Hydraulic constant-tension large-deformation anchor rod

Abstract

The utility model discloses a hydraulic constant-tension large-deformation anchor rod which is characterized in that the hydraulic constant-tension large-deformation anchor rod is formed by connecting an anchor rod body and a hydraulic tension device; the hydraulic spring exerciser is composed of a cylinder body and a piston assembly. The piston assembly comprises a piston and a piston rod which are connected, and the piston rod extends out of the bottom of the cylinder body and is used for being connected with an anchor rod body; the interior of the cylinder body and the piston assembly form a closed cavity. A one-way valve liquid injection port and an overflow valve which are communicated with the closed cavity are arranged on the end face of the piston; emulsified liquid with the volume being 80-90% of that of the sealed cavity is injected into the sealed cavity; the working pressure PM value set by the overflow valve is the maximum pressure for controlling surrounding rock expansion. When emulsion is injected into the sealing cavity through the one-way valve liquid injection opening, the piston rod tensions the rod body to apply set pre-tightening force to surrounding rock; when the surrounding rock expands and deforms, the overflow valve is opened to release part of the emulsion, yielding is conducted on the rock mass, and constant tension is kept to adapt to the surrounding rock expansion and deformation.

Description

TECHNICAL FIELD

[0001] The utility model relates to mine exploitation especially the anchor rod for roadway support. BACKGROUND

[0002] In mine exploitation, the anchor rod support is the most popular and effective support mode for the roadway surrounding rock. According to the current geological conditions of the mine being deeper and deeper, when the rock mass has the swelling features such as water absorption and stress relief, the surrounding rock generates swelling pressure. The swelling deformation of the surrounding rock has higher and higher requirements for the anchor rod support. In order to purposefully control the deformation of the surrounding rock and make the anchor rod play a role within the effective tensile strength, according to the yielding principle of controlling the deformation of the surrounding rock, the constant resistance large deformation anchor rod is mostly used for support. The structure of the existing constant resistance large deformation anchor rod is friction type, which is composed of a constant resistance device, a rod body, a tray and a nut. The constant resistance device includes a constant resistance sleeve and a constant resistance body (i.e. large and small sleeve), the constant resistance device is connected to the tail of the rod body, and the tray and the nut are sequentially installed at the tail of the constant resistance device. The pre-tightening force is applied to the surrounding rock by tightening the nut. The design principle of the existing constant resistance large deformation rod body is that when the deformation of the surrounding rock is small and the axial force applied to the rod body is less than the design constant tension of the constant resistance large deformation rod body, the constant resistance device does not move by the static friction force and relies on the elastic deformation of the rod body material to resist the deformation and damage of the rock mass. When the axial force applied to the rod body is greater than or equal to the design constant tension of the constant resistance large deformation rod body, the constant resistance body in the constant resistance device slips along the inner wall of the sleeve and relies on the dynamic and static friction force to maintain the constant resistance characteristic and relies on the deformation extension of the constant resistance device to resist the deformation and damage of the rock mass.

[0003] Since this constant resistance large deformation anchor rod relies on the resistance of the constant resistance body to play a role, it is called constant resistance large deformation anchor rod, and the dynamic and static friction forces are controlled by the expansion of the inner cylindrical surface of the sleeve. Due to the manufacturing process and the material itself, the dynamic and static friction forces of each rod cannot be consistent, so the so-called "constant resistance" is not constant and uncertain, and it is easy to fail in friction during deformation. At the same time, the pre-tensioning force is applied by tightening the nut, and the size of the tightening force depends on personal experience and control, which lacks scientific nature. Therefore, a more scientific constant force large deformation anchor rod is needed to solve the large deformation problem of the rod body under constant force.

[0004] The "large deformation" word above is relative to the general deformation of the surrounding rock and is not a specific deformation value. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, a hydraulic constant tension large deformation anchor rod is designed to adapt to the large deformation of the surrounding rock and maintain constant working tension.

[0006] A hydraulic constant tension large deformation anchor rod is characterized in that it is connected by an anchor rod body and a hydraulic tensioner; the hydraulic tensioner is composed of a cylinder body and a piston assembly; the cylinder body length is greater than the swelling deformation of the surrounding rock; the open end of the cylinder body is provided with a flange which is greater than the diameter of the surrounding rock anchor hole; the piston assembly is a connected piston and piston rod, the piston rod extends from the bottom of the cylinder body and is used for connecting the anchor rod body; the inside of the cylinder body and the piston assembly form a sealed cavity; the piston end face is provided with a one-way valve injection port and an overflow valve which are communicated with the sealed cavity; 80-90% of the capacity of the sealed cavity is filled with emulsion; the working pressure P M of the overflow valve is set as the maximum pressure for controlling the swelling of the surrounding rock.

