of the panels 1200 can include the centering, stabilizing wings 1704, while the center spreader plate 1701A can be of a simpler design.

Also, rather than use the tapered draw-up plates 401 to secure the upper ends of the steel guide shafts 301 to the

upper stiffener plate 214, both ends of the steel shaft 1301 can include internal, female threaded ends 1302, allowing the use of a relatively simple bolt/plate securing arrangement (not seen in the drawings) to quickly and easily secure the upper ends of the shafts 1301 to their respective upper stiffener plate.

Such a rotatable arrangement allows for quick and easy attachment and detachment of the shafts to the upper ends of the wall panels, in similar fashion to the lower ends of the shafts and also to the quick and easy bolting and unbolting of the upper spreader bars (analogous to bars 801) using standard nut-bolt-washer arrangements 1001. As pointed out above, the lower and upper, laterally extending, spreader bars 701 & 801, respectively, are readily and easily attached and detached and removed from the wall panels 200 by means of, for example, threaded or rotatable attachments, with the upper using nut and bolt attachments and the lower using a slotted, key-way arrangement or a threaded Acme-type coupling (e.g., the threaded arrangement 1302/1702 between elements 1301/1701 of Figs. 10-13).

Additionally, in order to give interim lateral support to the relatively thin, single wall structure of the barrier members 101, a series of laterally extending, insert beams 1220, each inserted at one end between two angle iron members forming a channel 1221 attached to the interior sides 1209 of the panels 1200, are included with the wall panels of the guide box assembly. The distal, "T" ends 1222 of the beams 1220 bear up against the sides of the main body 100 of the barrier member 101, providing it with lateral

support (to minimize barrier wall deflection) until back¬ fill material is added into the interior of the guide box assembly.

Thereafter the insert beams 1220 can be removed, either separately or in combination with the main body panels of the guide box assembly, leaving the interconnected, single- wall barrier member(s) vertically in place, stabilized by back-fill. The lateral extent of the opposed insert beams, which of course determines the size of the gap ( e . g. a one and half inch gap to laterally support the barrier body 100) formed between them, will depend upon the thickness of the barrier members to be installed within the guide box assem¬ bly(ies) , and different sets of laterally supporting, insert beams having different widths can be used with the same basic guide box assemblies to accommodate different wall thicknesses of barrier members.

It is noted that the main wall section 100 of the barrier member 101 is not totally rigid and does have some flexibility and can partially deflect under its own weight due to its single wall construction and relatively thinness, and hence some interim lateral support is desirable. On the other hand, such single wall construction typically is not like the membrane or relatively very thin, sheet-type material of the prior art which can, for example, be inflated or provided in rolls and basically have no capability of standing up on their own.

- Method of Installation (Figs . 2 + ) - As can be seen in Figures 2+, the initial steps in an exemplary embodiment of the containment wall installation methodology of the present invention is illustrated, in which a series of like barrier members 501 of the type of Figure 5 are ultimately interconnected and installed in the ground using guide box assemblies of the type of Figure 1.

Initially a trench 9 or other appropriate excavation opening is dug. The excavation of a trench 9 for installation of a containment wall W (as taught in Figure 1 of the '233 "grandparent" patent) without a guide box assembly may be satisfactorily implemented in areas with highly cohesive soils, but typically will not be satisfactory where the soil has a very high moisture content, is sandy or otherwise likely to "cave". Thus, the guide box assembly method of installation of the invention typically will be used where soil caving is likely to be a problem. The guide box assembly method of the invention is critical in such situations, as the excavation may have to be as deep as, e. g. , forty (40') feet, and the hole should be "clean" prior to the in-ground installation of the vertical barrier members 501 (101) . Additionally, when a single-wall-type barrier member 101 is used, direct lateral support of the sides of the barrier member along its vertical extent is highly desirable, if not essential, in order to keep the relatively thin main wall body 100 of the barrier member from curving and becoming out-of-line and/or out-of-plumb.

