A screw drill bit for the MJS method

Abstract

This application relates to a screw drill for the MJS method, belonging to the field of foundation pile construction. It includes a drill rod, a cutting drill bit, and a jet grouting mechanism. The drill rod and the cutting drill bit rotate coaxially relative to each other. A grout delivery channel is formed within the drill rod. The jet grouting mechanism includes a jetting seat with a grouting hole communicating with the grout delivery channel. The radial dimension of the cutting drill bit is larger than that of the drill rod. The jetting seat is located on one side of the drill rod and on the side of the cutting drill bit facing away from the ground, and the two are fixedly connected. This application utilizes the spatial relationship between the cutting drill bit, the drill rod, and the jetting seat to provide structural protection for the jetting seat during drilling. Simultaneously, it utilizes the structural principle of the screw drill to ensure that the jetting water flow serves as the driving force for the rotation of the cutting drill bit.

Description

Technical Field

[0001] This application relates to the field of pile foundation construction, and in particular to a screw drill for the MJS method. Background Technology

[0002] High-pressure jet grouting involves drilling a hole with a drilling rig, inserting a grouting pipe with a nozzle to a predetermined location in the soil layer, and then using high-pressure equipment to propel the grout into a high-pressure jet, which impacts and breaks down the soil. Some fine soil particles rise to the surface with the grout, while the remaining soil particles are mixed with the grout by the impact of the jet stream. After the grout solidifies, it forms a consolidated body in the soil, which, together with the soil between the piles, constitutes a composite foundation. The Metro Jet System (MJS) is an all-around high-pressure jet grouting method that, based on the original high-pressure jet grouting method, uses a unique multi-hole pipe and a front-end forced grout suction device to achieve forced grout discharge in the borehole and monitoring of ground pressure. By adjusting the forced grout discharge volume, the ground pressure is controlled, which allows for reasonable control of deep mud discharge and ground pressure, thus stabilizing the ground pressure. This reduces the possibility of surface deformation during construction, significantly reduces the impact on the environment, and further ensures the pile diameter.

[0003] Chinese utility model patent CN209742796U discloses a special drill bit for single-axis double-tube high-pressure jet grouting composite piles. It includes a central tube and a cavity in the center of the central tube. A core tube is sleeved on the outside of the central tube. A fixing pin base is fixed at the bottom of the core tube and a drill tip is connected to it through the fixing pin. A spiral blade and a jet grouting device are fixed on the outer wall of the core tube from bottom to top. Two soil cutting teeth are fixed on the left and right sides of the lower end of the spiral blade.

[0004] Regarding the aforementioned technologies, the inventors believe that the following defects exist: one end of the spraying rod of the spraying device is fixedly connected to the core tube, while the other end is suspended in the air, and the ends of the two sets of spraying rods shown in the attached drawings are located outside the spiral blades and soil cutting teeth; during drilling or drilling out, hard objects in the soil layer that are not broken by the spiral blades or soil cutting teeth will cause relatively serious structural damage to the spraying rod. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a screw drill for the MJS method.

[0006] The screw drill bit for the MJS method provided in this application adopts the following technical solution: A screw drill for the MJS method includes a drill rod, a cutting drill bit, and a jet grouting mechanism. The drill rod and the cutting drill bit rotate coaxially relative to each other. A grout delivery channel is provided inside the drill rod. The jet grouting mechanism includes a jetting seat with a grouting hole communicating with the grout delivery channel. The radial dimension of the cutting drill bit is larger than the radial dimension of the drill rod. The jetting seat is located on one side of the drill rod and on the side of the cutting drill bit facing away from the ground, and the two are fixedly connected.

[0007] By adopting the above technical solution, during the drilling process, the soil cutting drill bit directly rubs and collides with objects in the soil layer. The objects that can come into contact with the jet seat are debris that has been cut by the soil cutting drill bit, which can cause less damage to the jet seat.

[0008] Preferably, the drill rod includes a base rod and a power cylinder. The grout delivery channel is located on the base rod, and a power channel is also provided on the base rod. The power cylinder is coaxially and fixedly connected to the side of the base rod facing the soil cutting drill bit. The power cylinder and the soil cutting drill bit are coaxially and rotatably connected. The rotary jetting mechanism includes a power assembly located inside the power cylinder. The power cylinder is connected to the power channel. The power assembly includes a power screw and a torque rod. The end of the power screw facing the soil cutting drill bit is connected to the torque rod through a universal coupling. The torque rod is coaxially and fixedly connected to the soil cutting drill bit.

