Tunnel and pipe gallery sensing optical fiber detection device and laying method

Abstract

A tunnel and utility tunnel sensing optical fiber detection device and laying method, wherein the detection device includes a sensing optical fiber and an auxiliary induction cable. Both ends of the auxiliary induction cable are fixed on the tunnel and utility tunnel segments through fasteners. The auxiliary induction cable is tightened by a tensioning member and is made to closely adhere to the tunnel and utility tunnel segments. The sensing optical fiber is arranged substantially parallel to the auxiliary induction cable. A number of R-shaped metal wire hoops are provided between the sensing optical fiber and the auxiliary induction cable. Under the action of the tension of the auxiliary induction cable, the R-shaped metal wire hoops also closely adhere to the tunnel and utility tunnel segments. The R-shaped metal wire hoops transmit the segment vibration signals sensed by the auxiliary induction cable to the sensing optical fiber. The present invention has the advantage of higher sensitivity in sensing the vibration signals of the sensing optical fiber detection device.

Description

Technical Field

[0001] The present invention relates to the field of fiber optic vibration detection, and in particular to a tunnel and pipe gallery sensing fiber optic detection device and laying method. Background Art

[0002] The history of fiber optic sensors can be traced back to the 1970s. At that time, people began to realize that optical fibers not only have the property of transmitting light, but can themselves form a new basis for directly exchanging information, and can relate the quantity to be measured to the guided light in the optical fiber without any intermediate stage. Due to its incomparable advantages over conventional sensors and broad development prospects, many countries have spared no effort to increase the research efforts on fiber optic sensors, and many research results have emerged.

[0003] As a new type of sensor with obvious advantages, fiber optic sensors are not only used in high-tech fields, but also rapidly promoted in traditional industrial fields. Their products are constantly emerging, showing strong vitality. It can be predicted that with the increasing maturity of manufacturing technology and the continuous improvement of device performance, fiber optic sensors will surely show their application vitality in various fields such as ocean, chemical industry, civil engineering, water conservancy and electric power in the near future.

[0004] In order to detect the vibration conditions of tunnels and pipe galleries, at present, many projects have installed sensing optical fibers on the tunnel segments and pipe gallery segments as detectors of fiber optic sensors. The sensitivity of the entire fiber optic detection system depends to a large extent on the sensitivity of the sensing optical fiber.

[0005] The existing laying method of sensing optical fibers on tunnel segments and pipe gallery segments is as follows: First, screws or expansion screws are fixed on the segments at a predetermined distance interval, and then the sensing optical fiber is bound to the screws or expansion screws using plastic ties. This laying method has the advantages of simple structure and low laying cost. However, this method has problems with the detection sensitivity of the sensing optical fiber.

[0006] How to improve the detection sensitivity of the sensing optical fiber on tunnel or pipe gallery segments is an urgent problem for those skilled in the art. Summary of the Invention

[0007] In order to overcome the above problems, the invention provides to the society a tunnel and pipe gallery sensing fiber optic detection device and laying method with high detection sensitivity of the sensing optical fiber.

[0008] The technical solution of the present invention is: to provide a sensing optical fiber detection device for tunnels and pipe galleries, including a sensing optical fiber and an auxiliary induction cable. Both ends of the auxiliary induction cable are fixed on the tunnel and pipe gallery segments through fasteners. The auxiliary induction cable is tightened by a tensioning member and is made to closely adhere to the tunnel and pipe gallery segments. The sensing optical fiber is arranged substantially parallel to the auxiliary induction cable. Between the sensing optical fiber and the auxiliary induction cable, there are several R-shaped metal wire hoops. Under the action of the tension of the auxiliary induction cable, the R-shaped metal wire hoops also closely adhere to the tunnel and pipe gallery segments. The R-shaped metal wire hoops transmit the segment vibration signals sensed by the auxiliary induction cable to the sensing optical fiber.

[0009] As an improvement to the present invention, under the action of the tension of the auxiliary induction cable, the R-shaped metal wire hoops make the sensing optical fiber closely adhere to the tunnel and pipe gallery segments.

[0010] As an improvement to the present invention, the R-shaped metal wire hoop is made of a metal steel sheet and includes a first end. Starting from the first end, there are successively connected a first arc segment, a first flat segment, a second arc segment, a second flat segment, a third arc segment, and a second end. Among them, the first end and the second end are arranged oppositely, the first arc segment and the third arc segment are arranged oppositely for holding the sensing optical fiber, the first flat segment and the second flat segment are arranged oppositely, the second arc segment is a large semi-circle for holding the auxiliary induction cable, and through holes for fixing the R-shaped metal wire hoop on the segment are provided on the first end and the second end.

