Weak and broken surrounding rock pipe shed stress test structure and test method

Abstract

The present application relates to a kind of soft broken surrounding rock pipe shed stress test structure and test method, belong to the field of tunnel engineering, including several test steel pipes, the outer wall of test steel pipe is provided with two groups above strain gauge test group, the inner wall of test steel pipe is opened with several wire grooves, the outer wall of test steel pipe is opened with the wire hole corresponding to strain gauge test group one to one, wire hole is respectively connected with different wire groove;Strain gauge test group is connected with the one end of wire, wire other end passes through wire hole and extends into wire groove;Test steel pipe is slidably installed with inner cylinder, and the outer wall of inner cylinder is uniformly provided with the clamping portion corresponding to wire groove along axis line one to one.The beneficial effects of the present application are: multiple strain gauge test groups are sequentially arranged, the stress change of surrounding rock at different positions is tested, the data is more abundant, and the test result is more accurate;Clamping portion can pull wire from the end of test steel pipe, which is convenient for laying wire, and different wire grooves can distinguish the wire of different measuring points to prevent confusion.

Description

Technical Field

[0001] The present invention relates to the field of tunnel engineering, and in particular to a soft and broken surrounding rock pipe-roof stress testing structure and testing method. Background Art

[0002] Tunnels, as a vital component of modern transportation infrastructure, play an irreplaceable role in meeting the ever-increasing demand for transportation. Tunnel engineering often faces challenges such as weak strata, surrounding rock deformation, and ground subsidence, all of which require pipe-roof support.

[0003] However, due to the unique and complex nature of underground construction environments, monitoring the stress on pipe roofs during tunnel construction is extremely difficult. Data generated by various testing methods often suffer from significant errors, making it difficult to accurately determine the stress conditions within the pipe roof support. This is primarily due to factors such as failure to consider the lifespan of the testing equipment, short testing times, or insufficient testing. Furthermore, the harsh construction environment and errors by on-site staff can lead to instrument failure or even damage.

[0004] Patent No. 201320738746.3 discloses a "strain gauge protection device for monitoring force on a large pipe roof in a loess tunnel." However, its shortcomings include a small number of strain gauges, insufficient data, and inconvenient wiring inside the steel pipes of the pipe roof. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a pipe-roof stress testing structure and a testing method for soft and broken surrounding rock with convenient wiring.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: a weak and broken surrounding rock pipe-roof stress testing structure, comprising a plurality of test steel pipes, wherein two or more strain gauge test groups are sequentially arranged on the outer wall of the test steel pipe along the axial direction, and a plurality of wire slots are evenly opened on the inner wall of the test steel pipe around the axis, wherein the length direction of the wire slots is parallel to the axis of the test steel pipe, and the number of the wire slots corresponds to the number of the strain gauge test groups, and the outer wall of the test steel pipe is provided with wire holes corresponding to the strain gauge test groups one by one, wherein the wire holes are spirally distributed and respectively connected to different wire slots;

[0007] Each of the strain gauge test groups is connected to one end of a wire, and the other end of the wire passes through the wire hole, extends into the wire receiving slot, and extends out from one end of the test steel pipe;

[0008] An inner cylinder is slidably installed in the test steel pipe along the axial direction, the outer wall of the inner cylinder is in contact with the inner wall of the test steel pipe, and clamping parts for clamping the wires are evenly arranged on the outer wall of the inner cylinder around the axis and correspond one to one with the wire receiving grooves.

[0009] The beneficial effects of the present invention are: 1. Multiple strain gauge test groups are set up in sequence to test the stress changes of surrounding rocks at different positions, so the data is richer and the test results are more accurate.

[0010] 2. The clamping part can pull the wire out from the end of the test steel pipe, which is convenient for laying the wire. Different wire slots can distinguish the wires of different measuring points to prevent confusion.

[0011] 3. The inner tube and the test steel pipe cooperate to store the wires in the wire trough to prevent the wires from being damaged by the installation of the steel cage and protect the wires.

[0012] On the basis of the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the clamping portion includes a first clamping groove formed on the outer wall of the inner tube, the first clamping groove is parallel to the length direction of the wire receiving groove, and the first clamping groove is connected to the interior of the inner tube;

[0014] A rotating drum is rotatably installed inside the inner drum, and the outer wall of the rotating drum is in contact with the inner wall of the inner drum. A second clamping groove corresponding to the first clamping groove is opened on the outer wall of the rotating drum around the axis, and the second clamping groove is connected to the inside of the rotating drum.