[0009] By adopting the above technical solution, the power assembly applies the principle of screw drilling tools to this drilling tool. The water flow generates an impact force on the power screw to generate torque that drives the soil cutting drill bit to rotate, and the water flow can eventually be ejected through the grouting hole or the soil breaking nozzle.

[0010] Preferably, the power assembly further includes an adjusting piston, an adjusting channel is provided inside the torque rod, a first adjusting hole is also provided on the torque rod, the adjusting piston slides within the adjusting channel, a water passage is provided on the adjusting piston, a first adjusting water channel is provided on the soil cutting drill bit, a soil breaking nozzle is provided on the side of the soil cutting drill bit facing the ground, the soil breaking nozzle is connected to the first adjusting water channel, and the first adjusting water channel is connected to the water passage.

[0011] By adopting the above technical solution, the water passage of the adjusting piston can guide the water flow in the power cylinder to the soil cutting drill rod, and finally spray it out from the soil breaking nozzle to impact the soil below the soil cutting drill bit, thereby reducing the drilling pressure of the soil cutting drill bit.

[0012] Preferably, the drill rod further includes a protective sleeve, which is coaxially fixedly connected to one end of the base rod facing the cutting drill bit. The protective sleeve is located outside the power cylinder and is rotatably connected to the cutting drill bit. A grouting gap is formed between the protective sleeve and the power cylinder, and the grouting gap is simultaneously connected to the grouting hole and the grouting channel.

[0013] By adopting the above technical solution, the space formed by the grouting gap is for the concrete slurry to flow through, enter the soil cutting drill bit, and finally reach the jet grouting seat.

[0014] Preferably, the torque rod is further provided with a second adjustment hole, which is connected to the adjustment channel. The soil cutting drill bit is provided with a second adjustment water channel, which is connected to the second adjustment hole, the water passage, and the second adjustment water channel. The second adjustment water channel is connected to the grouting hole. The end of the adjustment piston facing the ground extends out from the soil cutting drill bit, and the first adjustment hole is located on the side of the second adjustment hole away from the ground.

[0015] By adopting the above technical solution, during drilling, the lower end of the adjusting piston moves upward relative to the soil layer below, connecting the first adjusting hole and the water passage, allowing the power water flow to break the soil. When the drill bit is raised and grouting is carried out simultaneously, the adjusting piston moves downward relative to the soil layer, connecting the second adjusting hole and the water passage, allowing the power water flow to be sprayed out from the grouting hole along with the concrete slurry. In other words, the power water flow provides power for the spraying of the concrete slurry.

[0016] Preferably, the adjustment channel is provided with an adjustment spring, one end of which abuts against the end of the adjustment piston away from the ground, and the other end abuts against the end arm of the adjustment channel.

[0017] By adopting the above technical solution, during the drilling tool lifting process, the presence of the adjusting spring allows the adjusting piston to be kept in the position where the second adjusting hole and the water passage are connected.

[0018] Preferably, a limiting block is fixedly connected to the end of the adjusting piston facing the ground. When the limiting block abuts against the soil cutting drill bit, the first adjusting hole is connected to the water passage. A limiting step is fixedly connected to the adjusting piston and located in the adjusting passage. When the limiting step abuts against the soil cutting drill bit, the second adjusting hole is connected to the water passage.

[0019] By adopting the above technical solution, the limit block and the display block limit the stroke range of the regulating piston, so that the regulating piston can continuously perform its own water flow guiding work and also keep the power component running smoothly.

[0020] Preferably, the direction of the grouting hole is tangential to the drill rod, and the direction of the grouting hole is opposite to the direction of the soil cutting drill bit.

[0021] By adopting the above technical solution, the liquid ejected from the grouting hole is aligned with the direction of the grouting hole. Therefore, during the process of the liquid ejected from the grouting hole, a reverse thrust can be generated on the jetting seat, providing auxiliary thrust for the rotation of the soil cutting drill bit.

[0022] Preferably, the base rod is also provided with a slurry pumping channel, and the port of the slurry pumping channel near the ground is located on the side wall of the base rod.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. By setting the jet seat on the side of the soil cutting drill bit away from the ground, during the drilling process, the soil cutting drill bit directly rubs and collides with objects in the soil layer. The objects that can come into contact with the jet seat are debris that has been cut by the soil cutting drill bit, which can cause less damage to the jet seat. 2. By setting up the power component, the principle of screw drilling tools is applied to this drilling tool. The water flow generates an impact force on the power screw, which generates a torque that drives the soil cutting drill bit to rotate. The water flow can eventually be ejected through the grouting hole or the soil breaking nozzle. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the screw drill used for the MJS method in the embodiments of this application.

