A detection system and method for detecting the excavation diameter of a cutter head of a shield machine

Abstract

The shield machine cutterhead excavation diameter detection system comprises an oil cylinder, an oil pipe, a sensor, a signal cable and a shield machine control center, the oil cylinder body is connected to the inner wall of a cutterhead ring plate, the oil cylinder top rod has an initial position of retracting the outer circumferential surface of the cutterhead and a detection position of abutting against the inner wall of a tunnel, the oil pipe is arranged along the spoke of a cutterhead slewing frame, the sensor is arranged on the cylinder body, the signal cable is arranged in a pressure-resistant pipe, the pressure-resistant pipe is composed of three sections, the first section is arranged along the oil pipe, the second and third sections are connected through a socket and a plug, the detection mode of abutting against the inner wall of the tunnel through the top rod and detecting the displacement of the top rod by the sensor avoids the direct detection of the inner wall of the tunnel by the sensor, the accuracy and reliability of the detection result are good, the top rod is not easy to be damaged, the service life is long, the strength of the signal cable can be enhanced, and the workload of the arrangement of the signal cable is reduced; the shield machine cutterhead excavation diameter detection method is simple to operate and easy to implement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield technology, in particular to a shield machine cutterhead excavation diameter detection system and a detection method. BACKGROUND

[0002] The shield machine is a large mechanical equipment which cuts the front soil by rotating the cutterhead to excavate a tunnel in the stratum or mountain. In order to facilitate the entry of the rear shield and the assembly of the segment, part of the cutters on the cutterhead will protrude from the outer circumference of the cutterhead, so that the diameter of the tunnel is slightly larger than the diameter of the shield. However, with the increase of the excavation depth of the tunnel, the part of the cutters will be worn, resulting in the diameter of the tunnel becoming smaller and smaller. At the same time, the stratum or mountain outside the tunnel tends to shrink inward, especially when the shield machine is stationary for a long time. The inward shrinkage is particularly obvious. The too small diameter of the tunnel is easy to cause the shield to be stuck. Therefore, the detection of the excavation diameter of the cutterhead of the shield machine is very important.

[0003] The existing detection systems of the excavation diameter of the cutterhead of the shield machine are roughly divided into two categories: contact type and non-contact type. The former mostly sets a hydraulic oil cavity on the cutters protruding from the outer circumference of the cutterhead. The wear condition of the cutters is judged by monitoring whether the hydraulic oil is pressureless, so as to indirectly obtain the cutterhead excavation diameter data. Since the part of the cutters protrudes from the outer circumference of the cutterhead, the counterforce of the rock and soil is greater. The setting of the hydraulic oil cavity reduces the overall strength of the cutters, resulting in a shorter service life of the cutters. At the same time, after the cutters are worn, the soil is easy to enter the hydraulic oil pipeline to form a blockage. In this case, the hydraulic oil can still establish pressure, and the accuracy and reliability of the detection result are poor. The latter mostly realizes detection through optical fiber sensors, Hall sensors, ultrasonic sensors and other ways. There are defects of strict sealing requirement and fragile cable. The rock, debris and mud remaining on the inner wall of the tunnel are easy to cause misjudgment, so that the accuracy and reliability of the detection result are poor. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a shield machine cutterhead excavation diameter detection system with good detection result accuracy and reliability, and a shield machine cutterhead excavation diameter detection method which is easy to operate and easy to implement.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is a shield machine cutterhead excavation diameter detection system, which comprises:

[0006] The oil cylinder comprises a cylinder body and a top rod. The cylinder body is sealingly connected to the inner wall of the cutterhead ring plate. One end of the top rod is axially slidably arranged in the cylinder body, and the other end is arranged in the through hole in the cutterhead ring plate. The top rod has an initial position of retracting the outer circumference of the cutterhead and a detection position of abutting against the inner wall of the tunnel.

