Karst geological cast-in-place pile drilling device and construction method

Abstract

The karst geological cast-in-place pile drilling device comprises a drill carriage, a drilling machine driving device, a pile casing, a drill rod and a drill bit, the drill carriage comprises a drill carriage body, a crawler belt, a winding and unwinding roller, a supporting frame, a shaft column and a pulley, the drilling machine driving device is slidably connected to the shaft column, and the top of the pile casing is fixedly connected with the drilling machine driving device through a detachable connecting structure; the drill rod is connected to the power output end at the bottom of the drilling machine driving device, the drill bit comprises a rotary drilling drill and a percussion drill, spiral blades wound spirally are arranged on the outer surface of the rotary drilling drill, the bottom of the percussion drill is conical, and a plurality of prismatic rock breaking teeth are distributed on the surface of the percussion drill. In the invention, the collaborative operation design of the rotary digging drill and the percussion drill can efficiently adapt to the alternate working conditions of soil layers and rock stratums in karst geology, the soil layer section cuts and conveys muck through the rotation of the spiral blades of the rotary digging drill, and the percussion drill can quickly impact and crush the rock stratums when entering the rock section; the method is suitable for cast-in-place pile construction under complex geological conditions in karst areas.

Description

Technical Field

[0001] This invention relates to the field of construction, and more particularly to drilling equipment and construction methods for karst geological cast-in-place piles. Background Technology

[0002] In the field of construction, karst geology, with its alternating distribution of rock and soil layers and complex geological structure, places high demands on the drilling of cast-in-place piles. Traditional drilling equipment faces the dual challenges of soil cutting efficiency and rock breaking capacity when operating under karst geological conditions. In the soil section, efficient slag removal is required to avoid siltation in the hole, while in the rock section, strong rock breaking capacity is needed to ensure the progress of hole formation. However, most existing drilling equipment cannot meet the operational requirements of both geological conditions, resulting in low construction efficiency or serious equipment wear and tear. There is an urgent need for a drilling equipment and construction method that can adapt to the characteristics of karst geology.

[0003] Existing karst geological drilling technologies generally have the following shortcomings: a single drill bit (such as using only rotary drilling or percussion drilling) cannot simultaneously meet the construction needs of soil and rock layers. When using rotary drilling, drilling is prone to stalling due to insufficient rock breaking ability when encountering rock layers. When using percussion drilling, there is a problem of low slag removal efficiency in soil layers. Furthermore, frequent drill bit replacement will significantly increase downtime and reduce construction efficiency. Summary of the Invention

[0004] This invention provides a drilling device and construction method for karst geological cast-in-place piles, aiming to improve the low efficiency of single drill bits in karst geological construction.

[0005] The present invention adopts the following technical solution: a drilling device for karst geological cast-in-place piles, comprising a drilling rig, a drilling rig drive device, a casing, a drill rod, and a drill bit. The drilling rig includes a main body, tracks, take-up and release rollers, a support frame, a shaft column, and pulleys. The drilling rig drive device is slidably connected to the shaft column. The top of the casing is fixedly connected to the drilling rig drive device via a detachable connection structure. The drill rod is connected to the power output end at the bottom of the drilling rig drive device. The drill bit includes a rotary drilling drill and an impact drilling drill. The outer surface of the rotary drilling drill is provided with spirally wound helical blades, and the bottom of the impact drilling drill is conical, with several prismatic rock-breaking teeth distributed on its surface.

[0006] As a further description of the above technical solution: the drill rod includes drill rod one, drill rod two, and drill rod two. The rotary drilling rig and the impact drilling rig are detachably connected to drill rod two and drill rod two, respectively. The impact drilling rig is initially set inside drill rod two and can extend to the bottom of the rotary drilling rig through drill rod two.

[0007] The outer surface of the rotary drilling rig is provided with spirally wound helical blades. When the drilling rig drive device drives the rotary drilling rig to rotate through the drill rod, the helical blades on the outer surface of the rotary drilling rig cut the soil layer and transport and collect the soil upward along the blades through the helical structure. The prismatic rock-breaking teeth on the surface of the impact drill are made of high-strength wear-resistant alloy steel and have a titanium carbide ceramic coating with a thickness of 0.2-0.4mm on the surface to improve the resistance to rock cuttings abrasion and prevent fracture under impact load.

[0008] As a further description of the above technical solution: the take-up and release roller is fixed on the top of the drilling rig body, and one end of the steel wire rope wound on the roller passes around the pulley and is connected to the top of the drilling rig drive device to form the lifting and traction structure of the drilling rig drive device.

