High-pressure jet grouting drill rod structure

Abstract

The utility model relates to the technical field of capital construction engineering, in particular to a high-pressure jet grouting drill rod structure which comprises a threaded drill rod and a supporting pipe coaxially sleeved on the periphery of the threaded drill rod, and a drill bit protruding out of the supporting pipe and a cement nozzle abutting against the drill bit are coaxially fixed at the lower end of the threaded drill rod. A clamping head is coaxially arranged at the upper end of the threaded drill rod; a plurality of limiting grooves arranged in the axial direction of the supporting pipe are formed in the side wall of the supporting pipe, and the clamping heads are telescopically and elastically clamped in the limiting grooves, so that the threaded drill rod and the supporting pipe are mutually clamped and fixed; when the clamping head is clamped to the limiting grooves in different positions in the axial direction of the threaded drill rod, the axial distance between the lower end of the supporting pipe and the drill bit is changed. According to the utility model, a mucous membrane generated during friction between the support pipe support and sludge clay can be damaged by adjusting the distance between the cement nozzle and the support pipe support before grouting, so that the grouting depth is prevented from being influenced, and the grouting effect is optimized.

Description

Technical Field

[0001] The utility model relates to the technical field of infrastructure engineering, in particular to a high-pressure rotary jet drilling rod structure. Background Art

[0002] High-pressure jet grouting pile technology is an advanced foundation reinforcement method. It uses a high-pressure rotary nozzle to inject cement slurry into the soil layer, fully mixes it with the soil, and forms a continuous overlapping cement reinforcement body, thereby enhancing the bearing capacity and stability of the foundation. This method has a wide range of applications, including various types of foundations such as silt, silty soil, fluid plastic soil, clay and sand, demonstrating its important role in engineering construction. Although high-pressure jet grouting pile technology has a wide range of applicability and significant reinforcement effects, it faces considerable challenges when dealing with specific geological conditions, especially silty soil layers. Due to their low bearing capacity and high plasticity, these strata make it very easy for newly excavated holes to collapse during drilling and grouting, which not only brings difficulties to the construction process, but also seriously affects the construction efficiency and the quality of the reinforcement body. In addition, groundwater problems are often encountered during the construction process. The water content of different underground soil layers varies. For example, when the soil layer has a high water content, it will directly affect the stability of the grouting material and the final reinforcement effect, further increasing the complexity and uncertainty of the construction.

[0003] In order to deal with the above problems as much as possible, the construction process of high-pressure jet grouting piles in the prior art usually uses a support pipe device as a support for the drill rod. The support pipe device as a support is installed on the outside of the drill rod to prevent the newly excavated hole from collapsing easily and to control the injection angle and range of the cement slurry. This method improves the reliability of construction to a certain extent, but there are still some limitations. In particular, because the distance between the support pipe and the nozzle on the drill rod is relatively close, the mucous film generated by the friction between the support pipe and the silt clay during the drilling process will greatly affect the grouting depth inside the soil layer in the subsequent grouting process, which ultimately limits the wide application and construction efficiency of high-pressure jet grouting pile technology. Utility Model Content

[0004] In order to solve the technical problems existing in the prior art, the utility model provides a high-pressure rotary jet drill rod structure, which can help to destroy the mucous membrane generated by the friction between the support pipe support and the silt clay by adjusting the distance between the cement nozzle and the support pipe before grouting, thereby preventing the grouting depth from being affected and optimizing the grouting effect.

[0005] The utility model discloses a high-pressure jet grouting drill rod structure, comprising a threaded drill rod and a support pipe coaxially sleeved on the outer periphery of the threaded drill rod, a drill bit protruding from the support pipe and a cement nozzle close to the drill bit are coaxially fixed to the lower end of the threaded drill rod, and the characteristics are:

[0006] A clamping joint is coaxially arranged on the upper end of the threaded drill rod;

[0007] The side wall of the support pipe is provided with a plurality of limit grooves arranged along the axial direction of the support pipe, and the clamping joint can be elastically clamped in the limit grooves in a telescopic manner so that the threaded drill rod and the support pipe are clamped and fixed to each other;

[0008] Wherein, when the clamping joint is clamped to the limiting grooves at different positions in the axial direction of the threaded drill rod, the axial distance between the lower end of the support pipe and the drill bit changes.

