A soft rock tunnel boring machine and construction method thereof

Abstract

A soft rock tunnel boring machine and a construction method thereof, wherein the soft rock tunnel boring machine comprises: a cutting arm, the cutting arm is transmission-connected to a cutting head, the cutting head is provided with cutting teeth, and the cutting arm is also provided with an anti-load mechanism, the anti-load mechanism is used to prevent the cutting head from being activated under load; in order to prevent the problem that the cutting head first contacts with soft surrounding rock and then starts cutting in an unstarted state, an anti-load mechanism is additionally installed on the cutting arm; in an unstarted state of the cutting head, the anti-load mechanism half-covers the cutting head, so that even if an operation error occurs, the cutting head cannot contact with the soft surrounding rock, and only after the cutting head is started, the cutting head is exposed and the formal work of cutting the surrounding rock is started, thereby reducing unnecessary wear of the cutting head and the cutting teeth and machine damage.

Description

Technical Field

[0001] The invention relates to the technical field of soft rock tunnel excavation, and in particular to a soft rock tunnel boring machine and a construction method thereof. Background Art

[0002] The soft surrounding rock has low strength and poor self-stabilization ability. After tunnel excavation, the ground stress is redistributed, resulting in a large loose circle around the tunnel. The construction of tunnels with soft surrounding rocks is more obviously affected by geological conditions. The construction difficulty is also increased due to large cross-sections, shallow burial depths, and crossing existing roads or buildings.

[0003] Cantilevered tunnel boring machines can be used for soft rock tunnel construction. The mechanical disturbance and over-excavation degree of the surrounding rock caused by the cantilevered tunnel boring machine excavation construction are small, which not only ensures safety, greatly improves the construction progress, solves environmental protection problems, but also ensures the excavation quality and saves completion time. The cantilevered tunnel boring machine generally consists of a walking mechanism, a bearing body, a shovel, a hydraulic cantilever, a cutting part, a slag conveying mechanism, etc.

[0004] However, in the actual excavation process, it was found that due to the large amount of floating dust in the working environment, which affects the operator's line of sight, the operator is not careful during operation, which will cause the cutter head to be in an unstarted state, contact the surrounding rock first, and then start the cutting action under load, resulting in unnecessary excessive wear of the cutting head and cutting teeth and damage to the machine.

[0005] In order to solve the above problems, the present invention proposes a soft rock tunnel boring machine and a construction method thereof. Summary of the invention

[0006] Technical issues to be solved

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art, meet practical needs, and provide a soft rock tunnel boring machine and a construction method thereof to solve the above technical problems.

[0008] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is:

[0009] A soft rock tunnel boring machine comprises a cutting arm, the cutting arm is connected to a cutting head in a transmission manner, the cutting head is provided with cutting teeth, and an anti-load mechanism is also installed on the cutting arm, the anti-load mechanism is used to prevent the cutting head from being activated under load.

[0010] Further, the anti-load mechanism comprises a fixing ring, the fixing ring is detachably fixed to the cutting arm, a protective plate is hinged on the fixing ring, the protective plate half covers the cutting head, an annular ring is provided on the side of the fixing ring away from the cutting head, and the annular ring is slidably sleeved on the cutting arm;

[0011] A connecting arm is hinged on the annular ring, and the other end of the connecting arm is movably connected to the protective plate; an opening and closing component is arranged between the fixed ring and the annular ring, and the opening and closing component is used to adjust the distance between the annular ring and the fixed ring to switch the protective plate to an open or closed state.

[0012] Furthermore, the opening and closing assembly includes a limit member, which is fixedly connected to the side of the fixed ring facing the annular ring. The limit member is a T-shaped structure. A slide rail groove is rotatably connected to one side of the annular ring close to the limit member. The bottom surface of the slide rail groove is inclined to the plane, and the overall shape is lower on the left and higher on the right. The T-shaped end of the limit member is inserted into the slide rail groove and is in rolling contact with the slide rail groove.

[0013] Furthermore, the opening and closing assembly includes a plurality of hydraulic telescopic columns, which are distributed along the axis of the fixed ring, and one end of the hydraulic telescopic column is fixed to the fixed ring, and the other end is detachably fixed to the annular ring; a speed sensor is installed on the annular ring for detecting the speed of the cutting arm.

[0014] Furthermore, the protective plate is provided with an arc-shaped structure, two protective plates are provided, and the two protective plates are symmetrically distributed along the central axis of the cutting head, and a plurality of sharp tooth grooves are also provided at the end of the arc-shaped structure.

[0015] Furthermore, a soil cleaning mechanism is provided on the inner side of the protective plate, and the soil cleaning mechanism is used to clean the accumulated soil on the inner side of the protective plate.