[0007] An oil pipe is arranged for supplying oil to the oil cylinder, one end of the oil pipe is communicated with the cylinder body, the other end is communicated with a oil distributor on the cutter head center block, when the oil pressure in the oil pipe rises, the ejector rod moves to the detection position, when the oil pressure in the oil pipe drops, the ejector rod moves to the initial position, the oil pipe is arranged along the spoke of the cutter head slewing frame;

[0008] A sensor is arranged on the cylinder body, the sensor is used for detecting the current position of the ejector rod;

[0009] A signal cable is arranged in a pressure-resistant pipe, the signal cable is composed of a first segment, a second segment and a third segment connected in sequence, one end of the first segment is connected with the sensor, the other end extends into the cutter head center block along the oil pipe, the second segment is arranged along the inner cavity of the cutter head slewing frame, one end of the second segment extends into the cutter head center block and is connected with the first segment, the other end extends into the rotating shaft in the center of the cutter head slewing frame in the axial direction and penetrates out of the outer circumferential surface of the rotating shaft in the radial direction, and is connected with a socket arranged on the outer circumferential surface of the rotating shaft, one end of the third segment is provided with a plug matched with the socket, and the other end is connected with a shield tunneling machine control center, the shield tunneling machine control center calculates the excavation diameter of the cutter head according to the detection value of the sensor.

[0010] Preferably, the cylinder body includes a cylinder barrel and an end cover, the cylinder barrel is sealingly connected to the milling plane of the inner wall of the cutter head ring plate, the end cover is sealingly connected to the end of the cylinder barrel away from the milling plane, an oil guide column is connected to the end cover, the oil guide column is coaxially inserted into the cylinder barrel, and a central hole and a hydraulic oil passage on one side or both sides of the central hole are arranged on the oil guide column;

[0011] The ejector rod includes an ejector rod head, an ejector rod barrel and a displacement barrel arranged coaxially, at least a part of the ejector rod head extends outwardly from the through hole, one end of the ejector rod barrel is connected to the end face of the ejector rod head facing the end cover, the other end of the ejector rod barrel is inserted into the cylinder barrel and located outside the oil guide column, the outer wall of the ejector rod barrel is dynamically sealingly connected with the inner wall of the cylinder barrel, a hydraulic oil cavity in communication with the hydraulic oil passage is formed between the inner wall of the ejector rod barrel and the outer wall of the oil guide column, and the displacement barrel is inserted into the central hole;

[0012] The sensor is in the form of a rod, the sensor is sealingly connected coaxially in the central hole, one end of the sensor is inserted into the displacement barrel and slidingly connected with the slip ring at the end of the displacement barrel, and the other end of the sensor is connected with the first segment of the signal cable.

[0013] Further preferably, a wear-resistant alloy layer is arranged on the end face of the ejector rod head away from the end cover, and the thickness of the wear-resistant alloy layer is not less than 5 mm.

[0014] Further preferably, when the ejector rod is in the initial position, the ejector rod head is located outside the outer circumferential surface of the cutter head, and the distance between the ejector rod head and the outer circumferential surface of the cutter head is not less than 5 mm.

[0015] Preferably, the material of the pressure-resistant pipe is the same as that of the oil pipe.

[0016] Preferably, the outer wall of the spoke is connected with a doorframe-shaped guard plate extending along the spoke, and the space between the guard plate and the spoke is used to accommodate the oil pipe and the first segment.

[0017] Preferably, the inner side of the cutter head ring plate is provided with a sealed cavity accommodating the cylinder body, and the sealed cavity is formed by sealingly connecting a plurality of side plates.

[0018] Preferably, the pressure-resistant pipe in which the first segment is located is arranged in the oil pipe, and the annular space between the outer wall of the pressure-resistant pipe and the inner wall of the oil pipe forms an oil supply channel, and the maximum oil pressure in the oil supply channel is half of the maximum pressure that the pressure-resistant pipe can withstand.

[0019] Further preferably, the two ends of the oil pipe are connected with a tee joint for separating the detection cable and the oil supply channel.

[0020] To achieve the above-mentioned purpose, the method in the technical solution adopted by the present application is a shield machine cutter head excavation diameter detection method, which uses the above-mentioned shield machine excavation diameter detection system for detection, and the detection method comprises the following steps:

[0021] S1. Stop the rotation of the cutter head, and insert the plug into the socket;

[0022] S2. Increase the pressure of the hydraulic oil in the oil pipe through the oil distributor, and when the detection value of the sensor does not change or changes around a certain value, the oil distributor stops increasing the pressure, and the shield machine control center records the detection value A1 of the sensor;

[0023] S3. Decrease the pressure of the hydraulic oil in the oil pipe through the oil distributor, and when the detection value of the sensor does not change or changes around a certain value, the oil distributor stops decreasing the pressure, and the shield machine control center records the detection value A2 of the sensor, and calculates the sliding distance of the ejector rod from the initial position to the detection position according to the difference between A1 and A2, and then calculates the excavation radius B1 of the cutter head at this position in combination with the distance between the ejector rod in the initial position and the center of the cutter head.