[0015] The beneficial effect of adopting the above further solution is that when the wire is passed through, the end of the wire is inserted into the first clamping groove and the second clamping groove, and the first clamping groove and the second clamping groove are staggered to form a clamping force, which clamps the wire and then pulls it.

[0016] Furthermore, one end of the inner cylinder extends out of the test steel pipe and the outer peripheral wall is evenly opened with a plurality of first limiting holes around the axis; one end of the rotating cylinder extends out of the test steel pipe and the outer peripheral wall is evenly opened with second limiting holes corresponding to the first limiting holes around the axis.

[0017] The beneficial effect of adopting the above further solution is that it is easy to fix the inner drum and the rotating drum to prevent relative rotation.

[0018] Furthermore, at least one sliding groove is opened on the inner wall of the test steel pipe along the length of the axis, and a sliding block corresponding to the sliding groove is fixed on the outer peripheral wall of the inner tube, and the sliding block slides in the sliding groove.

[0019] The beneficial effect of adopting the above further solution is: guiding the inner tube so that it can slide better in the test steel pipe.

[0020] Furthermore, there are five strain gauge test groups, each of which includes four strain gauges. The strain gauges are evenly attached to the outer wall of the test steel pipe and connected to the wire.

[0021] The beneficial effect of adopting the above further solution is that the circumference of the test steel pipe is covered with strain gauges to avoid test blind spots.

[0022] Furthermore, galvanized steel sleeves corresponding to the strain gauge test groups are sequentially arranged on the outer wall of the test steel pipe along the axial direction, and the galvanized steel sleeves are covered on the outside of the strain gauge test group.

[0023] The beneficial effect of adopting the above further solution is: protecting the strain gauge test group and preventing the strain gauge test group from being damaged due to collision when being placed in the test steel pipe and during stress testing.

[0024] A testing method, using the above-mentioned soft and broken surrounding rock pipe-roof stress testing structure, comprises the following steps:

[0025] S1. Drill several pipe-roof holes in the weak and broken surrounding rock of the tunnel;

[0026] S2. Use propulsion machinery and manual labor to install the test steel pipe and normal pipe-roof steel pipe into the pipe-roof drill hole;

[0027] S3. Divide the five strain gauge test groups into five measuring points. The four strain gauges at measuring point ① are numbered 1-1, 1-2, 1-3, and 1-4 in sequence. The four strain gauges at measuring point ② are numbered 2-1, 2-2, 2-3, and 2-4 in sequence. The same applies to the subsequent measuring points.

[0028] S4. Connect the five strain gauge test groups to the data acquisition equipment through wires;

[0029] S5. Place a steel cage into the test steel pipe and the pipe-roof steel pipe, and grout the pipe-roof holes;

[0030] S6. The data acquisition equipment continuously monitors the five strain gauge test groups through wires.

[0031] The beneficial effects of adopting the above scheme are: multiple test steel pipes are set up according to the stability of the surrounding rock, testing different positions, and then combined with multiple sets of strain gauge test groups, the data is richer and the test results are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the strain gauge test group of the present invention.

[0033] Figure 2 Schematic diagram of the wire hole of the present invention.

[0034] Figure 3 It is a schematic cross-sectional view of the test steel pipe of the present invention.

[0035] Figure 4 It is a schematic cross-sectional view of the test steel pipe, inner cylinder and rotating cylinder of the present invention.

[0036] Figure 5 It is a schematic diagram of the inner cylinder of the present invention.

[0037] Figure 6 It is a schematic diagram of a rotating drum of the present invention.

[0038] Figure 7 It is an overall schematic diagram of the present invention.