[0016] Furthermore, the soil clearing mechanism includes a slide groove, which is opened on the inner side of the protective plate, a slider is slidably connected in the slide groove, and a return spring is connected between the side wall of the slide groove and the slider, a shovel plate is fixedly connected to the slider, and the shovel plate is fitted with the inner side of the protective plate; the thickness of the shovel plate gradually increases from both sides to the middle.

[0017] Furthermore, a telescopic mechanism is provided in the cutting head, and the telescopic mechanism includes an auxiliary rod, and the auxiliary rod is slidably mounted in a telescopic slot provided on the cutting head, and the telescopic slot is provided between adjacent cutting teeth. A cavity is provided inside the cutting head, and a central axis is provided in the cavity, and the bottom of the central axis is slidably mounted in the lifting slot, and a supporting spring is connected between the central axis and the bottom wall of the lifting slot, and a plurality of annular portions are fixed to the periphery of the central axis, and the diameter of the annular portion gradually decreases from top to bottom, and the auxiliary rod is in contact with the outer surface of the annular portion and is matched to form an inclined surface; a wire groove that passes through the cutting head is provided at the bottom of the cavity, and a steel wire rope is passed through the wire groove, and one end of the steel wire rope is fixedly connected to the bottom end of the annular portion, and the other end is fixedly connected to the protective plate on the corresponding side;

[0018] A through slot is provided on the top of the cutting head, the through slot and the central axis are located on the same axis, the bottom of the through slot is arranged as a groove, the top of the central axis is arranged as a protrusion, the groove cooperates with the protrusion, and the cavity is connected to the water supply equipment through a water inlet pipe.

[0019] A construction method for a soft rock tunnel, the construction method using the soft rock tunnel boring machine, the construction method is as follows:

[0020] S1: Start the tunnel boring machine, drive the cutting arm to rotate, and the cutting arm drives the cutting head to rotate, completing the preparation work;

[0021] S2: The speed sensor detects the speed of the cutting arm. Once the speed of the cutting arm and the cutting head reaches the set value, a signal is sent to the control system of the device. The control system controls the hydraulic telescopic column to extend linearly, thereby pushing the annular ring away from the fixed ring. The annular ring applies tension to the protective plate through the connecting arm, so that the protective plate swings longitudinally while rotating with the fixed ring, thereby exposing the cutting head originally protected by the protective plate. Then the tunnel boring machine is operated to extend the cutting head to the area to be excavated, and cutting and excavation are carried out;

[0022] S3: The telescopic mechanism is started, and the protective plate is repeatedly opened to cooperate, and the wire rope is pulled periodically. When the wire rope tension is greater than the supporting force of the supporting spring, the central axis and the annular part move downward, and the annular part cooperates with the inclined surface of the auxiliary rod to squeeze the auxiliary rod to reciprocate out of the telescopic groove, thereby impacting the interval space between adjacent cutting teeth, and the cutting head rotates to destroy the rock and soil, while expanding and contracting along the way to impact the rock and soil;

[0023] S4: Cooling water is pumped out under pressure through an external water supply device and can enter the cavity through the water inlet pipe to cool the inside of the cutting head in the working state. During the downward movement of the central axis in S3, the protrusion on the top of the central axis will move downward, thereby separating from the groove at the bottom of the through slot, so that the through slot and the cavity are in a conductive state. The cooling water in the cavity will be ejected from the top through slot, thereby spraying water on the top area of ​​the cutting head that penetrates into the surrounding rock, cooling the cutting head in this area, and the water can moisten the rock and soil, making the rock and soil partially soft.

[0024] (3) Beneficial effects:

[0025] (1) In order to prevent the problem that the cutting head contacts with soft surrounding rock before starting to cut when the cutting head is not started, an anti-load mechanism is installed on the cutting arm. When the cutting head is not started, the anti-load mechanism half covers the cutting head. Even if there is an operation error, the cutting head cannot contact with the soft surrounding rock. Only after the cutting head is started, the cutting head is exposed and the formal cutting of the surrounding rock is started, thereby reducing unnecessary wear of the cutting head and cutting teeth and machine damage;

[0026] (2) When the anti-load mechanism of the present invention is working, if the cutting arm is not started, the cutting arm and the connected cutting head are both in a stationary state, and the fixing ring and the protective plate fixed on the cutting arm are also in a horizontal stationary state. Since the top length of the protective plate is greater than the cutting head, the cutting head will fall into the coverage of the protective plate when it is not started, which prevents the cutting head from contacting the soft surrounding rock first and then starting to cut due to misoperation; when the cutting arm is started, it drives the cutting head and the fixing ring to rotate, and the opening and closing component is started at this time, thereby pushing the annular ring away from the fixing ring. The annular ring applies a pulling force to the protective plate through the connecting arm, so that the protective plate swings longitudinally while rotating with the fixing ring, and the swinging angle of the protective plate depends on the distance that the opening and closing component pushes away from the annular ring. After the protective plate swings longitudinally, the original cutting head is exposed. The cutting head is started first and then the cutting action is performed, which can effectively reduce the wear of the cutting head and the cutting teeth and the damage to the machine;

