Embodiments described herein relate to rock anchors, and in particular, to expandable rock anchors that include multiple passages for draining fluid from the rock anchors.
Underground mining is widely used to excavate minerals and other materials from beneath the earth's surface. Underground mining is often performed in harsh environments, and mining equipment is regularly subjected to damaging conditions, including corrosive substances. The effects of these corrosive substances are particularly acute for equipment that is embedded in a mining application, since this type of equipment is often exposed to the harsh environment and unavailable for cleaning or inspection for extended periods of time. Furthermore, embedded mining equipment often provides structural support for a mine, so avoiding failure of this type of equipment is a priority.
Certain embodiments described herein relate to, include, or take the form of a self-draining rock anchor that includes an elongate anchor body and a bushing. The elongate anchor body is configured to be at least partially disposed in a cavity that extends from a surface of a rock structure into the rock structure. The elongate anchor body comprises a sidewall that extends along a length of the elongate anchor body. The sidewall defines first and second openings that extend through the sidewall. The bushing is disposed around the elongate anchor body and configured to interface with a washer disposed around the elongate anchor body. The bushing defines third and fourth openings that substantially align with the first and second openings in the elongate anchor body, respectively. The first and third openings form a first passage into an interior volume of the elongate anchor body, and the second and fourth openings form a second passage into the interior volume of the elongate anchor body. Further, the elongate anchor body has a first diameter in a first configuration. The interior volume of the elongate anchor body is configured to receive an inflation agent via at the least one of the first or second passages, thereby causing the elongate anchor body to expand to a second expanded configuration in which the elongate anchor body has a second diameter greater than the first diameter. In the second expanded configuration, an exterior surface of the sidewall of the elongate anchor body is configured to engage with an interior surface of the cavity, thereby retaining the elongate anchor body in the cavity. Further, the bushing is configured to exert a force on the washer, thereby causing the washer to exert a corresponding force on the surface of the rock structure. Additionally, the first and second passages facilitate substantially complete draining of the interior volume.
Other embodiments described generally reference a rock anchor comprising an anchor body and a bushing. The anchor body defines an interior volume and comprises a first sealed end and a second sealed end. The bushing is fixedly disposed around a portion of the anchor body and defines an exterior surface. The bushing is configured to be disposed at least partially within an inflation device in an inflation configuration. The inflation device defines an opening and comprises an inflation ring that is configured to encircle the bushing in the inflation configuration. The anchor body and the bushing define first and second substantially cylindrical passages extending from the exterior surface of the bushing into the interior volume of the anchor body. In the inflation configuration, at least one of the first or second substantially cylindrical passages is configured to align with the inflation ring, and the interior volume of the anchor body is configured to receive an inflation agent from the inflation ring via the at least one of the first or second substantially cylindrical passages, thereby causing the anchor body to expand from a first shape having a first diameter to a second shape having a second diameter greater than the first diameter. In a draining configuration, the first and second substantially cylindrical passages fluidly couple the interior volume to an ambient environment to drain substantially all fluid from the interior volume via the first and second passages, and the anchor body maintains the second shape.
Still other embodiments described generally reference a method for expanding and draining an expandable rock anchor that includes the steps of inserting, at least partially into a borehole, a rock anchor having a first shape having a first diameter that is less than a diameter of the borehole, the rock anchor defining first and second openings to an interior volume of the rock anchor. The steps further include substantially filling the interior volume with fluid using at least one of the first or second openings, thereby causing the rock anchor to expand to a second shape having a second diameter that is greater than the first diameter and substantially equal to the diameter of the borehole. The steps further include draining substantially all of the fluid from the interior volume using the first and second openings. In addition, the rock anchor maintains the second shape following the draining of substantially all of the fluid from the interior volume, and an exterior surface of the expanded rock anchor engages with an interior surface of the borehole, thereby retaining the rock anchor in the borehole.
Reference will now be made to representative embodiments illustrated in the accompanying figures. It should be understood that the following descriptions are not intended to limit this disclosure to one preferred embodiment. To the contrary, the disclosure provided herein is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments, and as defined by the appended claims.
The use of the same or similar reference numerals in different figures indicates similar, related, or identical items.
Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto.
Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the claims.
Rock excavations, including underground tunnels and other passageways common in mining and other subterranean activities can collapse. A collapse may harm people in and round the excavation and cause damage to equipment. As a result, techniques are required to support the rock excavations. Support structures can be inserted into ceilings and walls to strengthen them. For example, a tube-like structure may be inserted into a hole in the ceiling or wall and subsequently be expanded within the hole to add internal structural strength.
Rock anchors (e.g., rock bolts, anchor bolts, and the like), such as those described herein, are used for stabilizing rock excavations, such as mines. In various embodiments, expandable rock anchors may be inserted into a cavity (e.g., a borehole) in a rock structure or other mass and are inflated (e.g., expanded) by introducing an inflation agent (e.g., pressurized gas or fluid) to an interior volume of the rock anchor.
