This application relates generally to liner systems for vertical mine shafts and underground tunnels and, more particularly, to a low profile liner plate system and method for providing a waterproof shaft or tunnel.
Vertical mine shafts often encounter issues with water penetration, particularly when one or more vertical sections of the mine shaft pass through porous ground water containing layers. Prior attempts to address this issue include cast iron tubbing, welded steel panels, composite bolted systems and others. However, such technologies have proven expensive and timely to install.
PCT Publication No. WO 2011/097201 discloses a mine shaft liner plate system with a sealing arrangement, where the plates include a primary plate portion surrounded by flanges, and the primary plate portion includes a structural member at its radial outer side for added strength. The described plate system is particularly useful for installations in new mine shafts.
Many existing, older mine shafts have a concrete based shaft seal system, which was typically poured-in-place. Over tens of years the concrete system begins to degrade. The current method for upkeep is to periodically shut down the mine (e.g., once a year for several weeks), chip out the aged/worn concrete and replace it with new concrete or, in some cases, install a welded steel liner in the chipped out region and the back grout along the radially outer side of the line. However, this process is very time consuming and, therefore, costly.
Accordingly, it would be desirable and advantageous to provide a more economical system and method of sealing vertical mine shafts, and particularly rehabilitating vertical mine shafts and other types of tunnels.
In one aspect, a method of rehabilitating a vertical mine shaft bounded by a concrete wall structure is provided. The method involves: removing an interior portion of the concrete wall structure; and installing a liner plate system adjacent the concrete wall structure including: utilizing a plurality of arcuate liner plate units, each arcuate liner plate unit including a radially outer side and a radially inner side, the radially inner side including a peripherally extending seal recess having a seal material thereon, the seal material having an uncompressed radial thickness greater than a radial depth of the seal recess so as to protrude beyond a primary inner surface of the radially inner side; utilizing a plurality of liner lock plates, each lock plate having an inner side and an outer side, the outer side including a seal recess formed therein, the seal recess having a seal material thereon, the seal material having an uncompressed thickness greater than a depth of the seal recess so as to protrude beyond a primary outer surface of the outer side; arranging the arcuate liner plate units and the liner lock plates to form a cylindrical wall structure, with a first set of arcuate liner plate units forming a first ring and a second set of arcuate liner plate units forming a second ring, the first ring having a top edge, bottom edge and multiple vertical edge joints, the second ring having a top edge, bottom edge and multiple vertical edge joints, the top edge of the first ring abutting a bottom edge of the second ring to form a lateral edge joint, the vertical edge joints of the first ring circumferentially offset from the vertical edge joints of the second ring, the liner lock plates positioned along an inner side of the cylindrical wall structure with the seal material of the liner lock plates in contact with the seal material of the arcuate liner plate units; and utilizing threaded members to hold the liner lock plates adjacent the arcuate liner plate units such that the cylindrical wall structure formed by the combination of the liner lock plates and the arcuate liner plate units is a rigid, unitary structure.
In one implementation, each lock plate includes a plurality of openings therein, the threaded members are either mount studs welded to the radially inner side of the arcuate liner plate unit or bolts threadedly inserted into threaded openings at the radially inner side of the arcuate liner plate unit, in either case each threaded member passes through a respective one of the lock plate openings.
In one implementation, the liner lock plates include multiple T-shaped lock plates, where the ends of the T-shape are spaced apart from each other when the T-shaped lock plates are joined to the arcuate liner plate units.
In one implementation, the liner lock plates include multiple splice plates interconnecting the T-shaped lock plates, the splice plates including vertically oriented splice plates and laterally oriented splice plates.
In one implementation, each end of each T-shaped lock plate includes a recessed mating region at its radially inner side, each end of each splice plate includes a recessed mating region at its radially outer side, and the recessed mating regions of the T-shaped lock plates overlap the recessed mating regions of the splice plates.
In one implementation, the seal recess of each T-shaped lock plate extends to each end thereof; the seal recess of each splice plate extends from one recessed mating region of the splice plate to the other recessed mating region of the splice plate, and the ends of the T-shaped lock plate seal recesses are adjacent the ends of the splice plate seal recesses.
In one implementation, the liner lock plates include multiple intermediate plates connected between spaced apart T-shaped lock plates, the intermediate plates including vertically oriented intermediate plates and laterally oriented intermediate plates, each end of each T-shaped lock plate is positioned proximate to or in abutment with an end of an adjacent intermediate plate without any overlap between the T-shaped lock plates and the intermediate plates.