[0027] (3) The present invention provides a protective plate with an arc-shaped structure and two symmetrically arranged protective plates, which can better cover the end of the cutting head in a non-working state, thereby reducing damage to the machine during load startup or low-speed load operation; and the opened protective plate can also play the role of crushing teeth when rotating, and pre-crush the soft surrounding rock in the working area of ​​the cutting head, and the opening angle of the protective plate is adjustable, which can adapt to pre-crushing work in different areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A three-dimensional diagram of one embodiment of the present invention;

[0029] Figure 2 For the present invention Figure 1 Rear view of

[0030] Figure 3 A three-dimensional diagram of another embodiment of the present invention;

[0031] Figure 4 For the present invention Figure 3 Schematic diagram of the internal structure;

[0032] Figure 5 It is a schematic diagram of the internal structure of the slide rail groove in the present invention.

[0033] The reference numerals are as follows:

[0034] 1. Cutting arm; 2. Cutting head; 3. Cutting teeth; 4. Anti-load mechanism; 41. Fixed ring; 42. Protective plate; 43. Annular ring; 44. Connecting arm; 45. Opening and closing assembly; 451. Limiting piece; 452. Slide groove; 453. Hydraulic telescopic column; 454. Speed ​​sensor; 5. Arc structure; 6. Soil cleaning mechanism; 61. Slide groove; 63. Reset spring; 64. Shovel plate; 7. Sharp tooth groove; 8. Telescopic mechanism; 81. Auxiliary rod; 82. Telescopic groove; 83. Cavity; 84. Central axis; 85. Lifting groove; 86. Annular part; 87. Wire rope; 9. Through groove; 10. Water inlet pipe. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1-5 The present invention is further described with examples:

[0036] A soft rock tunnel boring machine comprises a cutting arm 1, the cutting arm 1 is connected to a cutting head 2, the cutting head 2 is provided with cutting teeth 3, and the cutting arm 1 is also provided with an anti-load mechanism 4, the anti-load mechanism 4 is used to prevent the cutting head 2 from being activated under load.

[0037] In order to prevent the problem that the cutting head 2 comes into contact with soft surrounding rock before starting cutting in an unstarted state, an anti-load mechanism 4 is additionally installed on the cutting arm 1. When the cutting head 2 is not started, the anti-load mechanism 4 half covers the cutting head 2. Even if an operation error occurs, the cutting head 2 cannot come into contact with the soft surrounding rock. Only after the cutting head 2 is started, the cutting head 2 is exposed and the formal work of cutting the surrounding rock is started, thereby reducing unnecessary wear of the cutting head 2 and the cutting teeth 3 and machine damage.

[0038] In this embodiment, the anti-load mechanism 4 includes a fixing ring 41, which is detachably fixed to the cutting arm 1, and a protective plate 42 is hinged on the fixing ring 41, and the protective plate 42 half covers the cutting head 2. An annular ring 43 is provided on the side of the fixing ring 41 away from the cutting head 2, and the annular ring 43 is slidably sleeved on the cutting arm 1;

[0039] A connecting arm 44 is hinged on the annular ring 43, and the other end of the connecting arm 44 is movably connected to the protective plate 42; an opening and closing assembly 45 is provided between the fixing ring 41 and the annular ring 43, and the opening and closing assembly 45 is used to adjust the distance between the annular ring 43 and the fixing ring 41 to switch the protective plate 42 between the open and closed states. When the anti-load mechanism 4 is working, if the cutting arm 1 is not started, the cutting arm 1 and the connected cutting head 2 are both in a static state, and the fixing ring 41 and the protective plate 42 fixed on the cutting arm 1 are also in a horizontal static state. Since the top length of the protective plate 42 is greater than the cutting head 2, the cutting head 2 will fall into the coverage of the protective plate 42 when it is not started, which prevents the cutting head 2 from contacting the soft surrounding rock first and then starting to cut due to misoperation; when the cutting arm 1 is started, it drives the cutting head 2 and the fixing ring 41 The annular ring 43 is activated to push the annular ring 43 away from the fixed ring 41. The annular ring 43 applies a pulling force to the protective plate 42 through the connecting arm 44, so that the protective plate 42 can swing longitudinally while rotating with the fixed ring 41. The swinging angle of the protective plate 42 depends on the distance that the opening and closing component 45 is pushed away from the annular ring 43. After the protective plate 42 swings longitudinally, the original cutting head 2 is exposed. The cutting head 2 is started before cutting, which can effectively reduce the wear of the cutting head 2 and the cutting teeth 3 and the damage to the machine.

