A method for back-reaming construction of a complex geological condition

Abstract

The application relates to the technical field of bottom drilling, and discloses a construction method for reverse circulation drilling and slag scooping under complex geological conditions, which comprises the following steps: construction preparation: positioning and rechecking by using a total station; protecting cylinder burying: placing a protecting cylinder at a drilling position; and drilling: the drilling equipment comprises a connecting rod, an air injection pipe and a slurry pumping pipe are arranged on the inner side of the connecting rod, a wind adjusting structure is connected to the lower end of the air injection pipe, a connecting rod is movably connected to the lower end of the connecting rod through bolts, a slag scooping cylinder is fixedly connected to the surface of the connecting rod through a support, a fixing frame is fixedly connected to the lower end of the slag scooping cylinder, an alloy cutter head is fixedly connected to the surface of the fixing frame, a jacking structure is fixedly connected to the surface of the alloy cutter head, and the jacking structure is used for improving the drilling effect of the alloy cutter head. Through the technical scheme, the problem that the existing reverse circulation drilling and slag scooping construction method cannot drill when encountering large-diameter boulders or pebbles, which greatly reduces the construction efficiency and delays the construction period, is solved.

Description

Technical Field

[0001] This invention relates to the field of bottom drilling technology, specifically to a reverse circulation drilling and slag removal construction method for complex geological conditions. Background Technology

[0002] Traditional reverse circulation drilling methods are slow or impossible to advance in areas with complex geological conditions, such as riverbanks or embankments, where there are isolated rocks.

[0003] A search revealed a reverse circulation drilling method (application publication number CN117072081A). This method utilizes reverse circulation drill pipe to extract circulating mud containing drill cuttings, significantly reducing the ineffective labor of repeatedly grinding drill cuttings and greatly improving drilling efficiency. Furthermore, this application employs a top-down reverse circulation pump-suction mud exchange and hole cleaning method, altering the pump suction point during hole cleaning and enhancing the removal of localized mud and drill cuttings, thus effectively improving operational efficiency and quality.

[0004] However, the existing reverse circulation drilling and slag removal methods mentioned above cannot be drilled when encountering large-diameter boulders or pebbles, which greatly reduces construction efficiency and delays the construction period. Therefore, we propose a reverse circulation drilling and slag removal method for complex geological conditions. Summary of the Invention

[0005] This invention proposes a reverse circulation drilling and slag removal method for complex geological conditions, which solves the problem mentioned in the background art that the existing reverse circulation drilling and slag removal methods cannot drill through when encountering large-diameter boulders or pebbles, which greatly reduces construction efficiency and delays the construction period.

[0006] The technical solution of the present invention is as follows:

[0007] A method for reverse circulation drilling and slag removal in complex geological conditions, comprising the following steps:

[0008] Construction preparation: Total station positioning and verification;

[0009] Casing installation: Position the casing at the drilling location;

[0010] Drilling: The drilling equipment includes a connecting rod, on the inner side of which an air injection pipe and a slurry extraction pipe are respectively provided. The lower end of the air injection pipe is connected to an air regulating structure. The lower end of the connecting rod is movably connected to a connecting rod by bolts. A slag removal cylinder is fixedly connected to the surface of the connecting rod by a bracket. A fixing frame is fixedly connected to the lower end of the slag removal cylinder. An alloy cutter head is fixedly connected to the surface of the fixing frame. A jacking structure is fixedly connected to the surface of the alloy cutter head. The jacking structure is used to enhance the drilling effect of the alloy cutter head. The air regulating structure is used to achieve uniform air blowing to different areas at the same height inside the connecting rod.

[0011] The reverse circulation drilling rig drives the connecting rod and the connecting rod to rotate and drill. Drilling is carried out through the alloy cutter head and the jacking structure. Ventilation is carried out through the air adjustment structure and the mud in the hole is extracted through the slurry extraction pipe.

[0012] This slag removal cylinder can squeeze oversized stones into its interior, and then lift the stones out to the ground and pour them out through the side opening.

[0013] Hole cleaning: Cleaning the inside of the drilled hole by replacing the slurry;

[0014] Pouring: The precast steel cage is vertically lowered from the hole and concrete of the required strength as specified in the drawings is poured.