Loose sand, gravel, or the like can interfere with the engagement of the barrier members 501 (101) . 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 the guide box assembly method of installation of the invention was developed and is particularly suitable for such situations. As noted above, the methodology of installation of the invention is illustrated in Figures 2-7 and comprises the utilization of the "guide box" assembly or apparatus referred to supra in connection with the discussion of Figure 1. As can be seen in Figures 2 & 3, initially a trench 9 is dug (using, for example, a back-hoe type of implement) , having an exemplary width of about forty-two (42") inches and a depth of about ten (10') feet, or of whatever depth is needed to reach, preferably, an underlying layer of fluid impermeable material ( e . g. clay layer 20, see Fig. 9) . Alternatively, the soil could be augured out, as detailed in the grandparent '233 patent.

A starting guide box assembly 1, completely assembled together as shown in Figure l, is positioned in the beginning of the trench 9, it being noted that both gates 601 are closed. The box assembly is generally centered (using, for example, the wing elements 1704/1705) and then more exactly centered and plumbed to exactly vertical and fixed in position at the top with temporary braces extending

from the top areas of the wall panels 200 (1200) to the ground adjacent to the trench 9.

The exterior walls of the assembly are typically spaced from the side walls of the excavation, and the guide box assembly also is preferably tapped down into the underlying impermeable strata 20, using, for example, the underside of the bucket of the backhoe, causing the base spreader bars 701 (1701) to be driven down into the underlying strata, initially anchoring the base spreader bars and hence the connected main body of the box assembly in place (note Fig. 13) . Some initial back-filling 26 can be added to the bottom of the trench 9 to laterally stabilize the bottom of the box guide(s) between the bottom areas of its exterior side walls 208 (1208) of the wall panels and the bottom areas of the side walls of the trench.

Then, a second, completely assembled, guide box assembly 2 is interconnected through the male/female interconnecting joint 205/206 to the initial or starting guide box assembly 1 and lowered down into the trench 9, with the joint elements interconnected and being slid down with respect to each other until their bottoms and tops are co-extensive, using a crane holding the second box assembly by means of a cable carriage 1002.

Then a third, fully assembled guide box assembly 3 is in like fashion interconnected to box assembly 2 and lowered down into the trench 9 until an interconnected series of box assemblies 1-3+, such as that generally shown in Figure 3, is created. This process is sequentially repeated, using straight or corner boxes as needed, until ultimately the

complete circuit needed for the containment wall W is completed.

As this process of sequentially adding in-line, box assemblies continues, barrier members 501 (101) are added into the interior spaces or longitudinal slots provided by the interconnected guide box assemblies 1+. If need be, one or more of the upper spreader bars 801 can be unbolted and removed (or moved to another location and re-bolted) to allow any needed access to the interiors of the boxes for insertion of the barrier members. Typically, the initial or starting box 1 will already include a barrier member, as illustrated in Figure 2 (for simplicity of illustration it is not shown in Fig. 4) . In the embodiment of Figures 10+ the insert beams 1220 provide lateral support to the main bodies 100 of the barrier members 101 along their full heights.

This barrier member insertion and assembly can commence once at least two or more box assemblies have been interconnected in the trench 9. Once the boxes 1+ have been interconnected, the interior gate(s) 6011, i.e. those gates not at the very ends ( cf . 60IE) of the line of box assemblies, can be lifted out, allowing the next barrier member 501 (101) to be interconnected to the preceding barrier member through their respective sealed, male/female joint elements.

Thus, in Figure 4, it can be seen that the gates between box assemblies 1 & 2 have been removed. To remove a gate 601, a cable is merely connected to its eye 603, and

the gate is then merely lifted up out of the assembly using, for example, a crane or cherry picker or the like.

The interconnected box assemblies 1+ thus provide a "clean," isolated, temporary, work space devoid of dirt or debris for inserting and interconnecting the barrier members 501 (101) completely isolated from the surrounding ground. In similar fashion to interconnecting and lowering the box assemblies, the male/female joint elements 509/510 & 502/502' (109/110 & 102/104) on the barrier members are initially aligned and then engaged as one member is lowered down with respect to the preceding member.