[0007] In order to reuse the hydraulic tensioner, the piston rod extends from the bottom of the cylinder body and is connected with the rod body through a threaded sleeve.

[0008] In order to prevent the cylinder from entering sundries from the open end during anchoring, a sealing cover is further included, and the open end of the cylinder is covered with the sealing cover during the operation of the device.

[0009] In order to better understand the advantages of the anchor rod, the use method and working principle are further described.

[0010] The use method is: first, drill an anchor hole on the surrounding rock according to the design, then expand the hole at the hole opening section, the expansion diameter matches the outer diameter of the cylinder body, and the expansion depth is greater than or equal to the length of the cylinder body, forming a stepped drill hole. Prepare work, adjust the overflow valve to the required overflow working pressure P M in advance, pre-inject 80-90% of the capacity of the sealed cavity with emulsion, the purpose is to leave 10-20% of the movement of the piston 6a. Install the anchor rod, first, put the anchor pad into the flange from the front end of the anchor rod body, put the anchoring agent into the bottom of the surrounding rock anchor hole, put the entire anchor rod into the surrounding rock anchor hole, and make the flange close to the drill hole opening, wait for the anchoring agent to solidify; after solidification, connect the injection gun to the one-way valve injection port through the lengthened injection pipe, start the injection pump to inject liquid into the sealed cavity, tension the anchor rod, tension to P0 value, P0 value is the liquid pressure value calculated according to the pre-tightening force applied to the surrounding rock, P0=N0 / A, N0 is the pre-tension, A is the effective area of the piston in the sealed cavity, and the P0 value is displayed in real time by the pressure gauge of the injection gun; after tensioning is completed, the quick connector is unscrewed, the injection gun and the injection lengthened pipe are removed, and the installation is completed.

[0011] The working principle is: the anchor rod works in three stages in the surrounding rock.

[0012] The first stage is the elastic deformation stage of the anchor rod body; the stress of the surrounding rock changes and then swells and deforms; when the deformation force does not reach the pressure P M controlled by the overflow valve, the deformation amount is compensated by the elastic deformation of the rod body and the tray.

[0013] The second stage is a deformation and elongation stage of the anchor rod body. With the change of the stress of the surrounding rock of the roadway, the axial force N applied on the rod body gradually increases, and the emulsion pressure P in the cylinder body also gradually increases. When P >= P M , the overflow valve opens to overflow part of the emulsion, the cylinder pressure decreases, and the piston rod generates a displacement L. When the stress of the surrounding rock P < P M , the overflow valve is closed, and the piston rod stops moving. In the moving process, the tension value of the anchor rod body decreases with the increase of the displacement, the stress of the surrounding rock is released, the deformation of the rock mass is resisted, and a new stable state of the rock mass is formed.

[0014] The third stage is a repeated adjustment and stabilization stage. The above process is repeated when the surrounding rock repeatedly comes under pressure until the surrounding rock is stable. The constant tension is maintained in the above process, and the purpose of large deformation is achieved.

[0015] When the coal mining face is applied, the hydraulic tensioner can be removed from the threaded sleeve using tools, and after being repaired, it can be reused.

[0016] The positive effects of the present application are:

[0017] 1. The hydraulic oil cylinder is used to realize tensioning, and the accurate tension data is directly displayed by the pressure gauge.

[0018] 2. When the deformation of the surrounding rock of the roadway occurs, the oil cylinder pressure is automatically adjusted by the overflow valve, and the anchor rod body can be elongated multiple times under constant tension to adapt to the prominent feature of large deformation of the surrounding rock.

[0019] 3. The piston rod of the hydraulic tensioner and the anchor rod body are designed as a movable coupling structure, which can be recycled and reused, greatly reducing the engineering cost.

[0020] The hydraulic constant tension large deformation anchor rod of the present application, if the rod body is replaced by an anchor cable, becomes a hydraulic constant tension large deformation anchor cable. At this time, a threaded rod needs to be welded on the connector head of the anchor cable to facilitate the threaded connection of the connecting sleeve and the hydraulic tensioner. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The structural principle diagram of the hydraulic anchor rod of the embodiment of the present application is shown in FIG. 1, Figure 2 the operation state diagram of the embodiment is shown in FIG. 2, Figure 3 and the working state diagram of the embodiment is shown in FIG. 3.

