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

Abstract

The invention relates to a weak broken surrounding rock pipe shed stress test structure and method, and belongs to the field of tunnel engineering, the weak broken surrounding rock pipe shed stress test structure comprises a plurality of test steel pipes, the outer walls of the test steel pipes are provided with more than two strain gauge test groups, and the inner walls of the test steel pipes are provided with a plurality of wire containing grooves; wire passing holes in one-to-one correspondence with the strain gauge test groups are formed in the outer wall of the test steel pipe, and the wire passing holes are respectively communicated with different wire accommodating grooves; the strain gauge test group is connected with one end of a wire, and the other end of the wire penetrates through the wire passing hole and extends into the wire accommodating groove; an inner cylinder is slidably mounted in the test steel pipe, and clamping parts in one-to-one correspondence with the wire accommodating grooves are uniformly arranged on the outer wall of the inner cylinder around the axis. The device has the advantages that the multiple strain gauge testing sets are arranged in sequence, surrounding rock stress changes at different positions are tested, data are richer, and the testing result is more accurate; the clamping part can pull the wire out of the end part of the test steel pipe, so that the wire is convenient to arrange, and different wire accommodating grooves can distinguish the wires at different test points to prevent confusion.

Description

Technical Field

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

[0002] As an important part of modern transportation infrastructure, tunnels play an irreplaceable role in meeting the growing transportation needs. Tunnel engineering often faces problems such as soft strata, surrounding rock deformation and surface subsidence, all of which require pipe-roof support.

[0003] However, due to the particularity and complexity of the underground construction environment, it is very difficult to monitor the stress of the pipe shed during tunnel construction. Usually, the data tested by many methods have large errors and cannot accurately determine the stress of the pipe shed support. First, the life of the test instrument is not considered, the test time is too short, the number of tests is insufficient, etc.; secondly, the harsh on-site construction environment and the work errors of on-site staff will lead to the failure or even damage of the test instrument.

[0004] Patent No. 201320738746.3 discloses a "strain gauge protection device for monitoring force on large pipe sheds in loess tunnels". Its disadvantages are that the number of strain gauges is small, the data is not rich enough, and it is not convenient to wire in the steel pipe of the pipe shed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a soft and broken surrounding rock pipe-roof stress testing structure and a testing method which are convenient for 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 rack stress test 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 receiving grooves are evenly opened on the inner wall of the test steel pipe around the axis, wherein the length direction of the wire receiving grooves is parallel to the axis of the test steel pipe, and the number of the wire receiving grooves 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, and the wire holes are spirally distributed and respectively connected to different wire receiving grooves;

[0007] The strain gauge test groups are all 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 corresponding to the wire receiving grooves are evenly arranged on the outer wall of the inner cylinder around the axis.

[0009] The beneficial effects of the present invention are as follows: 1. Multiple strain gauge test groups are arranged in sequence to test the stress changes of surrounding rocks at different positions, so that the data are 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] Based on the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the clamping parts all include 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, the outer wall of the rotating drum is in contact with the inner wall of the inner drum, and 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, and the wire is clamped and then pulled.

[0016] Furthermore, one end of the inner cylinder extends out of the test steel pipe and the outer wall is evenly provided with a plurality of first limiting holes around the axis, and one end of the rotating cylinder extends out of the test steel pipe and the outer wall is evenly provided with second limiting holes corresponding to the first limiting holes one by one 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 provided on the inner wall of the test steel tube along the length of the axis, and sliding blocks corresponding to the sliding grooves are fixedly connected to the outer peripheral wall of the inner tube, and the sliding blocks are slidably located in the sliding grooves.

[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 it is 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 shed holes at the soft and broken surrounding rock of the tunnel;

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

[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, and the same applies to the subsequent measuring points;

[0028] S4, connecting 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 shed steel pipe, and perform grouting on the pipe shed holes;

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

[0031] The beneficial effect of adopting the above scheme is: multiple test steel pipes are set up according to the stability of the surrounding rock, and different positions are tested. In combination 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 It is a schematic diagram of the strain gauge test group of the present invention.

[0033] Figure 2 It is a schematic diagram of the wire hole of the present invention.

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

[0035] Figure 4 It is a schematic cross-sectional view of the test steel tube, 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 listed as follows:

[0040] 1. Test steel pipe; 2. Strain gauge test group; 3. Wire 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. Sliding block; 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 test structure includes a plurality of test steel pipes 1, on the outer wall of the test steel pipe 1, two or more strain gauge test groups 2 are sequentially arranged at intervals along the axial direction, the inner wall of the test steel pipe 1 is evenly provided with a plurality of wire slots 3 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] 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 out from one end of the test steel pipe 1;

[0045] An inner cylinder 6 is slidably installed in the test steel tube 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 tube 1. Clamping parts for clamping the wire 5 corresponding to the wire receiving grooves 3 are evenly arranged on the outer wall of the inner cylinder 6 around the axis.