[0009] As a further description of the above technical solution: the guide rails on both sides of the shaft column and the sliders on both sides of the drilling rig drive device form a sliding pair, and the lifting trajectory of the drilling rig drive device is limited by the sliding of the sliders in the guide rails.

[0010] As a further description of the above technical solution: the track at the bottom of the drilling rig body is an anti-slip track, and the track surface is provided with staggered anti-slip ridges. The support frame is set on both sides of the axle column to support the stable operation of the drilling rig body on the karst geological surface.

[0011] As a further description of the above technical solution: the support frame is disposed on both sides of the shaft column and is used to support the stable operation of the drilling rig body on the karst geological surface.

[0012] The construction method of a drilling device for karst piles is as follows:

[0013] S1: Move the drilling rig to the construction position using the anti-slip tracks, adjust the level of the drilling rig using the support frame and fix it in place;

[0014] S2: Fix the casing to the drilling rig drive unit through a detachable connection structure, and press down multiple casing sections to the design depth;

[0015] S3: Select the drill bit according to the geological conditions: Rotary drilling rigs are used in soil sections. The rotary drilling rig is driven by the drilling rig drive device to rotate and use the spiral blades to cut and transport the excavated soil. In rock sections, an impact drill is lowered on the basis of the rotary drilling rig. The rock breaking teeth of the impact drill are used to break the rock, and then the rotary drilling rig cuts and transports the excavated soil and gravel.

[0016] S4: When it is necessary to increase the drilling depth, the drill bit is fed to the appropriate depth for operation by extending the length of drill rod one;

[0017] S5: During the drilling process, the tension of the wire rope is adjusted by the take-up and release rollers to control the lifting speed of the drilling machine drive device, while the guide rail is used to ensure the verticality of the drilling.

[0018] S6: After drilling to the designed depth, remove the drill bit and discharge the slag in the hole to complete the pile hole formation operation.

[0019] As a further step of the above technical solution, the switching standard between the soil layer and the rock layer in step S3 is as follows: when the output torque of the drilling rig drive device exceeds 1500 N·m, it is determined that the drilling rig has entered the rock layer and the operation is switched to impact drilling.

[0020] The present invention has the following beneficial effects:

[0021] 1. Firstly, the collaborative design of rotary drilling and impact drilling can efficiently adapt to the alternating working conditions of soil and rock layers in karst geology. In the soil layer section, the rotary drilling rig's spiral blades rotate to cut and transport the excavated soil, resulting in high operating efficiency and smooth excavation. When entering the rock section, the impact drilling rig is used. Its conical rock-breaking teeth, combined with high-strength wear-resistant alloy material and titanium carbide ceramic coating, can quickly impact and break the rock layer, avoiding the efficiency loss of a single drill bit when switching between soil and rock layers. This combination eliminates the need for frequent drill bit changes, reduces downtime, improves drilling efficiency, and ensures hole quality. It is especially suitable for cast-in-place pile construction under complex geological conditions in karst areas.

[0022] 2. The anti-slip track surface of the drilling rig body is equipped with staggered anti-slip ridges, which, together with the support frames on both sides of the shaft column, can stably support the drilling rig in karst and rugged terrain, preventing tilting or slippage during operation. The lifting and traction structure composed of take-up and release rollers and wire ropes, combined with the sliding pair design of guide rails and sliders, can precisely control the lifting speed and verticality of the drilling rig drive device to meet high-precision construction requirements. The drill rod adopts a multi-section detachable structure (drill rod one, two, and three). By extending drill rod one, the drilling depth can be flexibly adjusted to adapt to different pile depth requirements. The titanium carbide ceramic coating on the surface of the impact drill can improve resistance to rock cuttings abrasion, prevent breakage under impact load, extend the service life of the drill bit, and reduce construction costs. In addition, the detachable connection design of the casing and the drilling rig drive device makes it easy to quickly press down to the design depth, forming hole wall protection and reducing the risk of hole collapse. Attached Figure Description

[0023] Figure 1 This invention is three-dimensional. Figure 1 ;

[0024] Figure 2 This invention is three-dimensional. Figure 2 ;

[0025] Figure 3 This is a cross-sectional view of the drill bit.

[0026] Figure 4 This is a cross-sectional view of a rotary drilling rig.

[0027] Figure 5 This is a cross-sectional view of an impact drill.

