System and method of forming an underground slurry wall

A method of forming an underground slurry wall having the steps of: (a) providing a trencher having a trenching arm assembly with a cutting tooth track; (b) providing a dispensing tube proximate the cutting tooth track; (c) rotating the cutting tooth track; (d) extending the cutting tooth track below the outside surface, to, in turn, agitate the soil therebelow to a predetermined depth; (d) translating the trenching arm assembly across the outside surface so as to form an underground wall of agitated soil; (e) dispensing a clay-like material proximate the cutting tooth track; and (f) utilizing the cutting tooth track to mix the clay-like material into the soil while the cutting tooth track is rotating and translating, to, in turn, mix the clay-like material into the agitated soil. Systems are likewise disclosed.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The disclosure relates in general to trenching equipment and methods, and more particularly, to a system and method of forming an underground slurry wall which includes the mixing of outside material into an existing soil base through a trenching operation.

2. Background Art

The formation of underground slurry walls is well known in the art. An underground slurry wall is a non-structural wall that is a barrier to the movement of groundwater thereacross. Typically, the existing soil is mixed with an outside material (usually a clay-like material, such as bentonite) and then reintroduced into the trench. The addition of the outside material (hereinafter referred to as bentonite, although other materials are likewise contemplated) provides a barrier to the movement of horizontal groundwater. Additionally, for purposes of this material, clay-like material shall be defined as including bentonite, as well as other materials which may be natural or synthetic which are introduced into the soil during trenching so as to provide barrier properties to the soil. The disclosure is not limited to bentonite or to materials which include clay per se.

There are a number of manners in which to introduce the bentonite into the ground soil. For example, a deep trench may be dug, bentonite can be deposited into the deep trench, or mixed with the excavated soil, wherein the mixture is returned to the trench. It is understood that such a method may work for relatively shallow trenches, as it is difficult to dig deep trenches through such a method, and even for relatively shallow trenches, additional equipment, such as bracing and the like is required.

Other methods have a double trench approach. First a shallow trench is dug and bentonite is deposited into the shallow trench. Next, that trench may be backfilled so as to bury the bentonite. Once buried, a second trench is dug at the same location only deeper with trenching equipment that effectively mixes the bentonite through the entire depth with the existing soil. While such a trenching system is capable of use in deeper trenching environments, it is nevertheless less than optimal, as two separate trenches are required; first, a shallow trench to bury the bentonite, then a second deep trench on top of that trench to mix the bentonite to form the underground slurry wall. In many instances, such an approach results in extended time schedules, and often results in a very costly operation.

It is an object of the present invention to provide a relatively deep underground slurry wall, while mixing an outside material (such as bentonite) while forming the underground slurry wall in a single operation, while making a single pass across the landscape.

This objects as well as other objects of the present invention will become apparent in light of the present specification, claims, and drawings.

SUMMARY OF THE DISCLOSURE

The disclosure is directed to systems and methods for forming an underground slurry wall. Unlike prior art slurry walls that require multiple passes and multiple trenches, the present system is contemplated as forming the underground slurry wall in a single trenching operation.

More specifically, the method of forming an underground slurry wall comprises the steps of: (a) providing a trencher having a trenching arm assembly with a cutting tooth track; (b) providing a dispensing tube proximate the cutting tooth track; (c) rotating the cutting tooth track; (d) extending the cutting tooth track below the outside surface, to, in turn, agitate the soil therebelow to a predetermined depth; (d) translating the trenching arm assembly across the outside surface so as to form an underground wall of agitated soil; (e) dispensing a clay-like material proximate the cutting tooth track; and (f) utilizing the cutting tooth track to mix the clay-like material into the soil while the cutting tooth track is rotating and translating, to, in turn, mix the clay-like material into the agitated soil.

In a preferred embodiment, the clay-like material comprises bentonite.

In another preferred embodiment, the method further includes the steps of: (a) providing a storage container with the clay-like material remote of the trenching arm; and (b) feeding the clay-like material from the remote storage container to the dispensing tube at a predetermined rate.

In a preferred embodiment, the trencher further includes a cab spaced apart from the trenching arm, the storage container being coupled to the cab of the trencher.