In one implementation, each T-shaped lock plate covers a portion of one of the vertical edge joints and a portion of the lateral edge joint.
One implementation includes the further step of applying a chemical weld activator coating to seal members of the arcuate liner plate units and/or seal members of the locking plates so that when two seal members engage each other they become welded together.
One implementation includes the further step of performing a backgrouting operation at the radially outer side of the liner plate system to provide continuity between the liner plate system and the concrete wall structure.
In another aspect, a liner plate system for lining shafts or tunnels is provided. The system includes a plurality of curved liner plate units and a plurality of line lock plates. Each curved liner plate unit includes a radially outer side and a radially inner side, the radially inner side including a peripherally extending seal recess having a seal material thereon. Each liner lock plate has an inner side and an outer side, the outer side including a seal recess formed therein, the seal recess having a seal material thereon. The curved liner plate units and the liner lock plates arranged to form a curved wall structure. The curved liner plates form multiple rings, each ring having a first end edge, a second end edge and multiple interior edge joints. The rings are arranged end to end such that abutting end edges form multiple end edge joints. The interior edge joints of each ring are circumferentially offset from the interior edge joints of each adjacent ring. The liner lock plates are secured along an inner side of the curved wall structure with the seal material of the liner lock plates pressed into contact with the seal material of the curved liner plate units in order to seal both the end edge joints between adjacent rings and the interior edge joints of each ring.
In one implementation, a plurality of threaded members secure the liner lock plates to the curved liner plate units, wherein each liner lock plate includes a plurality of openings therein and through which a respective one of the threaded members extends.
In one implementation, the threaded members are formed by threaded mount studs extending inwardly from the radially inner sides of the curved liner plate units and nuts on the mount studs hold the liner lock plates adjacent the curved liner plate units and compress the seal material therebetween.
In one implementation, each of the curved liner plate units includes a plurality of threaded holes and the threaded members are formed by bolts, each bold extending through a respective one of the liner lock plate openings and into a respective one of the threaded holes to hold the liner lock plates adjacent the curved liner plate units and compress the seal material therebetween.
In one implementation, the seal material of the curved liner plate units is chemically welded to the seal material of the liner lock plates.
In one implementation, the seal recess of each liner lock plate aligns with side by side seal recesses of the curved liner plate units such that the seal material of the seal recess of each liner lock plate is pressed into contact with seal material of at least two curved liner plate units.
In one implementation, the liner lock plates include multiple T-shaped lock plates, where ends of the T-shape are spaced apart from each other when the T-shaped lock plates are joined to the curved liner plate units.
In one implementation, the liner lock plates include multiple splice plates interconnecting the T-shaped lock plates, each end of each T-shaped lock plate includes a recessed mating region at its radially inner side, each end of each splice plate includes a recessed mating region at its radially outer side, and the recessed mating regions of the T-shaped lock plates overlap the recessed mating regions of the splice plates.
In one implementation, the liner lock plates include multiple intermediate plates connected between spaced apart T-shaped lock plates, and each end of each T-shaped lock plate is positioned proximate to or in abutment with an end of an adjacent intermediate plate without any overlap between the T-shaped lock plates and the intermediate plates.
In one implementation, multiple seal joints are formed between ends of the T-shaped lock plates and adjacent ends of the intermediate plates, at each seal joint seal material of the T-shaped lock plate and seal material of the intermediate plate is compressed to create an abutting and sealing contact therebetween.
In one implementation, each T-shaped lock plate covers a portion of one of the interior edge joints and a portion of one of the end edge joints.
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In one example, the seal material may be formed by a polymeric seal that is applied via a plural component material processing technique. As used herein, the term plural component processing technique means blending two or more chemicals together in a specific or varying ratio with either direct impingement equipment, equipment utilizing a static mixer assembly to mix/bled the chemicals or by mixing in an open container by hand or by other mechanical mixing method to produce material that cures to some degree. Prior to applying the seal material, the seal recesses may be prepared by use of an abrasive blast process that forms a 3 mil minimum surface profile on the bottom and sides of the recess, which assures good bonding or adhesion of the seal member within the recess. Where the seal material is applied so as to protrude from the top of the recess, a planing type device may be used to trim the seal member down to a specified, desired height. However, other techniques could also be used to achieve the final height of the seal member. Moreover, other seal materials could be used as well. A chemical weld activator coating may be applied to surfaces of abutting seal members so that when the two seal members engage each other they become welded together, further enhancing the seal effect. By way of example, the polymeric seal material may be a plural component impingement mix polyurea product and the chemical weld activator may be a single component, brush applied material that will chemically bond thermoset polyurethane/polyurea material systems.