After the barrier members 501 (101) are slidingly engaged in place within the protected work space provided by the interconnected box assemblies 1+, the hollow cores or interiors 6 of the interconnected barrier members 501 are thereafter filled with sand or other granular material or back-fill 8 (note Figs. 7 & 9) . Additionally, if so desired, a bottom sealing layer 25 of impermeable, sealing material, such as, for example, bentonite, is added to the bottom of the trench 9 before the back-fill 8 to a depth of, for example, twelve (12") or eighteen (18") inches or more, embedding the lower portion of the barrier members 501

(101) , as well as further embedding the anchoring plates 701 _

(1701) , into sealing engagement with the underlying imperme- able strata 20.

Ultimately the rest (26A) of the excavation 9 surrounding the wall structure in the area(s) in which the barrier members 501 (101) have been installed is then filled, preferably with the material excavated to form the

trench 9 or other selected material. This procedure can be done just after a series of boxes have been placed and set into the trench 9 but only partially back-filled (26) to prevent any movement of the bottoms of the boxes, which had provided sufficient stability to the boxes.

Likewise the areas between the interior walls 209 (1209) of the wall panels 200 (1200) and their respective barrier member(s) 501 (101) are filled with back-fill or other selected material. However, complete back-filling for an installed box and its contained barrier member(s) should not occur until at least the very next box assembly and its barrier member(s) have been put in place, and, if some back¬ filling has gotten over into an area in which a guide box assembly or barrier member(s) still need to be placed, some preliminary, trench bottom clean-out may be necessary.

It is noted that the barrier members 501 (101) are not necessarily 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 501 may also be capped, if so desired, to prevent the filling of the cores 6 with water, as such could result in cracking or breakage of the structure if the contained liquid were to be frozen and thus expanded to form ice.

As the assembly of interconnected box assemblies 1+ and interconnected barrier members 501 (101) continues and the barrier members appropriately stabilized with fill, the previously used box assemblies can be removed and re-

assembled and re-used down the line. To do this, the tops of the guide shafts 301 (1301) are disconnected from the tops of the wall panels 200 (1200) , and any remaining upper spreader bars 801 preferably are unbolted and removed. The wall panels are then pulled up with the use of a crane or picker [with the guide shafts 301 (1301) sliding through them] out of the trench 9 (now at least partially and preferably completely refilled) , leaving the guide shafts still locked to the bottom spreader and anchoring plates 701 (1701) . Once the wall panels 200 (1200) clear the top of the shafts 301 (1201) , the main part of the guide box assembly separates into the two, separated and disconnected wall panels 200 (1200) , with the bottom spreader bars 701 (1701) remaining down in the bottom of the filled trench and the upper spreader bars 801 having been preferably removed.

As a final step in the removal of a box assembly, the lower ends of the guide shafts 301 (1301) are unlocked or disengaged by appropriately rotating them, and they are then pulled up out of the at least partially filled and typically fully filled trench, leaving the interconnected barrier members 501 (101) in place resting on the bottom anchoring plates 701 (1701) . The parts of each guide box assembly are then reassembled, using new anchoring, spreader plates 701

(1701) , and re-used down the line as further needed to form the complete containment wall .

Thus, after the installation of the various barrier members 101 (501) is completed, as can be seen in the simplified, generalized Figure 8, the exemplary embodiment of the general containment system W is formed. Thus, as

should now be understood, the containment wall W includes a series of interconnected, adjacent, associated barrier members 1 slidingly engaged to form a subterranean, vertical, sealed barrier wall W. The barrier wall W stands on and penetrates an underlying, impermeably strata (e.g. clay) , the two in combination isolating the ground and its contents G, which can include, for example, toxic wastes, from the surrounding area A. The vertical height of the containment wall W may be of the order of five to forty (5-40') feet or more, depending on the depth of the underlying impermeable layer.