[0011] As an improvement to the present invention, the auxiliary induction cable is a stainless steel cable, and the diameter of the stainless steel cable is selected between 2 mm and 10 mm.

[0012] As an improvement to the present invention, the fastener includes a connecting ring, a screw, a nut, and a connecting head. The connecting head is fixedly connected to the connecting ring. A screw hole is provided in the center of the connecting head. One end of the screw is movably connected to the connecting head through the screw hole, and the nut is provided at the end away from the thread of the screw.

[0013] As an improvement of the present invention, the tensioning member includes an intermediate connection frame, the intermediate connection frame includes a frame body, a first connecting member and a second connecting member, and the first connecting member and the second connecting member are respectively fixedly arranged in the middle of both ends of the frame body; a first through hole is provided in the center of the first connecting member, and a second through hole is provided in the center of the second connecting member; the first through hole is threadedly connected with a first adjusting screw, a first adjusting nut is arranged at one end of the first adjusting screw close to the first connecting member, and a first adjusting ring is arranged at the other end of the first adjusting screw far from the first connecting member; the second through hole is threadedly connected with a second adjusting screw, a second adjusting nut is arranged at one end of the second adjusting screw close to the second connecting member, and a second adjusting ring is arranged at the other end of the second adjusting screw far from the second connecting member.

[0014] The present invention also provides a method for laying a sensing optical fiber detection device for a tunnel and a pipe gallery, including the following steps:

[0015] S1. Fix two or more fasteners on the segment at a predetermined distance apart;

[0016] S2. Connect one end of the auxiliary induction cable to one of the fasteners with a wire rope buckle; connect the other end of the auxiliary induction cable to one end of the tensioning member with a wire rope buckle; connect the other end of the tensioning member to another fastener;

[0017] S3. Adjust the tightness of the tensioning member to tighten the auxiliary induction cable 2;

[0018] S4. Arrange the sensing optical fiber on one side of the auxiliary induction cable, and set an R-shaped metal wire hoop at a predetermined distance on the auxiliary induction cable. The R-shaped metal wire hoop holds the auxiliary induction cable and the sensing optical fiber, and at least makes the auxiliary induction cable closely attached to the segment;

[0019] S5. Fix the upper end of the R-shaped metal wire hoop to the segment.

[0020] As an improvement of the present invention, after step S5, there is also step S6, further adjusting the tightness of the tensioning member to further tighten the auxiliary induction cable, so that the sensing optical fiber, the R-shaped metal wire hoop and the auxiliary induction cable are closely attached to the segment.

[0021] In this method, the R-shaped metal wire hoop is made of a metal steel sheet, and includes a first end, and a first arc segment, a first plane segment, a second arc segment, a second plane segment, a third arc segment and a second end are sequentially connected starting from the first end. Among them, the first end and the second end are oppositely arranged, the first arc segment and the third arc segment are oppositely arranged for holding the sensing optical fiber, the first plane segment and the second plane segment are oppositely arranged, the second arc segment is a large semi-circle for holding the auxiliary induction cable, and through holes for fixing the R-shaped metal wire hoop on the segment are provided on the first end and the second end.

[0022] In this method, the tensioning member includes an intermediate connection frame, and the intermediate connection frame includes a frame body, a first connection member, and a second connection member. The first connection member and the second connection member are respectively fixedly arranged in the middle of both ends of the frame body; a first through hole is provided in the center of the first connection member, and a second through hole is provided in the center of the second connection member; the first through hole is threadedly connected to a first adjusting screw, a first adjusting nut is provided at one end of the first adjusting screw close to the first connection member, and a first adjusting ring is provided at the other end of the first adjusting screw away from the first connection member; the second through hole is threadedly connected to a second adjusting screw, a second adjusting nut is provided at one end of the second adjusting screw close to the second connection member, and a second adjusting ring is provided at the other end of the second adjusting screw away from the second connection member.