[0046] In this embodiment, the test steel pipe 1 is a steel pipe with a diameter of 100 and a length of 10 meters. 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 conical 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 to the side of the grouting port of the test steel pipe 1, and the wires 5 are pulled into the wire receiving groove 3 and laid along the wiring 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 side of the grouting port, 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 groove 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 inside 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 axially slide away from the inner cylinder 6;

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

[0054] The end of the conductor 5 is inserted into the second clamping groove 9 after passing through the wire hole 4, the wire receiving groove 3 and the first clamping groove 7 in sequence. 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 the conductor 5 is clamped, the inner drum 6 and the rotating drum 8 are pulled toward the grouting port at the same time to pull the conductor 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 confusion during the pulling process.

[0056] In addition, after the use of the rotating drum 8 is completed, it is selected whether to remove it according to the 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 the wiring is completed, and the rotating drum 8 is removed. When grouting is injected into the test steel pipe 1 from the grouting port, a 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 to make the second clamping groove 9 and the first clamping groove 7 completely staggered, forming a closed space at the wire receiving groove 3, and 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 does 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 outer 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, and the clamping part includes a plurality of groups of spring clips corresponding to the wire receiving grooves 3 one by one. The spring clips are evenly and fixedly arranged on the outer wall of the inner tube 6 along the axial direction of the inner tube 6, and 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 pry open the spring clips through the wire holes 4, clamp the end of the wire 5 on the spring clips, and then pull 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 Embodiment 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 first 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 embodiments 1-3, at least one sliding groove 12 is opened 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, each of the strain gauge test groups 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 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 pasting, and then a thin-walled galvanized copper tube is used 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 due to collision when placed in the test steel pipe 1 and during stress testing.

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

[0074] Example 7

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

[0076] S1. Drill several pipe shed holes at the soft and broken surrounding rock of the tunnel;

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

[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, and the same applies to the subsequent measuring points;

[0079] S4, connecting 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 shed steel pipe, and perform grouting on the pipe shed holes;

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

[0082] In this embodiment, the pipe-roof holes are evenly drilled along the soft and broken surrounding rock positions of the tunnel, and then a number of test steel pipes 1 and normal pipe-roof steel pipes are inserted. In the normal pipe-roof steel pipe, only a steel cage needs to be placed and grouting is performed, while the test steel pipe 1 needs to be installed with a strain gauge test group 2 and wiring;

[0083] The strain gauge test group 2 consists of five groups, each group has four strain gauges, a total of twenty, and twenty wires 5 are required for connection. Therefore, the four wires 5 of each strain gauge test group 2 are selected in four colors of red, yellow, green and blue, representing four strain gauges respectively;

[0084] Then, the four wires 5 of each strain gauge test group 2 are inserted into 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 colors of the wires 5, which are not easy to be confused.

[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 shed hole from being eroded by groundwater, and the strain gauge is connected to the data acquisition equipment.

[0086] After the concrete solidifies, when the soft and broken surrounding rock moves, the test steel pipe 1 itself is deformed under stress, which will drive the strain gauge to deform. When the strain gauge deforms, the resistance value will change, which is called "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 is to 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”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element 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] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0089] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0090] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

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

Claims

1. A weak and broken surrounding rock pipe rack stress testing structure, comprising a plurality of test steel pipes (1), characterized in that: The outer wall of the test steel pipe (1) is provided with two or more strain gauge test groups (2) arranged in sequence along the axis direction; the inner wall of the test steel pipe (1) is provided with a plurality of wire receiving grooves (3) evenly arranged around the axis; the length direction of the wire receiving grooves (3) is parallel to the axis of the test steel pipe (1); the number of the wire receiving grooves (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 distributed in a spiral shape and are 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 out 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).

2. According to claim 1, a soft and broken surrounding rock pipe-roof stress testing structure is characterized in that: The clamping portion comprises a first clamping groove (7) formed on the outer wall of the inner tube (6), the first clamping groove (7) being parallel to the length direction of the wire receiving groove (3), and the first clamping groove (7) being communicated with the interior of the inner tube (6); A rotating drum (8) is rotatably mounted inside the inner drum (6), the outer wall of the rotating drum (8) is in contact with the inner wall of the inner drum (6), and a second clamping groove (9) corresponding to the first clamping groove (7) is formed 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).

3. According to claim 2, a soft and broken surrounding rock pipe-roof stress testing structure is 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 arranged 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) are evenly arranged on the outer peripheral wall around the axis and correspond to the first limiting holes (10) one by one.

4. According to claim 3, a soft and broken surrounding rock pipe-roof stress testing structure is characterized in that: The inner wall of the test steel pipe (1) is provided with at least one sliding groove (12) 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).

5. According to claim 1, a soft and broken surrounding rock pipe-roof stress testing structure is characterized in that: The number of the strain gauge test groups (2) is five, and each of the strain gauge test groups (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).

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

7. A testing method, characterized in that: Using the soft and broken surrounding rock pipe-roof stress testing structure according to any one of claims 5 to 6 comprises the following steps: S1. Drill several pipe shed holes at the soft and broken surrounding rock of the tunnel; S2. Use propulsion machinery and manual collaboration to install the test steel pipe and normal pipe-roof steel pipe into the pipe-roof borehole; 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, and the same applies to the subsequent measuring points; S4, connecting 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 shed steel pipe, and perform grouting on the pipe shed holes; S6. The data acquisition equipment continuously monitors the five strain gauge test groups through wires.

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