As discussed above, it should be understood that one barrier member 1 is preferably slid down into interconnec¬ tion with the other, adjacent, preceding one, using the male/female joint and associated seals described more fully above, as part of their in-ground installation. Guide box assemblies, such as the ones described above, which tem¬ porarily isolate the barrier members 1 from the surrounding ground G/A, preferably are used to guide and hold the various, constituent, barrier members 1 as they are interconnected together to ultimately form the completed containment wall W, as all described above. If needed, lubricants can be used to assist in sliding the joint coupling and gasket elements of the barrier members 1+ with respect to one another.

Figure 9 is a side view of the vertical barrier member 501 forming part of the wall W in its implemented state, illustrating a cross-sectional view of the containment area,

showing via arrows 24 an exemplary migration of contaminants.

As shown in the figure, the containment wall W is implemented vertically in a mostly subterranean manner to a sufficient depth to communicate with the fluid impermeable strata 20 such as clay or the like. The fluid impermeable vertical barrier wall system, communicating with the clay strata, forms a relatively 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, for example, lakes, rivers, and the water supply. It should be noted that neither the aquifer 21 nor the contaminant 24 permeates the clay strata 20. Thus, the use of the present invention prevents migration of the contaminants 24 in the site, and cuts off flow of the natural aquifer 21 in the•containment area. The vertical barrier wall , with its over-all impermeably sealed barrier 7, prevents migration of the contaminant and any tainted water in the containment site. As noted above, in order to prevent leeching of the contaminant between the bottom of the barrier and the clay strata 20, a layer of bentonite 25 or the like may be deposited at the base of the trench prior to installation of the barrier system. Also, as noted above, to further prevent leaching under the barrier wall, the guide boxes for the barrier members preferably are "tapped" into the clay

strata 20 a short distance to further seal the system into the underlying strata.

- Pass-Through Containment (Figs . 14 -16) - An exemplary embodiment and application of the in- ground barrier system with the pass-through features of the present invention is illustrated in Figures 14 & 16.

As can be seen in these figures and using the exemplary guide box assemblies and the barrier members of the present invention and installation methodology of the invention, a confined, contaminated area G, which includes typically a hazardous waste area containing, for example, heavy metals, toxic fluids and other substances, is created within the confines of the interconnected barrier members 2001. These barrier members 2001 are installed down into the ground, isolating the contaminated area G from the surrounding areas A.

The barrier members 2001 preferably extend down to and sealingly interface with an impervious, underlying layer or substrata 2020 of clay or the like. In some areas it may be desirable or necessary to have the barrier members 2001 extend down to a depth that may not have an impervious substrata.

Adjacent to the walled, confined area G is a confined, dug-out, work and equipment area or cell E, which contains within its walls W' pumping and hazardous waste processing equipment 2400. The equipment 2400 can be either portable or permanently installed equipment used for, for example, the in situ treatment of contaminated material contained within the area G.

An initial, entry pass-through P' is included through a special barrier member 2001' and a special associated guide box assembly 2002' extending from the confined contaminated area G into the work/equipment area or cell E. As can also be seen in Figure 15, the pass-through P' includes easily connected pipe sections 2900, which pass through the special barrier member 2001' by means of a flanged fitting 2901 fused to the barrier member. Sealed connections are used between the flanged connection 2901, pipe sections 2900 and the main wall of the barrier member 2001' so that the flow of contaminated fluids through the barrier member 2001' is controlled and not unrestricted.

During the manufacture of the guide box, access holes 2902, forming pass-through areas, are provided in the wall panels 2200A' & 2200B' of the special guide box assembly 2002' in the areas adjacent to the pass-through P' in the special barrier member 2001'. The pass-through areas 2200A & 2200B can be produced by, for example, pre-drilling or cutting a series of holes in the wall panels of the guide box. The holes can be, if so desired, outfitted with appropriate piping, hardware and seals to allow the fluids to freely flow under control through the installed piping directly into the manifold or opening of the in si tu processing plan 2400, or be merely open areas as illustrated. The illustrated, open pass-through areas allow access to the fitting 2901 in order to connect the pipe sections 2900 to the fitting after the guide box assembly 2002' and its associated special barrier member 2001' are installed in the ground.

