A pile body drilling device capable of preventing hole collapse and a construction method thereof

Abstract

The present application relates to pile foundation construction technical field, especially a kind of pile body drilling device and construction method of hole collapse prevention, including drill rod device, double-layer cylindrical structure formed by inner layer drill rod and outer layer drill rod, the bottom end of the inner layer drill rod is equipped with first drill bit;Anti-collapsing and reducing structure has the slurry storage barrel and several slurry pipes in the hollow part between the inner layer drill rod and the outer layer drill rod, one end of the slurry pipe is connected with the slurry storage barrel, the other end is converted into horizontal state by additional elbow pipe and is equipped with grouting pipe at end portion, the slurry pipe of horizontal section is telescopic, the grouting pipe body is equipped with several grouting holes arranged uniformly and its end portion is equipped with second drill bit;The present application can prevent sidewall hole collapse while drilling into pile, and can realize reducing without changing drill bit, improve construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of pile foundation construction technology, and in particular to a pile drilling device and construction method that can prevent borehole collapse. Background Technology

[0002] Drilled pile construction technology is widely used due to its advantages such as wide applicability, good construction quality, fast drilling speed, low vibration and noise, and environmental friendliness. It can be used in various soil and rock layers, including fill, cohesive soil, silt, sand, gravelly soil, and soft rock. According to the drilling method, it can be divided into three categories: dry-operation drilled piles, wet-operation drilled piles, and all-steel casing drilled piles. Each drilling method has its drawbacks.

[0003] (1) Although dry drilling has fewer steps, faster drilling speed, and higher work efficiency, it is prone to hole collapse under complex geological conditions due to the lack of mud wall protection. (2) Although wet drilling has mud wall protection, the lateral resistance around the drill bit is large under special geological conditions such as water-rich, loose, and highly permeable strata. If the drill bit rises and falls quickly, the mud between the outside of the drill bit and the hole wall will erode the pile wall. In addition, the negative pressure generated at the bottom of the drill bit will easily cause the hole wall to shrink and collapse, thus affecting the construction efficiency and pile quality. (3) Although the all-steel casing method can effectively prevent hole collapse, it will increase the material and cost, require more site space, increase the construction steps, and prolong the construction period.

[0004] Furthermore, existing drilling rigs typically use umbrella-type or cone-type reaming drill bits when changing the cross-sectional dimensions of pile foundations. However, the surrounding soil and rock layers have poor stability and are more prone to collapse when disturbed or soaked by water, resulting in unsatisfactory diameter reduction. Current preventative and remedial measures for diameter reduction collapse typically include manual wall reinforcement, concrete backfilling, or re-excavation with additional piles. However, these methods have significant limitations in practical operation because they disrupt the stability of the soil and rock layers during diameter reduction, and they also affect the construction period and pile quality. In addition, most existing reaming drill bits can only achieve constant cross-section reaming and cannot meet the requirement of changing the cross-section to alter the pile size. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a pile drilling device and construction method that prevents borehole collapse. This allows for real-time grouting reinforcement of the soil sidewalls prone to collapse during pile construction, while simultaneously enabling changes in pile cross-sectional dimensions without switching drill bits. To achieve this objective, the invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a pile drilling device that can prevent borehole collapse, comprising:

[0007] A drill rod assembly, comprising a double-layer cylindrical structure formed by an inner drill rod and an outer drill rod, wherein a first drill bit is provided at the bottom end of the inner drill rod;

[0008] The anti-collapse hole and variable diameter structure has a slurry storage tank and several slurry delivery pipes located in the hollow part between the inner drill rod and the outer drill rod. One end of the slurry delivery pipe is connected to the slurry storage tank, and the other end is converted to a horizontal state by adding a bend and is provided with a grouting pipe at the end. The slurry delivery pipe and the drill rod device are telescopic. The grouting pipe has several grouting holes evenly arranged on its body and a second drill bit at its end.