Preferably, the step of feeding the clay-like material from the remote storage container further comprises the step of feeding the clay-like material through at least one flexible tube having a flexible auger positioned therein.

In another embodiment, the step of dispensing the clay-like material further comprises the steps of controlling the rate of flow of the clay-like material from within the dispensing tube.

In a preferred embodiment, the step of dispensing the clay-like material further comprises the step of providing an outside fluid to the clay-like material. Preferably, the outside fluid comprises water.

In another aspect of the disclosure, the disclosure is directed to a system for forming an underground slurry wall comprising a trencher, a material transport assembly, a material delivery assembly and a transport tube assembly. The trencher has a body, a boom pivotably coupled to and extending from the body and a trenching arm assembly pivotably coupled to and extending from the boom opposite the body. The material transport assembly has a distribution manifold spaced apart from the trenching arm. The material delivery assembly has a dispenser tube with a second end positioned adjacent the trenching arm, such that material dispensed from the second end can be mixed by the trenching arm during operation. The transport tube assembly extends from the distribution manifold to the dispenser tube. The transport tube assembly is configured to direct a clay-like material from the collection manifold to the dispenser tube during operation of the trenching arm, to, in turn, supply a clay-like material to the trenching arm during operation.

In a preferred embodiment, the material transport assembly further includes a collection manifold positioned adjacent to the trenching arm assembly. The collection manifold includes an inlet coupled to the tube transport assembly, and an outlet coupled to the dispensing tube.

In a preferred embodiment, the transport tube assembly further comprises at least one outer flexible tube that has an inner flexible auger extending therethrough, and a motor drive coupled to the flexible auger. The motor drive is configured to rotate the flexible auger within the outer flexible tube, to, in turn, direct the clay-like material from the distribution manifold to the collection manifold.

In another preferred embodiment, the at least one outer flexible tube comprises at least four outer flexible tubes, each of which includes an inner flexible auger extending therethrough, coupled to a motor drive.

In another preferred embodiment, the system includes a controller coupled to the motor drive. The controller is configured to control the speed of the motor drive, and in turn, the auger coupled thereto.

In another preferred embodiment, the dispensing tube further includes an auger extending therethrough, and a feed mixing tube positioned so as to be in fluid communication therewith. The transport tube assembly is coupled to the feed mixing tube, with the auger coupled to a motor.

In another preferred embodiment, a controller is coupled to the motor, to, in turn, control the speed of the motor and the speed of the auger.

In another aspect of the disclosure, the disclosure is directed to another system for forming an underground slurry wall comprising a trencher, a material transport assembly and a material delivery assembly. The trencher has a body, a boom pivotably coupled to and extending from the body and a trenching arm assembly pivotably coupled to and extending from the boom opposite the body. The material transport assembly is positioned proximate the trenching arm assembly. The material transport assembly has a cavity and an auger positioned proximate a lower end of the cavity. The material delivery assembly has a dispenser tube with a second end positioned adjacent the trenching arm, such that material dispensed from the second end can be mixed by the trenching arm during operation. Further, a feed mixing tube is in fluid communication with the dispenser tube spaced apart from the second end thereof. The auger of the material transport assembly is coupled to the feed mixing tube, to, in turn, direct a clay-like material from the cavity to the dispenser tube during operation of the trenching arm, to, in turn, supply a clay-like material to the trenching arm during operation.

DETAILED DESCRIPTION OF THE DISCLOSURE

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and described herein in detail a specific embodiment with the understanding that the present disclosure is to be considered as an exemplification and is not intended to be limited to the embodiment illustrated.

Referring now to the drawings and in particular toFIG. 1, the disclosure is directed to a trencher, such as trencher200, and more specifically to a trench material feed system10. Equipment such as trencher200is known in the art. Such trenchers can provide a trench of a specific desired depth in a single pass or in a single step. In various embodiments, a trench can be created that is of a desired width to a desired depth. Such trenchers will be described below in greater detail.