[0040] In this embodiment, the opening and closing component 45 includes a limit member 451, which is fixedly connected to the side of the fixed ring 41 facing the annular ring 43. The limit member 451 is a T-shaped structure. The side of the annular ring 43 close to the limit member 451 is rotatably connected to a slide rail groove 452 through a bearing. The bottom surface of the slide rail groove 452 is inclined to the plane, and the overall shape is lower on the left and higher on the right. The T-shaped end of the limit member 451 is inserted into the slide rail groove 452 and is in rolling contact with the slide rail groove 452.

[0041] When in use, when the protective plate 42 is in the horizontal state, the limiting member 451 is located at the deep position of the slide rail groove 452, that is, the lowest position of the groove bottom surface, and the fixed ring 41 drives the limiting member 451 to rotate circumferentially. Since the end of the limiting member 451 is in rolling contact with the slide rail groove 452, the friction force is small, so the annular ring 43 will not rotate synchronously with the fixed ring 41. Therefore, the limiting member 451 slides relatively in the slide rail groove 452, and when it gradually slides to the shallow area of ​​the groove, it can present the action of pushing away the annular ring 43. Through the linkage effect between the structures, the depth conversion of the limiting member 451 in the slide rail groove 452 directly reflects whether the cutting head 2 is started, thereby pulling the protective plate 42 to swing open in the longitudinal direction to expose the cutting head 2. This method is convenient and fast, and does not require an additional power source, saving energy.

[0042] In addition, the bottom surface of the slide rail groove 452 has an annular structure with the left side lower and the right side higher, so that the groove depth shows cyclical changes, driving the annular ring 43 to move back and forth, causing the protective plate 42 to expand back and forth, thereby being able to cooperate with the cutting head 1 to destroy weak surrounding rock, thereby enhancing the excavation performance of the present invention.

[0043] In this embodiment, the opening and closing component 45 includes a plurality of hydraulic telescopic columns 453, which are distributed along the axis of the fixed ring 41, and one end of the hydraulic telescopic column 453 is fixed to the fixed ring 41, and the other end is detachably fixed to the annular ring 43; a speed sensor 454 is installed on the annular ring 43 for detecting the speed of the cutting arm 1.

[0044] When in use, through the detection function of the speed sensor 454, once the speed of the cutting arm 1 and the cutting head 2 reaches the set value, a signal is sent to the control system of the device. The control system controls the liquid telescopic column 453 to extend linearly, thereby pushing the annular ring 43 away from the fixed ring 41, and realizing the opening of the protective plate 42. On the one hand, it can control the load starting situation of the cutting arm 1 when it is not started and at a low speed, reduce unnecessary wear of the cutting head 2 and the cutting teeth 3, and reduce machine damage; on the other hand, the swing angle of the protective plate 42 can be adjusted according to the extension distance of the telescopic column, so that the angle between the protective plate 42 and the axis of the cutting arm 1 can be controlled.

[0045] In this embodiment, the protective plate 42 is provided with an arc structure 5. Two protective plates 42 are provided, and the two protective plates 42 are symmetrically distributed along the central axis of the cutting head 2. The end of the arc structure 5 is also provided with a plurality of sharp tooth grooves 7.

[0046] By providing the protective plate 42 with an arc structure 5 and cooperating with two symmetrically arranged protective plates 42, the cutter head 2 in a non-working state can be better covered at the end, thereby reducing the damage to the machine during load startup or low-speed load operation; and the opened protective plate 42 cooperates with the sharp tooth groove 7 when rotating, and can also play the effect of crushing teeth, thereby pre-crushing the soft surrounding rock in the working area of ​​the cutter head 2, and the opening angle of the protective plate 42 is adjustable, which can adapt to the pre-crushing work in different areas.

[0047] In this embodiment, a soil cleaning mechanism 6 is also provided on the inner side of the protective plate 42, and the soil cleaning mechanism 6 is used to clean the accumulated soil on the inner side of the protective plate 42; the soil cleaning mechanism includes a slide groove 61, and the slide groove 61 is opened on the inner side of the protective plate 42; a slider is slidably connected in the slide groove 61, and a return spring 63 is connected between the side wall of the slide groove 61 and the slider; a shovel plate 64 is fixedly connected to the slider, and the shovel plate 64 is in contact with the inner side of the protective plate 42; the thickness of the shovel plate 64 gradually increases from both sides to the middle. When the protective plate 42 is in the opened state, the centrifugal force generated by the rotation of the cutting arm 1 drives the protective plate 42, so that the shovel plate 64 drives the slider to slide along the slide groove 61 toward the end of the protective plate 42 under the action of the centrifugal force. When the cutting arm 1 and the protective plate 42 stop rotating, the protective plate 42 is reset, the centrifugal force disappears, and the shovel plate 64 is reset under the action of the reset spring 63, forming a reciprocating movement of the shovel plate 64. The shovel plate 64 always maintains a fit state with the inner side of the protective plate 42 during the sliding process, thereby achieving the effect of shoveling away the accumulated soil on the inner side of the protective plate 42, preventing the protective plate 42 from accumulating too much weight and causing the swing angle to be affected.

