A construction method for small-sized jumbo micro-bench in fault fracture zone of water-rich railway tunnel

Abstract

The present application discloses a construction method for a small trolley with a micro-step in the fault fracture zone of a water-rich railway tunnel. The tunnel face is divided into an upper bench, a middle bench, and a lower bench, and blasting excavation is carried out in sequence. The excavation depth of the upper bench is controlled within 1 to 2 times the tunnel diameter, so that a support system can be established in the excavated tunnel in time and wet shotcrete can be applied to seal the loop as early as possible, thereby reducing the possibility of tunnel collapse. At the same time, during the excavation of the upper bench, a pile-forming mechanism horizontally drives into the lower bench soil layer under the counter-brace, and a rubber air cushion jacks up the jacking rod so that the jacking rod abuts against the top of the tunnel, thereby forming a double counter-bracing mechanism, so that the telescopic cantilever will not become unstable during operation, effectively improving construction safety.

Description

Technical Field

[0001] This application relates to the technical field of tunnel excavation, and in particular to a construction method of a small trolley with micro-benches in a fault fracture zone of a water-rich railway tunnel. Background Art

[0002] During the construction of railways, it is often necessary to pass through mountains, so tunnels need to be excavated during the construction process. At present, blasting method + bench method are generally used for the excavation of railway tunnels. For water-rich areas, before construction, it is also necessary to conduct advanced grouting on the surrounding soil layer of the tunnel to reinforce the surrounding soil layer of the tunnel.

[0003] When excavating a tunnel, first divide the bench on the tunnel face, generally divided into upper, middle and lower benches and follow the order from top to bottom for blasting excavation. When conducting blasting excavation, workers need to rely on a trolley to drill blast holes and charge explosives on the tunnel face. After the upper bench is blasted, the soil and rock debris generated by the blasting should be transported out in time, and then the middle and lower benches are blasted in turn. Finally, a tunnel support system is built inside the tunnel and wet shotcrete is applied to form a closed loop as early as possible.

[0004] However, in the actual blasting excavation process of the upper bench, the depth for the upper bench is relatively deep, resulting in the overlong cantilever end of the trolley being prone to instability. Therefore, improvements are needed. Summary of the Invention

[0005] In order to solve the problem that the trolley is prone to instability during use, this application provides a construction method of a small trolley with micro-benches in a fault fracture zone of a water-rich railway tunnel.

[0006] A construction method of a small trolley with micro-benches in a fault fracture zone of a water-rich railway tunnel provided by this application adopts the following technical solutions:

[0007] A construction method of a small trolley with micro-benches in a fault fracture zone of a water-rich railway tunnel includes the following steps:

[0008] S1. Conduct advanced grouting around the tunnel face to reinforce the surrounding soil layer of the tunnel face;

[0009] S2. Use an excavator to dig out the upper bench, middle bench and lower bench on the tunnel face; the tunnel invert area is the upper bench, and the position below the tunnel invert is divided into the middle bench and the lower bench from top to bottom. The excavation depth of the upper bench is controlled within 1-2 times the tunnel diameter, and the excavation depth of the middle bench is half of the excavation depth of the upper bench;

[0010] S3. Arrange the trolley, and use the anti-bracing device to fix the trolley inside the tunnel. The anti-bracing device includes an anti-bracing rod and a pile-forming mechanism arranged on the trolley frame. After the trolley is arranged in front of the lower bench, use the pile-forming mechanism to horizontally drive the anti-bracing rod into the soil layer of the lower bench;

[0011] S4. Blasting:

[0012] S41. The telescopic cantilever on the control console vehicle extends, and drill holes are drilled on the construction surface of the upper bench through the telescopic cantilever. Ammunition is loaded into the drilled holes, and then the telescopic cantilever is retracted. The reaction strut is pulled out from the lower bench soil layer by the pile-forming mechanism, the vehicle retreats, and blasting starts. After blasting, the soil slag is promptly cleaned up;

[0013] S42. Lower the height of the bench, then the telescopic cantilever on the control console vehicle extends, drill holes are drilled on the construction surface of the middle bench through the telescopic cantilever, and then ammunition is loaded into the drilled holes. After that, the telescopic cantilever is retracted. The reaction strut is pulled out from the lower bench soil layer by the pile-forming mechanism, the vehicle retreats, and the soil slag is promptly cleaned up after blasting;

[0014] S43. Drill holes on the construction surface of the lower bench, then load ammunition into the drilled holes, and promptly clean up the soil slag after blasting;

[0015] S5. Establish a support system inside the excavated tunnel and wet-spray concrete on the tunnel wall to form a closed loop in a timely manner;

[0016] S6. Repeat steps S3 - S5 until the excavation of the tunnel is completed.