[0028] Figure 6 This is a two-section view of the drill pipe structure.

[0029] Legend:

[0030] 1. Take-up and release rollers; 2. Wire rope; 3. Drilling rig drive unit; 4. Casing; 5. Pulley; 6. Track; 7. Drill rod one; 8. Drill rod two; 9. Drill bit; 9-1. Rotary drilling rig; 9-2. Impact drilling rig; 10. Drilling rig body; 11. Shaft column; 12. Support frame; 13. Drill rod two. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Reference Figure 1-6 A drilling device for karst geological cast-in-place piles includes a drilling rig, a drilling rig drive unit 3, a casing 4, a drill rod, and a drill bit 9. The drilling rig includes a main body 10, tracks 6, take-up and release rollers 1, a support frame 12, a shaft column 11, and pulleys 5. The drilling rig drive unit 3 is slidably connected to the shaft column 11. The top of the casing 4 is fixedly connected to the drilling rig drive unit 3 through a detachable connection structure. The drill rod is connected to the power output end at the bottom of the drilling rig drive unit 3. The drill bit 9 includes a rotary drilling rig 9-1 and an impact drilling rig 9-2. The outer surface of the rotary drilling rig 9-1 is provided with spirally wound helical blades. The bottom of the impact drilling rig 9-2 is conical, and the surface is distributed with several prismatic rock-breaking teeth. The device includes a drilling rig, a drive unit, a casing 4, a drill rod, and a drill bit 9 that combines the functions of a rotary drilling rig 9-1 and an impact drilling rig 9-2. The drilling rig moves via the tracks 6, the drive unit slides along the shaft column 11, and the casing 4 is detachably connected to the drive unit. During operation, the drilling rig moves across the karst geological surface via tracks 6, the support frame 12 is adjusted and fixed for leveling, and the drive unit moves up and down along the shaft column 11 to operate the drill rod and drill bit 9. The casing 4 forms a protective wall around the borehole. The combination of rotary drilling rig 9-1 and impact drilling rig 9-2 can adapt to switching between soil and rock strata. Its beneficial effect lies in the modular structural design, which enables coordinated operation of drilling rig movement, equipment lifting and lowering, and drill bit 9 switching, improving the equipment's environmental adaptability in karst geology and reducing construction preparation time.

