Low-clearance city tunnel hard bedrock pile forming equipment and pile forming method

Abstract

The invention relates to the technical field of tunnel construction, in particular to low-clearance city tunnel hard bedrock pile forming equipment and a pile forming method.The pile forming equipment comprises a percussion drill, a transmission device, a machine body, an onboard control system, a power system, a remote operation platform and an air compressor, and the remote operation platform is in signal connection with the onboard control system; the onboard control system is in control connection with the percussion drill, the transmission device, the machine body, the power system and the air compressor; the percussion drill comprises at least two drill rods which are in butt joint in the length direction, the tops of the drill rods are connected to the transmission device, and the transmission device is connected to the power system and the air compressor. Rock breaking is conducted in an air pressure vibration mode, drilling construction of drilling is conducted through the drill rods in butt joint in the length direction, the height needed by construction of the whole equipment is reduced, and the technical problem that in the prior art, the height in an extended tunnel hole is limited, and construction of large support pile construction equipment cannot be met is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a low-headroom urban tunnel hard bedrock pile-forming device and a pile-forming method. Background Art

[0002] When older tunnels, such as those with single-track lines and smaller cross-sections, struggle to accommodate modern traffic flows, expansion becomes imperative. Controlling the surrounding settlement caused by expansion and renovation is crucial for urban tunnels. Support pile foundations, a common support method, can be used to control deformation during tunnel expansion and renovation.

[0003] However, for tunnel renovation and expansion projects with underlying hard rock, support pile construction faces the following major technical challenges: currently, conventional foundation treatment and pile foundation construction equipment is relatively large, requiring a large construction clearance; the space inside the renovation and expansion tunnel is narrow and height-restricted (less than 8m), making it impossible for large equipment to enter the site for construction operations; and under hard rock conditions, small construction equipment has weak rock-breaking capabilities and low excavation efficiency. Summary of the Invention

[0004] The present invention aims to provide a low-headroom urban tunnel hard bedrock pile-forming equipment and method to solve the technical problem in the prior art that the height of the tunnel expansion hole is limited and cannot meet the requirements of large-scale support pile construction equipment. The specific technical solution is as follows:

[0005] The present invention provides a low-headroom urban tunnel hard bedrock pile-forming equipment, comprising an impact drill, a transmission device, a fuselage, an onboard control system, a power system, a remote operation platform and an air compressor. The onboard control system, the power system and the air compressor are all fixed to the fuselage, the remote operation platform is signal-connected to the onboard control system, and the onboard control system is control-connected to the impact drill, the transmission device, the fuselage, the power system and the air compressor; the impact drill comprises at least two drill rods butted together along the length direction, the tops of the drill rods are connected to the transmission device, and the transmission device is connected to the power system and the air compressor.

[0006] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that a tenon is provided at one end of the drill rod, and a tenon groove for connecting the opposite drill rod is provided at the other end of the drill rod, and a connecting piece is connected between the tenon and the tenon groove.

[0007] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that the impact drill further comprises a drill bit and a drill body, the drill bit is connected to the bottom end of the drill rod, and the drill body is sleeved on the outer circumference of the drill rod.

[0008] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that the transmission device includes a power head, a transmission bracket and a telescopic rod, the transmission bracket is installed on the fuselage, the power head is installed on the transmission bracket and connected to the drill rod, the telescopic rod is connected between the transmission bracket and the fuselage, and the telescopic rod is used to adjust the angle of the impact drill.

[0009] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that a protective groove is provided on the top of the transmission bracket, the protective groove is connected to the power head, and the protective groove is a deformable structure.

[0010] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that the transmission device also includes a limiter, which is detachably mounted on the transmission bracket, and an opening for clamping the drill body is provided inside the limiter.

[0011] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that an electronic gyroscope for detecting the transmission device and a camera for auxiliary positioning of the drill bit are provided on the transmission bracket.

[0012] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention is that the body includes a walking track, a walking bracket, a support leg and a rotary drive, the rotary drive is connected between the walking track and the walking bracket, and the support leg is installed on the walking bracket.