[0017] By adopting the above technical solution, the excavation depth of the upper bench in this application is controlled within 1 - 2 times the tunnel diameter. On the one hand, the length of the telescopic cantilever will not be too long, thereby reducing the possibility of the vehicle becoming unstable. On the other hand, a support system can be established inside the excavated tunnel and wet-sprayed with concrete in a timely manner to form a closed loop at an early stage, thereby reducing the possibility of the tunnel collapsing. At the same time, a reaction support device is set on the vehicle. When it is necessary to control the extension of the telescopic cantilever, the reaction strut is horizontally driven into the soil layer of the lower bench through the pile-forming mechanism, thereby forming a reaction support structure, making the vehicle not easily unstable. Moreover, the soil layer into which the reaction strut is driven is the soil layer of the lower bench, so the internal structure of the formed tunnel will not be damaged, maintaining the stability of the tunnel structure and being conducive to reducing the possibility of the tunnel collapsing.

[0018] Preferably, the pile-forming mechanism includes a movable plate and a first driving member for driving the movable plate to move along the axial direction of the tunnel. The reaction strut is arranged on the movable plate, and a second driving member for driving the reaction strut to rotate is arranged on the movable plate.

[0019] By adopting the above technical solution, when it is necessary to drive the reaction strut into the soil layer of the lower bench, the second driving member drives the reaction strut to rotate, and at the same time, the movable plate is pushed forward by the first driving member, so that the reaction strut can be driven into the soil layer of the lower bench and a stable reaction support structure can be formed.

[0020] Preferably, the telescopic cantilever includes a scissor-type mechanism arranged on the side of the frame of the trolley, a construction table is provided at the end of the scissor-type mechanism away from the frame, a rubber air cushion is laid on the upper surface of the scissor-type mechanism, one end of the rubber air cushion is connected to the end of the scissor-type mechanism away from the frame, and a winding device for winding up the rubber air cushion is provided on the top of the frame.

[0021] By adopting the above technical solution, when the scissor mechanism is extended, the rubber air cushion is unfolded and laid on the upper surface of the scissor mechanism, and then air is inflated into the rubber air cushion, and the rubber air cushion is inflated and expanded, so that it is convenient for workers to walk or carry objects on the scissor mechanism. When the ammunition is loaded, the gas in the rubber air cushion is first released, and then the scissor mechanism is retracted. During this period, the reeling device reels the rubber air cushion synchronously, so that the rubber air cushion will not get stuck in the scissor mechanism, so that the scissor structure can operate smoothly.

[0022] Preferably, the winding device includes a winding drum installed on the top of the stand, the winding drum is hollow, a central axis is coaxially arranged inside the winding drum, a coil spring is wound on the central axis, one end of the rubber air cushion is fixedly connected to the free end of the coil spring and is wound around the outer periphery of the coil spring and extends out of the winding drum.

[0023] By adopting the above technical solution, when the rubber air cushion is unfolded, the coil spring is compressed, and when the rubber air cushion is relaxed, the coil spring rebounds to automatically reel up the rubber air cushion.

[0024] Preferably, a clamping device for clamping the rubber air cushion is also provided on the top of the stand, and the clamping device is arranged between the winding device and the scissors-type mechanism. The clamping device includes a first clamping plate arranged above the rubber air cushion, a second clamping plate arranged below the rubber air cushion, and a driving assembly that drives the first clamping plate and the second clamping plate to move in opposite directions.