[0039] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0040] 1. Test steel pipe; 2. Strain gauge test group; 3. Wire receiving slot; 4. Wire hole; 5. Wire; 6. Inner cylinder; 7. First clamping slot; 8. Rotating cylinder; 9. Second clamping slot; 10. First limit hole; 11. Second limit hole; 12. Sliding slot; 13. Slider; 14. Galvanized steel sleeve. DETAILED DESCRIPTION

[0041] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0042] Example 1

[0043] like Figures 1 to 4 As shown, a weak and broken surrounding rock pipe-shed stress testing structure includes a plurality of test steel pipes 1. Two or more strain gauge test groups 2 are sequentially arranged on the outer wall of the test steel pipe 1 along the axial direction. A plurality of wire slots 3 are evenly opened on the inner wall of the test steel pipe 1 around the axis. The length direction of the wire slots 3 is parallel to the axis of the test steel pipe 1. The number of the wire slots 3 corresponds to the number of the strain gauge test groups 2. The outer wall of the test steel pipe 1 is provided with wire holes 4 corresponding to the strain gauge test groups 2. The wire holes 4 are spirally distributed and respectively connected to different wire slots 3.

[0044] Each of the strain gauge test groups 2 is connected to one end of a wire 5, and the other end of the wire 5 passes through the wire hole 4, extends into the wire receiving slot 3, and extends out from one end of the test steel pipe 1;

[0045] An inner cylinder 6 is slidably installed in the test steel pipe 1 along the axial direction, and the outer wall of the inner cylinder 6 is in contact with the inner wall of the test steel pipe 1. Clamping parts for clamping the wire 5 are evenly arranged on the outer wall of the inner cylinder 6 around the axis, corresponding to the wire receiving grooves 3 one by one.

[0046] In this embodiment, the test steel pipe 1 is a Φ100, 10-meter-long steel pipe, and the strain gauge test group 2 is arranged every two meters. One end of the test steel pipe 1 is a grouting port, and the other end is a slurry outlet. The slurry outlet is tapered and extends into the drilled pipe shed hole. The inner tube 6 is slidably located in the test steel pipe 1. The side of the wire groove 3 facing the slurry outlet is closed, and the side facing the grouting port is a through groove. The outer wall of the inner tube 6 and the wire groove 3 cooperate to form a wiring channel from the wire hole 4 to the grouting port.

[0047] The ends of the wires 5 of different strain gauge test groups 2 are placed in different wire holes 4, and the clamping part clamps the ends of the wires 5. Then the staff pulls the inner tube 6 toward the grouting port side of the test steel pipe 1. The wires 5 are pulled into the wire receiving groove 3 and laid along the routing channel until the inner tube 6 is separated from the test steel pipe 1. After the ends of the wires 5 are pulled out of the test steel pipe 1 from the grouting port side, the ends of the wires 5 are removed from the clamping part and connected to the data acquisition equipment. The wires 5 at different measuring points are located in different wire receiving grooves 3 to prevent confusion and facilitate testing.

[0048] When the wiring is completed, the inner tube 6 is inserted back into the test steel pipe 1 again to confine the wire 5 between the inner tube 6 and the wire receiving slot 3, which plays a limiting role. When the steel cage is subsequently inserted into the inner tube 6, the space where the steel cage is located can be separated from the wire 5 to prevent the wire 5 from being hung up.

[0049] Example 2

[0050] like Figures 4 to 6 As shown, preferably, on the basis of embodiment 1, the clamping portion includes a first clamping groove 7 opened on the outer wall of the inner tube 6, the first clamping groove 7 is parallel to the length direction of the wire receiving groove 3, and the first clamping groove 7 is connected to the interior of the inner tube 6;

[0051] A rotating drum 8 is rotatably installed inside the inner drum 6, and the outer wall of the rotating drum 8 is in contact with the inner wall of the inner drum 6. A second clamping groove 9 corresponding to the first clamping groove 7 is opened on the outer wall of the rotating drum 8 around the axis, and the second clamping groove 9 is connected to the inside of the rotating drum 8.

[0052] In this embodiment, both ends of the inner cylinder 6 and the rotating cylinder 8 are open, and the rotating cylinder 8 can rotate in the inner cylinder 6 and can also slide axially away from the inner cylinder 6;

[0053] The wire hole 4 on the outside of the test steel pipe 1 is connected to the wire receiving groove 3 on the inside. Insert the inner cylinder 6 into the test steel pipe 1, and insert the rotating cylinder 8 into the inner cylinder 6. Align the first clamping groove 7 of the inner cylinder 6 with the wire receiving groove 3. Adjust the second clamping groove 9 to align with the first clamping groove 7.