[0009] As a further implementation, the grouting pipe includes an inner grouting pipe and an outer grouting pipe, with grouting holes in the same position on both layers. The inner grouting pipe can be rotated to achieve misalignment of the inner and outer grouting holes.

[0010] As a further implementation, the second drill bit is a tapered triangular drill bit with spray holes.

[0011] As a further implementation, both the first drill bit and the second drill bit are equipped with a drive mechanism.

[0012] As a further implementation, a first sluice is provided at the bottom of the grout storage tank, with the same number of sluice pipes as the grout delivery pipes. The grout delivery pipes can slide in the first sluice to achieve uniform grouting reinforcement of the soil around the pile.

[0013] As a further implementation, both the inner and outer drill rods are composed of a telescopic structure consisting of multiple cylindrical sections. A second sliding groove is provided on the side wall of the lowest cylindrical section of the outer drill rod, and the second sliding groove is corresponding to the first sliding groove.

[0014] As a further implementation, the number of grout delivery pipes is four, and the first chute allows the grout delivery pipes to rotate 60°.

[0015] As a further implementation, a pad is provided above the first chute, and the size of its opening is the same as the diameter of the first chute and the slurry delivery pipe. The pad is connected to the top opening of the slurry delivery pipe through the opening, and the pad is placed inside the slurry storage tank and rotatably connected to the slurry storage tank.

[0016] As a further implementation, a control system is also included to control the anti-collapse hole and diameter change operations.

[0017] In a second aspect, the present invention provides a construction method for the pile drilling device with anti-collapse capability according to the first aspect, comprising the following steps:

[0018] Drilling into soft and loose strata, the second drill bit in front of each grouting pipe is operated to drill into the predetermined area and start grouting. After grouting is completed, the grouting pipe is retracted and rotated to a certain angle, and drilling and grouting are carried out again. After the grouting of this layer is completed, the grouting pipe is retracted and drilling continues downward. The above process is repeated until the pile body is drilled. If a diameter change is required, the connecting device on the grouting pipe is operated to rotate the inner grouting pipe, and the grout pump is changed to a high-pressure water pump. The nozzle is used to impact and cut the transverse soil to complete the diameter change. After the diameter change process is completed, the device is retrieved.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The drill rod of the drilling rig of the present invention consists of inner and outer double layers. The outer drill rod has a space for the grouting pipe to extend and rotate at a certain angle, so as to ensure that the grouting pipe can grout the surrounding strata evenly and prevent local hole collapse.

[0021] 2. The present invention has a drill bit at the end of the grouting pipe. When the soft and loose strata are reached, the drill bit in front of each grouting pipe is operated to drill into the predetermined area and start grouting. This can ensure that the soil layer is reinforced by grouting. The grouting tank can be rotated through the sluice of the storage tank and the external drill rod to ensure a wider range of grouting reinforcement.

[0022] 3. The double-layer grouting pipe of this invention can be rotated by ground operation to misalign the inner and outer double-layer grouting holes, preventing water from spraying around the grouting pipe and reducing water pressure. Water is only sprayed out from the horizontal nozzle to cut the soil and achieve horizontal hole expansion. The diameter change shape and size are controlled by the extension and retraction of the grouting pipe and the vertical movement of the drill rod to ensure the diameter change effect of the pile. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 This is a schematic diagram of the structure of the pile drilling device that can prevent hole collapse in an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the slurry storage tank structure in an embodiment of the present invention.

[0026] Figure 3 This is a top view of the slurry storage tank in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the connection between the slurry storage tank and the inner drill rod in an embodiment of the present invention.

[0028] Figure 5 This is a schematic diagram of the connection between the grout delivery pipe and the cushion layer in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the double-layer drill pipe structure in an embodiment of the present invention.

[0030] Figure 7 This is a top view schematic diagram of the double-layer drill pipe in an embodiment of the present invention.

[0031] Figure 8 This is a schematic diagram of the drill rod structure in an embodiment of the present invention.