[0022] Legend: 1. anchor rod body, 2. threaded sleeve, 3. sealing ring, 4. cylinder body, 5. emulsion, 6. piston rod, 6a. piston, 7. one-way valve injection port, 8. flange, 9. overflow valve, 10. lengthened injection pipe, 11. quick connector, 12. injection gun, 13. anchoring agent, 14. surrounding rock, 15. anchor pad, 16. sealing cover. Detailed Implementation

[0023] Example: Figure 1 As shown, a hydraulic constant-tension large-deformation anchor bolt is composed of an anchor bolt body 1 and a hydraulic tensioner. The hydraulic tensioner consists of a cylinder 4 and a piston assembly. The length of the cylinder 4 is greater than the expansion deformation of the surrounding rock, and the diameter of the cylinder 4 matches the diameter of the anchor hole in the surrounding rock orifice. The open end of the cylinder has a flange 8 larger than the diameter of the anchor hole in the surrounding rock. The piston assembly is a one-piece piston 6a and piston rod 6, with the piston rod 6 extending from the bottom of the cylinder 4 to connect to the anchor bolt body 1. The inside of the cylinder 4 and the piston assembly form a sealed cavity. The piston 6a end face has a one-way valve injection port 7 and an overflow valve 9 communicating with the sealed cavity. Emulsion is injected into the sealed cavity through the one-way valve injection port 7, with the injection volume being 80-90% of the sealed cavity, leaving 10-20% space for future pre-tightening. The working pressure P of the overflow valve 9 is... M The value is set to the maximum pressure that controls the expansion of the surrounding rock 14.

[0024] To better understand the structure of this utility model, refer to Figure 2 This application describes how to use it.

[0025] First, anchor holes are drilled in the surrounding rock 14 according to the design. Then, the borehole opening section in the surrounding rock is enlarged, with the enlarged diameter matching the outer diameter of the cylinder body 4, and the enlarged depth being greater than or equal to the length of the cylinder body 4, forming a stepped borehole. Preparatory work includes adjusting the overflow valve 9 to the required overflow working pressure P beforehand. M Pre-inject 80-90% of the sealing cavity volume of emulsion 5, leaving 10-20% of the piston 6a for movement. Install the anchor rod, insert the anchor plate 15 onto the front end of the anchor rod body 1 up to the flange 8, and insert the anchoring agent 13 into the bottom of the borehole. Insert the entire utility model into the borehole of the surrounding rock 14, and wait for the anchoring section of the rod body 1 to be firmly anchored. Then connect the injection gun 12 to the extended injection pipe 10, and then connect it to the one-way valve injection port 7 with the quick connector 11. Start the injection pump to inject emulsion 5 into the sealing cavity to tension the anchor rod to the P0 value. The P0 value is the liquid pressure value calculated according to the magnitude of the pre-tightening force applied to the surrounding rock 14. P0 = N0 / A, where N0 is the pre-tension force and A is the effective area of ​​the piston in the sealing cavity. The P0 value is displayed by the pressure gauge of the injection gun. After tensioning is completed, unscrew the quick connector 11 and remove the extended injection pipe 10 and the injection gun 12. To prevent debris from entering the cylinder body 4 through the opening during anchoring, cover the opening of the cylinder body 4 with the sealing cap 16. Installation complete.

[0026] To better understand the structure of this utility model, refer to Figure 3 Explain the working principle of this application.

[0027] When emulsion 5 is injected into the anchor hole in the surrounding rock, piston 6a moves towards the open side of the cylinder, and piston rod 6 pulls rod 1 to apply a set preload force P0 to the surrounding rock; when the surrounding rock expands and deforms, rod 1 pulls piston rod 6 to continue applying pressure to emulsion 5, until the pressure reaches the maximum working pressure P of overflow valve 9. M When the overflow valve 9 opens, some of the emulsion 5 is released. After the pressure is reduced, the piston 6a moves to the left and the piston rod 6 extends to compensate for the expansion and deformation of the surrounding rock. When the surrounding rock 14 expands and deforms again, the above process is repeated to maintain a constant tension on the surrounding rock 14 and achieve the purpose of large deformation.

Claims

1. A hydraulic constant-tension large-deformation anchor bolt, characterized in that, It is composed of an anchor bolt body and a hydraulic tensioner; the hydraulic tensioner consists of a cylinder and a piston assembly; wherein the length of the cylinder is greater than the expansion deformation of the surrounding rock, and the open end of the cylinder has a flange larger than the diameter of the anchor hole in the surrounding rock; the piston assembly is a one-piece piston and piston rod, with the piston rod extending from the bottom of the cylinder and connecting to the anchor bolt body; the inside of the cylinder and the piston assembly form a sealed cavity; the piston end face has a one-way valve injection port and an overflow valve communicating with the sealed cavity; the sealed cavity is filled with 80-90% of its capacity emulsion; the set working pressure P of the overflow valve is... M The value represents the maximum pressure required to control the expansion of the surrounding rock.

2. The hydraulic constant-tension large-deformation anchor bolt as described in claim 1, characterized in that, The cylinder body opening is equipped with a sealing cap.

3. The hydraulic constant-tension large-deformation anchor bolt as described in claim 1, characterized in that, The rod and the hydraulic tensioner are connected together by a threaded sleeve.

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