[0025] By adopting the above technical solution, when inflating the rubber air cushion, the driving assembly is first used to drive the first clamping plate and the second clamping plate to move in opposite directions to clamp the rubber air cushion, so that the flow path of the gas that subsequently rushes into the rubber air cushion is cut off, so that the rubber air cushion in the storage tube will not expand, and then the storage tube will not deform. When the rubber air cushion is deflated and needs to be rolled up, the driving assembly is used to drive the first clamping plate and the second clamping plate to move in opposite directions, so as to loosen the rubber air cushion so that the rolling device can roll up the rubber air cushion.

[0026] Preferably, the stand is also provided with an auxiliary supporting device, which includes two vertical plates arranged on the top of the stand, the two vertical plates are arranged opposite to each other, a movable plate is slidably connected between the two vertical plates, a top rod is fixedly connected to the top of the movable plate, the rubber air cushion passes through under the movable plate, and the movable plate is overlapped on the rubber air cushion.

[0027] By adopting the above technical solution, when drilling blast holes and loading ammunition on the construction surface of the upper bench, the length of the telescopic cantilever is the longest, and at this time, the jumbo is most likely to become unstable. Therefore, by adding an auxiliary support device, when the rubber air cushion is inflated, the rubber air cushion will push up the moving plate. By controlling the length of the ejector rod, when the rubber air cushion pushes up the moving plate, the ejector rod will abut against the top of the tunnel, thereby forming a counter-support structure and further reducing the possibility of the jumbo becoming unstable.

[0028] Preferably, a fixed cylinder is further fixedly connected between the two vertical plates. The fixed cylinder is located below the moving plate, and the rubber air cushion is wound around the fixed cylinder.

[0029] By adopting the above technical solution, on the one hand, the length of the ejector rod can be reduced, making it easier for the rubber air cushion to push the ejector rod upward, and on the other hand, the supporting force of the rubber air cushion can be enhanced, thereby playing a stable supporting role for the ejector rod.

[0030] Preferably, the jumbo frame includes an upper jumbo frame and a lower jumbo frame, and a plurality of adjusting hydraulic cylinders are arranged between the top of the lower jumbo frame and the bottom of the upper jumbo frame.

[0031] By adopting the above technical solution, it is convenient to adjust the height of the jumbo frame, thereby facilitating the drilling of blast holes and loading of ammunition on the construction surface of the upper bench and the middle bench. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram during the blasting excavation of the upper bench in this application;

[0033] Figure 2 is a schematic overall structure diagram of the jumbo in this application;

[0034] Figure 3 is a schematic structural diagram of the winding device in this application;

[0035] Figure 4 is in this application Figure 2 is an enlarged schematic diagram of A in

[0036] Description of the reference numerals:

[0037] 1. Upper bench; 2. Middle bench; 3. Lower bench; 4. Upper stage frame; 5. Lower stage frame; 6. Adjusting hydraulic cylinder; 7. Reaction support device; 71. Reaction support rod; 72. Pile forming mechanism; 721. Movable plate; 722. First driving member; 723. Second driving member; 8. Scissor mechanism; 9. Construction platform; 10. Rubber air cushion; 11. Rewinding device; 111. Rewinding drum; 112. Central axis; 113. Coil spring; 12. Clamping device; 121. First clamping plate; 122. Second clamping plate; 123. Driving assembly; 1231. Bi-directional threaded rod; 1232. Guide rod; 1233. Third driving member; 1234. Mounting seat; 13. Auxiliary support device; 131. Vertical plate; 132. Movable plate; 133. Jacking rod; 134. Fixed cylinder. Detailed implementation manners

[0038] The following will further describe the present application in detail with reference to the Figures 1-4 accompanying drawings.

[0039] The embodiment of the present application discloses a micro-bench construction method for a small trolley in a fault fracture zone of a water-rich railway tunnel, including the following steps:

[0040] S1. Conduct advanced grouting around the tunnel face to reinforce the soil layer around the tunnel face.

[0041] S2. Use an excavator to dig out the upper bench 1, middle bench 2 and lower bench 3 at the tunnel face; referring to Figure 1 , the invert area of the tunnel is the upper bench 1, and the position below the invert of the tunnel is divided into the middle bench 2 and the lower bench 3 from top to bottom. Among them, the excavation depth of the upper bench 1 is controlled within 1 to 2 times the tunnel diameter, and the excavation depth of the middle bench 2 is half of the excavation depth of the upper bench 1.