[0048] In this embodiment, a telescopic mechanism 8 is provided in the cutting head 2, and the telescopic mechanism 8 includes an auxiliary rod 81, and the auxiliary rod 81 is slidably installed in a telescopic groove 82 provided on the cutting head 2, and the telescopic groove 82 is provided between adjacent cutting teeth 3. A cavity 83 is provided inside the cutting head 2, and a central axis 84 is provided in the cavity 83. The bottom of the central axis 84 is slidably installed in the lifting groove 85. A supporting spring is connected between the central axis 84 and the bottom wall of the lifting groove 85. A plurality of annular portions 86 are fixed to the periphery of the central axis 84, and the diameter of the annular portion 86 gradually decreases from top to bottom, and the auxiliary rod 81 contacts the outer surface of the annular portion 86 and is matched to form an inclined surface; a wire groove penetrating the cutting head 2 is provided at the bottom of the cavity 83, and a steel wire rope 87 is passed through the wire groove, and one end of the steel wire rope 87 is fixedly connected to the bottom end of the annular portion 86, and the other end is fixedly connected to the protective plate 42 on the corresponding side;

[0049] A through slot 9 is provided on the top of the cutting head 2, and the through slot 9 and the central axis 84 are located on the same axis. The bottom of the through slot 9 is arranged as a groove, and the top of the central axis 84 is arranged as a protrusion. The groove cooperates with the protrusion, and the cavity 83 is connected to the water supply equipment through the water inlet pipe 10. When in use, the steel wire rope 87 is pulled periodically by the repeated opening action of the protective plate 42. When the tension of the steel wire rope 87 is greater than the supporting force of the supporting spring, the central axis 84 and the annular portion 86 are moved downward. On the one hand, the annular portion 86 cooperates with the inclined surface of the auxiliary rod 81 to squeeze the auxiliary rod 81 to reciprocate out of the telescopic groove 82, thereby impacting the interval space between adjacent pick teeth 3. On the one hand, the cutting head 2 can be rotated to destroy the rock and soil, and at the same time, the rock and soil can be impacted along the way, thereby expanding the degree and range of damage to the rock and soil, and making the excavation of soft rock smoother; on the other hand, when the auxiliary rod 81 is extended and retracted, the accumulated soil filled in the gap of the pick teeth 3 can also be impacted and brought out, so that the accumulated soil falls, the contact area between the pick teeth 3 and the soft rock is maintained, and the excavation efficiency is enhanced;

[0050] The external water supply equipment can pump out cooling water under pressure. On the one hand, it can enter the cavity 83 through the water inlet pipe 10 to cool the inside of the cutting head 2 in the working state, so as to maintain the efficient working state of the cutting head 2; on the other hand, in the process of the central axis 84 moving downward, the protrusion on the top of the central axis 84 will move downward, thereby separating from the groove at the bottom of the through groove 9, so that the through groove 9 and the cavity 83 are in a conductive state, and the cooling water in the cavity 83 will be ejected from the top through groove 9, thereby spraying water on the top area of ​​the cutting head 2 that penetrates deep into the surrounding rock, which can not only cool the cutting head 2 in the area, but also moisten the rock and soil with water, making the rock and soil locally soft and convenient for crushing, thereby promoting the excavation efficiency of the cutting head 2.

[0051] Through the linkage of the opening and closing component and the telescopic mechanism 8, the protective plate 42 is controlled to open reciprocally, so that the protective plate 42 can assist in crushing the rock and soil. At the same time, the telescopic mechanism in the cutting head 2 is linked to pull the wire rope 87 to move the central axis 84 downward, thereby pushing the auxiliary rod 81 to crush the accumulated soil while impacting the rock and soil, thereby increasing the destructive power of the cutting head 2; and controlling the conduction between the through groove 9 and the cavity 83 to allow the cooling water to be pressurized and injected to achieve the cooling effect, and to moisten the rock and soil, making the rock and soil softer and easier to be destroyed. With comprehensive assistance, the overall excavation efficiency is improved.