[0015] As a further technical solution of the present invention, a connecting member is movably connected between the connecting rod and the connecting rod. The connecting member is used to protect the bolts connecting the connecting rod and the connecting rod. An end plate is fixedly connected to the top of the connecting rod. A set of supports is provided at the axis of the slag removal cylinder. A steel wire rope is fixedly connected between the supports and the inner wall of the slag removal cylinder. The steel wire rope is fixedly connected to the slag removal cylinder through a fastening ring. An openable opening is provided on the lower side wall of the slag removal cylinder for the flow of slurry inside and outside the slag removal cylinder.

[0016] As a further technical solution of the present invention, the air regulating structure includes a connecting pipe movably connected to the lower end of the air injection pipe, an annular pipe fixedly connected to one end of the connecting pipe, an air guide pipe fixedly connected to one end of the connecting pipe, a movable plate movably connected inside the annular pipe, a protrusion fixedly connected to the lower end of the movable plate, a baffle fixedly connected to the inner side of the movable plate, and an air outlet pipe fixedly connected to the surface of the protrusion.

[0017] As a further technical solution of the present invention, the jacking structure includes a cavity formed between the alloy cutter head and the fixed frame. The cavity includes an upper cavity and a lower cavity that are interconnected. A movable column is movably connected between the upper cavity and the lower cavity. A limit block is fixedly connected to the lower end of the movable column. A movable cutter head is fixedly connected to the upper end of the movable column. A jacking spring is provided inside the upper cavity.

[0018] As a further technical solution of the present invention, the movable plate and the annular tube are slidably connected, the movable plate slides along the length direction of the annular tube, and the protrusion penetrates from the inside of the annular tube to its outside.

[0019] As a further technical solution of the present invention, the number of baffles is several groups and they are distributed in a ring array. The movable plate is an arc-shaped plate structure that matches the inner wall of the annular tube, and the movable plate is a circular ring structure.

[0020] As a further technical solution of the present invention, the number of air outlet pipes is several groups and they are distributed in a ring array. The air outlet pipes are connected to the inner side of the protrusion. The baffle is blown by the air guide pipes to realize the rotation and sliding of the movable plate, the protrusion, the baffle and the air outlet pipe inside the ring pipe.

[0021] As a further technical solution of the present invention, the alloy cutter head is configured with a cross-shaped conical structure, and the movable column is slidably connected to both the alloy cutter head and the fixed frame.

[0022] As a further technical solution of the present invention, the diameter of the limiting block is matched with the diameter of the lower cavity, and the upper and lower ends of the movable column are fixed to the movable cutter head and the limiting block by welding, respectively.

[0023] As a further technical solution of the present invention, the upper chamfer of the movable cutter head matches the alloy cutter head, the movable cutter head and the limiting block move up and down with the movable column, the inner diameter of the pushing spring is larger than the diameter of the movable column, and the outer diameter is smaller than the diameter of the limiting block.

[0024] The working principle and beneficial effects of this invention are as follows:

[0025] 1. In this invention, the jacking structure enhances the drilling effect during reverse circulation drilling of the formation using alloy cutter heads. The jacking and retractable structure greatly enhances the drilling effect of the alloy cutter heads on the bottom layer and effectively improves the drilling effect on harder rocks.

[0026] 2. In this invention, the air-adjusting structure, in conjunction with the pumping action of the pumping pipe, can increase the buoyancy of the mud, causing it to move upward and increasing its volume. This creates a negative pressure below the gas-liquid mixing section, which is continuously replenished by the mud from the lower part of this section. This greatly enhances the pumping effect during construction and improves the efficiency of hole cleaning. Attached Figure Description

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] Figure 1 This is a partial structural diagram of the present invention;

[0029] Figure 2 This is a partial structural diagram of one end of the slag removal cylinder of the present invention;

[0030] Figure 3 This is a partial structural diagram of the lower end of the air injection pipe of the present invention;

[0031] Figure 4 For the present invention Figure 3 A schematic diagram of the cut-out section of the structure;

[0032] Figure 5 For the present invention Figure 4 A schematic diagram of the partial structure cut out from another perspective;

[0033] Figure 6 This is a partial structural diagram showing the cut-out of the jacking structure of the present invention.

[0034] Figure 7 This is a partial sectional view when the present invention is used;

[0035] Figure 8 This is a partial front sectional view of the other side of the present invention.