[0013] The present invention also provides a method for forming piles in hard bedrock of a low-headroom urban tunnel, comprising the following steps:

[0014] S1: Construction preparation, leveling the site and entrance and exit passages to ensure that they can meet the requirements of tunnel pile foundation construction;

[0015] S2: Pile foundation setting out: Review the design parameters and use a total station to set out the pile position after confirmation. After the pile center is set out, mark the pile foundation design position to assist in positioning the drill bit.

[0016] S3: providing a low-headroom urban tunnel hard bedrock pile-driving device as claimed in claim 1, inputting the location information of each pile foundation on the remote operation platform, and the pile-driving device automatically moves to a position near the pile foundation according to the input information, and lowers the legs after the impact drill is positioned;

[0017] S4: Hang the steel casing at the marked position of the pile foundation, and drill the pile hole by rotating the drill rod. After drilling to the predetermined depth, stop drilling, connect a new drill rod to the original drill rod, and continue drilling downwards.

[0018] S5: After drilling to the designed elevation, stop the drill rod rotation, drill in and out, install the steel cage, and then pour concrete to form the pile foundation.

[0019] A further improvement of the low-headroom urban tunnel hard bedrock pile-forming method of the present invention is that the transmission device includes a power head, a transmission bracket, and a telescopic rod, the transmission bracket being mounted on the machine body, the power head being mounted on the transmission bracket and connected to the drill rod, and the telescopic rod being connected between the transmission bracket and the machine body;

[0020] When the impact drill is positioned, the angle between the transmission bracket and the body is increased by extending the telescopic rod, thereby adjusting the angle of the impact drill until the impact drill maintains a vertical state and is aligned with the pile foundation mark position.

[0021] The application of the technical solution of the present invention has the following beneficial effects:

[0022] The low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention breaks rock by means of air pressure vibration, and performs drilling construction by means of drill rods connected along the length direction, thereby reducing the height required for the construction of the entire equipment and solving the technical problem in the prior art that the height of the expanded tunnel hole is limited and cannot meet the construction requirements of large-scale support pile construction equipment. The present invention uses an air compressor to provide air pressure impact power, and the air pressure is connected by an air pressure pipe, a transmission device, a drill rod and a drill bit, thereby reducing the size of the device and meeting the requirements of limited space in the tunnel and hard rock breaking. Remote control, automatic positioning and other methods are implemented through a remote operation platform, an airborne control system, a camera and an electronic gyroscope, thereby achieving an unmanned drilling process and reducing the health hazards to construction workers during the construction process.

[0023] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a schematic structural diagram of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention;

[0026] Figure 2 This is a side view of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention;

[0027] Figure 3 This is a front view of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention;

[0028] Figure 4 This is a top view of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention;

[0029] Figure 5 This is a bottom view of the drill bit of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention;

[0030] Figure 6 This is a schematic structural diagram of a drill rod for a low-headroom urban tunnel hard bedrock pile-forming equipment according to the present invention;

[0031] Figure 7 This is a schematic diagram of the telescopic rod of the low-headroom urban tunnel hard bedrock pile-forming equipment of the present invention when it is retracted to the shortest position;

[0032] Figure 8 This is a schematic diagram of the low-headroom urban tunnel hard bedrock pile-forming equipment after the fuselage is rotated.

[0033] Figure 9 The present invention is a flow chart of a low-headroom urban tunnel hard bedrock pile forming method.

[0034] Among them, 1-impact drill, 1.1-drill bit, 1.2-drill body, 1.3-drill rod, 1.4-air pressure hole, 1.5-air guide groove, 2-transmission device, 2.1-power head, 2.2-protection groove, 2.3-transmission bracket, 2.4-telescopic rod, 2.5-limiter, 2.6-camera, 3-fuselage, 3.1-walking track, 3.2-walking bracket, 3.3-support leg, 3.4-rotation drive, 4-airborne control system, 4.1-antenna, 4.2-control system, 4.3-status indicator light, 5-power system, 6-air compressor, 7-air pressure pipe, 8-remote operation platform. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] See also Figures 1 to 8 As shown, a low-headroom urban tunnel hard bedrock pile-forming equipment includes an impact drill 1, a transmission device 2, a fuselage 3, an onboard control system 4, a power system 5, a remote operation platform 8 and an air compressor 6. The onboard control system 4, the power system 5 and the air compressor 6 are all fixed on the fuselage 3. The remote operation platform 8 is signal-connected to the onboard control system 4. The onboard control system 4 is control-connected to the impact drill 1, the transmission device 2, the fuselage 3, the power system 5 and the air compressor 6. The impact drill 1 includes at least two drill rods 1.3 connected along the length direction. The top of the drill rod 1.3 is connected to the transmission device 2, and the transmission device 2 is connected to the power system 5 and the air compressor 6.