[0052] A construction method for a soft rock tunnel, the construction method uses the soft rock tunnel boring machine mentioned above, the construction method is as follows:

[0053] S1: Start the tunnel boring machine, drive the cutting arm 1 to rotate, and the cutting arm 1 drives the cutting head 2 to rotate, completing the preparation work;

[0054] S2: The speed sensor 454 is used to detect the speed of the cutting arm 1. Once the speed of the cutting arm 1 and the cutting head 2 reaches the set value, a signal is sent to the control system of the device. The control system controls the hydraulic telescopic column to extend linearly, thereby pushing the annular ring 43 away from the fixed ring 41. The annular ring 43 applies a pulling force to the protective plate 42 through the connecting arm 44, so that the protective plate 42 swings longitudinally while rotating with the fixed ring 41, thereby exposing the cutting head 2 originally protected by the protective plate 42, and then the tunnel boring machine is operated to extend the cutting head 2 to the area to be excavated, and cutting and excavation are carried out;

[0055] S3: The telescopic mechanism 8 is started, and the steel wire rope 87 is pulled periodically by the action of repeatedly opening the protective plate 42. When the tension of the steel wire rope 87 is greater than the supporting force of the supporting spring, the central axis 84 and the annular portion 86 are moved downward, and the annular portion 86 cooperates with the inclined surface of the auxiliary rod 81 to squeeze the auxiliary rod 81 to reciprocate out of the telescopic groove 82, thereby impacting the interval space between adjacent cutting teeth 3, and the cutting head 2 rotates to destroy the rock and soil, while extending and retracting along the way to impact the rock and soil;

[0056] S4: Cooling water is pumped out under pressure through an external water supply device and can enter the cavity 83 through the water inlet pipe 10 to cool the inside of the cutting head 2 in the working state. During the downward movement of the central axis 84 in S3, the protrusion on the top of the central axis 84 will move downward, thereby separating from the groove at the bottom of the through groove 9, so that the through groove 9 and the cavity 83 are in a conductive state. The cooling water in the cavity 83 will be ejected from the top through groove 9, thereby spraying water on the top area of ​​the cutting head 2 that penetrates into the surrounding rock, cooling the cutting head 2 in this area, and the water can moisten the rock and soil, making the rock and soil partially soft.

[0057] Beneficial effects of the present invention:

[0058] In order to prevent the problem that the cutting head contacts with soft surrounding rock before starting to cut in the unstarted state, an anti-load mechanism is installed on the cutting arm. When the cutting head is not started, the anti-load mechanism half covers the cutting head. Even if there is an error in operation, the cutting head cannot contact with the soft surrounding rock. Only after the cutting head is started, the cutting head is exposed and the formal cutting of the surrounding rock is started, thereby reducing unnecessary wear of the cutting head and cutting teeth and machine damage.

[0059] When the anti-load mechanism is working, if the cutting arm is not started, the cutting arm and the connected cutting head are both in a stationary state, and the fixing ring and the protective plate fixed on the cutting arm are also in a horizontal stationary state. Since the top length of the protective plate is greater than the cutting head, the cutting head will fall into the coverage of the protective plate when it is not started, which prevents the cutting head from contacting the soft surrounding rock first and then starting to cut due to misoperation; when the cutting arm is started, it drives the cutting head and the fixing ring to rotate, and the opening and closing component is started at this time, thereby pushing the annular ring away from the fixing ring. The annular ring applies a pulling force to the protective plate through the connecting arm, so that the protective plate swings longitudinally while rotating with the fixing ring, and the swinging angle of the protective plate depends on the distance that the opening and closing component pushes away from the annular ring. After the protective plate swings longitudinally, the original cutting head is exposed. The cutting head is started first and then the cutting action is performed, which can effectively reduce the wear of the cutting head and the cutting teeth and the damage to the machine;

[0060] When in use, when the protective plate is in a horizontal state, the limiter is located at a deep position in the slide rail groove, and the fixed ring drives the limiter to rotate circumferentially. Since the end of the limiter is in rolling contact with the slide rail groove, the friction force is small, so the annular ring will not rotate synchronously with the fixed ring. Therefore, the limiter slides relatively in the slide rail groove, and when it gradually slides to the shallow area of ​​the groove, it can present the action of pushing away the annular ring. Through the linkage between the structures, the depth conversion of the limiter in the slide rail groove directly reflects whether the cutting head is started, thereby pulling the protective plate to swing open in the longitudinal direction to expose the cutting head. This method is convenient and fast, and does not require an additional power source, saving energy.