[0054] The end of the wire 5 is sequentially passed through the wire hole 4, the wire receiving groove 3 and the first clamping groove 7 and then inserted into the second clamping groove 9. Then the staff rotates the rotating drum 8, and the first clamping groove 7 and the second clamping groove 9 are staggered to form a clamping force. After clamping the wire 5, the inner drum 6 and the rotating drum 8 are pulled toward the grouting port at the same time to pull the wire 5.

[0055] When the drum 8 rotates, the second clamping grooves 9 and the first clamping grooves 7 have multiple groups, which can clamp multiple wires 5 at the same time, thereby improving the clamping efficiency and preventing them from being confused during the pulling process.

[0056] In addition, after use, the rotating drum 8 can be removed according to construction needs. If it is necessary to ensure that the test steel pipe 1 can be tightly combined with the pipe support hole after grouting, the inner cylinder 6 is inserted back into the test steel pipe 1 after wiring is completed, and the rotating drum 8 is removed. When grouting the test steel pipe 1 from the grouting port, part of the slurry flows from the first clamping groove 7 into the wire receiving groove 3, and the other part of the slurry flows out from the slurry outlet to fill the pipe support hole. After the slurry solidifies, the pipe support hole, the test steel pipe 1 and the inner cylinder 6 are tightly combined.

[0057] If it is necessary to protect the conductor 5, after the wiring is completed, the inner cylinder 6 and the rotating cylinder 8 are inserted back into the test steel pipe 1, and then the rotating cylinder 8 is rotated so that the second clamping groove 9 and the first clamping groove 7 are completely staggered, forming a closed space at the wire receiving groove 3. Then, a steel cage is placed in the rotating cylinder 8 and concrete slurry is injected. The slurry flows out from the slurry outlet and fills the pipe shed hole, but will not enter the wire receiving groove 3.

[0058] On the basis of this embodiment, a rubber layer or a corrugated tube is provided on the periphery of the conductor 5 for protection, which can prevent the conductor 5 from being damaged when being clamped and can also prevent the conductor 5 from being corroded by concrete, thereby extending the service life.

[0059] As a parallel technical solution of this embodiment, no holes or grooves are opened on the outer wall of the inner tube 6. The clamping part includes several groups of spring clips corresponding to the wire receiving grooves 3 one by one. The spring clips are evenly fixed on the outer wall of the inner tube 6 along the axial direction of the inner tube 6. When the inner tube 6 is inserted into the test steel pipe 1, each group of spring clips is located in the wire receiving groove 3. The staff pries open the spring clips through the wire hole 4, clamps the end of the wire 5 on the spring clips, and then pulls the inner tube 6 toward the grouting port until the inner tube 6 is separated from the test steel pipe 1. After the end of the wire 5 is pulled out of the test steel pipe 1 from the grouting port side, the end of the wire 5 is removed from the spring clip and connected to the data acquisition equipment.

[0060] Example 3

[0061] like Figures 5 and 6As shown, preferably, on the basis of Examples 1-2, one end of the inner cylinder 6 extends out of the test steel pipe 1 and the outer peripheral wall is evenly provided with a plurality of first limiting holes 10 around the axis, and one end of the rotating cylinder 8 extends out of the test steel pipe 1 and the outer peripheral wall is evenly provided with second limiting holes 11 corresponding to the first limiting holes 10 one by one around the axis.

[0062] In this embodiment, when the staff pulls the rotating drum 8 and the inner drum 6, the first limiting hole 10 and the second limiting hole 11 are aligned and a latch is inserted to prevent relative rotation.

[0063] Example 4

[0064] like Figures 4 to 6 As shown, preferably, on the basis of Examples 1-3, at least one sliding groove 12 is provided on the inner wall of the test steel pipe 1 along the axial length, and a slider 13 corresponding to the sliding groove 12 is fixed on the outer wall of the inner tube 6, and the slider 13 slides in the sliding groove 12.

[0065] In this embodiment, three sliding grooves 12 are opened in the test steel pipe 1, and the inner tube 6 cooperates with the sliding grooves 12 through three sliders 13 for limiting and guiding. The side of the sliding groove 12 facing the grouting port is a through groove, which facilitates the inner tube 6 to slide out of the test steel pipe 1.