[0033] The drill rods include drill rod 7, drill rod 8, and drill rod 13. A rotary drilling rig 9-1 and an impact drill 9-2 are detachably connected to drill rod 8 and drill rod 13, respectively. The impact drill 9-2 is initially located inside drill rod 8 and can extend to the bottom of the rotary drilling rig 9-1 via drill rod 13. The outer surface of the rotary drilling rig 9-1 is provided with helical blades. When the drilling rig drive device 3 drives the rotary drilling rig 9-1 to rotate via the drill rods, the helical blades on the outer surface of the rotary drilling rig 9-1 cut the soil layer and, through the helical structure, remove the soil... The material is conveyed and collected upwards along the blades; the prismatic rock-breaking teeth on the surface of the impact drill 9-2 are made of high-strength wear-resistant alloy steel, with a titanium carbide ceramic coating of 0.2-0.4mm thickness on the surface to improve resistance to rock cuttings abrasion and prevent breakage under impact load. The drill rod is divided into three sections: the rotary drill 9-1 is connected to the drill rod 2 8, and the impact drill 9-2 is connected to the drill rod 2 13. The rotary drill 9-1 has spiral blades on the outside, and the bottom of the impact drill 9-2 is conical with rock-breaking teeth and a titanium carbide coating, which can extend below the rotary drill 9-1. During soil drilling, the drive unit rotates the rotary drilling rig 9-1, with the helical blades cutting the soil and conveying slag along the helical structure. In rock formations, the impact drill 9-2 is lowered via drill rod 13, where the rock-breaking teeth, made of alloy material and coated, impact and break the rock. The rotary drilling rig 9-1 then discharges the slag. This design, through segmented drill rods and the extendable impact drill 9-2, enables efficient switching between soil and rock formations. The helical blades improve slag removal efficiency in soil formations, and the titanium carbide coating enhances the wear resistance of the impact drill 9-2 by 3-5 times, reducing the frequency of drill bit 9 replacement. The drilling rig drive unit 3 has a power output mechanism inside, with its bottom power output end connected to the drill rod. When the power output mechanism is activated, torque is transmitted through the drill rod to the drill bit 9, driving the rotary drilling rig 9-1. 1 or the impact drill 9-2 rotates to achieve soil cutting or rock breaking operations. The power output end at the bottom of the drill drive device 3 not only provides rotational torque, but also provides axial thrust and tension to control the extension and retraction of the drill rod. The take-up and release roller 1 is fixed on the top of the drill rig body 10. One end of the steel wire rope 2 wound on the roller passes around the pulley 5 and is connected to the top of the drill drive device 3 to form the lifting and traction structure of the drill drive device 3. The take-up and release roller 1 is fixed on the top of the drill rig, and the steel wire rope 2 is connected to the top of the drive device through the pulley 5 to form the lifting and traction structure. When the take-up and release roller 1 rotates, the steel wire rope 2 pulls the drive device up and down along the shaft column 11 through the pulley 5. The lifting and lowering speed is controlled by adjusting the rotation speed of the take-up and release roller 1 to ensure accurate positioning of the drill bit 9.Its beneficial effects are that by using the flexible traction of the steel wire rope 2 and the guidance of the pulley 5, the lifting and lowering of the drive device can be smoothly controlled, avoiding the risk of jamming in complex terrain due to rigid drive, and improving the accuracy of drilling depth control; the guide rails on both sides of the shaft column 11 and the sliders on both sides of the drilling rig drive device 3 form a sliding pair. The sliding of the slider in the guide rail limits the lifting and lowering trajectory of the drilling rig drive device 3. The guide rails on both sides of the shaft column 11 and the sliders of the drive device form a sliding pair, which limits the lifting and lowering trajectory. When the drive device is lifted and lowered, the slider slides in the guide rail, ensuring that it moves in the vertical direction and avoiding drilling deviation. It is suitable for scenarios with high requirements for hole verticality in karst geology; the track 6 at the bottom of the drilling rig body 10 is an anti-slip track. The surface of the track 6 is provided with staggered anti-slip ridges. The support frame 12 is set on both sides of the shaft column 11 to support the stable operation of the drilling rig body 10 on the karst geological surface. The bottom of the drilling rig is an anti-slip track 6 with staggered ridges on the surface. The support frame 12 is set on both sides of the shaft column 11. The raised edges of the track 6 enhance friction with the karst ground, while the support frame 12 adjusts and fixes the drilling rig to maintain stability in rugged terrain. Its beneficial effect is that the dual stabilizing structure of the anti-slip track 6 and support frame 12 prevents tilting or slippage during drilling operations, ensuring construction safety and providing a stable foundation for the drill bit 9. The support frame 12 is located on both sides of the axle column 11 to support the drilling rig body 10 for stable operation on the karst geological surface. By adjusting the telescopic length of the support frame 12, it can adapt to geological surfaces with different inclinations, ensuring the drilling rig's levelness and avoiding drilling deviations caused by uneven ground. This design improves the equipment's adaptability in complex terrain, reduces construction errors caused by unstable foundations, and ensures the quality of the borehole.

[0034] The construction method of a drilling device for karst piles is as follows:

[0035] S1: Move the drilling rig to the construction position via the anti-slip track 6, and adjust and fix the drilling rig using the support frame 12;

[0036] S2: Fix the casing 4 to the drilling rig drive device 3 via a detachable connection structure, and press down the multi-section casing 4 to the design depth;

[0037] S3: Select drill bit 9 according to geological conditions: Rotary drilling rig 9-1 is used in soil sections. The rotary drilling rig 9-1 is driven to rotate by the drilling rig drive device 3. The spiral blades are used to cut and transport the slag and soil. In rock sections, an impact drill 9-2 is lowered on the basis of the rotary drilling rig 9-1. The rock is broken by the rock-breaking teeth of the impact drill 9-2, and then the rotary drilling rig 9-1 cuts and transports the slag and gravel.

[0038] S4: When it is necessary to increase the drilling depth, the drill bit 9 is sent to the appropriate depth for operation by extending the length of drill rod 7;

[0039] S5: During the drilling process, the tension of the wire rope 2 is adjusted by the take-up and release roller 1 to control the lifting speed of the drilling machine drive device 3, while the guide rail is used to ensure the verticality of the drilling.