[0024] S4. pulling the plug out of the socket, rotating the cutter head 360° / n, wherein n is a natural number greater than or equal to 30;

[0025] S5. repeating steps S1 to S4 to obtain n excavation radii B1, B2 to Bn, and the shield machine control center simulates a tunnel cross section according to the n excavation radii and calculates the excavation diameter of the cutter head.

[0026] Due to the above technical scheme, the shield machine cutter head excavation diameter detection system provided by the application has the following advantages compared with the prior art:

[0027] 1. When the cutter head stops rotating, the top rod can be transformed between the detection position of abutting against the inner wall of the tunnel and the initial position of retracting the outer circumference of the cutter head through the action of the oil cylinder, and then the position of the top rod is detected by the sensor, so that the cutter head excavation diameter detection can be realized, the top rod is not easy to be damaged, the service life is long, and the accuracy and reliability of the detection result are good.

[0028] 2. The detection method of abutting the top rod against the inner wall of the tunnel and detecting the displacement of the top rod by the sensor avoids the direct detection of the sensor on the inner wall of the tunnel, reduces the setting requirements of the sensor, and avoids the misjudgment caused by the residual rock blocks, debris, mud and the like of the inner wall of the tunnel. By arranging the signal cable in the pressure-resistant pipe and making the first segment of the signal cable follow the oil pipe, the strength of the signal cable can be further enhanced, the workload of the signal cable arrangement can be reduced, and the accuracy and reliability of the detection result are better.

[0029] The shield machine cutter head excavation diameter detection method provided by the application has the advantages of simple operation, easy implementation, and good accuracy and reliability of the detection result compared with the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a rear view schematic diagram of the cutter head of the first embodiment of the application, and part is cut away for observation.

[0031] Figure 2 is Figure 1 is a sectional view schematic diagram of the spoke in the A-A direction.

[0032] Figure 3 is Figure 1 is a sectional view schematic diagram of the rotary frame.

[0033] Figure 4 is Figure 1 is a butt joint schematic diagram of the second segment and the third segment of the signal cable.

[0034] Figure 5 is Figure 1 is an enlarged sectional view schematic diagram of the oil cylinder.

[0035] Figure 6 is Figure 1 is a partial enlarged view of B in FIG. 2, and the view angle is adjusted for observation.

[0036] Figure 7 is Figure 6 is a partial enlarged view of the oil cylinder.

[0037] Figure 8 is a sectional view of the spoke in the A-A direction of Figure 1

[0038] Figure 9 is a partial enlarged view of B in FIG. 5, and the view angle is adjusted for observation. Figure 1

[0039] Figure 10 is a sectional enlarged view of the oil cylinder in the embodiment two.

[0040] 10. oil cylinder; 11. cylinder body; 111. cylinder barrel; 112. end cover; 113. oil guide column; 114. center hole; 115. hydraulic oil channel; 12. ejector rod; 121. ejector rod head; 122. ejector barrel; 123. displacement barrel; 124. hydraulic oil cavity; 125. slip ring; 126. wear-resistant alloy layer; 13. sealing plate; 14. oil pipe connecting port; 15. cable connecting port; 20. oil pipe; 21. tee joint; 30. sensor; 40. signal cable; 40a. first segment; 40b. second segment; 40c. third segment; 41. pressure-resistant pipe; 411. oil supply channel; 42. socket; 43. plug; 50. cutter head; 51. cutter head ring plate; 511. through hole; 512. milling plane; 513. sealing cavity; 514. side plate; 52. cutter head center block; 53. cutter head rotary frame; 531. spoke; 532. inner cavity; 533. rotating shaft; 534. guard plate; 60. tunnel inner wall. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present application are described in detail below with reference to the accompanying drawings, so that the advantages and features of the present application are more easily understood by those skilled in the art, and the scope of protection of the present application is more clearly defined.