[0009] According to a high-pressure jet-jet drill rod structure of the utility model, the side of the clamping joint is provided with an elastic telescopic buckle extending along the radial direction of the threaded drill rod;

[0010] The plurality of limit grooves include a first groove body and a second groove body arranged along the axial direction of the support pipe;

[0011] The bottom wall of the first trough body is formed with a guide surface, the guide surface extends obliquely downward from the bottom wall of the first trough body to the notch of the second trough body, and the upper end of the guide surface is away from the side wall of the threaded drill rod, and the lower end is close to the side wall of the threaded drill rod;

[0012] In the initial state, the elastic telescopic buckle is radially inserted into the first slot and abuts against the guide surface;

[0013] When the support pipe moves axially upward together with the first slot body and the second slot body, the elastic telescopic buckle radially retracts along the guide surface, and when the elastic telescopic buckle moves to the notch of the second slot body, it leaves the guide surface and is reset and inserted into the second slot body.

[0014] According to a high-pressure jet-jet drill rod structure of the utility model:

[0015] The first slot body is a strip-shaped slot extending laterally, so that the elastic telescopic buckle is fixedly buckled in the first slot body;

[0016] The second groove body is a circumferentially extending annular groove, so that the elastic telescopic buckle can slide circumferentially in the second groove body.

[0017] According to a high-pressure jet-jet drill rod structure of the utility model, a contact surface between the bottom of the elastic telescopic buckle and the guide surface forms a chamfer.

[0018] According to a high-pressure rotary jet drilling rod structure of the utility model, the support pipe is suitable for transmission connection with an external driving device, so as to drive the support pipe to rotate and move upward through the external device;

[0019] The clamping joint is provided with a built-in motor which is transmission-connected to the threaded drill rod.

[0020] According to a high-pressure rotary jet drilling rod structure of the utility model, an annular tube is slidably sleeved on the outer wall of the support tube, and the annular tube is connected to the inner cavity of the support tube at the upper end of the support tube; the annular tube is connected to an output tube extending outward.

[0021] According to a high-pressure jet grouting drill pipe structure of the utility model, the outer wall of the support pipe is surrounded by an annular groove, and a plurality of circumferentially distributed output holes are opened on the annular groove, and the annular pipe is slidably fitted in the annular groove;

[0022] According to a high-pressure jet-jet drill rod structure of the utility model, a plurality of circumferentially distributed through holes are provided on the matching surface of the annular tube and the annular groove.

[0023] The utility model discloses a high-pressure rotary jet drill rod structure which is similar to the prior art in that it includes a threaded drill rod, a drill bit is provided at the lower end of the threaded drill rod and a cement nozzle for external grouting is provided on the drill bit. In order to effectively prevent the hole from collapsing during the drilling process, a support pipe is additionally provided on the outside of the threaded drill rod as support. The threaded drill rod is coaxially sleeved inside the support pipe and the drill bit protrudes downward from the lower end of the support pipe. When drilling, the drill bit, together with the threaded drill rod and the support pipe as support, drills into the underground soil layer together. After drilling into a certain depth underground, cement slurry is injected into the soil layer through the cement nozzle on the drill bit to cast high-pressure rotary jet piles underground, thereby achieving the purpose of reinforcing the underground soil layer. The difference from the prior art lies in that, on the one hand, a clamping joint is coaxially arranged at the upper end of the threaded drill rod, and on the other hand, a plurality of limiting grooves arranged along the axial direction of the supporting pipe are arranged on the side wall of the supporting pipe. When the threaded drill rod is assembled inside the supporting pipe, the clamping joint can be elastically clamped in the limiting groove to make the threaded drill rod and the supporting pipe mutually clamped and fixed. When drilling underground, it can ensure that the threaded drill rod rotates together with the supporting pipe. At the same time, a plurality of limiting grooves are arranged in the axial direction to allow the clamping joint to be fixed on the threaded drill rod. When the support pipe is clamped in the limiting grooves at different positions in the axial direction, the axial distance between the lower end of the support pipe and the drill bit changes. Based on this structure, by controlling the retraction of the clamping joint on the threaded drill rod and clamping it in the axial direction to the limiting grooves at other positions in the support pipe, the support pipe is relatively displaced with the threaded drill rod in the axial direction, so that the axial distance between the lower end of the support pipe and the drill bit changes. This can help adjust the protruding length of the drill bit at the lower end of the support pipe, which is equivalent to facilitating the adjustment of the distance between the cement nozzle and the lower end of the support pipe. When drilling is required, the support pipe, threaded drill rod and drill bit are driven to rotate synchronously through an external driving device. With the cooperation of the drill bit, the threads rotating in the positive direction along the outer wall of the threaded drill rod also guide the threaded drill rod and the support pipe to drill downward into the soil layer. After drilling is completed, the high-pressure rotary jet drill rod needs to be switched to the rotary jet working state. In the process of switching to this working state, the protruding length of the threaded drill rod at the lower end of the support pipe is increased in advance, so that the cement nozzle on the threaded drill rod is switched from the original state close to the support pipe to the state far away from the support pipe in the soil layer. After increasing the distance between the cement nozzle and the support pipe, the soil layer can be slightly deformed, and cracks can be generated in the soil body due to micro-deformation, thereby destroying the mucous membrane generated by the friction between the support pipe and the silt clay, thereby preventing the grouting depth from being affected in the subsequent grouting process and optimizing the grouting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is the internal structure diagram of the utility model (initial state);

