Coring shovel used in relief method crustal stress measurement

Abstract

The coring shovel comprises a shovel body, a fixing plate, a wedge-shaped cushion block and a connecting rod, the shovel body is in a semi-cylindrical shape with an opening in the front end, the fixing plate is arranged at the tail end of the shovel body, the wedge-shaped cushion block is arranged on the inner side of the fixing plate, the wedge-shaped cushion block applies oblique thrust to a rock core so that the rock core can be broken from the root, and the connecting rod is connected with the shovel body. A connecting rod used for being connected with a drill rod is arranged on the outer side of the fixing plate. According to the coring shovel used in relief method crustal stress measurement, the connecting rod can be connected with the drill rod, the drill rod extends into the annular hole cavity, the wedge-shaped cushion block is arranged, inclined thrust is applied to a rock core, the rock core is extruded, the rock core is broken from the root, then the rock core is completely taken out through the shovel body, and therefore the rock core is completely taken out. The device can well take out the rock core with the strainometer, facilitates measurement of subsequent rock core data, and facilitates research of the rock core data.

Description

Technical Field

[0001] This application relates to the field of geostress measurement technology, and in particular to a core-sampling shovel used in stress relief method geostress measurement. Background Technology

[0002] The hollow inclusion strain gauge stress relief method is a method for measuring in-situ stress. It primarily calculates the three-dimensional stress state of the surrounding rock mass by measuring the strain values ​​within a hollow inclusion attached to the borehole wall during stress relief. During the test, the strain gauge is pushed into the mounting hole. As stress is relieved and the borehole diameter changes, the strain gauge records the strain on the borehole wall in different directions, thereby calculating the stress state.

[0003] The specific operational steps for measuring in-situ stress are as follows: First, a horizontal hole is drilled in the tunnel wall at the selected measuring point. The bottom of the hole is ground flat with a flat drill bit, and a funnel-shaped opening is made with a conical drill bit. Then, concentric small holes are drilled from the bottom of the hole, and a strain gauge with adhesive is inserted into the small hole. After the adhesive has cured, a thin-walled drill bit is used to extend the larger hole, causing the rock around the strain gauge to gradually separate from the surrounding rock, thereby relieving the stress in the core sample. However, when measuring in-situ stress using the stress relief method, for relatively intact rock masses, the core sample does not automatically break even if the drilling exceeds the specified depth during stress relief. After the measurement is completed, it is not possible to easily remove the core sample with the strain gauge, which is detrimental to subsequent core data measurement.

[0004] Therefore, how to provide a core-sampling shovel for stress measurement using the release method is a problem that needs to be considered by those skilled in the art. Utility Model Content

[0005] To solve or partially solve the problems existing in the related technologies, this application provides a core shovel for use in stress measurement by the relief method. The core is subjected to an oblique thrust, which squeezes the core and causes it to break from the root. The core is then completely removed by the shovel body.

[0006] The first aspect of this application provides a core shovel for stress relief measurement, comprising: a shovel body, a fixing plate, a wedge-shaped pad, and a connecting rod. The shovel body is a semi-cylindrical shape with an open front end. A fixing plate is provided at the end of the shovel body. A wedge-shaped pad is provided on the inner side of the fixing plate. The wedge-shaped pad applies an oblique thrust to the rock core to cause the rock core to break from the root. A connecting rod for connecting to a drill pipe is provided on the outer side of the fixing plate.

[0007] The end of the connecting rod is provided with an external thread, and the connection between the connecting rod and the fixed plate is surrounded by reinforcing ribs.

[0008] The fixing plate is a complete circle, and the wedge-shaped pad is set at the top or bottom of the inner side of the fixing plate.

[0009] The fixing plate is not a complete circle, and the wedge-shaped pad is set at the bottom of the inner side of the fixing plate.

[0010] The front end of the shovel is equipped with a limiting ring of the same diameter as the shovel body.