[0023] Compared with the prior art, the present invention adds an auxiliary induction cable, and tensions the auxiliary induction cable through a tensioning member, so that the auxiliary induction cable is closely attached to the segment. Then, after the auxiliary induction cable and the sensing optical fiber are held by an R-shaped metal wire hoop, the auxiliary induction cable and the sensing optical fiber are closely attached to the segment together. In this way, not only can the sensing optical fiber sense vibration signals, but the auxiliary induction cable can also transmit the vibration signals it senses to the sensing optical fiber through the R-shaped metal wire hoop, improving the sensitivity of the vibration signal induction of the sensing optical fiber detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic plan view of the present invention.

[0025] Figure 2 is Figure 1 a schematic structural view of the fastener in

[0026] Figure 3 is Figure 1 a schematic exploded structural view of the tensioning member in

[0027] Figure 4 is Figure 3 a schematic structural view after combination.

[0028] Figure 5 is Figure 1 a schematic structural view of the R-shaped metal wire hoop in

[0029] Figure 6 is a schematic block structural view of the anti-intrusion method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the purpose, technical solutions and advantages of the invention more clear and understandable, the following describes the invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and are not used to limit the invention.

[0031] Please refer to Figures 1 to 5 , Figures 1 to 5 which discloses a sensing optical fiber detection device for tunnels and pipe galleries, including a sensing optical fiber 1 and an auxiliary induction cable 2. Both ends of the auxiliary induction cable 2 are fixed on the tunnel and pipe gallery segments 4 through fasteners 21. The auxiliary induction cable 2 is tightened by a tensioning member 22 and is made to closely adhere to the tunnel and pipe gallery segments 4. The sensing optical fiber 1 is arranged substantially parallel to the auxiliary induction cable 2. A number of R-shaped metal wire hoops 3 are provided between the sensing optical fiber 1 and the auxiliary induction cable 2. Under the action of the tension of the auxiliary induction cable 2, the R-shaped metal wire hoops 3 also closely adhere to the tunnel and pipe gallery segments 4. The R-shaped metal wire hoops 3 transmit the segment vibration signals sensed by the auxiliary induction cable 2 to the sensing optical fiber 1. Figure 1 In , multiple auxiliary induction cables 2 are connected in series through multiple fasteners 21 and multiple tensioning members 22.

[0032] Preferably, under the action of the tension of the auxiliary induction cable 2, the R-shaped metal wire hoops 3 make the sensing optical fiber 1 closely adhere to the tunnel and pipe gallery segments 4.

[0033] Since the present invention adds an auxiliary induction cable 2 and tensions the auxiliary induction cable 2 through a tensioning member 22 to make the auxiliary induction cable 2 closely adhere to the segment, and then holds the auxiliary induction cable 2 and the sensing optical fiber 1 together through the R-shaped metal wire hoops 3 to make them closely adhere to the segment 4, not only can the sensing optical fiber 1 sense vibration signals, but also the auxiliary induction cable 2 can transmit the vibration signals it senses to the sensing optical fiber 1 through the R-shaped metal wire hoops 3, improving the sensitivity of the vibration signal induction of the sensing optical fiber detection device.

[0034] Please refer to Figure 2 , the fastener 21 includes a connecting ring 211, a screw 212, a nut 213 and a connecting head 214. The connecting head 214 is connected to the connecting ring 211. A screw hole (invisible in the figure) is provided at the center of the connecting head 214. One end of the screw 212 is movably connected to the connecting head 214 through the screw hole. The nut 213 is provided at one end away from the thread 2121 of the screw 212. During use, a screw tube (not shown) is fixed on the segment 4 in advance, and then the screw 212 of the fastener 21 is connected to the screw tube. In the present invention, the connecting head 214 and the connecting ring 211 can be fixedly connected or movably connected. When movably connected, the connecting ring 211 can be rotated, which is more conducive to the installation of the fastener 21.

[0035] Refer to Figure 3 and Figure 4, the tensioning member 22 includes an intermediate connection frame 221. The intermediate connection frame 221 includes a frame body 2211, a first connecting member 2212, and a second connecting member 2213. The first connecting member 2212 and the second connecting member are respectively fixed in the middle of both ends of the frame body 2211. A first through hole 22121 is provided in the center of the first connecting member 2212, and a second through hole 22131 is provided in the center of the second connecting member 2213. The first through hole is threadedly connected to a first adjusting screw 222. A first adjusting nut 2221 is provided at one end of the first adjusting screw 222 close to the first connecting member 2212 for adjusting the movement of the first adjusting screw 222 relative to the frame body 2211. A first adjusting ring 2222 is provided at the end of the first adjusting screw 222 far from the first connecting member 2212 for connecting with the auxiliary sensing cable 2. The second through hole is threadedly connected to a second adjusting screw 223. A second adjusting nut 2231 is provided at one end of the second adjusting screw 223 close to the second connecting member 2213 for adjusting the movement of the second adjusting screw 223 relative to the frame body 2211. A second adjusting ring 2232 is provided at the end of the second adjusting screw 223 far from the second connecting member 2213 for connecting with the auxiliary sensing cable 2. Rotating the first adjusting nut 2221 or the second adjusting nut 2231 can make the first adjusting screw 222 or the second adjusting screw 223 move relative to the frame body 2211, achieving the purpose of tensioning or loosening the auxiliary sensing cable 2.