[0026] Figure 2 It is the internal structure diagram of the utility model (after the support pipe is moved upward, the distance between the drill bit and the lower end of the support pipe is increased);

[0027] Figure 3 It is the external structure diagram of the utility model;

[0028] Figure 4 It is a structural diagram of a threaded drill rod of the utility model;

[0029] Figure 5 This is the internal structure diagram of the position switching mechanism of the utility model (the elastic telescopic buckle is located in the first slot);

[0030] Figure 6 This is the internal structure diagram of the position switching mechanism of the utility model (the elastic telescopic buckle enters the second slot body after the support pipe moves upward);

[0031] Figure 7 It is a partial structural diagram of the upper end of the support pipe of the utility model;

[0032] Figure 8 It is a partial structural diagram of the utility model;

[0033] Fig. 9 It is a partial structural diagram of the utility model;

[0034] Fig.10 It is a structural diagram of the annular tube of the utility model.

[0035] Reference numerals:

[0036] 1. Threaded drill rod, 2. Support pipe, 3. Drill bit, 4. Cement nozzle, 5. Card joint, 6. Elastic telescopic buckle, 7. First trough, 8. Second trough, 9. Guide surface, 10. Chamfered corner, 11. Built-in motor, 12. Annular tube, 13. Output tube, 14. Annular groove,

[0037] 15. Output hole, 16. Through hole, 17. Water outlet pipe, 18. Water pump pipe, 19. Chamfered surface,

[0038] 20. Boss. DETAILED DESCRIPTION

[0039] The embodiments of the utility model are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the utility model, and cannot be understood as limitations on the utility model. In the description of the utility model, it is necessary to understand that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the utility model.

[0040] like Figures 1 to 10 As shown, a high-pressure rotary jet drilling rod structure of this embodiment includes a threaded drill rod 1 and a support pipe 2. A drill bit 3 is coaxially fixed to the lower end of the threaded drill rod 1. A cement nozzle 4 is provided on the drill bit 3. The cement nozzle 4 and a delivery pipeline connected to the cement nozzle 4 are provided inside the threaded drill rod 1. This structure belongs to the prior art and will not be described in detail in this embodiment. The threaded drill rod 1 is coaxially sleeved inside the support pipe 2, and the drill bit 3 at the lower end of the threaded drill rod 1 protrudes downward from the lower end of the support pipe 2. In this state, the distance between the lower end of the support pipe 2 and the drill bit 3 is small, and the two are close to each other. In addition, a clamping joint 5 is coaxially installed on the upper end of the threaded drill rod 1, and the side wall of the support pipe 2 is formed with two limit grooves arranged along the axial direction of the support pipe 2. The clamping joint 5 can be elastically clamped in the limit grooves to make the threaded drill rod 1 and the support pipe 2 clamped and fixed to each other. When the clamping joint 5 is clamped in the limit grooves at different positions in the axial direction of the threaded drill rod 1, the axial distance between the lower end of the support pipe 2 and the drill bit 3 changes.