In many instances, it becomes necessary to mix in a separate component during the trenching process. For example, when making an underground barrier wall, it may become necessary to mix a clay like constituent into the mix to enhance the barrier properties of the natural soil. One such clay like constituent is bentonite, although other constituents are likewise contemplated for use. The remote material feed system10facilitates the inclusion and mixing of the prescribed amount of such a constituent during the formation of an underground barrier wall (often referred to as an underground slurry wall).

The trencher200utilized in association with the trenching remote material feed system10is shown inFIG. 1. Of course, the disclosure is not limited to any particular configuration and/or brand or model of trencher. In many instances, the trencher200comprises customized equipment that can be constructed from a conventional excavator. In other embodiments, a specialized trencher can be employed.

The exemplary trencher200is shown inFIGS. 1 and 2as comprising body202, track frame204, track206, boom208, boom cylinder210and trenching arm assembly212. The body202includes engine220, hydraulic pump222, counterweight224and cab226. Essentially, the body includes the power and control system for the trencher200.

The track frame is pivotally coupled to the body202and includes drive sprocket230, idler232and rollers234. Track206includes a plurality of shoes236which are rotatably coupled to each other. The track206spins around the drive sprocket230, idler232and rollers234so as to translate the trencher200across the ground or other surface.

The boom208includes first end240and second end242. The first end240is pivotally coupled to the body202and the second end242extends therefrom. The boom typically includes a boom cylinder210which facilitates the pivoting movement of the boom relative to the body202.

The trenching arm assembly212is shown inFIG. 1as comprising mounting housing250, arm cylinder252, arm254and cutting tooth track256. The mounting housing250may include hydraulic motors, or may draw hydraulic power from the engine220which is contained on the body202. The arm cylinder252facilitates the pivoting of the arm254relative to the boom208. The cutting tooth track256extends about arm254and includes a plurality of teeth258which are configured to dig into the ground. It will be understood that any number of differently configured trenchers are contemplated for use, and that the trencher200is merely exemplary.

As explained above, such a trencher200can be utilized in the present disclosure to form an underground slurry wall of a desired depth (limited only by the size of the trencher, the power thereof, and the length of the trenching arm assembly). It will be understood that bentonite (or other outside clay like material) can be mixed into the existing soil base in a single pass of the trenching equipment, thereby minimizing the time, expenditure and equipment required to form the underground slurry wall. It is contemplated that such underground slurry walls may be in excess of fifty feet deep, and may be closer to 100 feet deep or more, limited only by the trenching equipment, and the limitations thereof.

Trenching remote material feed system10is shown inFIG. 1as comprising material inlet hopper12, material transport assembly14, and material delivery assembly16. The material inlet hopper12is positioned on or proximate the body202of the trencher200. The material delivery assembly16is positioned at the second end242of boom208. The material transport assembly14extends between the material inlet hopper12and the material delivery assembly16and accounts for the movement of the material inlet hopper12relative to the material delivery assembly16, while, nevertheless delivering the necessary material between the material inlet hopper12and the material delivery assembly16. The material delivery assembly is positioned adjacent the trenching arm assembly.

The material inlet hopper12is shown inFIG. 3as comprising inlet20, walls22and outlet24. These structures define cavity23. The material inlet hopper, as shown, is configured so that the walls define a generally funnel like configuration wherein the inlet20is larger than the outlet, both of which are generally rectangular in shape. In one exemplary embodiment, the outlet has a rectangular configuration which is approximately 24 inches by 18 inches. Of course, other configurations are likewise contemplated, depending on the amount of material that is to be transmitted per unit time through the system10.

The material transport assembly14is shown inFIGS. 3,4and6as comprising distribution manifold30, collection manifold32and transport tube assembly34. The distribution manifold30is coupled to the material inlet hopper12at or near body202of the trencher200. The collection manifold32is coupled to the material delivery assembly16positioned at or near the mounting housing250of the trenching arm assembly212. The transport tube assembly34extends between the two manifolds.