[0025] Figure 2 This is a structural schematic diagram illustrating the working principle of the rotary spraying mechanism in the embodiments of this application.

[0026] Figure 3 This is a structural schematic diagram illustrating the working principle of the power component in the embodiments of this application.

[0027] Explanation of reference numerals in the attached drawings: 1. Drill rod; 11. Base rod; 111. Pumping channel; 112. Power channel; 113. Grouting channel; 12. Power cylinder; 13. Protective cylinder; 14. Grouting gap; 2. Soil cutting drill bit; 21. Soil breaking nozzle; 22. First regulating water channel; 23. Second regulating water channel; 3. Rotary jetting mechanism; 31. Jet seat; 311. Jet hole; 4. Power assembly; 41. Power screw; 42. Universal coupling; 43. Torque rod; 431. Adjustment channel; 432. First adjustment hole; 433. Second adjustment hole; 44. Adjusting piston; 441. Water passage; 442. Limiting block; 443. Limiting step; 444. Transition groove; 45. Adjusting spring. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0029] This application discloses a screw drill for the MJS method, such as... Figure 1 and 2 As shown, the system includes a drill rod 1, a soil cutting drill bit 2, and a jet grouting mechanism 3. The drill rod 1 connects the soil cutting drill bit 2 and the drilling rig, and delivers concrete slurry to the soil cutting drill bit 2. The soil cutting drill bit 2 is used to cut the soil structure. The jet grouting mechanism 3 is installed on the soil cutting drill bit 2, which drives the soil cutting drill bit 2 to rotate and sprays clean water and concrete slurry into the soil layer.

[0030] like Figure 1 and 2 As shown, the drill rod 1 includes a base rod 11, a power cylinder 12, and a protective cylinder 13. The power cylinder 12 and the protective cylinder 13 are coaxially fixedly connected to the end of the base rod 11 facing the ground. The power cylinder 12 is located inside the protective cylinder 13, and a grouting gap 14 is formed between the inner wall of the protective cylinder 13 and the outer wall of the power cylinder 12. The soil cutting drill bit 2 is coaxially rotatably connected to both the power cylinder 12 and the protective cylinder. A grouting channel 113 and a power channel 112 are provided on the base rod 11 along its length. The power channel 112 is connected to the power cylinder 12, and the grouting channel 113 is connected to the grouting gap 14. In this embodiment, there is only one power channel 112 and two grouting channels 113.

[0031] like Figure 1 and 2 As shown, the radial dimension of the cutting drill bit 2 is larger than that of the drill rod 1. The rotary jetting mechanism 3 includes a jetting seat 31, which is fixedly connected to the side of the cutting drill bit 2 facing away from the ground and located next to the protective cylinder 13. In this embodiment, there are four jetting seats 31, which are arranged in a circular array around the protective cylinder 13. The jetting seats 31 are provided with grouting holes 311, which face the tangential direction of the drill rod 1 and are opposite to the direction of the cutting drill bit 2. The grouting holes 311 are used to spray water or concrete slurry into the soil layer, and are therefore indirectly connected to the power channel 112 and the grouting channel 113 in the base rod 11. At the same time, the cutting drill bit 2 is also provided with a channel for the grouting holes 311 to indirectly connect with the grouting gap 14.

[0032] like Figure 2 and 3 As shown, the rotary jetting mechanism 3 includes a power assembly 4 located inside the power cylinder 12. The power assembly 4 includes a power screw 41 and a torque rod 43. One end of the power screw 41 facing the soil cutting drill bit 2 is connected to the torque rod 43 through a universal coupling 42, while the other end is suspended. The end of the torque rod 43 away from the power screw 41 is coaxially and fixedly connected to the soil cutting drill bit 2. At this time, the power assembly 4 forms the structure of a screw drill bit, with the power screw 41 as the rotor and the power cylinder 12 as the stator. High-pressure water is injected into the power cylinder 12 through the power channel 112 of the base rod 11, driving the power screw 41 to rotate. The power screw 41 transmits torque to the soil cutting drill bit 2 through the universal coupling 42 and the torque rod 43, causing it to rotate. The soil cutting drill bit 2 has a soil breaking nozzle 21 on the side facing the ground. The power assembly 4 also includes a rod-shaped adjusting piston 44. An adjusting channel 431 is coaxially provided on the torque rod 43. The adjusting piston 44 slides in the adjusting channel 431 and is used to guide the water flow in the power cylinder 12 to be selectively sprayed out from the soil breaking nozzle 21 or the grouting hole 311.