[0041] It can be understood that the high-pressure rotary jet drill rod structure of this embodiment is similar to the prior art in that it includes a threaded drill rod 1, a drill bit 3 is provided at the lower end of the threaded drill rod 1, and a cement nozzle 4 for external grouting is provided on the drill bit 3. In order to effectively prevent the collapse of the hole during the drilling process, a support pipe 2 is added to the outside of the threaded drill rod 1 as a support. The threaded drill rod 1 is coaxially sleeved inside the support pipe 2 and the drill bit 3 protrudes downward from the lower end of the support pipe 2. When drilling, the drill bit 3, together with the threaded drill rod 1 and the support pipe 2 used as support, drills into the underground soil layer together, and after drilling into a certain depth underground, cement slurry is injected into the soil layer through the cement nozzle 4 on the drill bit 3, so as to cast a high-pressure rotary jet pile underground and achieve the purpose of reinforcing the underground soil layer. The difference from the prior art is that, on the one hand, a clamping joint 5 is coaxially arranged at the upper end of the threaded drill rod 1, and on the other hand, two limiting grooves arranged along the axial direction of the supporting pipe 2 are arranged on the side wall of the supporting pipe 2. When the threaded drill rod 1 is assembled inside the supporting pipe 2, the clamping joint 5 can be elastically clamped in the limiting groove to make the threaded drill rod 1 and the supporting pipe 2 mutually clamped and fixed. When drilling underground, it can ensure that the threaded drill rod 1 and the supporting pipe 2 rotate together. At the same time, a plurality of limiting grooves are arranged in the axial direction to allow the clamping joint 5 to be in the axial direction of the threaded drill rod 1. When the support pipe 2 is clamped in the limiting grooves at different positions in the direction, the axial distance between the lower end of the support pipe 2 and the drill bit 3 changes. Based on this structure, by controlling the retraction of the clamping joint 5 on the threaded drill rod 1 and clamping it in the axial direction to the limiting grooves at other positions in the support pipe 2, the support pipe 2 is allowed to be relatively displaced with the threaded drill rod 1 in the axial direction, so that the axial distance between the lower end of the support pipe 2 and the drill bit 3 changes. This can help adjust the protruding length of the drill bit 3 at the lower end of the support pipe 2, which is equivalent to facilitating the adjustment of the distance between the cement nozzle 4 and the lower end of the support pipe 2. When drilling is required, the support pipe 2, the threaded drill rod 1 and the drill bit 3 are driven to rotate synchronously through an external driving device. With the cooperation of the drill bit 3, the threads rotating in the positive direction along the outer wall of the threaded drill rod 1 also guide the threaded drill rod 1 and the support pipe 2 to drill downward into the soil layer. After the drilling is completed, the high-pressure rotary jet drilling rod needs to be switched to the rotary jet working state. In the process of switching to this working state, the protruding length of the threaded drill rod 1 at the lower end of the support pipe 2 is increased in advance, so that the cement nozzle 4 on the threaded drill rod 1 is switched from the original state close to the support pipe 2 to the state far away from the support pipe 2 in the soil layer, thereby increasing the distance between the cement nozzle 4 and the support pipe 2 (such as Figure 2 and Figure 3 The state shown in the figure can cause the soil layer to produce a slight deformation, causing cracks in the soil due to the micro-deformation, thereby destroying the sticky film produced by the friction between the support pipe and the silt clay, thereby preventing the influence on the grouting depth during the subsequent grouting process and optimizing the grouting effect.