[0036] Please refer to Figure 5 , the R-shaped metal wire hoop 3 is made of metal steel sheets and includes a first end 31. Starting from the first end 31, a first arc segment 32, a first flat segment 33, a second arc segment 34, a second flat segment 35, a third arc segment 36, and a second end 37 are successively connected. Among them, the first end 31 and the second end 37 are oppositely arranged, the first arc segment 32 and the third arc segment 36 are oppositely arranged for holding the sensing optical fiber 1, the first flat segment 33 and the second flat segment 35 are oppositely arranged, and the second arc segment 34 is a large semi-circle for holding the auxiliary sensing cable 2. Through holes 38 for fixing the R-shaped metal wire hoop 3 on the segment are provided on the first end 31 and the second end 37. After the R-shaped metal wire hoop 3 is set, the R-shaped metal wire hoop 3 can hold the sensing optical fiber 1 tightly through the first arc segment 32 and the third arc segment 36 and stick it on the segment 4. The second arc segment 34 holds the auxiliary sensing cable 2 and sticks the auxiliary sensing cable 2 tightly on the segment 4. At the same time, one of the first flat segment 33 or the second flat segment 35 also sticks tightly on the segment 4, which can greatly improve the sensitivity of the present invention. In this embodiment, the through holes 38 are used to fix the R-shaped metal wire hoop 3 on the segment 4 through expansion screws.

[0037] Preferably, the auxiliary induction cable 2 is a stainless steel cable, and the diameter of the stainless steel cable is selected between 2 mm and 10 mm. Of course, the stainless steel cable can also be replaced by a common iron cable. Through experiments, if the diameter of the stainless steel cable is less than 2 mm, its detection sensitivity will decrease; if the diameter of the stainless steel cable is greater than 10 mm, its detection sensitivity will also decrease. Of course, the best range is to select the diameter of the stainless steel cable between 3 mm and 7 mm.

[0038] Please refer to Figure 6 , the present invention also provides a laying method for a tunnel and pipe gallery sensing optical fiber detection device, including the following steps:

[0039] S1. Fix two or more fasteners 21 on the segment 4 at a predetermined distance.

[0040] S2. Connect one end of the auxiliary induction cable 2 to one of the fasteners 21 with a wire rope buckle (not shown, the same below); connect the other end of the auxiliary induction cable 2 to one end of the tensioning member 22 with a wire rope buckle; connect the other end of the tensioning member 22 to another fastener 21.

[0041] S3. Adjust the tightness of the tensioning member 22 to make the auxiliary induction cable 2 taut.

[0042] S4. Arrange the sensing optical fiber 1 on one side of the auxiliary induction cable 2, and set an R-shaped metal wire hoop 3 at a predetermined distance on the auxiliary induction cable 2. The R-shaped metal wire hoop 3 holds the auxiliary induction cable 2 and the sensing optical fiber 1, and at least makes the auxiliary induction cable 2 closely attached to the segment.

[0043] S5. Fix the upper end of the R-shaped metal wire hoop 3 to the segment.

[0044] Preferably, after step S5, there is also step S6, further adjusting the tightness of the tensioning member 22 to make the auxiliary induction cable 2 further taut, so that the sensing optical fiber 1, the R-shaped metal wire hoop 3 and the auxiliary induction cable 2 are closely attached to the segment.