[0042] S3. Arrange the trolley: Fix the trolley inside the tunnel by using the reaction support device 7. Referring to Figure 1 , specifically, the trolley includes a stage frame, and the stage frame includes an upper stage frame 4 and a lower stage frame 5. A plurality of adjusting hydraulic cylinders 6 are arranged between the top of the lower stage frame 5 and the bottom of the upper stage frame 4. In the embodiment of the present application, four adjusting hydraulic cylinders 6 are provided, and the four adjusting hydraulic cylinders 6 are respectively distributed at the four corner points of the lower stage frame 4. The cylinder body of the adjusting hydraulic cylinder 6 is fixed to the top of the lower stage frame 4, and the piston rod of the adjusting hydraulic cylinder 6 is fixedly connected to the bottom of the upper stage frame 5. By setting the adjusting hydraulic cylinder 6, the height of the stage frame can be adjusted, so as to facilitate the subsequent blasting work on the middle bench 2.

[0043] Referring to Figure 1 and Figure 2 , the reaction support device 7 includes a reaction support rod 71 arranged on the lower stage frame 4 and a pile forming mechanism 72. After the trolley stops in front of the lower bench 3, the reaction support device 7 is horizontally driven into the soil layer of the lower bench 3 by using the pile forming mechanism 72.

[0044] Reference Figure 2 Specifically, the pile-forming mechanism 72 includes a movable plate 721 disposed on the lower bench 4 and a first driving member 722 that drives the movable plate 721 to move along the axial direction of the tunnel. The first driving member 722 is a hydraulic cylinder, and the piston cylinder of the hydraulic cylinder is vertically and fixedly connected to the movable plate 721. There are two anti-bracing rods 71, and the two anti-bracing rods 71 are spaced apart along the length direction of the movable plate 721. A second driving member 723 for driving the anti-bracing rod 71 to rotate is disposed on the movable plate 721. There are two second driving members 723, one second driving member 723 corresponding to one anti-bracing rod 71. The second driving member 723 is a motor, and the motor is installed on the side of the movable plate 721 away from the first driving member 722, and the output shaft of the motor is in transmission connection with the anti-bracing rod 71.

[0045] After the trolley stops in front of the lower bench 3, the second driving member 723 drives the anti-bracing rod 71 to rotate. At the same time, the first driving member 722 pushes the movable plate 721 forward, and the anti-bracing rod 71 drills into the soil layer of the lower bench 3 in the horizontal direction, thereby fixing the trolley.

[0046] S4. Blasting.

[0047] S41. Reference Figure 1 , extend the telescopic cantilever on the control trolley, the staff approaches the construction surface of the upper bench 1 through the telescopic cantilever, then drills blast holes on the construction surface of the upper bench 1, fills ammunition in the drilled blast holes, and then retracts the telescopic cantilever, uses the pile-forming mechanism 72 to pull out the anti-bracing rod 71 from the soil layer of the lower bench 3, the trolley retreats, starts blasting, and timely clears the soil residue after blasting.

[0048] Reference Figure 2 , specifically, the telescopic cantilever includes a scissor mechanism 8 installed on the side of the top of the upper bench 4. The scissor mechanism 8 is horizontally arranged, and a construction platform 9 is provided at one end of the scissor mechanism 8 away from the upper bench 4 for the staff to construct. A rubber air cushion 10 is also laid on the upper surface of the scissor mechanism 8. One end of the rubber air cushion 10 is fixedly connected to the end of the scissor mechanism 8 away from the upper bench 4. A winding device 11 for winding the rubber air cushion 10 and a clamping device 12 for clamping the rubber air cushion 10 are provided on the top of the upper bench 4. The clamping device 12 is arranged between the winding device 11 and the scissor mechanism 8.