[0032] Figure 9 This is a schematic diagram of the grout delivery pipe and grout injection pipe in an embodiment of the present invention.

[0033] Figure 10 This is a schematic diagram of the second drill bit structure in an embodiment of the present invention.

[0034] Figure 11 This is a schematic diagram of the nozzle range in an embodiment of the present invention.

[0035] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0036] The components are as follows: 1. Pump connection port; 2. Grout storage tank; 3. First chute; 4. Grout delivery pipe; 5. Outer drill rod; 6. Grouting pipe; 7. Central control box; 8. Second drill bit; 9. First drill bit; 10. Inner drill rod; 11. Wiring channel; 12. Control system; 13. Subbase; 14. Second chute; 15. Spray hole; 16. Inner grouting pipe; 17. Bearing; 18. Connector; 19. Outer grouting pipe; 20. Outer wall sliding key; 21. Cylinder. Detailed Implementation

[0037] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0038] Example 1

[0039] In a typical embodiment of the present invention, reference is made to Figure 1 As shown, a pile drilling device that can prevent hole collapse includes a drill rod device, a grout storage tank 2, a grout delivery pipe 4, an injection pipe 6, and a control system 12.

[0040] In this embodiment, as Figure 2 , Figure 3 , Figure 6As shown, the drill rod device has a double-layer cylindrical structure, mainly including an inner drill rod 10, an outer drill rod 5, a slurry storage tank 2, and a slurry delivery pipe 4. The space between the outer drill rod 5 and the inner drill rod 10 is hollow, accommodating the slurry storage tank 2 and the slurry delivery pipe 4. The outer drill rod 5 has a slurry connection port 1 on its upper side, which connects to the slurry pumping pipe. The inner drill rod 10 has centralized wiring connected to an external control system via a wiring channel 11, and its bottom end is equipped with a first drill bit 9, which houses a power head. The slurry storage tank 2 is connected to the side wall of the inner drill rod 10 via a connector 18. The bottom of the slurry storage tank 2 has a first groove 3, which is arc-shaped. Above the first groove 3 is a pad 13, the opening size of which is the same as the diameter of the first groove 3 and the slurry delivery pipe 4, facilitating connection and rotation with the slurry delivery pipe 4 and preventing slurry leakage from the first groove 3.

[0041] like Figure 8 As shown, both the inner drill rod 10 and the outer drill rod 5 consist of several sections of cylindrical body 21. Each section of cylindrical body 21 is connected by an outer wall sliding key 20, and a connecting piece is installed at the end of the cylindrical body. The last cylindrical body is connected by a steel wire, and a pulley-type mechanical structure is used to achieve drill rod extension and retraction. The extension and retraction of the inner and outer drill rods is necessary to achieve synchronous extension and retraction with the multiple sections of grouting pipe. If only the inner drill rod and the drill bit drill downwards, the synchronous grouting and reinforcement process of the grouting pipe cannot be achieved. Simultaneously, the extension and retraction of the outer drill rod also protects the interior, preventing water, soil, and grout leakage.

[0042] In this embodiment, the slurry storage tank 2 is located at the position of the first section of the inner and outer drill pipe (top section), and it is fixedly connected to the first section of the inner drill pipe through a connector.

[0043] Reference Figures 4-5 As shown, the bottom of the slurry storage tank 2 has four holes to facilitate the rotation of the slurry delivery pipe within the hole range. The holes are the first sluice grooves 3. The pad 13 is located at the bottom of the slurry storage tank 2 and has the same shape and size as the bottom of the slurry storage tank 2. The slurry delivery pipe is connected to the opening on the pad 13. The size of the opening is the same as the opening at the top of the slurry delivery pipe. The connection can be made by thread or other mechanical seal connection. There are ball bearings on the inner edge of the pad 13, which rotate with the slurry storage tank 2. The first sluice groove 13 at the corresponding position at the bottom of the slurry storage tank 2 enables the pad 13 to drive the slurry delivery pipe to rotate within the range of the first sluice groove 13. The pad 13 ensures that the slurry will not leak out from the first sluice groove 13.

