ROCK BOLT WITH ELONGATING SECTION

Abstract

A rock bolt device that includes a non-anchoring elongation section that allows elongation of the rock bolt device under tensile load to accommodate rock movement after installation of the rock bolt device.

Claims

1. A rock bolt to be installed with grout to anchor in and stabilize rock, the rock bolt comprising: a bolt body having a longitudinal axis and a length along the longitudinal axis between a proximal end of the bolt body to be disposed outside of the rock and a distal end to be disposed in the rock when the rock bolt is installed to stabilize the rock; a hollow core extending longitudinally through the bolt body and open adjacent the proximal end and the distal end to permit circulation of the grout through the hollow core and around an exterior of the bolt body to secure the bolt body in place with the grout when the rock bolt is installed to stabilize the rock; the bolt body including at least the following longitudinal sections with relative longitudinal positioning moving along the longitudinal axis in a direction from the distal end toward the proximal end: an anchor section comprising first exterior anchor projections to project into and anchor in the grout disposed between an exterior of the anchor section and the rock when the rock bolt is installed to stabilize the rock; a non-anchoring elongation section free of anchor projections on an exterior of the non-anchoring elongation section and having material properties for longitudinal elongation of the elongation section under tensile load following installation to accommodate rock movement in an axial direction of the longitudinal axis; a load absorption section comprising second exterior anchor projections to project into and anchor in the grout disposed between an exterior of the load absorption section and the rock when the rock bolt is installed to stabilize the rock; and a retention section to be disposed outside of the rock when the rock bolt is installed to stabilize the rock; a bearing plate engaged with the retention section of the bolt body and positionable along the retention section to contact a rock surface when the rock bolt is installed to stabilize the rock; and wherein the bolt body has a tensile load capacity of at least 25 tons and has a pre-installation configuration prior to installation to stabilize the rock and a loaded configuration at a tensile load of 25 tons, and the elongation section has a longitudinal length in the loaded configuration that is at least 15% longer than in the pre-installation configuration.

2. A stabilized rock adjacent a rock surface, comprising a rock bolt according to claim 1 penetrating across the rock surface with the anchor section, elongation section and load absorption section disposed in the rock and with the retention section and the bearing plate disposed outside of the rock and with grout disposed between the rock and the exterior of the anchor section and the exterior of the load absorption section engaging the first and second anchor projections.

3. A method of stabilizing rock, comprising: disposing the bolt body of the rock bolt of claim 1 across a surface of the rock with the anchor section, elongation section and load absorption section disposed in the rock and the retention section disposed outside of the rock; circulating grout through the hollow core and outside of the bolt body and around the exterior of the bolt body to engage the rock and the first and second anchor projections; and positioning the bearing plate engaged with the retention section to contact the rock surface.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0029] The FIGURE, including annotations, illustrate example features in relation to a rock bolt.

DETAILED DESCRIPTION

[0030] Reference is made to the FIGURE showing and describing features for an example rock bolt.

[0031] The foregoing discussion of the invention and different aspects thereof has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to only the form or forms specifically disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain best modes known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art. Although the description of the invention has included description of one or more possible embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate, disclaim or disavow any patentable subject matter. Furthermore, any feature described or claimed with respect to any disclosed variation may be combined in any combination with one or more of any other features of any other variation or variations, to the extent that the features are not necessarily technically compatible, and all such combinations are within the scope of the present invention. The description of a feature or features in a particular combination do not exclude the inclusion of an additional feature or features. Processing steps and sequencing are for illustration only, and such illustrations do not exclude inclusion of other steps or other sequencing of steps. Additional steps may be included between illustrated processing steps or before or after any illustrated processing step. Illustrated processing steps may include processing operations (e.g., sub-steps) in addition to particular processing operations illustrated or discussed with respect to the illustrated processing step.

[0032] The terms comprising, containing, including and having, and grammatical variations of those terms, are intended to be inclusive and nonlimiting in that the use of such terms indicates the presence of some condition or feature, but not to the exclusion of the presence also of any other condition or feature. The use of the terms comprising, containing, including and having, and grammatical variations of those terms in referring to the presence of one or more components, subcomponents or materials, also include and is intended to disclose the more specific embodiments in which the term comprising, containing, including or having (or the variation of such term) as the case may be, is replaced by any of the narrower terms consisting essentially of or consisting of or consisting of only (or the appropriate grammatical variation of such narrower terms). For example, a statement that some thing comprises a stated element or elements is also intended to include and disclose the more specific narrower embodiments of the thing consisting essentially of the stated element or elements, and the thing consisting of the stated element or elements. Examples of various features have been provided for purposes of illustration, and the terms example, for example and the like indicate illustrative examples that are not limiting and are not to be construed or interpreted as limiting a feature or features to any particular example. The term at least followed by a number (e.g., at least one) means that number or more than that number. The term at least a portion means all or a portion that is less than all. The term at least a part means all or a part that is less than all