[0036] In the diagram: 1. Slag removal cylinder; 2. Connecting rod; 3. Air injection pipe; 4. Fixing frame; 5. Alloy cutter head; 6. Pushing structure; 60. Cavity; 61. Upper cavity; 62. Lower cavity; 63. Movable column; 64. Limiting block; 65. Movable cutter head; 66. Pushing spring; 7. Air regulating structure; 70. Connecting pipe; 71. Annular pipe; 72. Air guide pipe; 73. Movable plate; 74. Protrusion; 75. Baffle; 76. Air outlet pipe; 8. Slurry extraction pipe; 9. Connecting piece; 10. Connecting rod; 11. End plate; 12. Steel wire rope;

[0037] A is the casing; B is the mud surface; C is the sediment; D is the openable opening. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] like Figures 1-5 and Figures 7-8 As shown in the figure, this embodiment proposes a reverse circulation drilling and slag removal construction method for complex geological conditions. The construction method includes the following steps:

[0041] Construction preparation: Total station positioning and verification;

[0042] Installation of casing A: Place casing A at the drilling location for positioning;

[0043] Drilling: The drilling equipment includes a connecting rod 2. An air injection pipe 3 and a slurry extraction pipe 8 are respectively installed on the inner side of the connecting rod 2. An air adjustment structure 7 is connected to the lower end of the air injection pipe 3. A connecting rod 10 is movably connected to the lower end of the connecting rod 2 by bolts. A slag removal cylinder 1 is fixedly connected to the surface of the connecting rod 10 by a bracket. A fixing frame 4 is fixedly connected to the lower end of the slag removal cylinder 1. An alloy cutter head 5 is fixedly connected to the surface of the fixing frame 4. A jacking structure 6 is fixedly connected to the surface of the alloy cutter head 5. The jacking structure 6 is used to enhance the drilling effect of the alloy cutter head 5. The air adjustment structure 7 is used to achieve uniform air blowing to different areas at the same height inside the connecting rod 10.

[0044] The reverse circulation drilling rig drives the connecting rod 2 and the connecting rod 10 to rotate and drill. The drilling is carried out through the alloy cutter head 5 and the jacking structure 6, and ventilation is carried out through the air adjustment structure 7. The mud in the hole is extracted through the slurry extraction pipe 8.

[0045] The slag removal cylinder 1 can squeeze oversized stones into its interior, and then lift the stones out of the cylinder to the ground and pour them out through the side wall opening.

[0046] Hole cleaning: Cleaning the inside of the drilled hole by replacing the slurry;

[0047] Pouring: The precast steel cage is vertically lowered from the hole and concrete of the required strength as specified in the drawings is poured.

[0048] A connector 9 is movably connected between the connecting rod 10 and the connecting rod 2. The connector 9 is used to protect the bolts connecting the connecting rod 10 and the connecting rod 2. An end plate 11 is fixedly connected to the top of the connecting rod 2. A set of supports is provided at the axis of the slag removal cylinder 1. A steel wire rope 12 is fixedly connected between the supports and the inner wall of the slag removal cylinder 1. The steel wire rope 12 is fixedly connected to the slag removal cylinder 1 through a fastening ring. An openable opening D is provided on the lower side wall of the slag removal cylinder 1. The openable opening is used for the flow of slurry inside and outside the slag removal cylinder 1.

[0049] The alloy cutter head 5 has a cross-shaped conical structure, and the movable column 63 is slidably connected to both the alloy cutter head 5 and the fixed frame 4.

[0050] The air conditioning structure 7 includes a connecting pipe 70 movably connected to the lower end of the air injection pipe 3. One end of the connecting pipe 70 is fixedly connected to an annular pipe 71 and another end of the connecting pipe 70 is fixedly connected to a guide pipe 72. A movable plate 73 is movably connected inside the annular pipe 71. A protrusion 74 is fixedly connected to the lower end of the movable plate 73. A baffle 75 is fixedly connected to the inner side of the movable plate 73. An air outlet pipe 76 is fixedly connected to the surface of the protrusion 74.

[0051] The movable plate 73 is slidably connected to the annular tube 71. The movable plate 73 slides along the length of the annular tube 71, and the protrusion 74 extends from the inside of the annular tube 71 to its outside. There are several sets of baffles 75 arranged in a ring array. The movable plate 73 is an arc-shaped plate structure that matches the inner wall of the annular tube 71, and the movable plate 73 is a circular ring structure. There are several sets of air outlet pipes 76 arranged in a ring array, and the air outlet pipes 76 are connected to the inner side of the protrusion 74. The movable plate 73, the protrusion 74, the baffles 75, and the air outlet pipes 76 rotate and slide inside the annular tube 71 by blowing the baffles 75 through the air guide pipe 72.