[0042] Specifically, elastic telescopic buckles 6 are respectively installed on the two opposite side surfaces of the clamping joint 5, and the elastic telescopic buckles 6 extend along the radial direction of the threaded drill rod 1. The limiting groove referred to in this embodiment includes a first slot body 7 and a second slot body 8, and the first slot body 7 and the second slot body 8 are arranged along the axial direction of the support pipe 2 and are spaced a certain distance apart from each other. In addition, a guide surface 9 is formed on the bottom wall of the first slot body 7, and the guide surface 9 extends downward from the bottom wall of the first slot body 7 to the slot opening of the second slot body 8, and the upper end of the guide surface 9 is away from the side wall of the threaded drill rod 1, and the lower end of the guide surface 9 is close to the side wall of the threaded drill rod 1. In the initial state, the elastic telescopic buckle 6 is radially inserted into the first slot body 7 and the bottom abuts against the guide surface 9. When the support pipe 2 moves axially upward together with the first slot body 7 and the second slot body 8, the elastic telescopic buckle 6 radially retracts along the guide surface 9, and when the elastic telescopic buckle 6 moves to the slot opening of the second slot body 8, it leaves the guide surface 9 and resets to be inserted into the second slot body 8. Figure 5 As shown, when it is put into use, the elastic telescopic buckle 6 in the initial state is inserted into the first slot body 7. When drilling is required, the external driving device drives the support pipe 2 to rotate. Since the elastic telescopic buckle 6 is inserted into the first slot body 7 at this time and the first slot body 7 limits the movement of the elastic telescopic buckle 6, so that the threaded drill rod 1 can be linked with the support pipe 2, the support pipe 2 can rotate with the threaded drill rod 1 through the elastic telescopic buckle 6, and then the drill bit 3 and the threaded body 41 also rotate synchronously, guiding the threaded drill rod 1 and the support pipe 2 to drill smoothly into the underground soil layer. Before completing the drilling of the soil layer and preparing for grouting, the construction device needs to be switched to the rotary spraying working state. At this time, the entire support pipe 2 is driven upward by the external driving device, combined with the Figure 6 As shown, during the overall upward movement of the support pipe 2, the first slot body 7, the guide surface 9 and the second slot body 8 also move upward accordingly. During this process, the elastic telescopic buckle 6 escapes from the first slot body 7 and the guide surface 9 gradually pushes the elastic telescopic buckle 6 back to the clamping joint 5. When the second slot body 8 moves up to the position corresponding to the elastic telescopic buckle 6, the elastic telescopic buckle 6 is reset and elastically inserted into the second slot body 8. After the elastic telescopic buckle 6 is clamped in the second slot body 8, the support pipe 2 and the threaded drill rod 1 can be staggered with each other in the axial direction. After the support pipe 2 moves up, the drill bit 3 at the lower end of the threaded drill rod 1 can protrude further at the lower end of the support pipe 2, effectively increasing the distance between the cement nozzle 4 and the support pipe 2, thereby causing the soil layer to produce a slight deformation, causing cracks in the soil due to the slight deformation, thereby destroying the mucous membrane produced by the friction between the support pipe support and the silt clay, thereby preventing the grouting depth from being affected in the subsequent grouting process and optimizing the grouting effect.

[0043] In one embodiment, the first slot body 7 is a strip-shaped slot extending laterally, so that the elastic telescopic buckle 6 is fixedly buckled in the first slot body 7, and the second slot body 8 is an annular slot extending circumferentially, so that the elastic telescopic buckle 6 can slide circumferentially in the second slot body 8. Due to this structure, when the elastic telescopic buckle 6 is inserted into the second slot body 8, the second slot body 8 allows the elastic telescopic buckle 6 to slide circumferentially, which is equivalent to the elastic telescopic buckle 6 being able to slide and rotate in the second slot body 8. At this time, the threaded drill rod 1 and the support pipe 2 are no longer linked to each other. When performing rotary grouting, as long as the threaded drill rod 1 is driven to rotate by the built-in motor 11, the elastic telescopic buckle 6 can rotate and slide in the second slot body 8 with the threaded drill rod 1, so as to avoid the second slot body 8 restricting the rotation of the threaded drill rod 1, so that the threaded drill rod 1, the drill bit 3 and the cement nozzle 4 can rotate smoothly, ensuring the smooth progress of the grouting process.

[0044] In one embodiment, a chamfer 10 is formed on the contact surface between the bottom of the elastic telescopic buckle 6 and the guide surface 9. The arc surface of the chamfer 10 can reduce the resistance of the guide surface 9 to the elastic telescopic buckle 6, so that the elastic telescopic buckle 6 can slide along the guide surface 9 more smoothly.

[0045] In one embodiment, the support pipe 2 is suitable for transmission connection with an external driving device, so as to drive the support pipe 2 to rotate and move up through the external device. In the drilling state, the external driving device drives the support pipe 2 to rotate and rotates the threaded drill rod 1. After the drilling is completed, the support pipe 2 is driven up by the external driving device, and the threaded drill rod 1 is staggered up and down to increase the distance between the cement nozzle 4 and the support pipe 2. The external driving device mentioned above can be realized by one or more transmission devices of the prior art in actual application, and this embodiment will not be repeated. The clamping joint 5 is equipped with a built-in motor 11 that is transmission-connected to the threaded drill rod 1. When switched to the rotary spraying working state, the built-in motor 11 can drive the threaded drill rod 1 to rotate alone.