[0033] like Figure 2 and 3 As shown, the torque rod 43 has a first adjustment hole 432 and a second adjustment hole 433. The first adjustment hole 432 and the second adjustment hole 433 are located at different axial positions on the torque rod 43, and there are multiple of each. The second adjustment hole 433 is located on the side of the first adjustment hole 432 that is furthest from the ground. The soil cutting drill bit 2 has four first adjustment channels 22 and four second adjustment channels 23. The soil breaking nozzle 21 is connected to the first adjustment channel 22, and the second adjustment channel 23 is connected to the grouting hole 311. The adjusting piston 44 has a water passage 441. Both ends of the water passage 441 are located on the side wall of the adjusting piston 44. When the upper end of the water passage 441 is aligned with the first adjustment hole 432, the lower end of the water passage 441 is connected to the first adjustment channel 22. When the upper end of the water passage 441 is aligned with the second adjustment hole 433, the lower end of the water passage 441 is connected to the second adjustment channel 23.

[0034] like Figure 2 and 3 As shown, an adjusting spring 45 is provided inside the adjusting channel 431. One end of the adjusting spring 45 abuts against the end of the adjusting piston 44 away from the ground, and the other end abuts against the end wall of the adjusting channel 431. The soil cutting drill bit 2 extends from the end of the adjusting piston 44 facing the ground and is fixedly connected to a limiting block 442. At the same time, a limiting step 443 is integrally formed on the adjusting piston 44 and coaxially within the adjusting channel 431. When the limiting block 442 abuts against the soil cutting drill bit 2, the first adjusting hole 432 communicates with the water passage 441. When the limiting step 443 abuts against the soil cutting drill bit 2, the second adjusting hole 433 communicates with the water passage 441. In the natural state, the adjusting spring 45 applies a thrust towards the ground to the adjusting piston 44, causing the limiting step 443 to abut against the soil cutting drill bit 2. At this time, the power cylinder 12 flows into the second adjusting water channel 23 through the second adjusting hole 433 and the water passage 441, and is finally ejected from the spray hole 311. During the drilling process, the soil below the cutting drill bit 2 abuts against the limiting block 442, thereby applying a thrust to the limiting block 442 to move the adjusting piston 44 upwards, and finally aligning the upper end of the water passage 441 with the first adjusting hole 432. This allows the high-pressure water flow in the power cylinder 12 to flow from the first adjusting hole 432 and the water passage 441 into the first adjusting water channel 22, and finally be ejected from the soil breaking nozzle 21, impacting the soil below the cutting drill bit 2 and improving the drilling efficiency of the cutting drill bit 2.

[0035] like Figure 2 and 3As shown, annular transition grooves 444 are provided on the side wall of the adjusting piston 44 at both ends of the water passage 441. The width of the transition grooves 444 is greater than the shortest distance between the first adjusting hole 432 and the second adjusting hole 433. Thus, within its own travel range, the adjusting piston 44 can always allow water from the power cylinder 12 to enter the water passage 441, so that the water that provides power to the power assembly 4 can keep flowing.

[0036] like Figure 1 and 2 As shown, the base rod 11 is also equipped with a grouting channel 111 for removing mud and sand from the borehole. The end of the grouting channel 111 near the ground is located on the side wall of the base rod 11 and close to the protective casing 13. During drilling, airflow is continuously supplied to the grouting channel 113, and high-pressure water is continuously supplied to the power channel 112. The mud mixture generated in the borehole is then extracted from the borehole through the grouting channel 111. During grouting, the drill bit is continuously raised, concrete grout is supplied to the grouting channel 113, and water with reduced pressure is supplied to the power channel 112. The grouting channel 111 continues to extract the mud mixture generated in the borehole from the borehole.

[0037] The implementation principle of a screw drill for the MJS method in this application embodiment is as follows: By combining the power principle of the screw drill with that of the traditional MJS drill bit, the water flow, which serves as the power source, provides rotational driving force to the soil cutting drill bit 2 and is ultimately ejected from the grouting hole 311 or the soil breaking nozzle 21. This is used to mix the mud and sand in the hole for easy suction, and to impact the soil on the hole wall or the soil below the soil cutting drill bit 2. When the drill is lifted, the powered water flow is ejected from the grouting hole 311, which provides lifting power to the concrete slurry that is also ejected from the grouting hole 311, thereby increasing the pile width.