[0042] Embodiment one

[0043] As Figures 1 to 7 ​​As shown, the shield tunneling machine cutterhead excavation diameter detection system provided by the present application comprises an oil cylinder 10, an oil pipe 20, a sensor 30, a signal cable 40 and a shield tunneling machine control center, wherein the oil cylinder 10 comprises a cylinder body 11 and a top rod 12, the cylinder body 11 is sealingly connected to the inner wall of a cutterhead ring plate 51, one end of the top rod 12 is axially slidably arranged in the cylinder body 11, the other end is arranged in a through hole 511 in the cutterhead ring plate 51, the top rod 12 has an initial position of retracting the outer circumferential surface of the cutterhead 50 and a detection position of abutting against the inner wall of a tunnel 60; the oil pipe 20 is used for supplying oil to the oil cylinder 10, one end of the oil pipe 20 is in communication with the cylinder body 11, the other end is in communication with a oil distributor on a cutterhead center block 52, when the oil pressure in the oil pipe 20 rises, the top rod 12 moves to the detection position, when the oil pressure in the oil pipe 20 drops, the top rod 12 moves to the initial position, the oil pipe 20 is arranged along a spoke 531 of a cutterhead slewing ring 53; the sensor 30 is arranged on the cylinder body 11, the sensor 30 is used for detecting the current position of the top rod 12; the signal cable 40 is arranged in a pressure-resistant pipe 41, the signal cable 40 is composed of a first section 40a, a second section 40b and a third section 40c connected in sequence, one end of the first section 40a is connected with the sensor 30, the other end extends into the cutterhead center block 52 along the oil pipe 20, the second section 40b is arranged along an inner cavity 532 of the cutterhead slewing ring 53, one end of the second section 40b extends into the cutterhead center block 52 and is connected with the first section 40a, the other end extends into a rotating shaft 533 in the center of the cutterhead slewing ring 53 in the axial direction and extends out from the outer circumferential surface of the rotating shaft 533 in the radial direction and is connected with a socket 42 arranged on the outer circumferential surface of the rotating shaft 533, one end of the third section 40c is provided with a plug 43 matched with the socket 42, the other end is connected with the shield tunneling machine control center (not shown in the figure), the shield tunneling machine control center calculates the excavation diameter of the cutterhead 50 according to the detection value of the sensor 30.

[0044] The advantages of such an arrangement are:

[0045] 1. When the cutterhead stops rotating, the top rod can be transformed between the detection position of abutting against the inner wall of the tunnel and the initial position of retracting the outer circumferential surface of the cutterhead by the action of the oil cylinder, and the position of the top rod is detected by the sensor, so that the cutterhead excavation diameter detection can be realized, the top rod is not easy to be damaged, the service life is long, and the accuracy and reliability of the detection result are good.

[0046] 2. The detection method of abutting against the inner wall of the tunnel by the top rod and detecting the displacement of the top rod by the sensor avoids the direct detection of the inner wall of the tunnel by the sensor, reduces the setting requirements of the sensor, and avoids the misjudgment caused by the residual rock blocks, debris and mud on the inner wall of the tunnel, the signal cable is arranged in the pressure-resistant pipe, and the first section of the signal cable is arranged along the oil pipe, which can further enhance the strength of the signal cable and reduce the workload of the signal cable arrangement, and the accuracy and reliability of the detection result are better.

[0047] The specific structure of the oil cylinder 10 and the arrangement of the sensor 30 in the embodiment will be described below.

[0048] In the embodiment, the cylinder body 11 includes a cylinder barrel 111 and an end cover 112. The cylinder barrel 111 is sealingly connected to the milling plane 512 on the inner wall of the cutter disc ring plate 51, and the end cover 112 is sealingly connected to the end of the cylinder barrel 111 away from the milling plane 512. The end cover 112 is connected with an oil guide column 113 which is coaxially inserted into the cylinder barrel 111. The oil guide column 113 is provided with a central hole 114 and hydraulic oil channels 115 symmetrically distributed on both sides of the central hole 114. The central hole 114 is sealingly connected with an end plate 13 at the opening of the end face of the end cover 112 away from the cylinder barrel 111, and the hydraulic oil channels 115 are in communication with the oil pipe connection port 14 provided on the outer circumferential surface of the end cover 112.