[0049] When the scissor mechanism 8 is extended, the rubber air cushion 10 is unfolded, and the rubber air cushion 10 is clamped by the clamping device 12, and then the rubber air cushion 10 is inflated, so that it is convenient for the staff to walk on the scissor mechanism 8 to carry equipment and goods. The existence of the clamping device 12 cuts off the flow path of the gas rushing into the rubber air cushion 10, so that the rubber air cushion 10 located in the storage tube will not expand, and then the storage tube will not be deformed due to the expansion of the rubber air cushion 10. When the scissor mechanism 8 needs to be retracted, the rubber air cushion 10 is first deflated, and then the clamping device 12 releases the rubber air cushion 10. While the scissor mechanism 8 is retracted, the reeling device 11 reels the rubber air cushion 10, so that the scissor mechanism 8 can be retracted smoothly.

[0050] Reference Figure 2 and Figure 3 Specifically, the winding device 11 includes a winding drum 111 installed on the top of the stand. The winding drum 111 is hollow. The winding drum 111 is coaxially fixedly connected to the middle shaft 112. A coil spring 113 is wound around the middle shaft 112. One end of the coil spring 113 is fixedly connected to the middle shaft 112. The end of the rubber air cushion 10 away from the scissor-fork mechanism 8 extends into the winding drum 111 and is wound around the outer periphery of the coil spring 113 and is fixedly connected to the free end of the coil spring 113. When the scissor-fork mechanism 8 is extended, the scissor-fork mechanism 8 drags the rubber air cushion 10, during which the coil spring 113 is compressed. When the scissor-fork mechanism 8 is retracted, the coil spring 113 rebounds to automatically rewind the rubber air cushion 10, so that the scissor-fork mechanism 8 can be retracted smoothly.

[0051] Reference Figure 2 and Figure 4 The clamping device 12 includes a first clamping plate 121 arranged above the rubber air cushion 10, a second clamping plate 122 arranged below the rubber air cushion 10, and a driving assembly 123 that drives the first clamping plate 121 and the second clamping plate 122 to move in opposite directions. The first clamping plate 121 and the second clamping plate 122 are arranged parallel to each other, and the lengths of the first clamping plate 121 and the second clamping plate 122 are both greater than the width of the rubber air cushion 10.

[0052] Reference Figure 4The driving assembly 123 includes a bidirectional threaded rod 1231, a guide rod 1232, and a third driving member 1233 for driving the bidirectional threaded rod 1231 to rotate. One end of the bidirectional threaded rod 1231 is rotatably connected to the upper stage 4, and the other end of the bidirectional threaded rod 1231 sequentially penetrates the second clamping plate 122 and the first clamping plate 121, and the two ends of the bidirectional threaded rod 1231 with opposite thread rotation directions are respectively threadedly connected to the first clamping plate 121 and the second clamping plate 122. One end of the guide rod 1232 is fixedly connected to the top of the upper stage 4, the guide rod 1232 is parallel to the bidirectional threaded rod 1231, and the end of the guide rod 1232 away from the upper stage 4 sequentially passes through the second clamping plate 122 and the first clamping plate 121. The third driving member 1233 is a motor, and the output shaft of the motor is in transmission connection with the bidirectional threaded rod 1231. The top of the upper stage 4 is fixedly connected with a mounting seat 1234 for mounting the third driving member 1233. When the third driving member 1233 drives the bidirectional threaded rod 1231 to rotate forward, the first clamping plate 121 and the second clamping plate 122 move in opposite directions; when the third driving member 1233 drives the bidirectional threaded rod 1231 to rotate reversely, the first clamping plate 121 and the second clamping plate 122 move in opposite directions, thereby clamping the rubber air cushion 10.

[0053] Reference Figure 2 In order to make the trolley stop more stably in the tunnel, an auxiliary support device 13 is also provided on the top of the upper gantry 4. The auxiliary support device 13 is arranged between the clamping device 12 and the scissor mechanism 8. The auxiliary support device 13 includes two vertical plates 131 fixed on the top of the upper gantry 4, and the two vertical plates 131 are arranged opposite to each other and are respectively located on both sides of the rubber air cushion 10. A fixed cylinder 134 is fixedly connected between the two vertical plates 131, and a movable plate 132 is slidably connected between the two vertical plates 131. A top rod 133 is fixedly connected to the upper surface of the movable plate 132, and the movable plate 132 is located above the fixed cylinder 134. The rubber air cushion 10 passes from under the movable plate 132 and is spirally wound on the fixed cylinder 134, and the movable plate 132 overlaps the rubber air cushion 10.