[0037] In this embodiment, the impact drill 1 utilizes a pneumatic vibrating down-the-hole impact drill 1, combined with a split air compressor 6, to achieve efficient rock breaking and hole cleaning. Furthermore, the segmented drill rod 1.3 and cyclic drilling method reduce the required height, meeting the space-constrained construction conditions within tunnels. Furthermore, the unmanned drilling process reduces health hazards during construction. The construction method, which includes steps such as equipment positioning, parameter adjustment, drilling extension, and pile construction, effectively improves construction efficiency and safety, making it suitable for support pile construction in tunnels with hard bedrock.

[0038] Preferably, Figure 6 As shown, one end of the drill rod 1.3 is provided with a tenon, and the other end of the drill rod 1.3 is provided with a tenon for connecting to the corresponding drill rod 1.3, and a connecting piece is connected between the tenon and the tenon. The cross-section of the tenon and the tenon is square. Specifically, the connecting piece can be a pin or a bolt. If a pin is used, a through hole for the pin to pass through is provided on the tenon and the tenon, and a structure with limiting components at both ends is required to prevent the pin from falling off during use. If a bolt is used, a threaded hole for the bolt to be screwed is provided on the tenon and the tenon. The docking structure of the tenon and the tenon allows the length of the drill rod 1.3 to be continuously extended, and the overall height of the pile-forming equipment does not need to be set too high, thereby meeting the needs of pile-forming construction in existing tunnels or other construction areas with limited height.

[0039] Preferably, Figure 1 and Figure 2 As shown, the impact drill 1 also includes a drill bit 1.1 and a drill body 1.2. The drill bit 1.1 is connected to the bottom end of the drill rod 1.3, and the drill body 1.2 is sleeved on the outer periphery of the drill rod 1.3. The impact drill 1, the transmission device 2 and the air compressor 6 are connected through an air pressure pipe 7. The high-frequency air pressure provided by the air compressor 6 drives the impact drill 1 to vibrate and break the rock. The impact drill 1 performs the drilling action by being driven by the power head 2.1. In this embodiment, the drill bit 1.1 is made of high-strength tungsten steel, and its diameter is the same as the design diameter of the pile foundation, and a diameter of 50 cm is selected. The drill bit 1.1 is provided with an air pressure hole 1.4; the drill body 1.2 contains an air chamber and a channel to realize high-frequency up and down vibration and vibration breaking of the rock through the external high-pressure gas supply. Drill rod 1.3 has an internal air passage connecting air pressure pipe 7 to air pressure holes 1.4 in percussion drill 1. Four circular air pressure holes 1.4 are connected to the air passage. Drill bit 1.1 is equipped with air guide grooves 1.5 for high-pressure air jet cleaning under the action of air pressure, blowing out rock debris. The length of one drill rod 1.3 and the drilling distance are both 2 meters.

[0040] Preferably, the transmission device 2 includes a power head 2.1, a transmission bracket 2.3, and a telescopic rod 2.4. The transmission bracket 2.3 is mounted on the machine body 3. The power head 2.1 is mounted on the transmission bracket 2.3 and connected to the drill rod 1.3. The telescopic rod 2.4 is connected between the transmission bracket 2.3 and the machine body 3. The telescopic rod 2.4 is used to adjust the angle of the impact drill 1. Furthermore, the power head 2.1 includes a vertical displacement driver and a torque driver, which can provide vertical force and torque to the impact drill 1. The telescopic rod 2.4 includes a hydraulic driver. The upper end of the telescopic rod 2.4 is hinged to the transmission bracket 2.3, and the lower end is mechanically connected to the travel bracket 3.2. The entire transmission device 2 can be retracted or erected by extending and retracting the telescopic rod 2.4. The telescopic rod 2.4 is provided with a hydraulic locking device, which can be used to fix the position of the transmission device 2 and the drill bit 1.1. The hydraulic locking device can be a KFH 25 type hydraulic locking device.