[0044] In this embodiment, four first sliding grooves 3 are provided, and four grouting pipes 4 are respectively matched with them. The grouting pipes 4 can slide in the first sliding grooves 3 to achieve uniform grouting reinforcement of the soil around the pile.

[0045] The first chute 3 is identical and is arc-shaped with a set radius. The first chute 3 allows the grout pipe 4 to rotate 60°.

[0046] The outer drill rod 5 is mainly for protecting the grout delivery pipe 4 and the grout storage tank 2. The lower side wall has a second sliding groove 14 for the grout delivery pipe 4 to flow grout and for the grouting pipe to rotate. The second sliding groove is located on the side wall of the lowest section of the outer drill rod 5, and the position of the second sliding groove 14 corresponds to the position of the first sliding groove 3. The second sliding groove 14 is also arc-shaped, so that when the grout delivery pipe 4 slides, the second sliding groove 14 can provide the same sliding space for it.

[0047] The anti-leakage measures at the second sliding groove 14 on the bottom side wall of the outer drill rod 5 are the same as those at the bottom of the slurry storage tank 2 (that is, a pad 13 is also connected around the slurry pipe 4, the pad 13 is fitted on the slurry pipe 4 and can cover the second sliding groove 14 outside the slurry pipe 4, the pad 13 here is arc-shaped and matches the shape of the inner wall of the outer drill rod 5). The pad can fix the slurry pipe 4 and prevent the slurry pipe 4 from moving or being damaged due to the long distance.

[0048] like Figure 4 and Figure 5 As shown, the upper end of the grout delivery pipe 4 is connected to the cushion layer 13 through the opening of the first sliding groove 3 of the grout storage tank 2. It can be understood that the grout delivery pipe is a telescopic pipe composed of various pipe sections. Each pipe section has a limiting component on the outside of its upper end and a blocking component on the inside of its lower end. The width is the difference in radius between the pipe sections. The last section of the grout delivery pipe 4 at the bottom is bent and connects to the grout delivery pipe 4 outside the drill rod through the second sliding groove 14 at the bottom of the outer drill rod 5 to deliver grout, while simultaneously fixing and limiting it.

[0049] In this embodiment, the grout delivery pipe 4, the inner drill rod 10, and the outer drill rod 5 can all extend and retract together, and the length of each section of the inner drill rod 10 and the outer drill rod 5 is adapted to the length of each section of the grout delivery pipe 4. Therefore, when the outer drill rod 5 extends downward, the lowest section of the cylinder can drive the grout delivery pipe 4 to extend downward together.

[0050] like Figures 9-11 As shown, the grouting pipe 6 is a hollow steel pipe with bidirectional openings. Grouting holes are evenly distributed throughout the pipe body. The pipe body is divided into inner and outer layers: an outer grouting pipe 19 and an inner grouting pipe 16. The grouting holes on the inner and outer grouting pipes are evenly distributed and without misalignment, facilitating grout ejection. One end of the grouting pipe 6 is connected to the grout delivery pipe 4, and the other end is connected to the front control box 7 of the second drill bit 8. The outer grouting pipe 19 is fixed by a connector 18 or threads, while the inner grouting pipe 16 is connected to a rotating shaft and can be rotated via a bearing 17. This allows the grouting holes of the grouting pipe 6 to be misaligned, enabling water or air to cut the soil through the nozzle and preventing diversion to other holes. The central control box 7 contains a power head, and there is a connector 18 and a bearing 17 at the connection with the grouting pipe 6. There are three spray holes 15 on the side of the second drill bit 8. The rotation of the shaft and the nozzle in the central control box 7, as well as the operation of the power head, are all remotely operated through the control system. The second drill bit 8 is a conical triangular drill bit.