In one embodiment, a bonded monolithic polymer seal (BMPS) material may be used, made up of a plural component system consisting of an “isocyanate” (also known as a diisocyanate with other variations that may include: isophorone diisocyanate, methylene diphenyl diisocyanate, toluene diisocyanate or hexamethylene diisocyanate) and mixed with one or more of the following: an alcohol, an hydroxyl, a polyol, or an amine, creating a “polyurethane or polyurea” compound. An example of this material is Custom Linings 911 pure polyurea, available from Custom Linings, Inc. of Beuna Vista, Colorado, but there are products that may be used.
Thus, the described system provides a low profile liner system (e.g., full radial depth from radially inner end of the bolt studs 24 to the radially outer side of the liner plates being less than 4 inches, such as between two and three inches). The liner system enables a method of rehabilitating a vertical mine shaft bounded by a concrete wall structure. The method involves (1) removing an interior portion of the concrete wall structure; (2) installing a liner plate system including: (a) utilizing a plurality of arcuate liner plate units, each arcuate liner plate unit including a radially outer side and a radially inner side, the radially inner side including a peripherally extending seal recess having a seal material thereon, the seal material having a radial thickness greater than a radial depth of the seal recess, each arcuate liner plate unit further including a plurality of threaded mount studs extending inwardly from the radially inner side; (b) utilizing a plurality of liner lock plates, each lock plate having an inner side and an outer side, the outer side including a seal recess formed therein, the seal recess having a seal material thereon, the seal material having a thickness greater than a depth of the seal recess, each lock plate further including a plurality of openings therein; and (3) arranging the arcuate liner plates and the liner lock plates to form a cylindrical wall structure, with a first set of arcuate liner plates forming a first ring and a second set of arcuate liner plates forming a second ring, the first ring having a top edge, bottom edge and multiple vertical edge joints, the second ring having a top edge, bottom edge and multiple vertical edge joints, the top edge of the first ring abutting a bottom edge of the second ring, the vertical edge joints of the first ring circumferentially offset from the vertical edge joints of the second ring, multiple liner lock plates positioned along the inner side of the first and second ring with the seal material of the liner lock plates in contact with the seal material of the arcuate liner plates, the threaded mount studs of the arcuate liner plates extending through openings of the liner lock plates, nuts on the mount studs holding the liner lock plates adjacent the arcuate liner plates.
As previously indicated, the threaded mount studs may either welded to the radially inner side of the liner plate or threadedly inserted into threaded openings at the radially inner side of the liner plate, with nuts used for securing the plates together. In another embodiment, represented by
The liner lock plates may include multiple T-shaped lock plates 14A, where the ends of each T-shaped lock plate are spaced apart from the ends of other T-shaped lock plates when the T-shaped lock plates are joined to the arcuate liner plates. The liner lock plates further include multiple intermediate splice plates interconnecting the T-shaped lock plates, the splice plates including vertically oriented splice plates 14C and laterally oriented splice plates 14B.
In the above-described illustrated embodiment, each end of each T-shaped lock plates may include a recessed mating region at its radially inner side, and each end of each intermediate plate may include a recessed mating region at its radially outer side. The recessed mating regions of the T-shaped lock plates overlap the recessed mating regions of the intermediate plates. In an alternative embodiment, the recessed mating regions, and resulting overlap of the lock plates, may be absent.
In this regard,
In both embodiments, the seal recess of each T-shaped lock plate extends to each end thereof In the embodiment of
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Regardless of the embodiment of the liner system, once the liner system is assembled/installed, a backgrouting operation at the radially outer side of the liner system (e.g., into the space 190 (see
While particular embodiments have been illustrated and described, it is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible.
This application claims the benefit of U.S. provisional application Ser. No. 61/704,067, filed Sep. 21, 2012, which is incorporated herein by reference.
Number | Date | Country | |
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61704067 | Sep 2012 | US |