[0011] The technical solution provided in this application may include the following beneficial effects:

[0012] This application provides a core shovel for stress relief measurement. It can be connected to a drill rod via a connecting rod. The drill rod is inserted into the annular cavity, and a wedge-shaped pad is used to apply an oblique thrust to the rock core, squeezing the rock core and causing it to break from the root. The rock core can then be completely removed by the shovel. The device can effectively remove rock cores with strain gauges, which is beneficial for subsequent measurement of rock core data and facilitates the study of the rock core data.

[0013] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0014] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0015] Figure 1 This is a schematic diagram of the device shown in Embodiment 1 of this application;

[0016] Figure 2 This is a schematic diagram of the device shown in Embodiment 2 of this application;

[0017] Figure 3 This is a schematic diagram of the measurement steps for measuring ground stress in existing technologies.

[0018] Figure label:

[0019] In the figure, 1-shovel body; 2-fixing plate; 3-connecting rod; 4-limiting ring; 5-reinforcing rib; 6-large hole; 7-small hole; 8-strain gauge; 9-annular cavity; 10-wedge pad; 11-rock core. Detailed Implementation

[0020] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0021] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0023] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0025] Example 1

[0026] like Figure 1 As shown, this embodiment discloses a core shovel for stress measurement using the relief method, including a shovel body 1 and a wedge-shaped pad 10. The shovel body 1 is a semi-cylindrical shape with an open front end, and a circular fixing plate 2 is provided at the end of the shovel body 1. In this embodiment, the wedge-shaped pad 10 is provided at the top of the inner side of the fixing plate 2, and the wedge-shaped surface of the wedge-shaped pad 10 is arranged facing the center of the fixing plate 2. A connecting rod 3 for connecting with the drill rod is provided at the outer center of the fixing plate 2.

[0027] In a preferred embodiment of this utility model, the end of the connecting rod 3 is provided with an external thread, and the connection part between the connecting rod 3 and the fixing plate 2 is surrounded by a reinforcing rib 5. The connecting rod 3 is fixed to the drill rod by the external thread. The setting of the reinforcing rib 5 improves the connection strength between the connecting rod 3 and the fixing plate 2.

[0028] In this embodiment, the core shovel can be connected to the drill rod via the connecting rod 3. The drill rod is inserted into the annular cavity 9, and the wedge-shaped pad 10 is used to apply an oblique thrust to the rock core 11, squeezing the rock core 11 and causing it to break from the root. Then, the rock core 11 can be completely removed by the shovel body 1.

[0029] refer to Figure 3 The measurement steps for core extraction using the core shovel in this embodiment are as follows:

[0030] S01. Drill a horizontal hole 6 with a diameter of 130mm on the tunnel wall at the selected measuring point, to a depth of 3 to 5 times the tunnel span. The specific location for removal depends on the condition of the drilled core 11, and generally a depth of 3 to 4 times the tunnel span is sufficient. The hole should be inclined upwards by 1 to 3 degrees to allow cooling water to flow out and facilitate cleaning of the hole.

[0031] S02. Grind the bottom of the large hole 6 flat with a flat drill bit, and then use a tapered drill bit to create a flared opening. Next, drill a concentric small hole 7 with a diameter of 36mm and a depth of 35-40cm from the bottom of the large hole. The flared opening plays a crucial role in ensuring the concentricity of the small hole 7 and allowing the hollow strain gauge 8 to smoothly enter the small hole 7 in the next step; therefore, the quality of the flared opening must be guaranteed. After drilling the small hole 7, rinse it thoroughly with water, and then insert a wiping head soaked in acetone into the small hole 7 to thoroughly remove oil and other dirt.

[0032] S03. Mix the adhesive (epoxy resin) and curing agent in a certain proportion, stir evenly, and then inject the mixture into the cavity of the strain gauge 8. Secure the plunger with a pin, and then use the mounting rod with a guide to insert it into the predetermined position in the small hole 7. After the conical head at the front of the strain gauge 8 touches the bottom of the small hole 7, push the mounting rod forcefully to cut the pin, allowing the plunger to enter the cavity. The adhesive in the cavity flows into the annular gap between the strain gauge 8 and the borehole wall through the central hole and the radial hole at the rear of the plunger. The sealing rings at both ends of the strain gauge 8 will prevent the adhesive from flowing out of this gap. After the adhesive cures, the strain gauge 8 is tightly bonded to the small hole 7.