[0045] In this method, the R-shaped metal wire hoop 3 is made of a metal steel sheet, including a first end 31, and successively connected with a first arc segment 32, a first plane segment 33, a second arc segment 34, a second plane segment 35, a third arc segment 36 and a second end 37 starting from the first end 31. Among them, the first end 31 and the second end 37 are oppositely arranged, the first arc segment 32 and the third arc segment 36 are oppositely arranged for holding the sensing optical fiber 1, the first plane segment 33 and the second plane segment 35 are oppositely arranged, the second arc segment 34 is a large semi-circle for holding the auxiliary induction cable 2, and through holes 38 for fixing the R-shaped metal wire hoop 3 on the segment are provided on the first end 31 and the second end 37.

[0046] In this method, the tensioning member 22 includes an intermediate connection frame 221. The intermediate connection frame 221 includes a frame body 2211, a first connection member 2212, and a second connection member 2213. The first connection member 2212 and the second connection member are respectively fixed to the middle of both ends of the frame body 2211. A first through hole is provided in the center of the first connection member 2212, and a second through hole is provided in the center of the second connection member 2213. The first through hole is threadedly connected to a first adjusting screw 222. A first adjusting nut 2221 is provided at one end of the first adjusting screw 222 close to the first connection member 2212, and a first adjusting ring 2222 is provided at the other end of the first adjusting screw 222 away from the first connection member 2212. The second through hole is threadedly connected to a second adjusting screw 223. A second adjusting nut 2231 is provided at one end of the second adjusting screw 223 close to the second connection member 2213, and a second adjusting ring 2232 is provided at the other end of the second adjusting screw 223 away from the second connection member 2213.

[0047] In this method, the fastening member 21 includes a connection ring 211, a screw 212, a nut 213, and a connection head 214. The connection head 214 is fixedly connected to the connection ring 211. A threaded hole is provided in the center of the connection head 214. One end of the screw 212 is movably connected to the connection head 214 through the threaded hole. The nut 213 is provided at one end away from the thread 2121 of the screw 212.

[0048] Without departing from the inventive concept, all equivalent changes made by applying the content of the description and drawings of the invention shall be construed as being included within the scope of the claims of the invention.

Claims

1. A tunnel and utility tunnel sensing optical fiber detection device, comprising a sensing optical fiber (1), characterized in that: It further includes an auxiliary induction cable (2), both ends of the auxiliary induction cable (2) are fixed on the tunnel and culvert segment (4) through fasteners (21), the auxiliary induction cable (2) is tightened by a tensioning member (22), and the auxiliary induction cable (2) is closely attached to the tunnel and culvert segment (4); the sensing optical fiber (1) is arranged substantially parallel to the auxiliary induction cable (2), and a number of R-shaped metal wire hoops (3) are provided between the sensing optical fiber (1) and the auxiliary induction cable (2). Under the action of the tension of the auxiliary induction cable (2), the R-shaped metal wire hoops (3) are also closely attached to the tunnel and culvert segment (4), and the R-shaped metal wire hoops (3) transmit the segment vibration signal sensed by the auxiliary induction cable (2) to the sensing optical fiber (1). The R-shaped metal wire hoop (3) is made of a metal steel sheet and includes a first end (31). Starting from the first end (31), a first arc segment (32), a first flat segment (33), a second arc segment (34), a second flat segment (35), a third arc segment (36) and a second end (37) are successively connected. Among them, the first end (31) and the second end (37) are oppositely arranged, the first arc segment (32) and the third arc segment (36) are oppositely arranged for holding the sensing optical fiber (1), the first flat segment (33) and the second flat segment (35) are oppositely arranged, the second arc segment (34) is a large semi-circle for holding the auxiliary induction cable (2), and perforations (38) for fixing the R-shaped metal wire hoop (3) on the segment are provided on the first end (31) and the second end (37). The auxiliary induction cable (2) is a stainless steel cable, and the diameter of the stainless steel cable is selected between 2 mm and 10 mm.

2. The tunnel and pipe gallery sensing optical fiber detection device according to claim 1, characterized in that: Under the action of the tension of the auxiliary induction cable (2), the R-shaped metal wire hoop (3) makes the sensing optical fiber (1) closely attached to the tunnel and culvert segment (4).

3. The tunnel and pipe gallery sensing optical fiber detection device according to claim 1 or 2, characterized in that: The fastener (21) includes a connecting ring (211), a screw (212), a nut (213) and a connecting head (214). The connecting head (214) is connected to the connecting ring (211). A screw hole is provided in the center of the connecting head (214). One end of the screw (212) is movably connected to the connecting head (214) through the screw hole, and the nut (213) is provided at one end away from the thread (2121) of the screw (212).