The distribution manifold includes housing50and elongated cylinders60that extend through the housing50. The housing includes base52, first end wall54, second end wall55, front wall56, back wall57and upper opening58. The base52in the embodiment shown comprises a rectangular configuration, although other embodiments are likewise contemplated. The first end wall54and the second end wall55are spaced apart from each other and extend substantially perpendicular to the base52. The front wall56and the back wall57are spaced apart from each other and span between the end walls. The upper ends of the end walls, the front wall and the back wall together define the upper opening58. Generally, the housing50comprises a rectangular cubic configuration.

The outlet24substantially matches upper opening58of the distribution manifold30so that the material inlet hopper can be positioned above the upper opening58. In turn, material from the material inlet hopper can flow to the distribution manifold.

In the embodiment shown, four elongated cylinders, such as cylinder60, extend through each of the front wall56and the back wall57, at an angular displacement. As is shown, the four elongated cylinders60extend upwardly from the back wall57to the front wall56. In the embodiment shown, the elongated cylinders are disposed at an angle of between 10° and 60° and more preferably to between 30° and 45°. The elongated cylinders are substantially linear. The four elongated cylinders are spaced apart and substantially parallel to each other.

The four elongated cylinders60are substantially identical, so a single elongated cylinder is disclosed in detail with the understanding that the remainder are substantially identical. The elongated cylinder60includes first end opening62and second end opening64. The cylinder60is of a substantially uniform diameter. Between the front wall56and the back wall57, a portion of the cylinder is removed so as to define upper inlet opening66. The upper inlet opening66is in fluid communication with the first end opening62and the second end opening64.

In the embodiment shown, the elongated cylinders are welded to the housing50so that they are fixed together. It will be understood that the elongated cylinders are coupled together in other manners so that they do not move relative to each other.

The collection manifold32is shown inFIGS. 3,4, and5as comprising housing70, that includes base79, first end wall71, second end wall72, front wall73, back wall74, top wall75, bottom wall76, inlet openings77and outlet opening78. The configuration of the housing70comprises a rectangular cubic configuration, generally. The inlet openings77substantially correspond in diameter and cross-sectional area to the elongated cylinders60of the distribution manifold32, and extends through the front wall73generally perpendicularly to the front wall73. An outlet is positioned at the base79of the manifold. The top wall75can be hinged to the front or back wall so as to preclude the undesirable ingress or egress of material from within the collection manifold.

Of course, the configuration of the collection manifold can be varied within the scope of the present disclosure. In particular, the collection manifold can have a different configuration and can be positioned in varying orientations at or near the mounting housing250of the trenching arm assembly212.

The transport tube assembly34is shown inFIGS. 3 and 4, comprises a plurality of members that extend between one of the four elongated cylinders60and a corresponding one of the inlet openings77on the collection manifold32. As each of the members is substantially identical, a single transport tube will be described with the understanding that the remaining members have similar features.

The transport tube includes outer flexible tube80, inner flexible auger82and motor drive84. The outer flexible tube80includes outer surface85, inner surface86, distribution end87, and collection end88. The outer flexible tube generally comprises a polymer based tubular member that can flex to the extent necessary. PVC, ABS plastic, or the like are contemplated for use, and the invention is not limited to any particular tubing material. The outer flexible tube80generally comprises a single monolithic element, however, it is also contemplated that the outer flexible tube80may comprise a plurality of components that are coupled together end to end, or the like.

In the embodiment shown, the outer flexible tube is on the order of fifty feet long, and of monolithic construction. The outer flexible tube can flex several feet in any direction between the distribution end87and the collection end88. The distribution end87is coupled to the first end opening62of the elongated cylinder60of the distribution manifold30. The collection end is sealingly coupled to the inlet opening77of the housing of the collection manifold32. For example, a clamp may be utilized at either end of the outer flexible tube to sealingly couple the outer flexible tube to the collection manifold and the distribution manifold. In other embodiments, fittings may be coupled to either end of the outer flexible tube which matingly engage other fittings on the manifolds. Of course, other devices are likewise contemplated, such as seals and the like.

The inner flexible auger82includes first end90and second end92. The inner flexible auger82extends from the first end opening62of the elongated cylinder60, to the inlet opening77. That is, the first end90of the inner flexible auger82is positioned at or near the first opening62of the elongated cylinder60. The second end92extends to the inlet opening77.