[0040] S6: After drilling to the designed depth, remove drill bit 9 and discharge the slag in the hole to complete the pile hole formation operation;

[0041] The construction method includes positioning, casing 4 installation, drill bit 9 switching, depth adjustment, process control, and hole formation. After the drilling rig is moved and positioned by the crawler 6, the support frame 12 is fixed, the casing 4 is pressed down to the design depth, the rotary drilling rig 9-1 is used to cut and transport the slag in the soil layer, and when entering the rock layer, the impact drill 9-2 is switched to break the rock, and then the rotary drilling rig 9-1 is used to remove the slag; the depth is adjusted by extending the drill rod 7, and the lifting and lowering roller 1 and the guide rail control the lifting and verticality. This method dynamically switches the drill bit 9 according to the geological conditions, combined with depth and verticality control, to achieve efficient construction of karst geological drilling, which improves efficiency compared with traditional processes.

[0042] The switching criteria between the soil and rock sections in step S3 are as follows: when the output torque of the drilling rig drive device 3 exceeds 1500 N·m, it is determined that the drilling rig has entered the rock layer and the operation is switched to the impact drill 9-2. This avoids the rotary drilling rig 9-1 forcibly breaking the rock, which would cause equipment wear and tear. This ensures the efficiency of rock breaking in the rock layer and avoids the inefficient operation of the impact drill 9-2 in the soil layer, thus optimizing the construction process and reducing the equipment failure rate.

[0043] Working Principle: The drilling rig moves across the karst geological surface via anti-slip tracks. The anti-slip ridges on the track surface enhance friction with the ground. Combined with the support frames 12 on both sides of the shaft column 11, the drilling rig's level can be adjusted and fixed, ensuring operational stability. The steel wire rope 2 wound by the take-up and release rollers 1 pulls the drilling rig drive device 3 via pulleys 5. The rotation of the take-up and release rollers 1 controls the tension of the steel wire rope 2, enabling the drive device to rise and fall along the guide rail of the shaft column 11. The guide rail and the slider of the drive device form a sliding pair, limiting its rising and falling trajectory and ensuring the verticality of the borehole. The drill rod adopts a multi-section detachable structure (drill rod one, two, and three). Drill rod one 7 is the base section, connected to the power output end of the drive device. When a deeper borehole is required, the length of drill rod one 7 is extended, allowing the drill bit 9 to be delivered to the target depth. The rotary drilling drill 9-1 is connected to drill rod two 8. When driven by the drive device to rotate, the spiral blades cut the soil layer and utilize the spiral structure to transport the excavated soil. The impact drill 9-2 is connected to the drill rod... The impact drill 9-2 is initially housed inside drill rod 28. When rock breaking is required, it extends downward through drill rod 213, extending below the bottom of rotary drill 9-1. Its conical bottom with prismatic rock-breaking teeth, combined with high-strength wear-resistant alloy material and titanium carbide ceramic coating, achieves rock strata impact breaking. The drill drive device 3 has a power output mechanism inside, and its bottom power output end is connected to the drill rod. When the power output mechanism is started, the torque is transmitted to the drill bit 9 through the drill rod, driving the rotary drill 9-1 or impact drill 9-2 to rotate, realizing soil cutting or rock strata breaking operations. The bottom power output end of the drill drive device 3 not only provides rotational torque, but also provides axial thrust and tension to control the extension and retraction of the drill rod.

[0044] First, the drilling rig is positioned and fixed via the track 6 and support frame 12. The casing 4, detachably connected to the drive unit, is then pressed down to the designed depth to form a protective borehole wall. During soil drilling, the rotary drilling rig 9-1 rotates to cut the soil, and the spiral blades transport and collect the excavated soil upwards. When entering the rock strata, the operation switches to the impact drilling rig 9-2, which breaks the rock through impact load. The rotary drilling rig 9-1 then cuts and discharges the crushed rock. The drilling depth is adjusted by extending the drill rod 7. During operation, the tension of the wire rope 2 is continuously adjusted via the take-up and release rollers 1 to control the lifting speed of the drive unit. Simultaneously, the guide rails ensure the verticality of the borehole. After reaching the designed depth, the drill bit 9 is removed and the excavated soil is discharged from the hole, completing the cast-in-place pile hole and achieving efficient switching between soil and rock strata construction under karst geological conditions.