The mass 184 may be any substantially solid material or combination of materials, including rock, soil, ice, sand, concrete, and so on. In some embodiments, the surface 182 of the mass 184 is a rock structure, such as a wall or ceiling in a tunnel. The mass 184 may be above or below ground level. In some embodiments, the mass 184 is a wall of a tunnel in an underground mine. The rock anchor 100 may be formed of any suitable material or combination of materials, including metal, polymers, composites, ceramics, and so on. In some embodiments, the rock anchor 100 is formed of steel. The rock anchor 100 may further include various treatments, coatings, and/or linings to improve performance in its application.
In certain applications, the inflation agents that are introduced to the rock anchor 100 are corrosive to the rock anchor. Similarly, while the rock anchor 100 is disposed in the mass 184, it may be exposed to additional corrosive substances, such as groundwater and other corrosive fluids. These corrosive substances may intrude into the interior volume of the rock anchor 100.
In conventional solutions, substantial amounts of inflation agents and other damaging intruded substances may remain in the rock anchors for extended periods of time, and as a result, corrode or otherwise damage the rock anchor. For example, the inflation agent may be water (e.g., groundwater) with corrosive properties that, if left in contact with the rock anchor, leads to corrosion or other damage to the rock anchor. This may affect the structural properties of the rock anchor, such as making it more prone to failure and requiring it to be removed from its application prematurely.
The rock anchors 100 described herein allow for substantially complete draining of fluids, including inflation agents and intruded substances, from their interior volumes. The rock anchors 100 include multiple passages into the interior volume for more effectively draining fluid from the rock anchors during or after inflation processes and during normal use.
Referring to
The passages 140A and 140B may also be used to drain inflation agents and/or other fluids from the interior volume(s), such as while the rock anchor 100 is disposed in a cavity 180 as shown in
As shown in
In some embodiments, the cross-sectional area of the single interior volume 215 of
As shown in
In some embodiments, an end of the bushing 120 defines a lip 322. The exterior diameter and/or the interior diameter of the bushing may increase along a portion of the length of the bushing. The lip 322 may be configured to interface with a washer during use of the rock anchor 100, as discussed in more detail below with respect to
In some embodiments, the bushing 120 is between 2 and 2.5 inches in length and between 1 and 1.5 inches in width. In another embodiment, the bushing is 2.31 inches long and 1.19 inches wide. In some embodiments, the rock anchor 100 is between 5 and 15 feet long, but it may be longer or shorter. In another embodiment, the rock anchor is 8 feet long. In some embodiments, the anchor body has a diameter between 0.5 and 3 inches in the unexpanded configuration and between 2 and 5 inches in the expanded configuration. In another embodiment, the anchor body diameter is 1 inch in the unexpanded configuration and 2 inches in the expanded configuration. The dimensions described in this section and elsewhere herein are for example purposes only. In practice, the described elements may be larger or smaller than described. In some embodiments, any value or measurement expressed herein may have a margin of error (e.g., plus-or-minus 5 percent), and need not be exact.
In some embodiments, the end cap 130 and/or the bushing 120 reinforce the sealed ends 151. For example, the end cap 130 and/or the bushing 120 may exert a force on the anchor body 110 that keep the surfaces of the sidewall pressed together, thus maintaining the seal.
In some embodiments, such as the embodiment of
The openings 344 and openings 342 may have the same shape and size (e.g., cross-sectional area) or may have different shapes and/or sizes from each other. For example, one or more openings 344 may have different shapes and/or sizes from other openings 344, and similarly, one or more openings 342 may have different shapes and/or sizes from other openings 344. Additionally, an opening 344 may have a different shape and/or size than the opening 342 with which it is aligned. The openings 344 and openings 342 may be formed using separate operations (e.g., drilled separately), or they may be formed by a single operation, (e.g., drilling through both the bushing 120 and the anchor body 110). As used herein, a passage may refer collectively to an opening 344 and a corresponding opening 342 that are aligned with one another.
The passages 140 may have a substantially circular cross-section (e.g., substantially cylindrical), or they may be shaped differently (e.g., rectangular, elliptical, irregular, or the like). The passages 140 (and the openings 344 and openings 342) may be formed using a variety of methods, including drilling, cutting, punching, boring, and so on. In some embodiments, the passages 140 are 3/16″ diameter holes. In another embodiment, the passages 140 are between 0.1 and 0.3 inches in diameter. In yet another embodiment, the passages 140 are between 0.05 and 0.5 inches in diameter.