[0051] The three nozzles are arranged in an isosceles triangle, with each nozzle having a spray range of 120°.

[0052] The control system 12 mainly includes several modules: inner drill rod extension and retraction control, outer drill rod extension and retraction control, drill bit control, first chute control of the slurry storage tank, extension and retraction control of the slurry delivery pipe, and remote control of the central control box.

[0053] Example 2

[0054] This embodiment provides a construction method for the pile drilling device with anti-collapse capability as described in Embodiment 1, including the following steps:

[0055] (1) When the borehole is designed to prevent collapse (mainly applicable to soil layers that are prone to collapse, such as sand, medium-coarse sand, and gravelly sand).

[0056] When using the anti-collapse pile drilling device described in Embodiment 1 for soil grouting reinforcement, a suitable drill bit should first be selected according to the geological conditions and installed at the end of the inner drill rod 10 of the double-layer drill rod. The grout delivery pipe 4 is connected to the first sliding groove 3 at the bottom of the grout storage tank 2. The grout delivery pipe 4 of appropriate length is spliced ​​together and the pipe sections are connected by connectors. At the end of the grout delivery pipe 4, the injection pipe 6 is connected to the central control box 7, and finally the second drill bit 8 is connected. Before drilling, ensure that the grout storage tank 2, grout delivery pipe 4, and injection pipe are clean and free of residue. A conversion valve is installed at the connection pipe of the grout storage tank 2 as needed and connected to the mud pump, high-pressure clean water pump, or air pump. The grout can be a suspension with cement as the main agent, or a two-liquid mixture of cement and water glass. The hydraulic drive device in the central control box 7 is connected to the control system 12 through built-in sensors and connecting lines. Before starting the operation, water is injected through the clean water pump to test the sealing of the device connection and the grouting situation. After testing for safety, drilling operations can be carried out.

[0057] During the drilling process, after the first drill bit 9 reaches the weak stratum that needs grouting reinforcement, the second drill bit 8 at the front end of the grouting pipe 6 is controlled by the control system 12 to drill into the soil layer, and the grouting pipe 6 is stretched to the reinforcement range through the connector 18 (during the drilling process, in order to prevent mud and sand from clogging the nozzle, water can be injected while drilling at a lower pressure). After reaching the designated position, the switching valve is opened to switch the pipeline valve connected to the grout storage tank 2 to the high-pressure mud pump, and the grout is sprayed into the surrounding stratum through the grouting pipe 6. After the grouting is completed, the grouting pipe 6 is retracted, and the outer drill rod is rotated 15° to 30° through the first slipway 3, and the grouting pipe 4 is extended again into the stratum to repeat the grouting process (the maximum rotation angle of the first slipway 3 is 60°) until the grouting reinforcement of the soil around the pile in this layer is completed.

[0058] If a cement suspension is used, after 30 minutes or 1 hour of initial setting, continue vertical drilling with the first drill bit 9 to the next grouting point. Repeat the grouting process after reaching the next stratum requiring reinforcement until drilling is complete. The vertical reinforcement spacing of the grouting holes should be determined based on field tests, and should preferably be 1.2m to 2.0m. The initial setting time of the grout should be determined based on the soil conditions and the purpose of grouting; it should preferably be 5 minutes to 20 minutes for sandy soil foundations and 1 hour to 2 hours for cohesive soil foundations.

[0059] (2) When changing the diameter during drilling (applicable to strata with good soil quality, such as silty clay)

[0060] When using the anti-collapse pile drilling device described in Example 1 to change the diameter in a stratum with good soil quality, such as silty clay, the preparation work is the same as in (1). After the device is drilled to the position where the diameter needs to be changed, the switching valve is switched from a mud pump to a high-pressure clean water pump or an air pump. The bearing 17 is controlled by the control system 12 to rotate the inner grouting pipe 16 and misalign it with the hole of the outer grouting pipe 19, so that the water or air can only be sprayed from the nozzle on the side of the second drill bit 8 to cut the transverse soil and realize hole enlargement.