[0038] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A screw drill for the MJS method, comprising a drill rod (1), a soil cutting drill bit (2), and a jet grouting mechanism (3), wherein the drill rod (1) and the soil cutting drill bit (2) rotate coaxially relative to each other, and a grout delivery channel (113) is provided inside the drill rod (1), characterized in that: The rotary jetting mechanism (3) includes a jetting seat (31), on which a jetting hole (311) communicating with the grouting channel (113) is provided. The radial dimension of the soil cutting drill bit (2) is greater than the radial dimension of the drill rod (1). The jetting seat (31) is located on one side of the drill rod (1), and the jetting seat (31) is located on the side of the soil cutting drill bit (2) away from the ground and the two are fixedly connected. The drill rod (1) includes a base rod (11) and a power cylinder (12). The grouting channel (113) is located on the base rod (11). The base rod (11) is also provided with a power channel (112). The power cylinder (12) is coaxially fixedly connected to the side of the base rod (11) facing the soil cutting drill bit (2). The power cylinder (12) and the soil cutting drill bit (2) are coaxially rotatably connected. The rotary jetting mechanism (3) includes a power assembly (4). The power assembly (4) is located inside the power cylinder (12). The power cylinder (12) is connected to the power channel (112). The power assembly (4) includes a power screw (41) and a torque rod (43). The end of the power screw (41) facing the soil cutting drill bit (2) is connected to the torque rod (43) through a universal coupling (42). The torque rod (43) is coaxially fixedly connected to the soil cutting drill bit (2). The power assembly (4) also includes an adjusting piston (44), an adjusting channel (431) is provided in the torque rod (43), a first adjusting hole (432) is also provided on the torque rod (43), the adjusting piston (44) slides in the adjusting channel (431), a water passage (441) is provided on the adjusting piston (44), a first adjusting water channel (22) is provided on the soil cutting drill bit (2), a soil breaking nozzle (21) is provided on the side of the soil cutting drill bit (2) facing the ground, the soil breaking nozzle (21) is connected to the first adjusting water channel (22), and the first adjusting water channel (22) is connected to the water passage (441).

2. A screw drill for the MJS method according to claim 1, characterized in that: The drill rod (1) also includes a protective sleeve (13), which is coaxially fixedly connected to one end of the base rod (11) facing the soil cutting drill bit (2). The protective sleeve (13) is located outside the power cylinder (12). The protective sleeve (13) is rotatably connected to the soil cutting drill bit (2). A grouting gap (14) is formed between the protective sleeve (13) and the power cylinder (12). The grouting gap (14) is simultaneously connected to the grouting hole (311) and the grouting channel (113).

3. A screw drill for the MJS method according to claim 2, characterized in that: The torque rod (43) is also provided with a second adjustment hole (433), which is connected to the adjustment channel (431). The soil cutting drill bit (2) is provided with a second adjustment water channel (23), which is connected to the second adjustment hole (433), the water passage (441), and the second adjustment water channel (23). The second adjustment water channel (23) is connected to the grouting hole (311). The adjusting piston (44) extends from the soil cutting drill bit (2) at one end facing the ground, and the first adjusting hole (432) is located on the side of the second adjusting hole (433) away from the ground.

4. A screw drill for the MJS method according to claim 3, characterized in that: An adjusting spring (45) is provided in the adjusting channel (431). One end of the adjusting spring (45) abuts against the end of the adjusting piston (44) away from the ground, and the other end abuts against the end arm of the adjusting channel (431).

5. A screw drill for the MJS method according to claim 3 or 4, characterized in that: The adjusting piston (44) is fixedly connected to a limiting block (442) at one end facing the ground. When the limiting block (442) abuts against the soil cutting drill bit (2), the first adjusting hole (432) is connected to the water passage (441). A limiting step (443) is fixedly connected on the adjusting piston (44) and located in the adjusting passage (431). When the limiting step (443) abuts against the soil cutting drill bit (2), the second adjusting hole (433) is connected to the water passage (441).

6. A screw drill for the MJS method according to claim 5, characterized in that: The direction of the grouting hole (311) is tangential to the drill rod (1), and the direction of the grouting hole (311) is opposite to the direction of the soil cutting drill bit (2).

7. A screw drill bit for the MJS method according to claim 6, characterized in that: The base rod (11) is also provided with a slurry pumping channel (111), and the port of the slurry pumping channel (111) near the ground is located on the side wall of the base rod (11).

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