In some embodiments, the passages have a longitudinal offset C of between 0.2 and 0.4 inches. In another embodiment, the longitudinal offset C is 0.3125 inches. In some embodiments, the distance from the bottom of the rock anchor 100 to the passage 140A (e.g., distance a in
In some embodiments, as shown in
As shown in
The rock anchor 100 includes a washer 190 disposed around the anchor body 110. The washer 190 is configured to contact a surface 182 of the mass 184 when the rock anchor 100 is in use. The bushing 120 is configured to interface with the washer 190. In some embodiments, the lip 322 of the bushing 120 interfaces with the washer 190 and keeps the washer 190 from sliding off the end of the rock anchor 100. In some embodiments, the bushing 120 exerts a force on the washer 190, and the washer 190, in turn, exerts a corresponding force on the surface 182 (e.g., upward with respect to
In some embodiments, the force exerted by the bushing 120 on the washer 190 is caused at least partially by a reduction in the overall length of the rock anchor 100 that occurs during expansion of the rock anchor. For example, the rock anchor 100 may have a first length in the unexpanded configuration and a shorter second length in the expanded configuration. This may result from the expansion of the anchor body of the rock anchor 100. In some embodiments, when the length of the rock anchor 100 is reduced during expansion, it causes the bushing 120 to be drawn toward the cavity 180, which may cause the bushing to exert the force on the washer 190, which in turn exerts the corresponding force on the surface 182 because the washer is disposed between the bushing and the surface.
In some embodiments, the diameter of the cavity 180 is substantially equal to the diameter of the anchor body 110 in the expanded configuration, which is greater than the diameter of the anchor body 110 in the unexpanded configuration. In some embodiments, the diameter of the cavity 180 is between 1 and 5 inches. In another embodiment, the diameter of the cavity is 2 inches.
As shown in
The rock anchor 100 in
As shown in
As described above, the rock anchor 100, including the anchor body 110, the bushing 120, the end cap 130, and the washer 190 may be formed of any suitable material or combination of materials, including metal, polymers, composites, ceramics, and so on. In some embodiments, the rock anchor 100 is formed of steel. The rock anchor 100 may further include various treatments, coatings, and/or linings to improve performance in its application.
After inflation, the inflation chuck 750 is removed from the rock anchor 700 and the rock anchor 700 is in a draining configuration. In some embodiments, in the draining configuration, the passages 740 couple the interior volume of the rock anchor 700 to the ambient environment, and the fluid or gas drains from the interior volume via the passages 740. In some embodiments, the draining occurs as a result of pressure release and/or gravity. As discussed above, in various embodiments, substantially all of the fluid or gas is drained from the rock anchor 700.
At step 830, substantially all of the inflation agent is drained from the rock anchor. In various embodiments, fluid, including the inflation agent, is drained from the rock anchor using at least two passages in the rock anchor. In some embodiments, removing the inflation device from the rock anchor, for example in response to the rock anchor reaching the second configuration having the second shape, fluidly couples the interior volume to the ambient environment via the passages. In some embodiments, fluid flows out of the interior volume of the rock anchor via at least one passage and air flows into the interior volume of the rock anchor via at least one passage. This enables more fluid to be drained from the interior volume than conventional techniques, which may leave substantial amounts of fluid in the interior volume. In some embodiments, during the use of the rock anchor (e.g., while it is disposed in a borehole), groundwater or other fluid may be introduced into the interior volume. The passages allow this fluid to be drained from the rock anchor throughout the use of the inflation anchor. In various embodiments, the rock anchor maintains the second expanded shape after the inflation agent has been drained from the rock anchor.
In some embodiments, draining is facilitated by fluidly coupling the interior volume to an ambient environment (e.g., by decoupling an inflation chuck). This allows free flow of fluid and air. In various embodiments, draining is assisted by gravity pulling fluid downward toward a passage. In other embodiments, a draining device may be used to remove the inflation agent or other fluids from the rock anchor. For example, in some embodiments, a low pressure may be induced at one or more passages, for example using a vacuum device, to draw out fluid. Additionally or alternatively, pressurized gas, such as air, may be introduced into a passage, thereby causing fluid to exit one or more passages. In the above examples, one or more passages may have to be vented to the ambient environment. In some embodiments, draining is a substantially isothermal process.
As noted above, many embodiments described herein reference a modular button assembly for a portable electronic device. It may be appreciated, however, that this is merely one example; other configurations, implementations, and constructions are contemplated in view of the various principles and methods of operations—and reasonable alternatives thereto—described in reference to the embodiments described above.
One may appreciate that although many embodiments are disclosed above, that the operations and steps presented with respect to methods and techniques described herein are meant as exemplary and accordingly are not exhaustive. One may further appreciate that alternate step order or fewer or additional operations may be required or desired for particular embodiments.
Although the disclosure above is described in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments but is instead defined by the claims herein presented.
This application is a non-provisional patent application of and claims the benefit to U.S. Provisional Patent Application No. 62/614,050, filed Jan. 5, 2018 and titled “Self-Draining Rock Anchor,” the disclosure of which is hereby incorporated herein by reference in its entirety.
Number | Name | Date | Kind |
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4423986 | Skogberg | Jan 1984 | A |
20070217869 | Dawe | Sep 2007 | A1 |
20130236251 | Smith | Sep 2013 | A1 |
Number | Date | Country | |
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62614050 | Jan 2018 | US |