The motor drive84is coupled to the first end90of the inner flexible auger, and is fixedly coupled to the distribution manifold, and in particular at the first end opening62. The motor drive84is controlled from the controller94which can be located within cab226of the body202. The motor drive84may comprise a separate or distinct motor unit, or, may be hydraulic, which can be coupled to the engine220of the trencher200. When actuated, the motor drive84rotates the inner flexible auger82in the desired direction of rotation. The controller controls the rotative speed of the motor drive, to, in turn, control the speed at which the auger rotates.

The material delivery assembly16, shown inFIG. 7, comprises dispensing tube40, auger42, motor assembly44and feed mixing tube46. The dispensing tube40includes first end102, second end104, inner surface106and passageway108. The passageway108extends from the first end102to the second end104. In the embodiment shown, the passageway108is substantially uniform between the first and second ends.

The auger42includes first end110and second end112. The first end110corresponds to the first end102of the dispensing tube40. The second end112corresponds to the second end104of the dispensing tube40. The second end of the dispensing tube is positioned adjacent to the trenching arm so that material exiting therefrom can be quickly mixed by the trenching arm during operation. It will be understood that the second end position relative to the trenching arm can be varied to achieve the desired mixing of the constituents. The first end110of the auger42is coupled to motor assembly44, which includes motor114and controller116. The motor114comprises, for example, a hydraulic motor, which may be powered locally, or from the engine220of the body202of the trencher200. The controller116is coupled to the cab226, so that the controller can be instructed from within the cab, to control, for example, the speed of the motor114, and, in turn, the speed of the auger to which the motor is coupled.

The feed mixing tube46is shown inFIG. 7as comprising first end118, second end120, inner surface122and passageway124. The first end118of the feed mixing tube46is coupled to the outlet opening78of the collection manifold32. The second end120is coupled to the dispensing tube between the first and second ends, so as to direct material toward and into the auger42. The feed mixing tube46may also include an inlet for water or another fluid, such that the material from within the collection manifold can be mixed with water (or another fluid) just prior to, or just as the material is entering into the auger42so as to form a slurry that is introduced to the trenching arm for mixing.

The second end of the dispensing tube is104is directed into the trench proximate the arm254, so that the material exiting from within the material delivery assembly is mixed with the trenching soil to result in a substantially uniform distribution through the trench.

In operation, such equipment is well suited to providing a particular fill material into a trench for mixing with existing soil so as to form an underground slurry wall (sometimes referred to as a barrier wall). For example, it is often necessary to mix a clay-like material, such as bentonite or the like, into existing soil (also referred to as native soils) to alter the properties of that soil in a desirable manner. The percentage of bentonite that is required is based on the properties of the native soils, as well as the existing surrounding conditions. It is not uncommon to have a bentonite percentage of between 1% and 5%. The particular requirements of a project are typically determined through analysis and calculations which are commonly known to those of skill in the art.

In the past, it has been known to add bentonite into native soil at a trenching site to enhance the barrier properties of the soil to form a slurry wall. Typically, this is achieved by digging a small trench of relative shallow depth, and then inserting the desired amount of bentonite, and, optionally, refilling with soil. A trencher is then brought over the same trench, at, typically, a significantly greater trenching depth to mix the soil in the trench with the inserted bentonite. Problematically, this tends to require a multitude of steps, namely the digging of a first shallow trench, refilling of the trench, and then a second trenching operation so as to mix the soil with the inserted material (bentonite).

Advantageously, with the present system, a user can make a single trenching operation to the required depth and mix the material (bentonite) in a single operation. Moreover, in the preferred embodiment, the bentonite, or other material that is contemplated (as disclosed above), can be supplied remote of the trench. This is often very useful where there is very little stable ground on either side of the trench. Where there is plenty of stable ground, the bentonite can be supplied to the collection manifold directly by way of a loader, excavator, truck, conveyor or the like.

The embodiment that will be described in detail comprises one wherein the bentonite is supplied to the distribution manifold located at or near the body of the trencher (i.e., the embodiment shown inFIGS. 1 through 7). It will be understood that the disclosure is not limited to such a structure, and that, indeed, a number of different manners of delivery are contemplated.