Claims

1. A drilling device for karst geological cast-in-place piles, comprising a drilling rig, a drilling machine drive unit (3), a casing (4), a drill rod, and a drill bit (9), characterized in that: The drilling rig includes a main body (10), tracks (6), take-up and release rollers (1), support frame (12), shaft column (11) and pulleys (5). The drilling rig drive device (3) is slidably connected to the shaft column (11). The top of the casing (4) is fixedly connected to the drilling rig drive device (3) through a detachable connection structure. The drill rod is connected to the power output end at the bottom of the drilling rig drive device (3). The drill bit (9) includes a rotary drilling rig (9-1) and an impact drilling rig (9-2). The outer surface of the rotary drilling rig (9-1) is provided with spirally wound spiral blades. The bottom of the impact drilling rig (9-2) is conical, and the surface is distributed with several prismatic rock-breaking teeth.

2. The drilling device for karst geological cast-in-place piles according to claim 1, characterized in that: The drill rod includes drill rod one (7), drill rod two (8) and drill rod two (13). The rotary drilling rig (9-1) and the impact drill (9-2) are detachably connected to drill rod two (8) and drill rod two (13) respectively. The impact drill (9-2) is initially set inside drill rod two (8) and can extend to the bottom of the rotary drilling rig (9-1) through drill rod two (13). The outer surface of the rotary drilling rig (9-1) is provided with spirally wound helical blades. When the drilling rig drive device (3) drives the rotary drilling rig (9-1) to rotate through the drill rod, the helical blades on the outer surface of the rotary drilling rig (9-1) cut the soil layer and transport and collect the soil upward along the blades through the helical structure. The prismatic rock-breaking teeth on the surface of the impact drill (9-2) are made of high-strength wear-resistant alloy steel and have a titanium carbide ceramic coating with a thickness of 0.2-0.4mm on the surface to improve the resistance to rock cuttings abrasion and prevent fracture under impact load.

3. The drilling device for karst geological cast-in-place piles according to claim 1, characterized in that: The take-up and release roller (1) is fixed on the top of the drill rig body (10). One end of the steel wire rope (2) wound on the roller passes around the pulley (5) and is connected to the top of the drill drive device (3) to form the lifting and traction structure of the drill drive device (3).

4. A drilling device for karst geological cast-in-place piles according to any one of claims 1 to 3, characterized in that: The guide rails on both sides of the shaft column (11) and the sliders on both sides of the drilling rig drive device (3) form a sliding pair, and the sliding of the sliders in the guide rails restricts the lifting trajectory of the drilling rig drive device (3).

5. The drilling device for karst geological cast-in-place piles according to claim 1, characterized in that: The track (6) at the bottom of the drilling rig body (10) is an anti-slip track, and the surface of the track (6) is provided with staggered anti-slip ridges. The support frame (12) is set on both sides of the shaft column (11) to support the stable operation of the drilling rig body (10) on the karst geological surface.

6. The drilling device for karst geological cast-in-place piles according to claim 1, characterized in that: The support frame (12) is set on both sides of the shaft column (11) to support the stable operation of the drilling rig body (10) on the karst geological surface.

7. A construction method for a drilling device for karst geological cast-in-place piles, comprising the drilling device for karst geological cast-in-place piles as described in claims 1 to 6, characterized in that: The steps are as follows: S1: Move the drilling rig to the construction position via the anti-slip tracks (6), and adjust and fix the drilling rig using the support frame (12); S2: Fix the casing (4) to the drilling rig drive device (3) through the detachable connection structure, and press down the multi-section casing (4) to the design depth; S3: Select the drill bit (9) according to the geological conditions: In the soil section, a rotary drilling rig (9-1) is used. The rotary drilling rig (9-1) is driven to rotate by the drilling rig drive device (3). The spiral blades are used to cut and transport the slag and soil. In the rock section, an impact drill (9-2) is lowered on the basis of the rotary drilling rig (9-1). The rock is broken by the rock-breaking teeth of the impact drill (9-2). Then, the rotary drilling rig (9-1) cuts and transports the slag and gravel. S4: When it is necessary to increase the drilling depth, the drill bit (9) is sent to the appropriate depth for operation by extending the length of drill rod 1 (7); S5: During the drilling process, the tension of the wire rope (2) is adjusted by the take-up and release rollers (1) to control the lifting speed of the drilling machine drive device (3), while the guide rail is used to ensure the verticality of the drilling. S6: After drilling to the designed depth, remove the drill bit (9) and discharge the slag in the hole to complete the hole-forming operation of the cast-in-place pile.

8. The construction method of a drilling device for karst piles according to claim 7, characterized in that: The switching criteria between the soil layer and the rock layer in step S3 is as follows: when the output torque of the drilling rig drive device (3) exceeds 1500 N·m, it is determined that the rock layer has been entered and the operation is switched to the impact drill (9-2).

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