Unlike most, if not all, of the other guide box assemblies 2002, the special guide box assembly 2002' is left in the ground after the barrier wall W is completed.

This provides additional security and strength for the special barrier members 2001' and its pass-through P'.

A second, exit pass-through P" is included through a like special barrier member 2001' and a like special associated guide box assembly 2002' extending from the work/equipment area E out to the surrounding area A. This provides an exit line for the discharge of, for example, clear, cleaned processed fluids from the processing and treatment equipment 2400. If so desired, this exit line, carrying cleaned up fluids and not e.g. toxic contaminants, can merely exit directly into the surrounding ground area A below the surface.

Thus, the pipe sections 2900 extend initially from the contaminated area G at entry pipe 2900A through the first pass-through P' into the work/equipment area E to the processing and treatment equipment 2400 and from there out to the outside area A through the second pass-through P" at exit or discharge pipe section 2900B.

In addition to the special guide box assemblies 2002', which include the special pass-throughways P' & P", the guide box assemblies 2002 which surround the plant area E are also preferably left in the ground after the walls & W have been completely formed. As can be seen in Figures 14 & 16, the two, encircled, adjacent areas G & E share a common barrier wall with the initial pass-through P' being located in the common barrier wall. The presence of the

guide boxes provides supporting walls surrounding the work/equipment area after the area has been excavated or dug out, resulting in an open but confined, protected and sealed work area. As can also be seen in Figure 16, a set of criss¬ crossing spreader beams 2905 can be included at the bottom of the dug-out work/equipment area E to prevent any inward movement of the guide boxes 2002 after the chamber E has been evacuated. These beams 2905 would be preferably installed prior to the total excavation of the work/equipment chamber E and can be attached to special pockets at the base of the guide box wall panels provided for this purpose in guide box assemblies designed to be used for this purpose or application. Additional support beams can be provided across opposed guide box wall panels 2200A, 2200B at levels higher than the floor or base of the work/equipment area E, if so desired. Likewise a partial or complete roof could be erected over the area E, if so desired, for protection of the workers and equipment from the weather.

The detail structure of exemplary barrier members and guide box assemblies and their installation methodology will be discussed below.

However, it should be understood that, rather than the containment wall W completely surrounding or going completely around the contaminated area G three hundred sixty (360°) degrees, a contaminated area can be effectively contained by a barrier wall which covers much less than 360° going only partially around it, taking into account the

natural direction(ε) of flow or migration of the contaminants. Additionally, rather than a straight or flat barrier surface around the pass-through area (P) , the wall in that area could be effectively curved in the lateral direction leading into the initial pass-through, in essence funneling the contaminants to the pass-through.

An exemplary embodiment and application of the in- ground barrier system with the pasε-through features of the present invention is illustrated in Figures 14 & 16. As can be seen in these figures and using the exemplary guide box assemblies and the barrier members of the present invention and installation methodology of the invention, a confined, contaminated area G, which includes typically a hazardous waste area containing, for example, heavy metals, toxic fluids and other substances, is created within the confines of the interconnected barrier members 2001. These barrier members 2001 are installed down into the ground, isolating the contaminated area G from the surrounding areas A. The barrier members 2001 preferably extend down to and sealingly interface with an impervious, underlying layer or substrata 2020 of clay or the like. In some areas it may be desirable or necessary to have the barrier members 2001 extend down to a depth that may not have an impervious substrata.

Adjacent to the walled, confined area G is a confined, dug-out, work and equipment area or cell E, which contains within its walls W pumping and hazardous waste processing equipment 2400. The equipment 2400 can be either portable

or permanently installed equipment used for, for example, the in si tu treatment of contaminated material contained within the area G.