[0052] In this embodiment, during use, the pumping action of the pumping pipe 8 can increase the buoyancy of the mud, drive the mud upward, and increase the volume of the mud. A negative pressure is formed below the gas-liquid mixing section, which is continuously replenished by the mud in the lower part of the section. This can greatly enhance the pumping effect during construction and improve the efficiency of hole cleaning.

[0053] During the process of aerating the mud inside the connecting rod 2 through the air injection pipe 3, the airflow enters the interior of the connecting pipe 70 from the air injection pipe 3, and blows the airflow to the surface of the baffle 75 through the air guide pipe 72, thereby pushing the baffle 75, together with the movable plate 73 and the protrusion 74, to rotate. Finally, the gas is discharged into the mud through the air outlet pipe 76. The uniformity of the air blowing effect of the device can be increased by the rotation of the air outlet pipe 76, thereby further enhancing the slurry pumping and hole cleaning effect during the construction process.

[0054] Example 2

[0055] like Figure 6 As shown, based on Embodiment 1, a push-moving structure 6 is also proposed, including a cavity 60 opened between the alloy cutter head 5 and the fixed frame 4. The cavity 60 includes an upper cavity 61 and a lower cavity 62 that are interconnected. A movable column 63 is movably connected between the upper cavity 61 and the lower cavity 62. A limit block 64 is fixedly connected to the lower end of the movable column 63, and a movable cutter head 65 is fixedly connected to the upper end of the movable column 63. A push-moving spring 66 is provided inside the upper cavity 61.

[0056] The diameter of the limiting block 64 matches the diameter of the lower cavity 62. The upper and lower ends of the movable column 63 are fixed to the movable cutter head 65 and the limiting block 64 by welding, respectively. The upper chamfer of the movable cutter head 65 matches the alloy cutter head 5. The movable cutter head 65 and the limiting block 64 move up and down with the movable column 63. The inner diameter of the actuating spring 66 is larger than the diameter of the movable column 63, and the outer diameter is smaller than the diameter of the limiting block 64.

[0057] In this embodiment, the drilling effect can be enhanced during the reverse circulation drilling of the formation using the alloy cutter head 5. The structure that can be pushed and retracted greatly enhances the drilling effect of the alloy cutter head 5 on the bottom layer and effectively enhances the drilling effect on harder rocks.

[0058] During drilling, the movable cutter head 65 can be pushed upward by the jacking spring 66, so that the movable cutter head 65 floats up and down, which can enhance the drilling effect during construction. At the same time, the limiting block 64 limits the maximum distance that the movable cutter head 65 pushes outward. When the top of the movable cutter head 65 is subjected to pressure, it will be flush with the surface of the alloy cutter head 5, and at most it will retract to the inner side of the alloy cutter head 5. At this time, the limiting block 64 moves to the uppermost position of the lower cavity 62, thereby enhancing the drilling ability of the alloy cutter head 5 through the pushing and retraction of the jacking spring 66.

[0059] During use, the connecting rod 2 can be driven by the drilling rig to rotate the connecting rod 10, which in turn drives the slag removal cylinder 1 to rotate. This, in turn, drives the fixed frame 4, alloy cutter head 5, and jacking structure 6 to drill. During drilling, air is injected into the air injection pipe 3 by an air compressor, and airflow is output into the mud through the air regulating structure 7. At the same time, the mud is extracted by a suction pump through the slurry extraction pipe 8. Oversized stones can be squeezed into the slag removal cylinder 1 and supported by the wire rope 12. The stones accumulated in the cylinder can then be lifted to the ground and poured out from the side wall opening. This device structure can effectively solve the problem of large-diameter boulders or pebbles that cannot be drilled during reverse circulation drilling.

[0060] It should be noted that the secondary cleaning process involves the air compressor generating high-pressure gas, which is then sprayed out and mixed with the mud inside the connecting rod 2. The mixture disperses within the connecting rod 2, forming bubbles. These bubbles are buoyed upwards by the mud, causing the mud to move upwards. As the mud rises, the pressure decreases and the volume increases. This creates a negative pressure below the gas-liquid mixing section, which is continuously replenished by the mud in the lower part of this section. The sediment C at the bottom of the borehole is driven into the connecting rod 2 by the movement of the mud and discharged out of the borehole with the mud, forming a continuous cycle that greatly improves the cleaning efficiency.