[0061] The radius of the enlarged hole can be adjusted according to the water pressure, and the angle is approximately 120°. Figure 8 As shown. After the surface soil is cut, the grouting pipe 6 is extended laterally to increase the lateral diameter change depth. Then, vertical cutting is performed by the vertical displacement of the main drill rod to control the cross-sectional dimensions and shape. After the diameter change is completed, the grouting pipe 6 and the grout delivery pipe 4 are disassembled and flushed to prevent residual grout from remaining.

[0062] The main rotating rod consists of inner and outer drill rods. The drill rig is moved vertically by the power head, which drives the drill rod to move, causing the nozzle 15 to also move vertically, thus achieving vertical soil cutting. Different diameters can be cut by adjusting the water pressure.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pile drilling device capable of preventing borehole collapse, characterized in that, include: A drill rod assembly, comprising a double-layer cylindrical structure formed by an inner drill rod and an outer drill rod, wherein a first drill bit is provided at the bottom end of the inner drill rod; The anti-collapse hole and variable diameter structure has a slurry storage tank and several slurry delivery pipes located in the hollow part between the inner drill rod and the outer drill rod. One end of the slurry delivery pipe is connected to the slurry storage tank, and the other end is converted to a horizontal state by adding a bend and is provided with a grouting pipe at the end. The slurry delivery pipe and the drill rod device are telescopic. The grouting pipe has several grouting holes evenly arranged on its body and a second drill bit at its end. The grouting pipe includes an inner grouting pipe and an outer grouting pipe, and both layers have grouting holes at the same position. The inner grouting pipe can be rotated to achieve misalignment of the inner and outer grouting holes. The bottom of the grout storage tank has a first sluice with the same number of grout delivery pipes as the grout delivery pipes. The grout delivery pipes can slide in the first sluice to achieve uniform grouting reinforcement of the soil around the pile. Both the inner and outer drill rods are telescopic structures composed of multiple cylindrical sections. The bottommost cylindrical sidewall of the outer drill rod is provided with a second sliding groove, which corresponds to the first sliding groove. A pad is provided above the first sliding groove, and the size of its opening is the same as the diameter of the first sliding groove and the grout delivery pipe. The pad is connected to the top opening of the grout delivery pipe through the opening. The pad is placed inside the grout storage tank and is rotatably connected to the grout storage tank.

2. The pile drilling device with anti-collapse capability according to claim 1, characterized in that, The second drill bit is a conical triangular drill bit, and a spray hole is provided on the conical triangular drill bit.

3. The pile drilling device for preventing borehole collapse according to claim 1, characterized in that, Both the first drill bit and the second drill bit are equipped with a drive mechanism.

4. The pile drilling device for preventing borehole collapse according to claim 3, characterized in that, The number of grout delivery pipes is four, and the first chute allows the grout delivery pipes to rotate 60°.

5. A pile drilling device capable of preventing borehole collapse according to claim 1, characterized in that, It also includes a control system for controlling the anti-collapse hole and diameter change operations.

6. The construction method of the pile drilling device with anti-collapse capability according to claim 1, characterized in that, Includes the following steps: When the outer drill pipe extends downwards, the bottom section of the cylinder extends downwards along with the grouting pipe, drilling into the soft and loose strata. The second drill bit in front of each grouting pipe is operated to drill into the predetermined area and start grouting. After grouting is completed, the grouting pipe is retracted and rotated to a certain angle, and drilling and grouting are carried out again. After the grouting of this layer is completed, the grouting pipe is retracted and drilling continues downwards, and the above process is repeated until drilling is completed. If a diameter change is required, the connecting device on the grouting pipe is operated to rotate the inner grouting pipe, and the grout pump is changed to a high-pressure water pump. The nozzle is used to impact and cut the transverse soil to complete the diameter change. After the diameter change process is completed, the device is retrieved.

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