An initial, entry pass-through P' is included through a special barrier member 2001' and a special associated guide box assembly 2002' extending from the confined contaminated area G into the work/equipment area or cell E. As can also be seen in Figure 15, the pass-through P' includes easily connected pipe sections 2900, which pass through the special barrier member 2001' by means of a flanged fitting 2901 fused to the barrier member. Sealed connections are used between the flanged connection 2901, pipe sections 2900 and the main wall of the barrier member 2001' so that the flow of contaminated fluids through the barrier member 2001' is controlled and not unrestricted.

During the manufacture of the guide box, access holes 2902, forming pass-through areas, are provided in the wall panels 2200A' & 2200B' of the special guide box assembly 2002' in the areas adjacent to the pass-through P' in the special barrier member 2001'. The pass-through areas 2200A & 2200B can be produced by, for example, pre-drilling or cutting a series of holes in the wall panels of the guide box. The holes can be, if so desired, outfitted with appropriate piping, hardware and seals to allow the fluids to freely flow under control through the installed piping directly into the manifold or opening of the in si tu processing plan 2400, or be merely open areas as illustrated. The illustrated, open pass-through areas allow access to the fitting 2901 in order to connect the pipe

sections 2900 to the fitting after the guide box assembly 2002' and its aεεociated εpecial barrier member 2001' are installed in the ground.

Unlike most, if not all, of the other guide box assemblies 2002, the special guide box assembly 2002' is left in the ground after the barrier wall is completed.

This provides additional security and strength for the special barrier members 2001' and its pass-through P'.

A second, exit pass-through P" is included through a like special barrier member 2001' and a like special associated guide box assembly 2002' extending from the work/equipment area E out to the surrounding area A. This provides an exit line for the discharge of, for example, clear, cleaned processed fluids from the processing and treatment equipment 2400. If so desired, this exit line, carrying cleaned up fluids and not e.g. toxic contaminants, can merely exit directly into the surrounding ground area A below the surface.

Thus, the pipe sections 2900 extend initially from the contaminated area G at entry pipe 2900A through the first pass-through P' into the work/equipment area E to the processing and treatment equipment 2400 and from there out to the outside area A through the second pass-through P" at exit or discharge pipe section 2900B. In addition to the special guide box assemblies 2002', which include the special pasε-throughwayε P' & P", the guide box assemblies 2002 which surround the plant area E are also preferably left in the ground after the walls & W have been completely formed. As can be seen in Figures

14 & 16, the two, encircled, adjacent areas G & E share a common barrier wall with the initial pass-through P' being located in the common barrier wall. The presence of the guide boxes provides supporting walls surrounding the work/equipment area after the area has been excavated or dug out, resulting in an open but confined, protected and sealed work area.

As can also be seen in Figure 16, a set of criss¬ crossing spreader beams 2905 can be included at the bottom of the dug-out work/equipment area E to prevent any inward movement of the guide boxes 2002 after the chamber E has been evacuated. These beams 2905 would be preferably installed prior to the total excavation of the work/equipment chamber E and can be attached to special pockets at the base of the guide box wall panels provided for this purpose in guide box assemblies designed to be used for this purpose or application.

Additional support beams can be provided across opposed guide box wall panels 2200A, 2200B at levels higher than the floor or base of the work/equipment area E, if so desired. Likewise a partial or complete roof could be erected over the area E, if so desired, for protection of the workers and equipment from the weather.

The detail structure of exemplary barrier members and guide box assemblies and their installation methodology was discussed above with reference to Figures 1-10.

However, it should be understood that, rather than the containment wall W completely surrounding or going completely around the contaminated area G three hundred

sixty (360°) degrees, a contaminated area can be effectively contained by a barrier wall which covers much lesε than 360° going only partially around it, taking into account the natural direction(ε) of flow or migration of the contaminants. Additionally, rather than a straight or flat barrier surface around the pass-through area (P) , the wall in that area could be effectively curved in the lateral direction leading into the initial pasε-through, in essence funneling the contaminants to the pass-through. Although the preferred application for the present invention is the containment of fluid wastes overlying a fluid impermeable strata, the invention can also be applied to other fields or applications such as, for example, soil containment for levees, containment of solid wastes, etc. It is noted that 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 embodimentε 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.