[0054] When the rubber air cushion 10 is inflated, the rubber air cushion 10 expands and pushes up the moving plate 132. By controlling the length of the push rod 133, the push rod 133 can be in contact with the top of the tunnel after the rubber air cushion 10 is inflated, thereby forming a reverse support structure, making the trolley less likely to lose stability. The presence of the fixed cylinder 134 can, on the one hand, reduce the length of the push rod 133, making it easier for the rubber air cushion 10 to push the push rod 133 upward, and on the other hand, it can enhance the supporting force of the rubber air cushion 10, thereby providing a stable support for the push rod 133.

[0055] S42. Lower the height of the gantry. Control the upper bench 1 to move downward by adjusting the hydraulic cylinder 6 until the telescopic cantilever moves to the construction height of the middle bench 2. Then control the scissor mechanism 8 to extend until the construction platform 9 moves to the construction surface of the middle bench 2. Use the clamping device 12 to clamp the rubber air cushion 10, and then inflate the rubber air cushion 10. The staff transports tools and goods to the construction platform 9 through the rubber air cushion 10. After drilling blast holes and loading ammunition on the construction surface of the middle bench 2, deflate the rubber air cushion 10, then release the clamping device 12 from the rubber air cushion 10, and retract the scissor mechanism 8. Next, use the pile-forming mechanism 72 to pull out the anti-bracing rod 71 from the soil layer of the lower bench 3. The trolley reverses, and then starts blasting. After the blasting is completed, promptly clean up the soil slag.

[0056] S43. Drill blast holes on the construction surface of the lower bench 3, then load ammunition into the drilled blast holes, and promptly clean up the soil slag after the blasting is completed.

[0057] S5. Establish a support system inside the excavated tunnel and wet-spray concrete on the tunnel wall to form a closed loop in a timely manner. Specifically, the support system includes a steel mesh laid on the inner wall of the tunnel and a support arch erected inside the tunnel.

[0058] S6. Repeat steps S3 to S5 until the excavation of the tunnel is completed.

[0059] The implementation principle of a small trolley micro-bench construction method for a water-rich tunnel fault fracture zone of a railway is as follows:

[0060] In this application, the tunnel face is divided into an upper bench 1, a middle bench 2, and a lower bench 3 for blasting excavation in sequence, and the excavation depth of the upper bench 1 is controlled within 1 to 2 times the tunnel diameter, so that the excavation depth will not be too large. On the one hand, the length of the telescopic cantilever will not be too long, thereby reducing the possibility of the trolley becoming unstable. On the other hand, a support system can be established inside the excavated tunnel in a timely manner and wet-sprayed with concrete to be closed into a loop as early as possible, thereby reducing the possibility of the tunnel collapsing. And during the blasting excavation process, the trolley is restricted inside the tunnel by the anti-bracing device 7 and the auxiliary support device 13, effectively reducing the possibility of the trolley becoming unstable and improving the construction safety.