[0049] The ejector rod 12 includes a rod head 121, a rod barrel 122 and a displacement barrel 123 which are coaxially arranged. A part of the rod head 121 extends outwardly through the through hole 511, one end of the rod barrel 122 is connected to the end face of the rod head 121 facing the end cover 112, and the other end is inserted into the cylinder barrel 111 and located outside the oil guide column 113. The outer wall of the rod barrel 122 is dynamically sealingly connected with the inner wall of the cylinder barrel 111, and the inner wall of the rod barrel 122 and the outer wall of the oil guide column 113 form a hydraulic oil cavity 124 which is in communication with the hydraulic oil channels 115. The displacement barrel 123 is inserted into the central hole 114.

[0050] The sensor 30 is in the shape of a rod and is sealingly connected coaxially in the central hole 114. One end of the sensor 30 is inserted into the displacement barrel 123 and is slidingly connected with the slip ring 125 at the end of the displacement barrel 123, and the other end is connected with the cable connection port 15 provided on the outer circumferential surface of the end cover 112 and is connected with the first section 40a of the signal cable 40 through the cable connection port 15. The cable connection port 15 and the oil pipe connection port 14 are arranged at an angle of 90° on the outer circumferential surface of the end cover 112.

[0051] Since the sensor 30 is arranged in the central hole 114 of the end cover 12 and is slidingly connected with the slip ring 125 at the end of the displacement barrel 123 of the ejector rod 12, the oil cylinder 10 has a position detection function, and has a compact structure, is easy to connect and is easy to arrange on the cutter disc 50 of the shield tunneling machine.

[0052] To reduce wear on the push rod head 121 at the detection position and the initial position, in this embodiment, a wear-resistant alloy layer 126 is provided on the end face of the push rod head 121 away from the end cover 112. The wear-resistant alloy layer 126 is formed by welding wear-resistant alloy to balance economy and wear resistance. The thickness of the wear-resistant alloy layer 126 is 5mm. When the push rod 12 is in the initial position, the end face of the push rod head 121 away from the end cover 112 is located inside the outer circumferential surface of the cutter head 50 (the sheet metal surface of the cutter head, located outside the cutter head ring plate 51), and the distance between the end face of the push rod head 121 away from the end cover 112 and the outer circumferential surface of the cutter head 50 is 5mm.

[0053] Due to the harsh environment in the area where the cutter head 50 is located, in order to enhance the protection of the oil pipe 20, signal cable 40, and cylinder 11, in this embodiment, the pressure-resistant pipe 41 is made of the same material as the oil pipe 20. The outer wall of the spoke 531 is connected to a protective plate 534 with a cross-section in the shape of a door frame. The protective plate 534 extends along the spoke 531. The space between the protective plate 534 and the spoke 531 is used to accommodate the first segment 40c of the oil pipe 20 and the signal cable 40. At the same time, the inner side of the cutter head ring plate 51 is provided with a sealing cavity 513 to accommodate the cylinder 11. The sealing cavity 513 is formed by sealing and connecting multiple side plates 514.

[0054] Example 2

[0055] like Figures 8 to 10 As shown, Embodiment 2 is basically the same as Embodiment 1, except that in Embodiment 2, the pressure-resistant tube 41 is a silicone flexible tube, and the pressure-resistant tube 41 where the first segment 40c of the signal cable 40 is located is inserted into the oil pipe 20. The annular cavity between the outer wall of the pressure-resistant tube 41 and the inner wall of the oil pipe 20 forms an oil supply channel 411. The maximum oil pressure in the oil supply channel 411 is half of the maximum pressure that the pressure-resistant tube 41 can withstand. Furthermore, the two ends of the oil pipe 20 are connected to a tee 21 for separating the detection cable 40 and the oil supply channel 411. The tee 21 near the oil cylinder 10 is located in the sealed cavity 513, and the tee 21 away from the oil cylinder 10 is located in the center block 52 of the cutter head.