[0061] Alternatively, through the detection of the speed sensor, once the speed of the cutting arm and the cutting head reaches the set value, a signal is sent to the control system of the device, and the control system controls the liquid telescopic column to extend linearly, thereby pushing the annular ring away from the fixed ring to open the protective plate. On the one hand, it can control the load start-up situation when the cutting arm is not started and the speed is low, reduce unnecessary wear of the cutting head and cutting teeth, and reduce machine damage; on the other hand, the swing angle of the protective plate can be adjusted according to the extension distance of the telescopic column, so that the angle between the protective plate and the axis of the cutting arm can be controlled;

[0062] When in use, the steel wire rope 87 is pulled periodically by the repeated opening action of the protective plate 42. When the tension of the steel wire rope 87 is greater than the supporting force of the supporting spring, the central axis 84 and the annular portion 86 are moved downward. On the one hand, the annular portion 86 cooperates with the inclined surface of the auxiliary rod 81 to squeeze the auxiliary rod 81 to reciprocate out of the telescopic groove 82, thereby impacting the interval space between adjacent pick teeth 3. On the one hand, the cutting head 2 can be rotated to destroy the rock and soil, and at the same time, the rock and soil can be impacted along the way, thereby expanding the degree and range of damage to the rock and soil, and making the excavation of soft rock smoother; on the other hand, when the auxiliary rod 81 is extended and retracted, the accumulated soil filled in the gap of the pick teeth 3 can also be impacted and brought out, so that the accumulated soil falls, the contact area between the pick teeth 3 and the soft rock is maintained, and the excavation efficiency is enhanced;

[0063] The external water supply equipment can pump out cooling water under pressure. On the one hand, it can enter the cavity 83 through the water inlet pipe 10 to cool the inside of the cutting head 2 in the working state, so as to maintain the efficient working state of the cutting head 2; on the other hand, in the process of the central axis 84 moving downward, the protrusion on the top of the central axis 84 will move downward, thereby separating from the groove at the bottom of the through groove 9, so that the through groove 9 and the cavity 83 are in a conductive state, and the cooling water in the cavity 83 will be ejected from the top through groove 9, thereby spraying water on the top area of ​​the cutting head 2 that penetrates deep into the surrounding rock, which can not only cool the cutting head 2 in the area, but also moisten the rock and soil with water, making the rock and soil locally soft and convenient for crushing, thereby promoting the excavation efficiency of the cutting head 2.

[0064] Through the linkage of the opening and closing component and the telescopic mechanism 8, the protective plate 42 is controlled to open reciprocally, so that the protective plate 42 can assist in crushing the rock and soil. At the same time, the telescopic mechanism in the cutting head 2 is linked to pull the wire rope 87 to move the central axis 84 downward, thereby pushing the auxiliary rod 81 to crush the accumulated soil while impacting the rock and soil, thereby increasing the destructive power of the cutting head 2; and controlling the conduction between the through groove 9 and the cavity 83 to allow the cooling water to be pressurized and injected to achieve the cooling effect, and to moisten the rock and soil, making the rock and soil softer and easier to be destroyed. With comprehensive assistance, the overall excavation efficiency is improved.

[0065] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A soft rock tunnel boring machine, comprising a cutting arm (1), characterized in that: The cutting arm (1) is connected to a cutting head (2) in a transmission manner, and cutting teeth (3) are distributed on the cutting head (2). The cutting arm (1) is also provided with an anti-load mechanism (4), and the anti-load mechanism (4) is used to prevent the cutting head (2) from being activated under a load state; the anti-load mechanism (4) comprises a fixing ring (41), and the fixing ring (41) is detachably fixed to the cutting arm (1); a protective plate (42) is hingedly connected to the fixing ring (41), and the protective plate (42) half covers the cutting head (2); an annular ring (43) is provided on the side of the fixing ring (41) away from the cutting head (2), and the annular ring (43) is slidably sleeved on the cutting arm (1); A connecting arm (44) is hinged on the annular ring (43), and the other end of the connecting arm (44) is movably connected to the protective plate (42); an opening and closing component (45) is provided between the fixing ring (41) and the annular ring (43), and the opening and closing component (45) is used to adjust the distance between the annular ring (43) and the fixing ring (41) to switch the protective plate (42) between an open state and a closed state; a telescopic mechanism (8) is provided in the cutting head (2), and the telescopic mechanism (8) ) comprises an auxiliary rod (81), the auxiliary rod (81) is slidably mounted in a telescopic groove (82) provided on the cutting head (2), the telescopic groove (82) is provided between adjacent cutting teeth (3), a cavity (83) is provided inside the cutting head (2), a central axis (84) is provided in the cavity (83), the bottom of the central axis (84) is slidably mounted in a lifting groove (85), and a supporting spring is connected between the central axis (84) and the bottom wall of the lifting groove (85); A plurality of annular portions (86) are fixed on the periphery of the central axis (84), the diameter of the annular portion (86) gradually decreases from top to bottom, and the auxiliary rod (81) contacts the outer surface of the annular portion (86) and is matched to form an inclined surface; a wire groove penetrating the cutting head (2) is provided at the bottom of the cavity (83), a steel wire rope (87) is passed through the wire groove, one end of the steel wire rope (87) is fixedly connected to the bottom end of the annular portion (86), and the other end is fixedly connected to the protective plate (42) on the corresponding side; A through slot (9) is provided on the top of the cutting head (2); the through slot (9) and the central axis (84) are located on the same axis; the bottom of the through slot (9) is arranged as a groove; the top of the central axis (84) is arranged as a protrusion; the groove and the protrusion cooperate; and the cavity (83) is connected to a water supply device via a water inlet pipe (10).