[0046] In one embodiment, the outer wall of the support pipe 2 is slidably sleeved with an annular tube 12, so the annular tube 12 will not rotate with the support pipe 2, and the support pipe 2 can slide relative to the annular tube 12 during the rotation process, and the annular tube 12 is connected to the inner cavity of the support pipe 2 at the upper end of the support pipe 2, and an output pipe 13 extending outward is connected to the annular tube 12. Therefore, during the drilling process, the soil that is transmitted upward to the upper end of the support pipe 2 by the threaded body of the outer wall of the threaded drill rod 1 also enters the annular tube 12, and then is discharged to the outside through the output pipe 13, so that the excess soil in the drilling process is smoothly and timely discharged to the outside, and the soil in the soil layer is prevented from being squeezed and deformed, which affects the subsequent grouting effect.

[0047] Specifically, in the above structure, the outer wall of the support pipe 2 is surrounded by an annular groove 14, and the annular pipe 12 is slidably fitted in the annular groove 14, so that it can be ensured that the annular pipe 12 and even the output pipe 13 will not rotate with the support pipe 2, and when the support pipe 2 rotates during the drilling process, it will only slide relative to the annular pipe 12. In addition, a plurality of circumferentially distributed output holes 15 are provided on the annular groove 14, and correspondingly, a plurality of circumferentially distributed through holes 16 are also provided on the matching surface of the annular pipe 12 with the annular groove 14, so that when the annular pipe 12 slides and rotates relatively in the annular groove 14 on the outer wall of the support pipe 2, the soil entering the upper end of the support pipe 2 can pass through the output holes 15 and the through holes 16 of the annular pipe 12 in sequence and smoothly enter the annular pipe 12, and finally can be discharged to the outside through the output pipe 13.

[0048] Furthermore, a drainage system is provided in the support pipe 2, and the drainage system includes an outlet pipe 17 and a suction pipe 18. The outlet pipe 17 and the suction pipe 18 are located at the lower end of the support pipe 2 and are separated by a certain distance. The outlet pipe 17 and the suction pipe 18 are respectively provided with water pressure sensors, and the corresponding water pressure threshold can be preset in the control system of the drainage system. During the grouting process, the support pipe 2 inserted into the underground soil layer, together with the outlet pipe 17 and the suction pipe 18 of the drainage system and the sensor, are also in the underground soil layer. The drainage system can monitor the water pressure in the underground soil layer through the water pressure sensors on the outlet pipe 17 and the suction pipe 18, and then Then judge the water content in the underground soil layer. If the water pressure of the soil layer detected by the water pressure sensor by the drainage system is lower than the preset water pressure threshold, it means that the water content of the underground soil layer is relatively small. Therefore, water is output to the soil layer through the outlet pipe 17 to increase the water content of the soil layer so as to adjust the water environment of the underground soil layer and meet the requirements of grouting. On the contrary, when the water pressure of the soil layer detected by the drainage system through the water pressure sensor is higher than the preset water pressure threshold, it means that the water content of the underground soil layer is relatively large. Therefore, the water of the soil layer is sucked out through the water pumping pipe 18 to reduce the water content of the soil layer. Similarly, the water environment of the underground soil layer can be adjusted to meet the requirements of grouting and optimize the grouting effect.

[0049] In one embodiment, a downwardly inclined chamfered surface 19 is formed at the lower end of the support pipe 2, and the pipe openings of the water outlet pipe 17 and the water suction pipe 18 are respectively arranged on the chamfered surface 19, so that the pipe openings of the water outlet pipe 17 and the water suction pipe 18 are inclined downward along the chamfered surface 19. This structure can more efficiently adjust the moisture content of the underground soil layer.

[0050] In one embodiment, a boss 20 is integrally formed on the top of the drill bit 3 , and the cement nozzle 4 is disposed on the side wall of the boss 20 and extends out laterally, so that the drill bit 3 can be easily installed with the cement nozzle 4 .