[0041] Preferably, a protective groove 2.2 is provided on the top of the transmission bracket 2.3. The protective groove 2.2 is connected to the power head 2.1 and is a deformable structure. The protective groove 2.2 is used to protect the air pressure tube 7. The protective groove 2.2 is made of a chain structure or a flexible material, which can deform as the impact drill 1 drills, thereby further reducing the height of the entire pile-forming device. The flexible material can be a rubber protective sleeve.

[0042] Preferably, the transmission device 2 further includes a stopper 2.5, which is detachably mounted on the transmission bracket 2.3 and has an opening formed therein for retaining the drill body 1.2. The stopper 2.5 can be replaced with a hole having a matching diameter according to the diameter of the drill body 1.2. The stopper 2.5 ensures that the impact drill 1 remains vertical during vertical drilling.

[0043] Preferably, the transmission bracket 2.3 is equipped with an electronic gyroscope for detecting the transmission device 2 and a camera 2.6 for assisting in positioning the drill bit 1.1. The electronic gyroscope can detect the posture of the transmission device 2 and assist in adjusting the impact drill 1 to a vertical position. The electronic gyroscope and camera 2.6 can more accurately position the impact drill 1.

[0044] Preferably, Figure 1 and Figure 4As shown, the machine body 3 includes a track 3.1, a running frame 3.2, a leg 3.3, and a rotary actuator 3.4. The rotary actuator 3.4 is connected between the track 3.1 and the running frame 3.2, and the leg 3.3 is mounted on the running frame 3.2. The machine body 3 is used to carry and support the various components on the upper portion and can be rotated and positioned. The track 3.1 is used to move the entire device, and the running frame 3.2 is used to connect the rotary actuator 3.4 to the various components of the device. The rotary actuator 3.4 includes a rotary motor, which is mechanically connected to the track 3.1 and the running frame 3.2 and is used to control the steering and positioning of the running frame 3.2 and the connected components above it.

[0045] Preferably, Figure 1 and Figure 2 As shown, the support legs 3.3 are four-point support legs 3.3, including a telescopic hydraulic drive, which is symmetrically arranged with respect to the central axis of the walking frame 3.2. When the pile-forming equipment reaches the designated position, the telescopic hydraulic drive drives the four support legs 3.3 to be lowered to contact the ground to provide support during drilling.

[0046] The onboard control system 4 includes an antenna 4.1, a control system 4.2, and a status indicator light 4.3. The antenna 4.1 is used to receive signals from the remote operation platform 8 and send signals from the equipment. The control system 4.2 controls the transmission device 2 and power system 5 of the pile-forming equipment according to the control signals.

[0047] The power system 5 includes a housing, an electric motor, and a hydraulic system. The electric motor is powered by an external power supply and provides power to the transmission 2, the fuselage 3, the onboard control system 4, and the hydraulic system.

[0048] The air compressor 6 includes a diesel engine and is fixed in an open position during operation to compress air and provide air of a specified frequency and pressure.

[0049] Preferably, the remote operation platform 8 uses an industrial computer to control the pile-forming equipment.

[0050] like Figure 9 As shown, the present invention also provides a method for forming piles in hard bedrock of a low-headroom urban tunnel, comprising the following steps:

[0051] S1: Construction preparation, leveling the site and entrance and exit passages to ensure that they can meet the requirements of tunnel pile foundation construction;

[0052] S2: Pile foundation setting out: Review the design parameters and use a total station to set out the pile position after confirmation. After the pile center is set out, mark the pile foundation design position to assist in positioning the drill bit 1.1.

[0053] S3: Provide the low-headroom urban tunnel hard bedrock pile-driving equipment as claimed in claim 1, input the position information of each pile foundation on the remote operation platform 8, and the pile-driving equipment automatically moves to a position near the pile foundation according to the input information, and lowers the support legs 3.3 after the impact drill 1 is positioned;

[0054] S4: The steel casing is placed at the marked position of the pile foundation, and the pile hole is formed by rotating the drill rod 1.3. After the pile hole reaches the predetermined depth, the drilling is stopped, and a new drill rod 1.3 is connected to the original drill rod 1.3 to continue drilling downwards.