[0056] The advantage of such arrangement is that the pressure outside the pressure-resistant pipe 41 can be controlled, and the protection effect of the first section 40a of the signal cable 40 is further improved. Specifically, in addition to large rocks and soil falling from the cutter head 50, there will also be mud with a large pressure (such as a slurry shield tunneling machine). When cracks appear at the connecting part of the spoke 531 and the guard plate 534 due to the impact of rocks and soil, the mud with a large pressure will enter the cavity surrounded by the guard plate 534 and the spoke 531, thereby threatening the pressure-resistant pipe 41 and the oil pipe 20. In this case, the pressure resistance of the oil pipe 20 is much higher than that of the pressure-resistant pipe 41. By arranging the pressure-resistant pipe 41 of the first section 40a in the oil pipe 20, the external pressure on the pressure-resistant pipe 41 can be controlled by controlling the pressure of the oil supply channel 411. In fact, since the top rod 12 only serves as a detection function, the oil pressure required to push the top rod 12 does not need to be very high, and is usually below 2.5mpa. That is, the oil pressure in the oil supply channel 411 does not exceed 2.5mpa. In this way, ordinary silicone hoses can withstand it, and the arrangement of the pressure-resistant pipe 41 and the sealed connection at the three-way joint 21 are facilitated.

[0057] The application also provides a shield tunneling machine cutter head excavation diameter detection method, which uses the shield tunneling machine excavation diameter detection system of any of the above embodiments for detection, and includes the following steps:

[0058] S1. Stop the rotation of the cutter head, and insert the plug into the socket;

[0059] S2. Increase the pressure of the hydraulic oil in the oil pipe through the oil distributor. When the detection value of the sensor does not change or changes around a certain value, the oil distributor stops increasing the pressure, and the shield tunneling machine control center records the detection value A1 of the sensor;

[0060] S3. Decrease the pressure of the hydraulic oil in the oil pipe through the oil distributor. When the detection value of the sensor does not change or changes around a certain value, the oil distributor stops decreasing the pressure, and the shield tunneling machine control center records the detection value A2 of the sensor, and calculates the sliding distance of the top rod from the initial position to the detection position according to the difference between A1 and A2, and then calculates the excavation radius B1 of the cutter head at this position according to the distance between the top rod at the initial position and the center of the cutter head;

[0061] S4. Pull out the plug from the socket, and rotate the cutter head by 360° / n, wherein n is a natural number greater than or equal to 30;

[0062] S5. Repeat steps S1 to S4 to obtain n excavation radii B1, B2 to Bn, and the shield tunneling machine control center simulates the cross section of the tunnel according to the n excavation radii, and calculates the excavation diameter of the cutter head.

[0063] The method is simple to operate and easy to implement, and has good accuracy and reliability of the detection result.

[0064] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A shield tunneling machine cutterhead excavation diameter detection system, comprising: a cylinder having a cylinder body and a top rod, one end of the top rod being axially slidably disposed in the cylinder body and the other end being disposed in a through hole in a cutterhead ring plate, the top rod having an initial position in which the top rod retracts from the outer circumferential surface of the cutterhead and a detection position in which the top rod abuts against the inner wall of a tunnel; a pipe for supplying oil to the cylinder, one end of the pipe being in communication with the cylinder body and the other end being in communication with a oil distributor on a cutterhead center block, the top rod moving to the detection position when the oil pressure in the pipe rises and moving to the initial position when the oil pressure in the pipe drops; a sensor disposed on the cylinder body for detecting the current position of the top rod; a signal cable disposed in a pressure-resistant pipe; characterized in that: the cylinder body is sealingly connected to the inner wall of the cutterhead ring plate, the inner side of the cutterhead ring plate is provided with an enclosed cavity accommodating the cylinder body, the enclosed cavity being formed by a plurality of side plates sealingly connected together; the signal cable is composed of a first section, a second section and a third section connected in sequence, one end of the first section being connected to the sensor and the other end extending into the cutterhead center block along with the pipe; the second section is disposed along the inner cavity of a cutterhead slewing frame, one end of the second section extending into the cutterhead center block and being connected to the first section, the other end extending into a rotating shaft in the center of the cutterhead slewing frame in the axial direction and extending out of the outer circumferential surface of the rotating shaft in the radial direction and being connected to a socket provided on the outer circumferential surface of the rotating shaft; one end of the third section is provided with a plug matched with the socket, and the other end is connected to a shield tunneling machine control center, the shield tunneling machine control center calculating the excavation diameter of the cutterhead according to the detection value of the sensor; the pipe is disposed along a spoke of the cutterhead slewing frame, the outer wall of the spoke being connected with a guard plate having a door frame-shaped cross section, the guard plate extending along the spoke, the space between the guard plate and the spoke being used for accommodating the pipe and the first section, the pressure-resistant pipe in which the first section is disposed being disposed in the pipe, the material of the pressure-resistant pipe being the same as that of the pipe, the annular space between the outer wall of the pressure-resistant pipe and the inner wall of the pipe forming an oil supply channel, the maximum oil pressure in the oil supply channel being half of the maximum pressure that the pressure-resistant pipe can withstand, the two ends of the pipe being connected with a tee for separating the signal cable and the oil supply channel, the tee close to the cylinder being disposed in the enclosed cavity, and the tee away from the cylinder being disposed in the cutterhead center block.