[0051] It should also be noted that during the grouting process, the threaded drill rod 1 can switch to reverse rotation in the soil layer. During the reverse rotation, the threaded body of the outer wall of the threaded drill rod 1 can gradually guide the threaded drill rod 1 to pull out the soil layer upward, so that the entire high-pressure rotary jet drill rod can gradually move upward. During the gradual upward movement, the cement nozzle 4 rotates synchronously with the threaded drill rod 1 and sprays cement slurry onto the soil layer. During this process, the cement nozzle 4 also sprays cement onto the soil layer at a full angle of 360° while gradually moving upward with the threaded drill rod 1, thereby achieving the effect of fully grouting the underground soil layer. While the cement nozzle 4 moves upward and grouting at all angles, the drainage system also synchronously adjusts the water pressure of the soil layer at the lower end of the support pipe 2, such as pumping water for soil layers with higher water content, or replenishing water for soil layers with lower water content, so as to adjust the water environment of the underground soil layer as much as possible to meet the requirements of grouting and optimize the grouting effect.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A high-pressure jet grouting drill rod structure, comprising a threaded drill rod (1) and a support pipe (2) coaxially sleeved on the outer periphery of the threaded drill rod (1), a drill bit (3) protruding from the support pipe (2) and a cement nozzle (4) close to the drill bit (3) being coaxially fixed to the lower end of the threaded drill rod (1), characterized in that: A clamping joint (5) is coaxially arranged on the upper end of the threaded drill rod (1); The side wall of the support pipe (2) is provided with a plurality of limit grooves arranged along the axial direction of the support pipe (2), and the clamping joint (5) can be elastically clamped in the limit grooves in a telescopic manner so that the threaded drill rod (1) and the support pipe (2) are mutually clamped and fixed; When the clamping joint (5) is clamped to limiting grooves at different positions in the axial direction of the threaded drill rod (1), the axial distance between the lower end of the support pipe (2) and the drill bit (3) changes.

2. The high-pressure jet grouting drill pipe structure according to claim 1, characterized in that: The side surface of the clamping joint (5) is provided with an elastic telescopic buckle (6) extending along the radial direction of the threaded drill rod (1); The plurality of limiting grooves include a first groove body (7) and a second groove body (8) arranged along the axial direction of the support pipe (2); The bottom wall of the first trough body (7) is formed with a guide surface (9), the guide surface (9) extends obliquely downward from the bottom wall of the first trough body (7) to the notch of the second trough body (8), and the upper end of the guide surface (9) is away from the side wall of the threaded drill rod (1), and the lower end is close to the side wall of the threaded drill rod (1); In the initial state, the elastic telescopic buckle (6) is radially inserted into the first slot (7) and abuts against the guide surface (9); When the support pipe (2) together with the first slot body (7) and the second slot body (8) move axially upward, the elastic telescopic buckle (6) radially retracts along the guide surface (9), and when the elastic telescopic buckle (6) moves to the slot opening of the second slot body (8), it leaves the guide surface (9) and is reset and inserted into the second slot body (8).

3. The high-pressure jet grouting drill pipe structure according to claim 2 is characterized in that: The first groove body (7) is a strip-shaped groove extending transversely, so that the elastic telescopic buckle (6) can be fixedly buckled in the first groove body (7); The second groove body (8) is a circumferentially extending annular groove, so that the elastic telescopic buckle (6) can slide circumferentially in the second groove body (8).

4. The high-pressure jet grouting drill pipe structure according to claim 2, characterized in that: A chamfer (10) is formed between the contact surface between the bottom of the elastic telescopic buckle (6) and the guide surface (9).

5. The high-pressure jet grouting drill pipe structure according to claim 2, characterized in that: The support pipe (2) is suitable for transmission connection with an external driving device, so as to drive the support pipe (2) to rotate and move upward through the external device; The clamping joint (5) is provided with a built-in motor (11) which is transmission-connected to the threaded drill rod (1).

6. The high-pressure jet grouting drill pipe structure according to claim 1, characterized in that: An annular tube (12) is slidably sleeved on the outer wall of the support tube (2); the annular tube (12) is connected to the inner cavity of the support tube (2) at the upper end of the support tube (2); and the annular tube (12) is connected to an output tube (13) extending outwards.

7. The high-pressure jet grouting drill pipe structure according to claim 6, characterized in that: The outer wall of the support pipe (2) is surrounded by an annular groove (14), a plurality of circumferentially distributed output holes (15) are provided on the annular groove (14), and the annular pipe (12) is slidably fitted in the annular groove (14).

8. The high-pressure jet grouting drill pipe structure according to claim 7, characterized in that: A plurality of circumferentially distributed through holes (16) are provided on the matching surface of the annular tube (12) and the annular groove (14).

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