2. The soft rock tunnel boring machine according to claim 1, characterized in that: The opening and closing assembly (45) comprises a limiting member (451), wherein the limiting member (451) is fixedly connected to a side of the fixing ring (41) facing the annular ring (43), the limiting member (451) is a T-shaped structure, and a side of the annular ring (43) close to the limiting member (451) is rotatably connected to a slide rail groove (452), the bottom surface of the slide rail groove (452) being inclined to the plane, and the overall structure is lower on the left and higher on the right; the T-shaped end of the limiting member (451) is inserted into the slide rail groove (452) and is in rolling contact with the slide rail groove (452).

3. The soft rock tunnel boring machine according to claim 1, characterized in that: The opening and closing assembly (45) comprises a plurality of hydraulic telescopic columns (453), the plurality of hydraulic telescopic columns (453) being distributed along the axis of the fixing ring (41), and one end of the hydraulic telescopic column (453) being fixed to the fixing ring (41), and the other end being detachably fixed to the annular ring (43); a rotation speed sensor (454) is mounted on the annular ring (43) for detecting the rotation speed of the cutting arm (1).

4. The soft rock tunnel boring machine according to claim 2 or 3, characterized in that: The protective plate (42) is provided with an arc-shaped structure (5), two protective plates (42) are provided, and the two protective plates (42) are symmetrically distributed along the central axis of the cutting head (2), and a plurality of sharp tooth grooves (7) are also provided at the end of the arc-shaped structure (5).

5. The soft rock tunnel boring machine according to claim 4, characterized in that: A soil clearing mechanism (6) is also provided on the inner side of the protective plate (42), and the soil clearing mechanism (6) is used to clear the accumulated soil on the inner side of the protective plate (42).

6. The soft rock tunnel boring machine according to claim 5, characterized in that: The soil clearing mechanism (6) comprises a slide groove (61), wherein the slide groove (61) is arranged on the inner side of the protective plate (42), a slider is slidably connected in the slide groove (61), and a return spring (63) is connected between the side wall of the slide groove (61) and the slider, a shovel plate (64) is fixedly connected to the slider, and the shovel plate (64) is in contact with the inner side of the protective plate (42); the thickness of the shovel plate (64) gradually increases from both sides to the middle.

7. A construction method for a soft rock tunnel, characterized in that: The construction method uses the soft rock tunnel boring machine described in claim 6, and the construction method is as follows: S1: starting the tunnel boring machine, driving the cutting arm (1) to rotate, and the cutting arm (1) drives the cutting head (2) to rotate, completing the preparation work; S2: The rotation speed of the cutting arm (1) is detected by a rotation speed sensor (454). Once the rotation speed of the cutting arm (1) and the cutting head (2) reaches a set value, a signal is sent to the control system of the device. The control system controls the hydraulic telescopic column to extend linearly, thereby pushing the annular ring (43) away from the fixed ring (41). The annular ring (43) applies a pulling force to the protective plate (42) through the connecting arm (44), so that the protective plate (42) swings in the longitudinal direction while rotating with the fixed ring (41), thereby exposing the cutting head (2) originally protected by the protective plate (42). Then, the tunnel boring machine is operated to extend the cutting head (2) to the area to be excavated, and cutting and excavation are carried out; S3: The telescopic mechanism (8) is started, and the steel wire rope (87) is pulled periodically by the repeated opening action of the protective plate (42). When the pulling force of the steel wire rope (87) is greater than the supporting force of the supporting spring, the central axis (84) and the annular portion (86) are moved downward, and the annular portion (86) cooperates with the inclined surface of the auxiliary rod (81), which squeezes the auxiliary rod (81) to reciprocate out of the telescopic groove (82), thereby impacting the interval space between adjacent cutting teeth (3), and the cutting head (2) rotates to destroy the rock and soil, while the cutting head (2) is extended and retracted along the way to impact the rock and soil; S4: Cooling water is pumped out under pressure through an external water supply device and can enter the cavity (83) through the water inlet pipe (10) to cool the inside of the cutting head (2) in the working state. During the downward movement of the middle axis (84) in S3, the top protrusion of the middle axis (84) will move downward, thereby separating from the bottom groove of the through groove (9), so that the through groove (9) and the cavity (83) are in a conductive state. The cooling water in the cavity (83) will be ejected from the top through groove (9), thereby spraying water on the top area of ​​the cutting head (2) that penetrates into the surrounding rock, cooling the cutting head (2) in this area, and the water can moisten the rock and soil, making the rock and soil partially soft.

Images