2. The shield machine cutterhead excavation diameter detection system according to claim 1, characterized in that: The cylinder comprises a cylinder barrel and an end cover, the cylinder barrel is sealingly connected to a milling plane of an inner wall of the cutter disc ring plate, the end cover is sealingly connected to an end of the cylinder barrel away from the milling plane, an oil guide column is connected to the end cover, the oil guide column is coaxially inserted into the cylinder barrel, the oil guide column is provided with a central hole and a hydraulic oil channel on one side or both sides of the central hole; the ejector rod comprises a coaxially arranged ejector rod head, an ejector rod barrel and a displacement barrel, at least a part of the ejector rod head extends outwardly through the through hole, one end of the ejector rod barrel is connected to an end face of the ejector rod head facing the end cover, the other end is inserted into the cylinder barrel and located outside the oil guide column, the outer wall of the ejector rod barrel is dynamically sealingly connected to the inner wall of the cylinder barrel, a hydraulic oil cavity in communication with the hydraulic oil channel is formed between the inner wall of the ejector rod barrel and the outer wall of the oil guide column, the displacement barrel is inserted into the central hole; the sensor is in the form of a rod, the sensor is coaxially and sealingly connected to the central hole, one end of the sensor is inserted into the displacement barrel and slidingly connected to a slip ring at the end of the displacement barrel, the other end is connected to the first segment of the signal cable.

3. The shield machine cutterhead excavation diameter detection system of claim 2, wherein: The end face of the ejector rod head away from the end cover is provided with a wear-resistant alloy layer, the thickness of the wear-resistant alloy layer is not less than 5 mm.

4. The shield machine cutterhead excavation diameter detection system of claim 2, wherein: When the ejector rod is in the initial position, the end face of the ejector rod head away from the end cover is located inside the outer circumferential surface of the cutter disc, and the distance between the end face of the ejector rod head away from the end cover and the outer circumferential surface of the cutter disc is not less than 5 mm.

5. A method for detecting the excavation diameter of a cutter head of a tunneling machine, characterized in that: The detection method comprises the following steps: S1. stopping the rotation of the cutter disc, inserting the plug into the socket; S2. boosting the hydraulic oil in the oil pipe by the oil distributor, when the detection value of the sensor does not change or changes around a certain value, the oil distributor stops boosting, the control center of the shield tunneling machine records the detection value A1 of the sensor; S3. reducing the hydraulic oil in the oil pipe by the oil distributor, when the detection value of the sensor does not change or changes around a certain value, the oil distributor stops reducing, the control center of the shield tunneling machine records the detection value A2 of the sensor, and calculates the sliding distance of the ejector rod from the initial position to the detection position according to the difference between A1 and A2, and then calculates the excavation radius B1 of the cutter disc at this position according to the distance between the ejector rod in the initial position and the center of the cutter disc; S4. pulling the plug out of the socket, and rotating the cutter disc by 360° / n, wherein n is a natural number greater than or equal to 30; S5. repeating steps S1 to S4 to obtain n excavation radii B1, B2 to Bn, and the control center of the shield tunneling machine simulates the cross section of the tunnel according to the n excavation radii and calculates the excavation diameter of the cutter disc.

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