[0061] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A construction method for a small trolley with a micro-step in the fault fracture zone of a water-rich railway tunnel, characterized in that: It includes the following steps: S1. Carry out advanced grouting around the tunnel face to reinforce the soil layer around the tunnel face; S2. Use an excavator to dig out the upper bench (1), middle bench (2) and lower bench (3) at the tunnel face; the tunnel invert area is the upper bench (1), and the position below the tunnel invert is divided into the middle bench (2) and the lower bench (3) from top to bottom. Among them, the excavation depth of the upper bench (1) is controlled within 1 to 2 times the tunnel diameter, and the excavation depth of the middle bench (2) is half of the excavation depth of the upper bench (1); S3. Arrange the trolley and fix the trolley inside the tunnel by using the reaction support device (7). The reaction support device (7) includes a reaction support rod (71) and a pile-forming mechanism (72) arranged on the trolley frame. After the trolley is arranged in front of the lower bench (3), use the pile-forming mechanism (72) to horizontally drive the reaction support rod (71) into the soil layer of the lower bench (3); S4. Blasting: S41. Control the telescopic cantilever on the trolley to extend, and drill blast holes on the construction surface of the upper bench (1) through the telescopic cantilever. Load ammunition into the drilled blast holes, then retract the telescopic cantilever, pull out the reaction support rod (71) from the soil layer of the lower bench (3) by using the pile-forming mechanism (72), the trolley retreats, and start blasting. After blasting, promptly clean up the soil slag; S42. Lower the height of the trolley frame, then control the telescopic cantilever on the trolley to extend, drill blast holes on the construction surface of the middle bench (2) through the telescopic cantilever, then load ammunition into the drilled blast holes, then retract the telescopic cantilever, pull out the reaction support rod (71) from the soil layer of the lower bench (3) by using the pile-forming mechanism (72), the trolley retreats, and promptly clean up the soil slag after blasting; S43. Drill blast holes on the construction surface of the lower bench (3), then load ammunition into the drilled blast holes, and promptly clean up the soil slag after blasting; S5. Set up a support system inside the excavated tunnel and wet-spray concrete on the tunnel wall to form a closed loop in time; S6. Repeat steps S3 - S5 until the excavation of the tunnel is completed; The pile-forming mechanism (72) includes a movable plate (721) and a first driving member (722) for driving the movable plate (721) to move along the axial direction of the tunnel. The reaction support rod (71) is arranged on the movable plate (721), and a second driving member (723) for driving the reaction support rod (71) to rotate is arranged on the movable plate (721); The telescopic cantilever includes a scissor mechanism (8) arranged on the side of the trolley frame. A construction platform (9) is arranged at the end of the scissor mechanism (8) far from the trolley frame. A rubber air cushion (10) is laid flat on the upper surface of the scissor mechanism (8). One end of the rubber air cushion (10) is connected to the end of the scissor mechanism (8) far from the trolley frame. A winding device (11) for winding the rubber air cushion (10) is arranged at the top of the trolley frame.

2. The construction method for a small trolley with a micro-step in the fault fracture zone of a water-rich railway tunnel according to claim 1, characterized in that: The coiling device (11) includes a coiling drum (111) installed on the top of the bench. The coiling drum (111) is hollow, and a central shaft (112) is coaxially arranged inside the coiling drum (111). A coil spring (113) is wound around the central shaft (112). One end of the rubber air cushion (10) is fixedly connected to the free end of the coil spring (113), wound around the outer periphery of the coil spring (113), and extends out of the coiling drum (111).

3. A construction method for a small bench with a micro-step in a water-rich fault fracture zone of a railway tunnel according to claim 1, characterized in that: A clamping device (12) for clamping the rubber air cushion (10) is further arranged on the top of the bench. The clamping device (12) is arranged between the coiling device (11) and the scissor mechanism (8). The clamping device (12) includes a first clamping plate (121) arranged above the rubber air cushion (10), a second clamping plate (122) arranged below the rubber air cushion (10), and a driving assembly (123) for driving the first clamping plate (121) and the second clamping plate (122) to move in opposite or the same directions.

4. A construction method for a small bench with a micro-step in a water-rich fault fracture zone of a railway tunnel according to claim 1, characterized in that: An auxiliary support device (13) is further arranged on the top of the bench. The auxiliary support device (13) includes two vertical plates (131) arranged on the top of the bench. The two vertical plates (131) are arranged oppositely, and a moving plate (132) is slidably connected between the two vertical plates (131). A top rod (133) is fixedly connected to the top of the moving plate (132). The rubber air cushion (10) passes through below the movable plate (721), and the moving plate (132) is lapped on the rubber air cushion (10).

5. A construction method for a small bench with a micro-step in a water-rich fault fracture zone of a railway tunnel according to claim 4, characterized in that: A fixed cylinder (134) is further fixedly connected between the two vertical plates (131). The fixed cylinder (134) is located below the moving plate (132), and the rubber air cushion (10) is wound around the fixed cylinder (134).

6. A construction method for a small bench with a micro-step in a water-rich fault fracture zone of a railway tunnel according to claim 1, characterized in that: The bench includes an upper bench (4) and a lower bench (5), and a plurality of adjusting hydraulic cylinders (6) are arranged between the top of the lower bench (5) and the bottom of the upper bench (4).

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