[0066] Example 5

[0067] like Figures 4 to 6 As shown, preferably, based on Examples 1-4, the number of strain gauge test groups 2 is five, and each strain gauge test group 2 includes four strain gauges, and the strain gauges are evenly attached to the outer wall of the test steel pipe 1 and connected to the wire 5.

[0068] In this embodiment, the entire circumference of the test steel pipe 1 is covered with strain gauges to avoid test blind spots.

[0069] Specifically, the strain gauge uses a specification of 3mm*2mm. The strain gauge is installed using glue for the initial bonding, followed by a thin-walled galvanized copper tube for secondary protection. To facilitate the installation of the test instrument, the length of the wire 5 used is 45m.

[0070] Example 6

[0071] like Figure 7 As shown, preferably, on the basis of Examples 1-5, galvanized steel sleeves 14 corresponding to the strain gauge test groups 2 are sequentially arranged on the outer wall of the test steel pipe 1 along the axial direction, and the galvanized steel sleeves 14 are covered on the outside of the strain gauge test group 2.

[0072] In this embodiment, in order to ensure the survival rate of the strain gauge, a galvanized steel sleeve 14 is provided to protect the strain gauge test group 2 to prevent the strain gauge test group 2 from being damaged by collision when placed in the test steel pipe 1 and during stress testing.

[0073] Based on this embodiment, the galvanized steel sleeve 14 is installed by splitting the steel pipe into two halves, and then joining and welding it to the test steel pipe 1.

[0074] Example 7

[0075] like Figures 1 to 7 As shown, preferably, based on Example 1, a testing method using the above-mentioned weak and broken surrounding rock pipe-roof stress testing structure includes the following steps:

[0076] S1. Drill several pipe-roof holes in the weak and broken surrounding rock of the tunnel;

[0077] S2. Use propulsion machinery and manual labor to install the test steel pipe and normal pipe-roof steel pipe into the pipe-roof drill hole;

[0078] S3. Divide the five strain gauge test groups into five measuring points. The four strain gauges at measuring point ① are numbered 1-1, 1-2, 1-3, and 1-4 in sequence. The four strain gauges at measuring point ② are numbered 2-1, 2-2, 2-3, and 2-4 in sequence. The same applies to the subsequent measuring points.

[0079] S4. Connect the five strain gauge test groups to the data acquisition equipment through wires;

[0080] S5. Place a steel cage into the test steel pipe and the pipe-roof steel pipe, and grout the pipe-roof holes;

[0081] S6. The data acquisition equipment continuously monitors the five strain gauge test groups through wires.

[0082] In this embodiment, pipe-roof holes are evenly drilled along the weak and broken surrounding rock of the tunnel, and then several test steel pipes 1 and normal pipe-roof steel pipes are inserted. The normal pipe-roof steel pipes only need to be placed in the steel cage and grouting, while the test steel pipes 1 need to be installed with the strain gauge test group 2 and wiring.

[0083] The strain gauge test group 2 consists of five groups, each group has four strain gauges, totaling twenty, requiring twenty wires 5 for connection. Therefore, the four wires 5 of each strain gauge test group 2 are colored red, yellow, green, and blue, representing four strain gauges respectively.

[0084] Then, the four wires 5 of each strain gauge test group 2 are passed through the same wire hole 4 and arranged in the same wire receiving slot 3. The two strain gauge test groups 2 are distinguished by different wire receiving slots 3. The strain gauges of the same strain gauge test group 2 are distinguished by the color of the wires 5 to prevent confusion.

[0085] After the wiring is completed, a steel cage is placed in the test steel pipe 1 and grouting is performed to prevent the pipe support hole from being eroded by groundwater, and the strain gauge is connected to the data acquisition equipment.

[0086] After the concrete solidifies, when the weak and broken surrounding rock moves, the test steel pipe 1 itself is subjected to force and deforms, which will cause the strain gauge to deform. When the strain gauge deforms, it will produce a change in resistance, which is called the "strain effect". The resistance change is transmitted to the data acquisition equipment, and the data can reflect the stress condition of the entire test steel pipe 1.