As an initial matter, it will be understood that the distribution manifold is located remotely from the trenching arm assembly, such as, for example, on top of the body202of the trencher200, or in close proximity thereto. The collection manifold is positioned proximate the mounting housing250of the trenching arm assembly212. The transport tube assembly34extends therebetween. In the embodiment shown, there are a total of four outer flexible tubes which extend between the distribution manifold and the collection manifold. In the embodiment shown, it is contemplated that each of the flexible tubes may be between twenty and one hundred feet long, although, it is contemplated that they may be longer or shorter as well.

In such an embodiment, bentonite is typically provided in a bulk bag, a large sack, or in another storage container. The bentonite is then removed from the bulk bag and placed into the collection manifold. It will be understood, that in certain embodiments, the collection manifold may include a bulk bag piercing structure so that a full bulk bag can be dropped into the collection manifold onto the piercing structure, and then, the piercing structure can puncture the bulk bag allowing the bentonite to be released into the housing.

Once the bentonite is within the housing of the collection manifold, the transport tube assembly is activated. That is, the motor drive84is activated directing the inner flexible augers to rotate at a speed prescribed by the controller94. As the inner flexible augers rotate, the bentonite is first directed into the upper inlet opening66of the elongated cylinders in the distribution manifold. Continuous rotation of the inner flexible auger then pushes and draws the material into the outer flexible tube80. Thus, taken from the distribution manifold and directed to the collection manifold. The rate of material delivery from the distribution manifold to the collection manifold can be metered by adjusting the speed of the motor drive so as to control the rotational speed of the inner flexible auger. An increase in speed, will correspondingly increase the quantity of material delivered to the collection manifold.

As the bentonite reaches the collection manifold, it collects therewithin and is directed to the outlet opening78. From within the outlet opening78, bentonite is directed to the first end of the feed mixing tube46. At this point, the bentonite can be mixed with water to achieve a certain desired consistency of the material.

As the bentonite reaches the second end of the feed mixing tube, the bentonite is directed into the dispensing tube and then driven toward the second end thereof by the auger42positioned within the dispensing tube. It will be understood that the ultimate feed rate of the bentonite through the dispensing tube is controlled by the speed of the auger42. It will also be understood that the speed of the auger can be coupled to the speed of the trencher along the trench, as well as the speed of the cutting tooth track256of the trencher, so as to insure that the proper amount of bentonite is delivered to the trench to achieve the proper mix of materials.

It will be understood that a controller may control the speed of the auger relative to the other parameters, such as cutting tooth track speed, trenching speed, water supply pressure, trench soil constituents and variations, among other parameters. The user can also manually adjust and alter the speed of the auger, and in turn, the rate at which the bentonite is supplied into the soil.

While the distribution manifold is shown as being coupled to the body of the trencher, it will be understood that the distribution manifold can be positioned on, for example, a skid or a pallet, which is positioned on the ground or on other equipment, such as a truck or the like. It will also be understood that the collection manifold may be associated with the boom or the trenching arm assembly, or, alternatively, may be coupled to another structure proximate the location of the trenching arm assembly.

It will be understood that in other embodiments, wherein a remote delivery is not required or desired, an alternate delivery system is contemplated for use. Such an embodiment is shown inFIGS. 8 through 10, as comprising a single material transport assembly14′. With reference toFIGS. 9 and 10, The single material transport assembly14′ includes a body having an angled shape so as to define a cavity with an auger170positioned at the bottom thereof. Such a single material transport assembly14′ can be coupled to either one or both of the boom or the trenching arm assembly, or, in other embodiments, positioned proximate thereto, such that gravity feed of the bentonite is facilitated proximate to the material delivery assembly.

The bentonite is dropped into the body (and, in the embodiment shown, the bentonite can be dropped into the body with the entirety of the bulk bag, wherein the bulk bag is pierced). The bentonite then is through gravity directed to the auger and the auger directs the same to the outlet opening178.

The outlet opening178is coupled to the first end118of the feed mixing tube. Once the bentonite reaches the first end118, the operation is substantially identical to that of the embodiment described above.