4. The tunnel and utility tunnel sensing optical fiber detection device according to claim 1 or 2, characterized in that: The tensioning member (22) includes an intermediate connection frame (221), the intermediate connection frame (221) includes a frame body (2211), a first connecting member (2212) and a second connecting member (2213), and the first connecting member (2212) and the second connecting member are respectively fixed at the middle of both ends of the frame body (2211); a first through hole is provided in the center of the first connecting member (2212), and a second through hole is provided in the center of the second connecting member (2213); the first through hole is in threaded connection with a first adjusting screw rod (222), a first adjusting nut (2221) is provided at one end of the first adjusting screw rod (222) close to the first connecting member (2212), and a first adjusting ring (2222) is provided at the other end of the first adjusting screw rod (222) far from the first connecting member (2212); the second through hole is in threaded connection with a second adjusting screw rod (223), a second adjusting nut (2231) is provided at one end of the second adjusting screw rod (223) close to the second connecting member (2213), and a second adjusting ring (2232) is provided at the other end of the second adjusting screw rod (223) far from the second connecting member (2213).

5. A method for laying a sensing optical fiber detection device for a tunnel and a pipe gallery, characterized in that: Comprising the following steps: S1. Fix two or more fasteners (21) on the segment at a predetermined interval; S2. Connect one end of the auxiliary induction cable (2) to one of the fasteners (21) with a wire rope clip; connect the other end of the auxiliary induction cable (2) to one end of the tensioning member (22) with a wire rope clip; connect the other end of the tensioning member (22) to another fastener (21); S3. Adjust the tightness of the tensioning member (22) to tension the auxiliary induction cable (2); S4. Arrange the sensing optical fiber (1) on one side of the auxiliary induction cable (2), and set an R-shaped metal wire hoop (3) at a predetermined interval on the auxiliary induction cable (2), and the R-shaped metal wire hoop (3) holds the auxiliary induction cable (2) and the sensing optical fiber (1) and at least makes the auxiliary induction cable (2) closely attached to the segment; S5. Fix the upper end of the R-shaped metal wire hoop (3) to the segment. After the step S5, there is also a step S6, further adjusting the tightness of the tensioning member (22) to further tension the auxiliary induction cable (2) so that the sensing optical fiber (1), the R-shaped metal wire hoop (3) and the auxiliary induction cable (2) are closely attached to the segment.

6. The laying method of the sensing optical fiber detection device for tunnels and pipe galleries according to claim 5, characterized in that: ​ 7. The laying method of the tunnel and pipe gallery sensing optical fiber detection device according to claim 5 or 6, characterized in that: The R-shaped metal wire hoop (3) is made of metal steel sheets and includes a first end (31). Starting from the first end (31), a first arc segment (32), a first flat segment (33), a second arc segment (34), a second flat segment (35), a third arc segment (36) and a second end (37) are sequentially connected. Among them, the first end (31) and the second end (37) are oppositely arranged, the first arc segment (32) and the third arc segment (36) are oppositely arranged for holding the sensing optical fiber (1), the first flat segment (33) and the second flat segment (35) are oppositely arranged for increasing the contact area between the R-shaped metal wire hoop (3) and the segment. The second arc segment (34) is a large semi-circle for holding the auxiliary induction cable (2). Perforations (38) for fixing the R-shaped metal wire hoop (3) on the segment are provided on the first end (31) and the second end (37).

8. The laying method of the sensing optical fiber detection device for tunnels and pipe galleries according to claim 5 or 6, characterized in that: The tensioning member (22) includes an intermediate connection frame (221). The intermediate connection frame (221) includes a frame body (2211), a first connecting member (2212) and a second connecting member (2213). The first connecting member (2212) and the second connecting member are respectively fixed in the middle of both ends of the frame body (2211). A first through hole is provided in the center of the first connecting member (2212), and a second through hole is provided in the center of the second connecting member (2213). The first through hole is threadedly connected to a first adjusting screw (222). A first adjusting nut (2221) is provided at one end of the first adjusting screw (222) close to the first connecting member (2212), and a first adjusting ring (2222) is provided at the other end of the first adjusting screw (222) far from the first connecting member (2212). The second through hole is threadedly connected to a second adjusting screw (223). A second adjusting nut (2231) is provided at one end of the second adjusting screw (223) close to the second connecting member (2213), and a second adjusting ring (2232) is provided at the other end of the second adjusting screw (223) far from the second connecting member (2213).

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