[0061] It should be noted that before starting reverse circulation drilling, the drill bit center should be checked again to ensure it coincides with the center of casing A and the pile center. The drilling rig should also be checked for levelness. Only after these checks are confirmed to be correct can the next step be carried out. The drill bit should be started without advancing any footage. Mud circulation should be initiated, and drilling should begin once normal mud circulation is established. For the first 2 meters of drilling, a low drilling speed and slow advance should be maintained to ensure the verticality of the drill rod. During drilling, the drilling speed and advance rate should be adjusted according to the geological conditions, and the mud discharge should be observed continuously. Mud parameters should be recorded every hour, and cuttings samples should be collected. An additional cuttings sample should be collected at stratum transition points. During drilling, the advance rate should be controlled. Based on the drilling depth and observation of the collected cuttings, the geological data on the design drawings should be compared. If any discrepancies are found, the owner, supervisor, surveyor, and designer should be notified immediately, and construction measures should be improved accordingly.

[0062] If drilling fails to advance for an extended period, and the cuttings sample is compared with geological data, it can be determined that there is an isolated boulder below. The traditional conical drill bit should be replaced with a cuttings removal cylinder 1 drill bit to continue drilling. Oversized stones should be squeezed into the cylinder, and then the stones inside the cylinder should be lifted to the ground and poured out through the side opening. Since the drilling geology is a sand layer, after successful drilling, the traditional conical drill bit should be replaced in time to prevent hole collapse during the cuttings removal cylinder 1 drill bit operation.

[0063] If drilling fails to advance for an extended period and the use of the slag removal cylinder drill bit fails to resolve the issue, it can be determined that there is a large area of ​​hard material below, such as abandoned concrete revetment, steel pipes, or other complex conditions. In such cases, low-headroom rotary drilling can be introduced. Low-headroom rotary drilling has the advantages of high drilling efficiency, low height, and convenient assembly, but it is not suitable for clay or medium-coarse sand formations, is prone to borehole collapse, and generates significant construction noise. After successful drilling, a reverse circulation drilling rig should be promptly switched to continue drilling.

[0064] The drilling process should be continuous and should not be stopped for extended periods.

[0065] Determination of final hole elevation: Final hole elevation = Drill table elevation - (Drill rod length + Drill bit length - Drill bit taper length).

[0066] After drilling, the mud parameters are tested, and then the first cleaning of the hole is performed.

[0067] It should be noted that during the process of aerating the mud inside the connecting rod 2 through the air injection pipe 3, the airflow is injected into the interior of the connecting pipe 70 through the air injection pipe 3, and blown to the surface of the baffle 75 through the air guide pipe 72, thereby pushing the baffle 75, together with the movable plate 73 and the protrusion 74, to rotate. Finally, the gas is discharged into the mud through the air outlet pipe 76. The uniformity of the air blowing effect of the device can be increased by the rotation of the air outlet pipe 76, thereby further enhancing the slurry pumping and hole cleaning effect during the construction process.

[0068] It should be noted that during the drilling process, the movable cutter head 65 can be pushed upward by the jacking spring 66, so that the movable cutter head 65 floats up and down, which can enhance the drilling effect during the construction process. At the same time, the limiting block 64 limits the maximum distance that the movable cutter head 65 pushes outward. When the top of the movable cutter head 65 is subjected to pressure, it will be flush with the surface of the alloy cutter head 5, and at most it will retract to the inner side of the alloy cutter head 5. At this time, the limiting block 64 moves to the uppermost position of the lower cavity 62, thereby enhancing the drilling ability of the alloy cutter head 5 through the pushing and retraction of the jacking spring 66.