[0055] S5: After the hole is drilled to the designed elevation, the drill rod 1.3 is stopped and the drill rod 1.3 is pulled out to install the steel cage and then pour concrete to form the pile foundation.

[0056] Preferably, the transmission device 2 includes a power head 2.1, a transmission bracket 2.3 and a telescopic rod 2.4, the transmission bracket 2.3 is mounted on the fuselage 3, the power head 2.1 is mounted on the transmission bracket 2.3 and connected to the drill rod 1.3, and the telescopic rod 2.4 is connected between the transmission bracket 2.3 and the fuselage 3;

[0057] When the impact drill 1 is positioned, the angle between the transmission bracket 2.3 and the body 3 is increased by extending the telescopic rod 2.4, thereby adjusting the angle of the impact drill 1 until the impact drill 1 remains in a vertical state and is aligned with the pile foundation mark position.

[0058] Specifically, in step S3, positioning the drill bit 1.1 involves the remote operating platform 8 controlling the telescopic rod 2.4 based on the electronic gyroscope signal to adjust the impact drill 1 to a vertical position, securing it with a hydraulic locking device, and controlling the crawler track 3.1 and rotary drive 3.4 to move the drill bit 1.1 to the pile foundation stakeout position. The drill bit 1.1 is then fine-tuned using the camera 2.6 to ensure accurate positioning.

[0059] Specifically, in step S4, the impact rock breaking parameters include the propulsion force, rotation speed and torque of the power head 2.1, and the air pressure and frequency provided by the air compressor 6.

[0060] Specifically, step S4 includes the following steps:

[0061] Step S4.1: Turn on the power system 5 and the air compressor 6.

[0062] Step S4.2: Hoist and install the steel casing.

[0063] Step S4.3: Adjust the impact rock breaking parameters, and then start the downward vibration impact rock breaking. The drill bit 1.1 rotates and grinds the rock, and high-pressure air is used to remove the rock debris.

[0064] Step S4.4: After drilling to a certain depth, use the drill rod 1.3 to extend the drilling and continue drilling.

[0065] Step S4.5: After drilling to the target depth, retract the drill rod 1.3, the drill bit 1.1 and the support legs 3.3.

[0066] Specifically, step S4.4 includes stopping drilling after drilling to a certain depth, disconnecting the transmission head from the impact drill 1, lifting the power head 2.1 upward, adding a drill rod 1.3 to connect the power head 2.1 and the impact drill 1, and continuing to drill downward.

[0067] The low-headroom urban tunnel hard bedrock pile forming equipment of the present invention breaks rock by means of air pressure vibration, and performs drilling construction by means of a drill rod 1.3 connected along the length direction, thereby reducing the height required for the construction of the entire equipment and solving the technical problem in the prior art that the height of the expanded tunnel hole is limited and cannot meet the construction requirements of large-scale support pile construction equipment. The present invention uses an air compressor 6 to provide air pressure impact power, and the air pressure is connected by an air pressure pipe 7, a transmission device 2, a drill rod 1.3 and a drill bit 1.1, thereby reducing the size of the device and meeting the requirements of limited space in the tunnel and hard rock breaking. Remote control, automatic positioning and other methods are implemented through a remote operation platform 8, an airborne control system 4, a camera 2.6 and an electronic gyroscope, thereby achieving unmanned drilling and reducing the health hazards to construction workers during the construction process.

[0068] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A low-headroom urban tunnel hard bedrock pile-forming equipment, characterized in that: The invention comprises an impact drill (1), a transmission device (2), a fuselage (3), an airborne control system (4), a power system (5), a remote operation platform (8) and an air compressor (6); the airborne control system (4), the power system (5) and the air compressor (6) are all fixed on the fuselage (3); the remote operation platform (8) is connected to the airborne control system (4) by signal; the airborne control system (4) is control-connected to the impact drill (1), the transmission device (2), the fuselage (3), the power system (5) and the air compressor (6); the impact drill (1) comprises at least two drill rods (1.3) butt-jointed along the length direction; the top of the drill rods (1.3) is connected to the transmission device (2); the transmission device (2) is connected to the power system (5) and the air compressor (6).

2. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 1 is characterized in that: One end of the drill rod (1.3) is provided with a tenon, and the other end of the drill rod (1.3) is provided with a tenon groove for connecting to a corresponding drill rod (1.3), and a connecting piece is connected between the tenon and the tenon groove.

3. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 1 is characterized in that: The impact drill (1) further comprises a drill bit (1.1) and a drill body (1.2); the drill bit (1.1) is connected to the bottom end of the drill rod (1.3); and the drill body (1.2) is sleeved on the outer circumference of the drill rod (1.3).

4. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 3 is characterized in that: The transmission device (2) comprises a power head (2.1), a transmission bracket (2.3) and a telescopic rod (2.4); the transmission bracket (2.3) is mounted on the machine body (3); the power head (2.1) is mounted on the transmission bracket (2.3) and connected to the drill rod (1.3); the telescopic rod (2.4) is connected between the transmission bracket (2.3) and the machine body (3); and the telescopic rod (2.4) is used to adjust the angle of the impact drill (1).

5. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 4 is characterized in that: A protection groove (2.2) is provided on the top of the transmission bracket (2.3); the protection groove (2.2) is connected to the power head (2.1); and the protection groove (2.2) is a deformable structure.

6. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 4 is characterized in that: The transmission device (2) further comprises a stopper (2.5), the stopper (2.5) being detachably mounted on the transmission bracket (2.3), and an opening for clamping the drill body (1.2) is provided inside the stopper (2.5).

7. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 4 is characterized in that: The transmission bracket (2.3) is provided with an electronic gyroscope for detecting the transmission device (2) and a camera (2.6) for auxiliary positioning of the drill bit (1.1).

8. The low-headroom urban tunnel hard bedrock pile-forming equipment according to claim 1 is characterized in that: The fuselage (3) comprises a walking track (3.1), a walking frame (3.2), a leg (3.3) and a rotary drive (3.4); the rotary drive (3.4) is connected between the walking track (3.1) and the walking frame (3.2); and the leg (3.3) is mounted on the walking frame (3.2).

9. A method for forming piles in hard bedrock of low-headroom urban tunnels, characterized in that: The steps include: S1: Construction preparation, leveling the site and entrance and exit passages to ensure that they can meet the requirements of pile foundation construction in the tunnel; S2: Pile foundation setting out, review the design parameters, and after confirmation, use the total station to set out the pile position. After the pile center is set out, mark the pile foundation design position to assist in positioning the drill bit (1.1); S3: providing the low-headroom urban tunnel hard bedrock pile-forming equipment as claimed in claim 1, inputting the position information of each pile foundation on the remote operation platform (8), and the pile-forming equipment automatically moves to the position near the pile foundation according to the input information, and lowering the legs (3.3) after the impact drill (1) is positioned; S4: Hanging a steel casing at the marked position of the pile foundation, rotating the drill rod (1.3) to drill to form a pile hole, stopping the drilling after reaching a predetermined depth, and connecting a drill rod (1.3) to the original drill rod (1.3) to continue drilling downwards; S5: After the hole is drilled to the designed elevation, the drill rod (1.3) is stopped and the drill rod (1.3) is pulled out and the steel cage is installed, and then concrete is poured to form a pile foundation.

10. The method for forming piles in hard bedrock of low-headroom urban tunnels according to claim 9, characterized in that: The transmission device (2) comprises a power head (2.1), a transmission bracket (2.3) and a telescopic rod (2.4); the transmission bracket (2.3) is mounted on the machine body (3); the power head (2.1) is mounted on the transmission bracket (2.3) and connected to the drill rod (1.3); and the telescopic rod (2.4) is connected between the transmission bracket (2.3) and the machine body (3); When the impact drill (1) is positioned, the angle between the transmission bracket (2.3) and the body (3) is increased by extending the telescopic rod (2.4), thereby adjusting the angle of the impact drill (1) until the impact drill (1) remains in a vertical state and is aligned with the pile foundation mark position.

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