[0087] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0089] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0090] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0091] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0092] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A weak and broken surrounding rock pipe shed stress testing structure, comprising a plurality of test steel pipes (1), characterized in that: Two or more strain gauge test groups (2) are sequentially arranged on the outer wall of the test steel tube (1) along the axis direction; a plurality of wire receiving grooves (3) are evenly opened on the inner wall of the test steel tube (1) around the axis; the length direction of the wire receiving grooves (3) is parallel to the axis of the test steel tube (1); the number of the wire receiving grooves (3) corresponds to the number of the strain gauge test groups (2); and wire holes (4) corresponding to the strain gauge test groups (2) are opened on the outer wall of the test steel tube (1); the wire holes (4) are spirally distributed and respectively connected to different wire receiving grooves (3); The strain gauge test group (2) is connected to one end of a wire (5), and the other end of the wire (5) passes through the wire hole (4), extends into the wire receiving slot (3), and extends from one end of the test steel pipe (1); An inner cylinder (6) is slidably mounted in the test steel pipe (1) along the axial direction, the outer wall of the inner cylinder (6) is in contact with the inner wall of the test steel pipe (1), and clamping portions for clamping the wire (5) are evenly arranged on the outer wall of the inner cylinder (6) around the axis and correspond one to one with the wire receiving grooves (3); The clamping portion includes a first clamping groove (7) formed on the outer wall of the inner cylinder (6), the first clamping groove (7) is parallel to the length direction of the wire receiving groove (3), and the first clamping groove (7) is connected to the interior of the inner cylinder (6); A rotating drum (8) is rotatably mounted inside the inner drum (6), and the outer wall of the rotating drum (8) is in contact with the inner wall of the inner drum (6). The rotating drum 8 can rotate inside the inner drum 6 and can also slide axially away from the inner drum 6. A second clamping groove (9) corresponding to the first clamping groove (7) is provided on the outer wall of the rotating drum (8) around the axis, and the second clamping groove (9) is communicated with the interior of the rotating drum (8).

2. A weak and broken surrounding rock pipe-roof stress testing structure according to claim 1, characterized in that: One end of the inner cylinder (6) extends out of the test steel pipe (1) and a plurality of first limiting holes (10) are evenly opened on the outer peripheral wall around the axis. One end of the rotating cylinder (8) extends out of the test steel pipe (1) and a plurality of second limiting holes (11) corresponding to the first limiting holes (10) are evenly opened on the outer peripheral wall around the axis.

3. A weak and broken surrounding rock pipe-roof stress testing structure according to claim 2, characterized in that: At least one sliding groove (12) is provided on the inner wall of the test steel pipe (1) along the length of the axis, and a sliding block (13) corresponding to the sliding groove (12) is fixedly connected to the outer peripheral wall of the inner tube (6), and the sliding block (13) is slidably located in the sliding groove (12).

4. A weak and broken surrounding rock pipe-roof stress testing structure according to claim 1, characterized in that: The number of the strain gauge test groups (2) is five, and each strain gauge test group (2) includes four strain gauges. The strain gauges are evenly attached to the outer wall of the test steel pipe (1) and connected to the wire (5).

5. A weak and broken surrounding rock pipe-roof stress testing structure according to claim 4, characterized in that: Galvanized steel sleeves (14) corresponding to the strain gauge test groups (2) are sequentially arranged on the outer wall of the test steel pipe (1) along the axial direction, and the galvanized steel sleeves (14) are covered on the outside of the strain gauge test group (2).

6. A testing method, characterized in that: Using the soft and broken surrounding rock pipe-roof stress testing structure according to any one of claims 4 to 5 comprises the following steps: S1. Drill several pipe-roof holes in the weak and broken surrounding rock of the tunnel; S2. Use propulsion machinery and manual labor to install the test steel pipe and normal pipe-roof steel pipe into the pipe-roof drill hole; S3. Divide the five strain gauge test groups into five measuring points. The four strain gauges at measuring point ① are numbered 1-1, 1-2, 1-3, and 1-4 in sequence. The four strain gauges at measuring point ② are numbered 2-1, 2-2, 2-3, and 2-4 in sequence. The same applies to the subsequent measuring points. S4. Connect the five strain gauge test groups to the data acquisition equipment through wires; S5. Place a steel cage into the test steel pipe and the pipe-roof steel pipe, and grout the pipe-roof holes; S6. The data acquisition equipment continuously monitors the five strain gauge test groups through wires.

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