[0069] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reverse circulation drilling and slag removal in complex geological conditions, characterized in that, The construction method includes the following steps: Construction preparation: Total station positioning and verification; Casing installation: Position the casing at the drilling location; Drilling: The drilling equipment includes a connecting rod (2), and an air injection pipe (3) and a slurry extraction pipe (8) are respectively provided on the inner side of the connecting rod (2). The lower end of the air injection pipe (3) is connected to an air regulating structure (7). The lower end of the connecting rod (2) is movably connected to a connecting rod (10) by bolts. The surface of the connecting rod (10) is fixedly connected to a slag removal cylinder (1) by a bracket. The lower end of the slag removal cylinder (1) is fixedly connected to a fixing frame (4). The surface of the fixing frame (4) is fixedly connected to an alloy cutter head (5). The surface of the alloy cutter head (5) is fixedly connected to a jacking structure (6). The jacking structure (6) is used to enhance the drilling effect of the alloy cutter head (5). The air regulating structure (7) is used to achieve uniform air blowing to different areas at the same height inside the connecting rod (10). The reverse circulation drilling rig drives the connecting rod (2) and connecting rod (10) to rotate and drill, and drills through the alloy cutter head (5) and the jacking structure (6), and ventilates through the air regulating structure (7), and extracts the mud in the hole through the slurry extraction pipe (8). The slag removal cylinder (1) can squeeze oversized pebbles into the interior of the slag removal cylinder (1), and then lift the pebbles in the slag removal cylinder (1) to the ground and pour them out from the side wall opening; Hole cleaning: Cleaning the inside of the drilled hole by replacing the slurry; Pouring: The precast steel cage is vertically lowered from the hole position, and concrete of the required strength is poured. The air conditioning structure (7) includes a connecting pipe (70) movably connected to the lower end of the air injection pipe (3). One end of the connecting pipe (70) is fixedly connected to an annular pipe (71), and one end of the connecting pipe (70) is fixedly connected to a guide pipe (72). The annular pipe (71) is movably connected to a movable plate (73). The lower end of the movable plate (73) is fixedly connected to a protrusion (74). The inner side of the movable plate (73) is fixedly connected to a baffle (75), and the surface of the protrusion (74) is fixedly connected to an air outlet pipe (76). The movable plate (73) and the annular tube (71) are slidably connected. The movable plate (73) slides along the length of the annular tube (71). The protrusion (74) extends from the inside of the annular tube (71) to its outside. The number of baffles (75) is several groups and they are arranged in a ring array. The movable plate (73) is an arc-shaped plate structure that matches the inner wall of the annular tube (71), and the movable plate (73) is a circular ring structure. The number of air outlet pipes (76) is several groups and they are arranged in a ring array. The air outlet pipes (76) are connected to the inner side of the protrusion (74). The baffle (75) is blown by the air guide pipe (72) to realize the rotation and sliding of the movable plate (73), the protrusion (74), the baffle (75) and the air outlet pipe (76) inside the ring pipe (71).

2. The method for reverse circulation drilling and slag removal in complex geological conditions according to claim 1, characterized in that, A connector (9) is movably connected between the connecting rod (10) and the connecting rod (2). The connector (9) is used to protect the bolts connecting the connecting rod (10) and the connecting rod (2). An end plate (11) is fixedly connected to the top of the connecting rod (2). A set of supports is provided at the axis of the slag removal cylinder (1). A steel wire rope (12) is fixedly connected between the support and the inner wall of the slag removal cylinder (1). The steel wire rope (12) is fixedly connected to the slag removal cylinder (1) through a fastening ring. An openable opening is provided on the lower side wall of the slag removal cylinder (1). The openable opening is used for the flow of slurry inside and outside the slag removal cylinder (1).

3. The method for reverse circulation drilling and slag removal in complex geological conditions according to claim 1, characterized in that, The jacking structure (6) includes a cavity (60) opened between the alloy cutter head (5) and the fixed frame (4). The cavity (60) includes an upper cavity (61) and a lower cavity (62) that are connected to each other. A movable column (63) is movably connected between the upper cavity (61) and the lower cavity (62). A limit block (64) is fixedly connected to the lower end of the movable column (63). A movable cutter head (65) is fixedly connected to the upper end of the movable column (63). A jacking spring (66) is provided inside the upper cavity (61).

4. The method for reverse circulation drilling and slag removal in complex geological conditions according to claim 3, characterized in that, The alloy cutter head (5) is a cross-shaped conical structure, and the movable column (63) is slidably connected to the alloy cutter head (5) and the fixed frame (4).

5. The method for reverse circulation drilling and slag removal in complex geological conditions according to claim 4, characterized in that, The diameter of the limiting block (64) matches the diameter of the lower cavity (62), and the upper and lower ends of the movable column (63) are fixed to the movable cutter head (65) and the limiting block (64) by welding, respectively.

6. The method for reverse circulation drilling and slag removal in complex geological conditions according to claim 5, characterized in that, The upper chamfer of the movable cutter head (65) matches the alloy cutter head (5). The movable cutter head (65) and the limiting block (64) move up and down with the movable column (63). The inner diameter of the push spring (66) is larger than the diameter of the movable column (63), and the outer diameter is smaller than the diameter of the limiting block (64).

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