[0033] S04. After the binder has cured (generally requiring about 20 hours), the stress relief test can be conducted. Before stress relief, the wire cable of strain gauge 8 is first passed through the core 11 tube, drill rod, and the waterline tee at the rear, and connected to the bridge converter. Then, a thin-walled drill bit with a diameter of 130mm is used to continue deepening the large hole 6, so that the rock around strain gauge 8 gradually separates from the surrounding rock, thereby achieving stress relief of the core 11. During the stress relief process, the strain values ​​measured by each strain gauge in strain gauge 8 are automatically recorded by the bridge converter and data acquisition device. According to the instructions, strain data is recorded every 2cm of advance.

[0034] After stress relief is completed, the strain data stored in the data acquisition unit is printed out by computer, and the stress relief curve is plotted accordingly, which is the curve of the strain value of each strain gauge changing with the depth of stress relief.

[0035] S05. The core shovel is transported to the annular cavity 9 by the drill rod of the fully hydraulic drilling rig. During the gradual insertion of the core shovel, the rock core 11 comes into contact with the wedge-shaped pad 10. The wedge-shaped pad 10 squeezes the rock core into the gap between the rock core and the borehole, so that the rock core 11 is subjected to a downward thrust. As the core shovel extends, the rock core 11 is subjected to increased force until it breaks off from the root. Then the drill rod retracts, driving the core shovel to take the rock core 11 out of the large hole 6.

[0036] Example 2

[0037] like Figure 2 As shown, the difference between this embodiment and embodiment 1 is that the shape of the fixing plate 2 in this embodiment is larger than a semicircle but not a full circle. The wedge-shaped pad 10 is set at the bottom of the inner side of the fixing plate 2. The front end of the shovel body 1 is provided with a limiting ring 4 of the same diameter as the shovel body 1. The purpose of the limiting ring 4 is that when the wedge-shaped pad 10 squeezes the rock core 11, the limiting ring 4 can provide a fulcrum for the rock core 11 to break on the other side, ensuring that the rock core 11 breaks from the limiting ring 4. And when the rock core 11 breaks and is taken out, it can prevent the rock core from falling off the core shovel to a certain extent.

[0038] Finally, it should be noted that in this document, relationships such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "include," "contain," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0039] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0040] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A core-sampling shovel used in stress measurement using the release method, characterized in that, include: The shovel body comprises a shovel body, a fixing plate, a wedge-shaped pad, and a connecting rod. The shovel body is a semi-cylindrical shape with an open front end. The fixing plate is located at the end of the shovel body. The wedge-shaped pad is located on the inner side of the fixing plate. The wedge-shaped pad applies an oblique thrust to the rock core to break the rock core from the root. The connecting rod for connecting to the drill pipe is located on the outer side of the fixing plate.

2. The core-sampling shovel for stress measurement using the release method according to claim 1, characterized in that, The end of the connecting rod is provided with an external thread, and the connection between the connecting rod and the fixing plate is surrounded by reinforcing ribs.

3. The core-sampling shovel for stress measurement using the release method according to claim 1 or 2, characterized in that, The fixing plate is a complete circle, and the wedge-shaped pad is located at the top or bottom of the inner side of the fixing plate.

4. The core-sampling shovel for stress measurement using the release method according to claim 1 or 2, characterized in that, The fixing plate is not a complete circle, and the wedge-shaped pad is located at the bottom of the inner side of the fixing plate.

5. The core-sampling shovel for stress measurement using the release method according to claim 4, characterized in that, The front end of the shovel is provided with a limiting ring of the same diameter as the shovel body.

Images